Citation Nr: 21007858 Decision Date: 02/10/21 Archive Date: 02/10/21 DOCKET NO. 10-27 806 DATE: February 10, 2021 ORDER From March 2, 2008, entitlement to a total disability evaluation based on individual unemployability (TDIU), on the basis of substitution, is granted. Entitlement to dependency and indemnity compensation (DIC) under 38 U.S.C. § 1318 is denied. FINDINGS OF FACT 1. From March 2, 2008, the Veteran’s service-connected disabilities prevented him from securing or following a substantially gainful occupation. 2. The Veteran died in August 2017. He was not a former prisoner of war (POW), and he was not in receipt of compensation at the 100 percent rate due to service-connected disability for a period of at least five years immediately after his discharge from active service, or for 10 or more years prior to his death. Nor would he have been in receipt of such compensation in either case, but for clear and unmistakable error (CUE) in a prior decision, which has not been claimed. CONCLUSIONS OF LAW 1. From March 2, 2008, the criteria for entitlement to a TDIU, on the basis of substitution, have been met. 38 U.S.C. §§ 1155, 5103, 5103A, 5107; 38 C.F.R. §§ 3.102, 3.59, 3.340, 3.41, 4.1, 4.3, 4.16. 2. The criteria for DIC benefits pursuant to the provisions of 38 U.S.C. § 1318 have not been met. 38 U.S.C. § 1318; 38 C.F.R. § 3.22. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran had active duty service in the United States Army from October 1975 to October 1978. The Veteran died in August 2017, and the appellant is his surviving spouse. A September 2020 letter reflects that she has been accepted as the Veteran's substitute for purposes of processing his appeal to completion. See 38 U.S.C. § 5121A; 38 C.F.R. § 3.1010. As an initial matter the Board expresses its condolences to the appellant for the loss of her husband and recognizes the valuable service he provided to the United States through his service in the Army. This matter comes to the Board of Veterans’ Appeals (Board) on appeal from an August 2009 rating decision and a December 2017 decisional letter. The record shows that the Veteran’s claim for a TDIU was initially remanded by the Board in decisions dated in January 2013, May 2013, and September 2016. The Board later denied the claim in a June 2017 decision. An appeal of this determination was filed on the Veteran’s behalf to the United States Court of Appeals for Veterans Claims (Court) in October 2017, and the Court permitted the Veteran’s surviving spouse to replace him as the appellant on the Court’s docket. In a July 2019 Order, the Court vacated the Board’s decision and remanded the matter to the Board for development consistent with the parties' Joint Motion for Remand (Joint Motion). The Board remanded the issue again in decisions dated in May 2020 and August 2020. The case has since been returned to the Board for appellate review. The Board finds that the agency of original jurisdiction (AOJ) substantially complied with prior remand directives, to the extent possible, and no further action in this regard is warranted. See Dyment v. West, 13 Vet. App. 141, 146-47 (1999) (concluding that a remand is not required under Stegall v. West, 11 Vet. App. 268 (1998) where there was substantial compliance with the Board's remand instructions). In the May 2020 remand, the Board noted that in November 2017, the appellant submitted VA Form 21P-534EZ, Application for DIC, Death Pension, and/or Accrued Benefits. The Board also noted that entitlement to accrued benefits was denied by the AOJ in the December 2017 decisional letter, and that the appellant submitted a notice of disagreement with that decision in December 2019. The Board notes that this notice of disagreement was received in December 2018. In this regard, the Board also notes that a review of the claims file shows that the AOJ subsequently determined that the December 2017 decision denying the appellant’s claim for entitlement to accrued benefits was issued in error as the record reflected that her case was currently pending on appeal before the Court, and no further action would be taken on the accrued issue at that level as it surpassed the AOJ's review. See March 2019 Deferred Rating Decision. The AOJ also notified the appellant of this determination in a March 2019 letter. The Board further stated in the May 2020 remand that the Court remanded the appeal for a TDIU in March 2020. In this regard, the Board again notes that the order for the Joint Motion addressing this claim was issued by the Court in July 2019. The Board also notes that in the absence of a specific request to substitute, VA is to treat qualifying claims for accrued benefits, survivors pension, or DIC as requests to substitute. 38 C.F.R. § 3.1010(c)(2). However, the Board noted in the May 2020 remand that there was no current request for substitution, and the Veteran's pending claim for a TDIU was therefore an appeal for accrued benefits. The Board instructed the AOJ to issue a statement of the case that addressed the issue of entitlement to a TDIU for accrued benefits purposes. The Board also found that the issue of entitlement to DIC under 38 U.S.C. § 1318 was inextricably intertwined with this issue. When the case returned to the Board in August 2020, the Board noted that the AOJ had issued a supplemental statement of the case for the issue of entitlement to a TDIU for accrued benefits purposes rather than a statement of the case, and the appellant therefore did not file a VA Form 9 to perfect her appeal for a TDIU for accrued benefits purposes. The Board stated that without the VA Form 9, the Board did not have jurisdiction over the claim. The Board remanded the issue for the AOJ to make a determination regarding whether substitution was warranted. If substitution was granted, the Board instructed the AOJ to send notice to the appellant and her representative in addition to issuing a supplemental statement of the case. If substitution was not granted, the AOJ was instructed to send the appellant and her representative notice and issue a statement of the case that addressed the issue of entitlement to a TDIU for accrued benefits purposes and notice of what was required to perfect an appeal. The Board once again remanded the issue of entitlement to DIC under 38 U.S.C. § 1318 as inextricably intertwined with the TDIU claim. As previously noted, the AOJ later determined that the Veteran was a valid substitute claimant in the September 2020 letter. Although the AOJ subsequently issued a November 2020 supplemental statement of the case that characterized the issue on appeal as entitlement to a TDIU for accrued benefits purposes rather than substitution purposes, there is no prejudice to the appellant in proceeding with the adjudication of this issue given that the Board is granting entitlement to a TDIU on the basis of substitution for the entire period on appeal. Moreover, there is no need for the appellant to submit a VA Form 9 for this appeal as the Veteran already perfected an appeal of the issue during his lifetime. See July 2010 VA Form 9. The Board also notes that although the representative characterized the appellant’s claim for a TDIU on the basis of accrued benefits in a December 2020 statement, it is clear that the representative did not intend to waive the appellant’s right to substitute given that the representative submitted a new March 2020 Employability Evaluation to be considered in connection with this claim. In this regard, the Board notes that a claim for accrued benefits must be adjudicated on the basis of the evidence of record at the date of the Veteran's death. 38 C.F.R. § 3.1000. As such, the Board will proceed to adjudicate the claim on the basis of substitution. Regarding the appellant’s appeal of the issue of entitlement to DIC under 38 U.S.C. § 1318, after the AOJ addressed the issue in a May 27, 2019 statement of the case, the appellant's representative submitted a letter on July 9, 2019 requesting for the letter to be treated as a substantive appeal for any matter for which the time for filing had not run. The AOJ then certified the appeal to the Board in October 2019, and the Board accepted jurisdiction of the issue in the May 2020 and August 2020 remands. See Percy v. Shinseki, 23 Vet. App. 37, 45 (2009). 1. Entitlement to a TDIU, on the basis of substitution. In order to establish entitlement to a TDIU due to service-connected disabilities, there must be impairment so severe that it is impossible for the average person to follow a substantially gainful occupation. See 38 U.S.C. § 1555; 38 C.F.R. §§ 3.340, 3.341, 4.16. In reaching such a determination, the central inquiry is "whether the veteran's service connected disabilities alone are of sufficient severity to produce unemployability." Hatlestad v. Brown, 5 Vet. App. 524, 529 (1993). Consideration may be given to the veteran's level of education, special training, and previous work experience in arriving at a conclusion, but not to his age or to the impairment caused by non-service-connected disabilities. See 38 C.F.R. §§ 3.341, 4.16, 4.19 (2017); Van Hoose v. Brown, 4 Vet. App. 361 (1993). The regulatory scheme for a TDIU provides both objective and subjective criteria. Hatlestad, 5 Vet. App. at 529; VAOPGCPREC 75-91 (Dec. 27, 1991), 57 Fed. Reg. 2317 (1992). The objective criteria, set forth at 38 C.F.R. § 4.16(a), provide for a TDIU when, due to a service-connected disability, a veteran is unable to secure or follow a substantially gainful occupation, and has a single disability rated 60 percent or more, or at least one disability 40 percent or more with additional disability sufficient to bring the combined evaluation to 70 percent. 38 C.F.R. §§ 3.340, 3.341, 4.16(a). In exceptional circumstances, where the veteran does not meet the aforementioned percentage requirements, a total rating may nonetheless be assigned upon a showing that the individual is unable to obtain or retain substantially gainful employment. 38 C.F.R. § 4.16(b). Marginal employment shall not be considered substantially gainful employment. For purposes of 38 C.F.R. § 4.16, marginal employment generally shall be deemed to exist when a Veteran's earned annual income does not exceed the amount established by the U.S. Department of Commerce as the poverty threshold for one person. 38 C.F.R. § 4.16(a). Marginal employment may also be held to exist, on a facts found basis (includes but is not limited to employment in a protected environment such as a family business or sheltered workshop), when earned annual income exceeds the poverty threshold. Id. Consideration shall be given in all claims to the nature of the employment and the reason for termination. Id. In Ray v. Wilkie, 31 Vet. App. 58, 73 (2019), the Court defined the term "unable to secure and follow a substantially gainful occupation" as having two components: one economic and one noneconomic. The economic component means an occupation earning more than marginal income (outside of a protected environment) as determined by the U.S. Department of Commerce as the poverty threshold for one person. The non-economic component includes consideration of: Veteran's history, education, skill, and training; whether the veteran has the physical ability to perform the type of activities required by the occupation at issue; and whether the veteran has the mental ability to perform the activities required by the occupation at issue. The record reflects that the Veteran submitted a VA Form 21-8940, Veteran's Application for Increased Compensation Based on Unemployability, on March 2, 2009. The AOJ also construed this submission as an increased rating claim for his already established right and left knee disabilities. See August 2009 rating decision; August 2009 rating codesheet. As the Veteran's TDIU claim on appeal was raised in the context of his increased rating claims for his already established right and left knee disabilities, the appeal period begins on March 2, 2008. See Rice v. Shinseki, 22 Vet. App. 447, 453-54 (2009); 38 C.F.R. § 3.400(o)(2). During the entire appeal period, the Veteran was in receipt of a 20 percent rating for residuals of left knee injury, with limited flexion; and a 10 percent rating for chronic right knee strain associated with residuals of left knee injury, with limited flexion. Effective from March 18, 2009, the Veteran was awarded a 10 percent rating for low back disability associated with residuals of left knee injury, with limited flexion. Effective from August 21, 2009, the Veteran was awarded a 30 percent rating for major depressive disorder. The Veteran's combined disability rating was 30 percent from March 2, 2008 to March 17, 2009; 40 percent from March 18, 2009 to August 20, 2009; and 60 percent on and after August 21, 2009. The Board notes that for the purpose of determining entitlement to TDIU based on a single disability, multiple disabilities resulting from a common etiology will be considered as one disability. 38 C.F.R. § 4.16(a). The record shows that the AOJ granted service connection for the Veteran's right knee disability and low back disability as secondary to the Veteran’s left knee disability. See 38 C.F.R. § 3.310; February 2006 rating decision; August 2009 rating decision. The AOJ also granted service connection for major depressive disorder as secondary to both the left and right knee disabilities. See October 2009 rating decision. Therefore, these secondary disabilities as well as the Veteran’s primary left knee disability are treated as one disability under 38 C.F.R. § 4.16(a). As the combined disability rating of these disabilities was 60 percent on and after August 21, 2009, the Veteran met the schedular requirements for a TDIU as of this date. See 38 C.F.R. § 4.25; Moody v. Wilkie, 30 Vet. App. 329, 339 (2018) (concluding that 38 C.F.R. § 4.16(a) clearly requires aggregation based on the combined ratings table to determine whether multiple service-connected disabilities "considered as one disability" meet the 60 percent or 40 percent thresholds). Prior to August 21, 2009, the Veteran's service-connected disabilities did not render him eligible for a TDIU under the schedular percentage requirements contemplated by VA regulation. See 38 C.F.R. §§ 3.340, 3.341, 4.16(a). However, all Veterans who are shown to be unable to secure and follow a substantially gainful occupation by reason of service-connected disability shall be rated totally disabled. 38 C.F.R. § 4.16(b). Accordingly, the question becomes whether entitlement to a TDIU on an extraschedular basis is warranted during this period. The record shows that in the September 2016 decision, the Board remanded the issue of entitlement to a TDIU for the AOJ to refer the case to the Director of Compensation Service for consideration of whether entitlement to a TDIU was warranted on an extraschedular basis under 38 C.F.R. § 4.16(b). In an undated memorandum associated with the claims file in October 2016, the AOJ referred the case to the Director of Compensation Service, recommending that entitlement to a TDIU on an extraschedular basis be denied. In March 2017, the Director determined that a TDIU was not warranted on an extraschedular basis. In the August 2020 remand, the Board similarly instructed the AOJ the consider whether the claim for a TDIU should be referred to the Director of Compensation Service for consideration of whether entitlement to a TDIU was warranted on an extraschedular basis under 38 C.F.R. § 4.16(b). The AOJ subsequently referred the case to the Director of Compensation Service in September 2020, recommending that entitlement to a TDIU be granted on an extraschedular basis effective from March 12, 2009. In November 2020, the Director determined that a TDIU was not warranted on an extraschedular basis. As these steps have been completed, the Board may address whether entitlement to a TDIU is warranted at any point in the appeal period, de novo, with the Directors’ decisions being in essence the de facto decisions of the AOJ and, as such, not evidence. See Wages v. McDonald, 27 Vet. App. 233, 238-239 (2015). In a VA Form 21-8940 submitted in November 2004, the Veteran reported that he was unable to secure or follow substantially gainful employment as a result of his left knee, hearing loss, and heart disease. He reported that he last worked full time, and became too disabled to work, in January 1992. The Veteran identified his recent work history as including working 40 hours a week as a pipe maker from October 1979 to March 1985, and 40 hours a week as a paper maker from December 1986 to January 1992. The Veteran completed 4 years of high school, and he indicated that he also received training in field wiring during his period of active duty service. He denied receiving any education or training since he became too disabled to work. This information is generally consistent with the information reported in a VA Form 21-8940 subsequently submitted on March 12, 2009, except that the Veteran reported that he was unable to secure or follow substantially gainful employment only as a result of his knees. In another VA Form 21-8940 submitted later in March 2009, the Veteran wrote "knees, etc." under the section for the service-connected disability that prevented him from securing or following substantially gainful employment. The Veteran also changed his work description for the pipe company to forklift operator and noted that he worked in this position from 1980 to 1986. He additionally changed his work description for the paper company to machine operator. The Veteran appeared to indicate in the remarks section that pain related to his knees prevented gainful employment. An additional VA Form 21-8940 submitted in December 2019 noted that the service-connected disabilities that prevented the Veteran from securing or following any substantially gainful occupation included major depressive disorder, his left and right knee disabilities, and his low back disability. Although this form was similar to the previous forms in noting that the Veteran last worked fulltime in January 1992 in his role as a papermaker, the form also stated that he had a position working as a van driver for approximately 20 hours a week from May 2003 to January 2004. The highest gross earnings per month were unknown. As such, the record reflects that the Veteran did not engage in substantially gainful employment during the appeal period. In the Veteran's Social Security Administration (SSA) records dated in November 1992, he noted that his work history included working as a field wireman for the Army from October 1975 to October 1978, a fork lift operatory for a pipe company from August 1980 to August 1985, and a process specialist for a paper company from December 1986 to May 1992. In an associated record that appeared to be related to his duties in the Army, the Veteran indicated that he used machines, tools, or equipment; technical knowledge or skills; and wrote, completed reports, or performed similar duties. He did not have supervisory responsibilities. The Veteran reported that he climbed 80 feet telephone poles to connect wires, a task that required skills. He also had to file a report at the end of each job. This position typically involved 8 hours of walking and standing, and 0 hours of sitting. He occasionally engaged in bending. The heaviest weight lifted was marked as 50 pounds with 100 pounds as the next available category, and the weight frequently lifted/carried was marked as over 50 pounds. In an additional record that appeared to be related to the Veteran's position as a forklift operator, the Veteran noted that he used machines, tools, or equipment; technical knowledge or skills; and wrote, completed reports, or performed similar duties. He did not have supervisory responsibilities. The Veteran reported that he operated a forklift that carried hundreds of pounds, and he filed reports on all pipes that came through his department. This position typically involved 3 hours of walking, 2 hours of standing, and 4 hours of sitting. He also occasionally engaged in bending. The heaviest weight lifted was marked as 100 pounds, and the weight frequently lifted/carried was marked as over 50 pounds. In another record that appeared to his address his employment as a process specialist for a paper company, the Veteran indicated that he used machines, tools, or equipment; technical knowledge or skills; and wrote, completed reports, or performed similar duties. He did not have supervisory responsibilities. The Veteran reported that he worked on a paper machine that carried about 60 inches of paper on a 70 pound shaft. The need to move swiftly in this position required skill. He also had to file a report on every roll of paper that came through. This position typically involved 8 hours of walking and standing, and 0 hours of sitting. He also constantly engaged in bending. The heaviest weight lifted was marked as 100 pounds, and the weight frequently lifted/carried was marked as over 50 pounds. The Board notes that the information in these records is generally consistent with the Veteran's reported job duties for these positions in SSA records dated in May 1990. In those records, the Veteran indicated that his job for the pipe company also entailed loading pipes onto a truck and truck driving. Prior to the beginning of the appeal period, an August 1994 VA examination noted that the Veteran was an unemployed paper mill process specialist who was currently on SSA disability due to a heart problem. The diagnoses were hypertension, under treatment; and palpitations, under treatment. The Board notes that a May 1998 SSA disability determination indicates that the Veteran's disability began in May 1992 and lists the primary diagnosis as atrial fibrillation and the secondary diagnosis as hypertension. In April 2003, a VA examiner conducting an examination related to the Veteran’s left knee noted that the Veteran had experienced increased problems with left knee pain and recurrent swelling in the years since he sustained a left knee injury during service. He reported having limited range of motion was taking ibuprofen once or twice a day. The examiner noted that the Veteran favored his left knee with ambulation. In August 2004, a VA examination related to the left knee stated that the Veteran injured his left knee in 1976 when he slipped off a tank, fell, and hit his knee on a rock. He had experienced pain in his left knee since then, and he treated his symptoms with ibuprofen. At times, his knee gave way and swelled. The examiner indicated that the Veteran had not worked since 1994 as a result of his heart problem rather than his knee. The Veteran's daily activities were limited, and he was not able to mow, engage in handyman work, shop, walk for prolonged periods, bend, lift, or stand, etc. There was also additional limitation following repetitive use and during flare ups. The examiner did not detect any instability in the knee. The examiner noted that the Veteran walked with a cane and tended to favor the left knee. Another VA examination concerning the left knee was conducted in March 2005. The examiner noted that the Veteran reported having constant left peripatellar/retropatellar knee pain that was associated with daily locking, frequent swelling (twice a week), and infrequent giving way (twice a month). He reported that activities such as walking or standing for periods greater than 30 minutes, climbing inclines, or squatting caused flare ups of his disability. He reported that the flare ups lasted approximately two days and were eased with rest, elevation, and ibuprofen. The examiner noted that from a functional standpoint, the Veteran had been employed for the past few years due to disability-related problems. He informed the examiner that he avoided squatting or climbing inclines. The Veteran reported that he was no longer able to perform yardwork or work around the house due to his left knee disability. The examiner noted that the Veteran had one doctor visit in the past year, but he was not incapacitated. He used a cane and a left knee brace on a daily basis, and he took motrin 3 times a day for his left knee disability. The Veteran had also been given hydrocodone by his doctor which he took every 8 hours for severe pain. The Veteran complained that the medication caused sedation. In February 2006, a VA examination related to the left knee noted that the Veteran had experienced pain and stiffness in his knees since service, and the symptoms had worsened in the past 3 to 4 years. The pain initially came and went, but it had become constant in the past year or more. Although he had been treated with ibuprofen and tramadol by his primary care physician, he reported that the medication did not completely relieve his pain. His knee hurt and awakened him from sleep. It had not swelled to the extent that it required being aspirated or injected. He saw a knee specialist approximately two years ago who recommended continuing conservative treatment. The Veteran wore a support on the knee which stabilized and prevented flexion. Although the knee was consistently painful, there were no flare ups per se. The examiner also noted that for approximately one year, the Veteran had experienced general right knee discomfort, but no swelling or effusion of the right knee. He used a cane to walk as the left knee occasionally gave out. The examiner noted that the Veteran was medically retired because of a heart problem, and his knee problems did not affect his occupation. However, the examiner noted that the Veteran's knee problems limited his daily activity as he could not do any work around the yard, prolonged walking, or standing as a result of the discomfort. On March 12, 2009, a VA treatment record noted that the Veteran complained of pain in his back and bilateral knees. He reported that his knees had bothered him since he injured them during service, and he took ibuprofen and tramadol with moderate benefit. He was still seeking a more effective medication. He also complained of chronic low back pain with right costophrenic angle pain at times. There was pain on palpation over the lower lumbar vertebra and mild tenderness over the left costophrenic angle. The record also indicated that soft tissue pain was present, and range of motion was limited considering the Veteran's body habitus. In April 2009, the Veteran attended an additional VA examination specific to his knees. The examiner noted that since the February 2006 VA examination, the Veteran complained of increasing pain and stiffness with his knees. His bilateral knee pain had been chronic for the past 4 to 5 years. He took ibuprofen and tramadol daily for the chronic pain, and he was recently given Percocet to take as needed for severe pain. He experienced flare ups that were preceded by prolonged walking and standing. In addition, both his knees occasionally swelled with the left worse than the right. The left knee also occasionally locked, but this symptom was not present in the right knee. Both knees frequently gave way during flare ups. The examiner noted that the Veteran had not worked since 1994 and indicated that he was receiving Supplemental Security Income (SSI). When the Veteran was experiencing a flare up at home, he tried to stop the offending activity and get off his feet. His symptoms could be eased over one hour following ingestion of medication. Functionally, the Veteran reported that he could sit for 6 hours. He could also use his hands without difficulty. The Veteran reported that he was limited to 15 minutes of standing and walking, and he was unable to climb or walk. He used a cane for both knees to ambulate, and he wore a left knee brace on a daily basis. He also wore a right knee brace intermittently when experiencing a flare up. The examiner stated that he had not been incapacitated in the past 12 months for his knees. In June 2009, a VA examination related to the Veteran's lumbar spine and left knee disabilities was conducted. The Veteran continued to report left knee pain since service, and he indicated that his knee gave out. Although he previously had intermittent pain, he currently had fulltime pain and described his knee as wobbly. The Veteran was using a cane and brace in addition to taking Vicodin and tramadol. The examiner stated that he had not worked since 1992 at a paper company, and he was off for his heart as well as knee problems. The Veteran's low back began bothering him approximately two years ago without any antecedent injury. It just began hurting and felt like a stab in the low back. He had no radiating pain, bowel or bladder problems, or numbness. The diagnoses were left knee arthralgia status post contusion and laceration, chronic lumbar sprain, and morbid obesity. The Veteran did not describe having flare ups. The examiner noted that the Veteran experienced functional impairment in that he had some discomfort when he bended. He was able to walk normally without assistive devices, but he used a brace and cane. He did have objective evidence of painful motion in his back, and very minimal spasm was present. There was no weakness or tenderness, and his neurologic functioning was normal. In the examiner's opinion, the Veteran was incapacitated every day with his knee and back. In an October 2009 letter, Dr. K., MD, stated that the Veteran had been under her care since 1989. The pain he presented in knees for the past 5 or 6 years was worsening, and he had been experiencing associated back pain aggravated when walking. X-rays of the knees showed early degenerative changes on the right and loss of joint medical compartment consistent with early degenerative change. The degenerative changes of the knees were associated with more difficulty with ambulation and believed to be contributing to back pain. Later in October 2009, the Veteran was provided with a VA examination related to psychiatric disorders. The examiner noted that the Veteran had a period of light duty during service after his left knee injury. He was subsequently able to return to duty and his knee did not bother him a great deal. Following his discharge, the Veteran worked for a while for a railroad company before relocating and taking a job at a PVC pipe company. The examiner indicated that he remained in this location for approximately 3 to 4 years until about 1985 when he returned home to be closer to family following the death of his mother. He took a job at a paper company for a period of approximately 7 years until 1992. The Veteran took a medical retirement from this company due to heart problems, which the Veteran identified as atrial fibrillation and hypertension. The Veteran was told that he should probably not continue working in any occupation that was strenuous as it was dangerous to his health and could precipitate a heart attack. As a result, the Veteran began to receive SSA disability benefits. The Veteran nevertheless informed the examiner that throughout the late 1980's and 1990's, his knee was bothering him more and more. Although his left knee was the injured knee, his right knee also had problems as he often shifted his weight to his right knee to avoid putting weight on his injured left knee. The examiner noted that the Veteran showed him a letter from his private physician dated in 1989 that referred to the Veteran's knee injury and knee pain. The letter stated that he had pain in both his left and right knee caused by degenerative changes to the knee joints, and he would probably experience knee pain as well as low back pain when walking as a result of his knee problems. As the Veteran had increasing problems with his knees, he used over the counter pain medicine. More recently, the Veteran had also received prescription pain medicine that now included narcotic pain medicine such as hydrocodone to help relieve the pain. He reported that his knee pain was often very severe, rating the pain as a 9 out of 10 without pain medication. With pain medication, the pain was a 6 out of 10. The Veteran walked with the aid of a cane and was unable to stand or walk for long periods. The Veteran also reported trouble sleeping at night as a result of his knee pain. The Veteran reported that he usually slept only 3 to 4 hours a night and woke up throughout the night several times due to pain. In recent years, he had been increasingly less able to pursue activities that he used to perform with his children and grandchildren. The Veteran reported that he was previously active and went on walks, played Frisbee, threw balls, and played with his young grandchildren by running around the backyard. These activities were no longer possible as the Veteran experienced pain with overexertion. He was also unable to walk without the aid of his cane. The examiner observed that the Veteran did demonstrate evidence of being in pain when he walked into the office and sat down as well as when he rose from a seated position, noting that he grimaced and groaned to indicate pain. The Veteran additionally reported that he had been feeling more depressed in the last several months. He felt that his depression was related to his problems with chronic pain and its associated limitations. It bothered him that his activities were limited and his ability to do activities with his wife or children was considerably diminished by his problems with chronic pain. The Veteran had been married for 13 years, and he had a stepdaughter and two step-grandchildren who he was very fond of and liked to join in activities. The Veteran's depression consisted of feeling sadness and a sad mood the better part of most days, feeling down, and feeling hopeless and helpless to improve his situation as well as pessimistic about the future. The Veteran also felt discouraged, wishing he could cry at times. He reported that he had not allowed himself to feel better, but he denied any suicidal or homicidal ideation. The mental status examination revealed that the Veteran was casually and neatly dressed and groomed. He was cooperative and pleasant, and the examiner stated that he gave no reason to doubt the credibility of the information he provided. The Veteran displayed considerable sadness, looking downcast and rarely smiling. He also made poor eye contact, but his speech was within normal limits. The Veteran's mood was basically sad, and his affect was appropriate to his mood. He was alert and oriented in all spheres, and his thought processes were logical and tight. There was no loosening of associations, and his memory was largely intact. He reported no hallucinations, and no delusional material was noted. The Veteran's judgement and insight were noted to be adequate. The examiner found the Veteran to be competent for VA purposes and not in need of any psychiatric hospitalization. The Axis I diagnosis was major depressive disorder. The examiner separately noted that the Veteran had not worked since 1992 due to disability from a heart condition. His social functioning was affected by his limitations; ability to ambulate and stand; and chronic pain, a symptom that sometimes made the Veteran not want to be around people. His thought processing and communication appeared to be relatively unimpaired, although somewhat affected by depression. His behavior showed evidence of depression, but it was otherwise within normal limits. The Veteran was able to handle his activities of daily living, including his finances. Despite the noted diagnosis, the examiner stated that he did not find evidence of a psychiatric disorder in the examination that day. In December 2009, the Veteran attended another VA examination specific to his psychiatric disability. The examiner noted that the Veteran reported being followed in the mental health clinic, and his records indicated that he took bupropion. The Veteran reported that he had been depressed a lot since October, and he felt that things were worsening. He indicated that although his medication had been working, it currently seemed as if it was no longer working. He reported that his appetite fluctuated, but he ate two meals a day. The Veteran had lost 10 pounds over the past 6 months without trying to do so. He reported that he only slept 3 hours a night. It was sometimes difficult to sleep due to the Veteran dwelling on tings, and he awakened during the night as a result of pain. He was sometimes unable to return to sleep, and he napped during the day. The Veteran usually went to bed between 10:00 pm or 11:00 pm, and he rose from bed around 8:00 am. The Veteran felt that he was very depressed every day, and he reported being unable to participate in previous activities such as hiking or traveling. The Veteran informed the examiner that he had to keep his knee straight most of the time. He denied having anhedonia or suicidal or homicidal ideation. The Veteran reported that he got along well with his wife, and they were close. He had not worked since 1994 when he was working for a paper company. The Veteran reported that he developed a heart condition, and he now received SSA disability benefits. He spent his time watching television or performing chores around the house. He also visited his father and one or two friends in addition to occasionally attending church. The examiner noted that the Veteran was casually groomed and fully cooperative. Although he walked with the aid of a cane, he did not display any overt pain behaviors during the interview. His speech was within normal limits, his mood was somewhat depressed, and his affect was appropriate to content. The Veteran's thought processes and associations were logical and tight, and there was no loosening of associations or confusion noted. His memory was largely intact, he was oriented to all spheres, he did not report any hallucinations, and no delusional behavior was noted. The Veteran's insight and judgment were adequate. The Veteran continued to be found competent. The Axis I diagnosis was adjustment disorder with depressed mood. The examiner believed that the Veteran's symptoms were relatively mild, and the frequency was somewhat unclear. The symptoms had persisted for a number of years, and the examiner stated that he did not find evidence that depression precluded employment. The Veteran did not report any gross impairment in social functioning, and there was no noted impairment in thought processing or communication. The examiner did not find evidence that any psychiatric disorder precluded activities of daily living. In February 2013, a VA examination was conducted to evaluate the Veteran's lumbar spine disability. The Veteran reported that he experienced flare ups that occurred with walking more than 20 feet and consisted of low back pain. The examiner noted that the Veteran experienced functional loss and/or functional impairment in the form of less movement than normal, pain on movement, and disturbance of locomotion. In terms of assistive devices, he regularly used a brace, and he constantly used a cane. The examiner noted that these assistive devices were for the left knee. The examiner opined that the Veteran's lumbar spine disability did not impact his ability to work. A VA examination that addressed the Veteran's psychiatric disability was also conducted in February 2013. The diagnosis was adjustment disorder with depressed mood, chronic. The examiner noted although a mental condition had been formally diagnosed, the symptoms were not severe enough either to interfere with occupational and social functioning or to require continuous medication. The Veteran continued to be married, and he was noted to have two children and grandchildren with good relationships. The examiner stated that he last worked in 1996 for a paper company, and he left due to heart problems. He had not worked since that time. Regarding treatment, the Veteran had not been seen in individual therapy in approximately 14 months. There was no recent psychiatric appointment noted, but the Veteran reported that he continued to take bupropion and zolpidem. The Veteran indicated that a good mood could come and go, and a good day could consist of going out to eat with family, spending time with family, and walking a little. On a bad day, the Veteran had no interest in these sorts activities. His mood was often dependent on his pain level. The Veteran usually slept for 6 hours a night and took brief 15 to 20 minute naps twice a day. He enjoyed reading, watching television such as football and sporting events, and walking when it was not painful. The Veteran's only symptom was noted to be a depressed mood. He continued to be competent to manage his financial affairs. The examiner remarked that there were no functional limitations related to employment activities. The Veteran's depression was mild and did not impact either physical or sedentary employment activities. In May 2013, an additional VA examination concerning the Veteran's lumbar spine disability was conducted. The Veteran reported that he currently had chronic back pain that was a 9 out of 10 in severity. He took hydrocodone daily for pain, and he reported having no problems from the medication. He had symptoms of stiffness in his back, but no spasms, radiculopathy, bowel/bladder impairment, or neurologic deficits. The Veteran regularly used a cane for his knees and back. He described having flare ups that limited walking and standing. With flare ups, his forward flexion was limited to 45 degrees. He did not have weakness, incoordination, or fatigue. The examiner identified his functional loss or impairment as pain on movement. The examiner opined that the Veteran's lumbar spine disability did impact his ability to work. The examiner noted that the Veteran could sit for 30 to 40 minutes with reposition, stand for 10 minutes, and walk 0.5 blocks. He avoided climbing and bending, and he limited his weightlifting to light weight for both his knees and back. The examiner also noted that the Veteran was examined in February 2013. From a TDIU standpoint, he was observed for approximately 45 minutes without appreciable discomfort with his back and knees while sitting. Based on history, observation, and physical examinations, and well as taking education into consideration, the Veteran would be employable from a sedentary standpoint, regarding his lumbar spine and bilateral knee disability. Historically, the knees and back played the same role physically in regard to the Veteran's ability to function in a work environment. Also in May 2013, a VA examination related to the knees was conducted. The Veteran complained of bilateral knee pain which he rated as moderate to severe. He took hydrocodone three times a day for pain that was helpful and was not associated with side effects. He had stiffness and crepitus to the knees, and his left knee occasionally locked and gave way. The pain in his knees was aggravated with ambulation such as walking and standing. His knees also occasionally swelled, and his left knee was more symptomatic than his right. The Veteran reported having flare ups that limited standing and walking. There was no loss of motion in the right knee during flare ups, but the left knee flexed only to 45 degrees during such events. Both knees weakened with flare ups; and there was some discoordination of the left knee, but not the right knee. The examiner noted that the Veteran had functional loss or impairment that included pain on movement in both knees. His also regularly a cane in relation to both knees. He constantly used a left knee brace, and he used a right knee brace as needed. The examiner opined that the Veteran's knee disabilities impacted his ability to work, noting that he could sit for 30 minutes before he needed to reposition to improve for another 30 minutes. He could stand for 10 minutes, but he had to sit due to pain in his knees and back. He could walk 0.5 blocks before having pain. The Veteran avoided climbing and squatting due to pain in his knees and back. He had good arm function and vision. The examiner noted that the Veteran was observed for 45 minutes without significant distress. Based on history, observation, clinical examination, and review of x-rays, it was the examiner's opinion that it was as likely as not that the Veteran could function in a sedentary environment, taking his knees into consideration. He would have more activity limitations noted above with knees as well as the back, but these limitations would not preclude his ability to function in a sedentary environment. The examiner indicated that the same opinion applied to the lumbar spine disability. The Veteran was noted to have the ability to sit for long periods of time without distress, and he was able to ambulate on his own for short distances without major difficulty. He had good range of motion with the spine, and he had adequate range of motion with his knees that allowed him to ambulate on his own as well as rise from a seated position. A review of the x-rays revealed good joint space with both knees and minimal degenerative joint disease changes in the back with good disc spacing. The Veteran also attended a VA examination in May 2013 that addressed his psychiatric disability. The diagnosis was still adjustment disorder with depressed mood, chronic. The examiner opined that the Veteran had occupational and social impairment due to mild or transient symptoms which decreased work efficiency and ability to perform occupational tasks only during periods of significant stress, or; symptoms controlled by medication. Regarding social functioning, the Veteran's relationship with his wife was described as good. They sometimes went fishing together, and he liked television and occasionally attend church. He also had some friends who came by to see him. He remained unemployed, and the examiner stated that he was on SSA disability for his heart and knee. The Veteran took bupropion and zolpidem medication, and he reported sleeping for approximately 5 hours each night. He reported having some depression related to pain in his knee and back as well as his inability to do as much as he had done previously. He denied having suicidal ideation. The Veteran reported losing a few pounds and having a decreased appetite when depressed. Depressed mood continued to be the only identified symptom. The Veteran was found competent to manage his financial affairs. The examiner stated that the Veteran's symptoms were mild, and it was less likely than not that they precluded employment. The examiner stated that the Veteran reported having mild depression that did not significantly impair functioning. In March 2020, P.T., a vocational consultant, completed an Employability Evaluation in connection with the claim for a TDIU on appeal. P.T. indicated that she had reviewed the entire claims file and established telephone contact with the appellant and the Veteran’s daughter, a nurse, before reaching an opinion. P.T. noted that the Veteran was service-connected for his right knee, left knee, and low back disabilities; and physically, the Veteran had difficulty sitting, standing, and walking. He frequently changed position due to pain and discomfort. If running errands or attending appointments, he would either park his car very close to the building or have his wife drop him off near the entrance. When sitting, he used a reclining chair due to pain from his back. He was only able to stand for a few minutes at a time before needing to sit. He required a cane when walking and often leaned on his wife for support. P.T. observed that the Veteran was also service-connected for major depressive disorder, and he awoke frequently at night due to nightmares related to his time in service. The Veteran's wife reported that he terminated therapy based on his perception that the therapist and others in the group did not listen to him. Due to his lack of sleep, the Veteran had difficulty concentrating and focusing on tasks. The Veteran's wife needed to continuously remind him to complete tasks he had started. P.T. noted that the Veteran's daughter recalled that the Veteran had been severely depressed with sleep issues. He either slept on a reclining chair or sofa. Often during the day, he would go to a nearby lake to sit by himself. While the Veteran's wife attended family functions, the Veteran would only stay for a few minutes before leaving to return home. Physically, the Veteran's daughter reported that he was unable to pick up items weighing more than five pounds. He was unable to bend, and he frequently changed position from sitting to standing. The Veteran's daughter described his gait as unsteady, and she noted that he used pain medications and a heating pad to help with the pain. Consistent with the information reported in the VA Form 21-8940 received in December 2019, P.T. noted that the Veteran had a high school education and his work history included work as a van driver from May 2003 to January 2004, as a paper maker from December 1986 to January 1992, and as a forklift operator from October 1979 to March 1985. P.T. noted that as the appellant was unable to provide specific information regarding the Veteran's responsibilities as a van driver, P.T. had reviewed a similar job description on the Area Agency on Aging website. This description indicated that the position included responsibilities such as assisting passengers on and off a van, assisting passengers with parcels, assisting in planning routes to offer maximum service at minimum mileage, and notifying clients in advance of route changes or cancellations. The Veteran's daughter explained that the position was part-time, and she believed that the Veteran worked on an as-needed basis. As a paper maker, the Veteran was responsible for operating a paper machine, which cut paper to specific measurements. He had to load the paper onto the machine and filed a report at the end of his shift. His work for the forklift company included responsibilities such as loading pipe onto trucks. The Board notes that this information is consistent with the Veteran’s reports in his SSA records. P.T. noted that her analysis was based on the Dictionary of Occupational Titles, the Occupational Outlook Handbook, and the Occupational Information Network/Standard Occupational Classification Coding System. These resources indicated that the Veteran's occupation as a van driver required medium physical demand level. The Department of Labor defined medium work as exerting 20 to 50 pounds of force occasionally, and/or 10 to 25 pounds of force frequently, and/or greater than negligible up to 10 pounds of force constantly to move objects. The physical demand requirements were in excess of those for light work. The position required occasional stooping, fingering, and constant reaching and handling. Another resource also suggested frequent sitting and occasional kneeling and crouching/squatting. It was also described as semi-skilled work and light truck or delivery services drivers. In terms of the temperaments required by the position, P.T. identified performing repetitive work and dealing with people beyond giving and receiving instructions. Another resource indicated that required abilities included problem sensitivity, deductive reasoning, inducting reasoning, and selective attention. Communication with supervisors, peers or subordinates; communicating with persons outside the organization; establishing and maintaining interpersonal relationships; and performing for or working directly with the public were other indicated skills. The above resources also indicated that the Veteran's position for the paper company was analogous to a cutter operator and associated with a medium physical demand level. The position required occasional stooping and fingering in addition to frequent reaching, handling, and fingering. The resources indicated that the position involved skilled work and the related temperaments were described as situations requiring the precise attainment of set limits, tolerances, and standards. Work abilities also entailed problem sensitivity, deductive reasoning, inductive reasoning, and selective attention. The physical demands included constant standing; frequent and constant handling, reaching, and fingering; and frequent walking, bending/stooping, and twisting. Similar to the van driver position, the work involved communication with supervisors, peers or subordinates; communicating with persons outside the organization; establishing and maintaining interpersonal relationships; and performing for or working directly with the public. P.T. indicated that the prior position as a forklift operator was comparable to industrial truck operator and required a medium physical demand level. The position involved semi-skilled work and was associated with temperaments such as performing repetitive work and situations that required the precise attainment of set limits, tolerances, or standards. The position required constant reaching and handling; frequent fingering, standing, and sitting; occasional and frequent bending/stooping and twisting; and occasional walking, climbing, and squatting/crouching. The relevant work abilities were problem sensitivity, deductive reasoning, inductive reasoning, and selective attention. The work also included communication with supervisors, peers or subordinates; communicating with persons outside the organization; establishing and maintaining interpersonal relationships; and performing for or working directly with the public. P.T. opined that the Veteran was more likely than not precluded from securing and following substantially gainful employment, to include sedentary employment, from at least March 2009 to the time he passed away in August 2017, due his service-connected residuals of his left knee injury, chronic right knee strain, and low back disability. His service-connected major depressive disorder more likely than not contributed to his inability to secure and follow substantially gainful employment from at least August 2009 to August 2017 when he passed away. In addition to the information gained from P.T.'s interview of the appellant and the Veteran's daughter, P.T. noted that the opinion was supported by the medical evidence of record in which the Veteran's complaints of chronic bilateral knee pain were well-documented. P.T. highlighted the findings from the April 2009 VA examination that the Veteran had flare ups with prolonged standing and walking, that both knees gave out during flare ups, the Veteran's limitation to 15 minutes of standing and walking, and his inability to climb or squat. He also used a cane to ambulate and wore a brace on both knees. The June 2009 VA examination additionally noted discomfort when bending and pain in the low back. P.T. also highlighted the fact that the examiner at that time opined that the Veteran was incapacitated on a daily basis as a result of his knee and back conditions. P.T. also noted that the Veteran's report in a June 2011 VA treatment record that although the Veteran wanted to travel more with his wife, he was unable to tolerate sitting in a car for extended periods as there was not enough room to stretch his knees out. P.T. observed that the findings from the February 2013 VA examination revealed that the Veteran had flare ups of the back with walking distances greater than 20 feet; and his low back disability caused a functional impact due to less movement than normal, pain on movement, and disturbance of locomotion. He constantly used a cane and regularly used a brace. P.T. noted that since 2009, the Veteran had only been able to walk less than 20 feet. P.T. noted that the examiner at that time opined that this back disability did not impact his ability to work. P.T. highlighted the Veteran's subsequent report from the May 2013 VA examination that his pain was a 9 out 10, he had stiffness in his back, and he had flare ups that limited walking, standing, and forward flexion. Pain on movement caused additional functional loss. The Veteran regularly used a cane, he was able to sit for 20 to 40 minutes with repositioning, he could stand for 10 minutes, and he could walk one half a block. He was limited with lifting and avoiding climbing and bending. P.T. additionally noted that the May 2013 VA examination revealed moderate to severe bilateral knee pain and stiffness, that the left knee occasionally locked and gave out, and that the bilateral knee pain was aggravated by ambulation and standing. During a flare up, the Veteran reported that range of motion decreased, and he experienced weakness. P.T. reiterated several of the findings noted above, including that pain on movement was noted bilaterally and that the examiner opined that the Veteran could function in a sedentary work environment. P.T. noted that she disagreed with the opinions from the February 2013 and May 2013 VA examiners as the Veteran's service-connected knee and spine conditions precluded his ability to secure and follow substantially gainful employment, to include sedentary unskilled work, since at least March 2009 to August 2017. The Department of Labor defined sedentary labor as work that involved exerting up to 10 pounds of force occasionally and/or a negligible amount of force frequently to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involved sitting most of the time, but it might involve walking or standing for brief periods of time. Jobs were sedentary if walking and standing were required only occasionally and all other sedentary criteria were met. P.T. highlighted the May 2013 VA examination findings that the Veteran could only sit for 30 minutes before needing to change position to sit for another 30 minutes. Additionally, both the May 2013 VA examinations showed that he was unable to consistently stand for longer than 10 minutes or walk farther than one half a block due to his constant knee and low back pain. Given the Veteran's inability to sit, stand, or walk on a prolonged or consistent basis, it was at least as likely as not that he would have been precluded from performing any occupations, no matter the physical demand, including sedentary occupations, from at least March 2009 to August 2017. P.T. emphasized the fact that sedentary work required occasional standing and walking. Occasional was also defined as an activity or condition that existed up to one third of the time, i.e., up to 20 minutes per hour. Therefore, the Veteran's inability to stand longer than 10 minutes and walk more than half a block was inconsistent with the exertional demands of sedentary employment. P.T. further opined that the Veteran's severe pain from his back and bilateral knee disabilities would have likely interfered with his ability to sustain concentration on work tasks for 2 consecutive hours as was required of all competitive employment. These lapses of concentration during periods of increased pain would likely have led to off-task behavior that would have compounded over the course of a day to be in excess of employer tolerances. In P.T.'s vocational experience, employees were only permitted to be off task up to 10 percent of the workday. In addition, the need for unscheduled breaks associated with adjusting positions for knee pain every 30 minutes would not be tolerated as it would have required the Veteran to pause his work task every half hour and result in additional time spent off task. P.T. also noted that the Veteran's major depressive disorder was manifested by nightmares, sleep disturbances, feelings of hopelessness and helplessness, lack of interest in activities, and concentration issues. P.T. opined that the disability caused him to become irritable, angry, and isolative. He also had minimal interactions with friends and family. As the ability to sustain adequate pace and productivity and the ability to interact appropriately and effectively with others were requirements of all employment, regardless of skill or exertional level, these symptoms would also contribute to the Veteran's unemployability since at least August 2009. P.T. noted that in addition to the symptoms of depression noted in the October 2009 VA examination, an October 2009 VA treatment record noted that he continued to experience insomnia, anhedonia, low energy, and difficulties with concentration. He reported being woken up from nightmares and low levels of suicidal thoughts were noted. The December 2009 VA examination reflected worsening depression with the Veteran sleeping for only 3 hours each night due to difficulty falling asleep and dwelling on things. He usually napped during the day and felt depressed daily. A subsequent May 2011 VA treatment record also indicated that the Veteran was feeling more irritable and "out of it" lately. A June 2011 VA treatment record similarly noted that the Veteran felt irritable and "snappy" at times. The depressed mood continued to be present during the February 2013 VA examination in which the Veteran’s twice daily naps of 15 to 20 minutes were noted. The depressed mood was also noted during the May 2013 VA examination, and the Veteran was found to have occupational and social impairment due to mild or transient symptoms which decreased work efficiency and the ability to perform occupational tasks only during periods of significant stress. It was noted that the Veteran only obtained approximately 5 hours of sleep per night. P.T. noted that as the ability to establish and maintain interpersonal relationships with others was essential in any occupation in the competitive labor market, and it was more likely than not that the Veteran's irritability would likely have precluded him from any employment, to include sedentary employment, from at least August 2009. All employment required the ability to interact with supervisors and co-workers with an appropriate and respectful manner and respond appropriately to feedback or criticism. In addition to requiring interaction with supervisors and co-workers, the Veteran's past employment required interacting with members of the public. Given his irritability, he would have experienced difficulty interacting with others appropriately and effectively on a consistent basis; and this symptom would have precluded him from meeting employer expectations of appropriate interpersonal communication. In addition, the Veteran's depressive disorder was manifested with depressed mood, a chronic sleep impairment, and concentration impairments. These symptoms would more likely than not have impacted his ability to concentrate and focus on work tasks for 2 consecutive hours and precluded him from starting and completing tasks in a timely and accurate manner. His concentrations issues would also likely have impaired his ability to learn and retain task instructions. These issues would have resulted in more errors and more likely than not lead to dismissal from employment. In addition to contributing to concentration difficulties, the sleep impairment would have impaired his ability to sustain an adequate pace, his productivity, and his reliability. The Veteran's need for daily naps due to fatigue from sleep disturbance would further contribute to his inability to sustain an adequate pace and productivity, issues which would not be tolerated in any employment. P.T. also highlighted the fact that the Veteran's past work was significant for employment in occupations within the medium physical demand level. Skills that he may have acquired from past work would no longer be applicable due to changes in how these occupations were performed, industry requirements, and equipment utilized. Furthermore, the Veteran education was limited to high school and he did not have any other degree, training, or skills, that would have readily transferred to, or provided an advantage in, a sedentary occupation. He also lacked computer skills which were typically required for occupation within the sedentary physical demand level. P.T. summarized that the physical limitations from the Veteran's left and right knee disabilities and his low back disability impacted his ability to secure and follow substantially gainful employment as they severely limited his ability to sit, stand, and walk for any period of time without experiencing pain. Additionally, the Veteran's psychiatric disability further limited his ability to sustain adequate pace, productivity, reliability, concentration, and focus. His concentration issues further impacted his ability to learn and retain task instructions. The Board finds that P.T’s March 2020 opinion provides great probative value as P.T. considered the relevant evidence of record as well as occupational literature and provided a rationale that included a thorough discussion of this evidence. Without even considering the functional effects of the Veteran’s lumbar spine disability that did not become service-connected until March 18, 2009, the Board finds that this opinion supports that the conclusion that the Veteran’s right and left knee disabilities for which service connection was in effect for the entire appeal period rendered him unable to secure or follow a substantially gainful occupation. As highlighted by P.T., the VA examination reports specific to the knees discussed that it was associated with functional limitations in standing and walking. See, e.g., February 2006 VA examination, April 2009 VA examination. In addition, the Veteran’s recent work history involved positions that were all characterized by P.T. as involving a medium physical demand level and were noted to be largely associated with tasks that required either constant or frequent standing as well as either frequent or occasional walking. Although the position of van driver involved frequent sitting, it also involved occasional crouching/squatting which the VA examination reports indicate would be problematic in light of the Veteran’s reports that his left knee locked, and his knees gave way at times. Moreover, the Veteran reported that he had problems sleeping as a result of his knee pain during the October 2006 and October 2009 VA examinations, and P.T.’s opinion reflects that the Veteran’s difficulty sleeping as a result of pain would have caused significant problems in terms of both concentration and productivity. Although the Board has considered the May 2013 VA examiner’s opinion that the Veteran was able to function in a sedentary occupation despite the limitations from his knee disabilities, P.T.’s opinion also supports the conclusion that the Veteran’s work experience and high school education did not provide him with the skills necessary to secure or follow substantially gainful employment in a purely sedentary occupation. It is clear from the record as well as P.T.’s opinion that the Veteran’s subsequently service-connected low back and major depressive disorder disabilities only further contributed to the unemployability that was caused by the physical limitations associated with his right and left knee disabilities. The Board has considered this evidence as well as the Veteran's education and work history in concluding that the Veteran would have been unable to function in any type of employment as a result of symptoms from his service-connected right and left knee disabilities during the appeal period. The Board also notes that the Veteran appeared able to perform certain aspects of daily living. However, the law recognizes that a person may be too disabled to engage in employment although he or she is fairly comfortable at home or upon limited activity. See 38 C.F.R. § 4.10. In addition, a Veteran does not have to prove that he is 100 percent unemployable in order to establish an inability to secure or follow a substantially gainful occupation, as required for a TDIU award. See 38 C.F.R. § 3.340(a); Roberson v. Principi, 251 F.3d 1378, 1385 (Fed. Cir. 2001). Resolving all benefit of the doubt in the Veteran's favor, the Board finds that the combined functional limitations of Veteran's service-connected right and left knee disabilities rendered him unable to secure or follow a substantially gainful occupation from March 2, 2008. On and after March 18, 2009, the Veteran’s low back disability also contributed to his unemployability; and on and after August 21, 2009, the symptoms of the Veteran’s major depressive disorder added to the Veteran’s inability to secure or follow a substantially gainful occupation. Thus, entitlement to a TDIU is warranted for the entire appeal period. See 38 C.F.R. § 5107(b); Gilbert v. Derwinski, 1 Vet. App. 49, 53-56 (1990). 2. Entitlement to DIC under 38 U.S.C. § 1318. VA death benefits may be paid to a deceased veteran's surviving spouse or children in the same manner as if the veteran's death was service-connected. 38 U.S.C. § 1318(a); 38 C.F.R. § 3.22(a). A deceased veteran is one who died not as the result of his or her own willful misconduct and was in receipt of or entitled to receive compensation at the time of death for a service-connected disability continuously rated totally disabling for a period of 10 or more years immediately preceding death; or continuously rated totally disabling for a period of not less than five years from the date of the veteran's discharge or other release from active duty; or the veteran was a former POW and died after September 30, 1999, and the disability was continuously rated totally disabling for a period of not less than one year immediately preceding death. 38 U.S.C. § 1318(b); 38 C.F.R. § 3.22(a). The total rating may be either schedular or based on unemployability. 38 C.F.R. § 3.22(c). Claims for DIC benefits under 38 U.S.C. § 1318 must be adjudicated without consideration of hypothetical entitlement for benefits raised for the first time after a Veteran's death. See, e.g., Rodriguez v. Peake, 511 F.3d 1147 (2008). In this case, the Veteran was discharged from his active service in October 1968, and he died in August 2017. The Veteran was in receipt of a 10 percent rating for residuals of left knee injury, with limited flexion effective from November 6, 2000 to October 6, 2005, and a 20 percent rating thereafter. Effective from March 10, 2005, he was awarded a 10 percent rating for chronic right knee strain associated with residuals of left knee injury, with limited flexion. Effective from March 18, 2009, the Veteran was awarded a 10 percent rating for low back disability associated with residuals of left knee injury, with limited flexion. Effective from August 21, 2009, the Veteran was awarded a 30 percent rating for major depressive disorder. The Veteran's combined disability rating was 10 percent from November 6, 2000 to March 9, 2005; 20 percent from March 10, 2005 to October 6, 2005; 30 percent from October 7, 2005 to March 17, 2009; 40 percent from March 18, 2009 to August 20, 2009; and 60 percent on and after August 21, 2009. In light of the Board’s decision herein, the Veteran was also awarded a TDIU effective from March 2, 2008. However, the Board notes that this March 2, 2008 effective date is less than 10 years before the date of the Veteran’s death in August 2017. After a full review of the record, the Board finds that the Veteran was not continuously rated totally disabled (either schedular or based on unemployability) for a period of at least 10 years immediately preceding his death, nor was he continuously rated totally disabled since his release from active duty for a period of not less than five years after his discharge from service. As the durational requirements for a total disability rating under 38 U.S.C. § 1318 have not been met, nor has the evidentiary record shown the Veteran was former POW, entitlement to DIC benefits under 38 U.S.C. § 1318 is denied as a matter of law. See Sabonis v. Brown, 6 Vet. App. 426, 430 (1994) (where the law and not the evidence is dispositive, the Board should deny the claim on the ground of lack of legal merit). The Board has also considered whether either of the aforementioned durational requirements for a total rating necessary to satisfy 38 U.S.C. § 1318 would have been met, but for CUE in a decision on a claim filed during the Veteran's lifetime. 38 C.F.R. § 3.22(b)(1). Previous determinations which are final and binding, including decisions of the assignment of disability ratings, will be accepted as correct in the absence of CUE. 38 C.F.R. § 3.105(a). In order for a claim of CUE to be valid, there must have been an error in the prior adjudication of the claim; either the correct facts, as they are known at the time, were not before the adjudicator or the statutory or regulatory provisions extant at the time were incorrectly applied. See Damrel v. Brown, 6 Vet. App. 242, 245 (1994), citing Russell v. Principi, 3 Vet. App. 310, 313-1 (1992) (en banc). In this case, a claim of CUE to any previous rating decision has not been raised. For the reasons stated above, the Board finds that the criteria for DIC benefits pursuant to the provisions of 38 U.S.C. § 1318 have not been met. See Sabonis, 6 Vet. App. at 430; Gilbert v. Derwinski, 1 Vet. App. 49, 55 (1990). GAYLE STROMMEN Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board K.C. Spragins, Counsel The Board’s decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.