Citation Nr: 21012941 Decision Date: 03/08/21 Archive Date: 03/08/21 DOCKET NO. 14-19 101 DATE: March 8, 2021 ORDER Entitlement to a disability rating in excess of 70 percent prior to January 10, 2014, for posttraumatic stress disorder (PTSD), unspecified depressive disorder, and stimulant use disorder is denied. Entitlement to a 10 percent disability rating prior to February 1, 2017 for tension headaches is granted. Entitlement to a 50 percent disability rating for tension headaches from February 1, 2017 is granted. Entitlement to a compensable disability rating for left great ingrown toenail is denied. Entitlement to service connection for a left leg disability to include as due to an undiagnosed illness is denied. Entitlement to service connection for obstructive sleep apnea (OSA) is granted. REMAND Entitlement to a total disability rating based upon individual unemployability (TDIU) due to service-connected disabilities is remanded. FINDINGS OF FACT 1. Prior to January 10, 2014, the preponderance of the evidence indicates that the Veteran’s psychiatric disabilities resulted in occupational and social impairment with reduced reliability and productivity with deficiencies in most areas, but did not manifest with total occupational and social impairment. 2. Prior to February 1, 2017, the preponderance of the evidence indicates that the Veteran’s tension headaches manifested with characteristic prostrating attacks averaging one in 2 months over the last several months. 3. From February 1, 2017, the preponderance of the evidence indicates that the Veteran has migraines with very frequent completely prostrating and prolonged attacks productive of severe economic inadaptability. 4. The preponderance of the evidence indicates that the Veteran’s left great ingrown toenail did not more nearly approximate at least 5 percent, but less than 20 percent, of the entire body, or at least 5 percent, but less than 20 percent, of exposed areas affected, or; intermittent systemic therapy such as corticosteroids or other immunosuppressive drugs required for a total duration of less than six weeks during the past 12-month period and did not more nearly approximate (1) characteristic lesions involving at least 5 percent, but less than 20 percent, of the entire body affected; or (2) at least 5 percent, but less than 20 percent, of exposed areas affected; or (3) intermittent systemic therapy required for a total duration of less than 6 weeks over the past 12- month period. 5. The preponderance of the evidence indicates that the Veteran’s left leg disabilities were diagnosed as degenerative joint disease of the left hip and left knee strain, which were not causally related to active service, including to his service in the Persian Gulf. 6. Resolving all reasonable doubt in the Veteran’s favor, the Board finds that the Veteran’s OSA was causally related to and permanently aggravated by his service-connected PTSD. CONCLUSIONS OF LAW 1. The criteria for a disability rating in excess of 70 percent prior to January 10, 2014, for PTSD, unspecified depressive disorder, and stimulant use disorder have not been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.7, 4.126, 4.130, Diagnostic Code 9411. 2. The criteria for a 10 percent disability rating prior to February 1, 2017 for tension headaches have been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.124a, Diagnostic Code 8100. 3. The criteria for a disability rating of 50 percent for tension headaches from February 1, 2017 have been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.124a, Diagnostic Code 8100. 4. The criteria for a compensable disability rating for left great ingrown toenail have not been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.118, Diagnostic Code 7813. 5. The criteria for service connection for a left leg disability, to include as due to an undiagnosed illness, are not met. 38 U.S.C. §§ 1110, 1131, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.317. 6. The criteria for service connection for OSA, to include as secondary to his psychiatric disabilities, have been met. 38 U.S.C. §§ 1110, 1131, 5107; 38 C.F.R. §§ 3.102, 3.310. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran had active duty service from June 1984 to December 1991. This matter comes before the Board of Veterans’ Appeals (Board) on appeal from a June 2012 rating decision by a Department of Veterans Affairs (VA) Regional Office (RO). The Board remanded the issues for further development in April 2016. The Board notes that actions requested in the prior remand have been undertaken. Accordingly, the Board finds that there has been substantial compliance with the prior remand instructions and no further action is necessary. See D’Aries v. Peake, 22 Vet. App. 97 (2008) (holding that only substantial, and not strict, compliance with the terms of a Board remand is required pursuant to Stegall v. West, 11 Vet. App. 268 (1998)). Increased Rating Disability ratings are determined by applying the criteria set forth in the VA Schedule of Rating Disabilities (Rating Schedule) and are intended to represent the average impairment of earning capacity resulting from disability. 38 U.S.C. § 1155; 38 C.F.R. § 4.1. Separate diagnostic codes identify the various disabilities. Disabilities must be reviewed in relation to their history. 38 C.F.R. § 4.1. Other applicable, general policy considerations are: interpreting reports of examination in light of the whole recorded history, reconciling the various reports into a consistent picture so that the current rating may accurately reflect the elements of disability, 38 C.F.R. § 4.2; resolving any reasonable doubt regarding the degree of disability in favor of the claimant, 38 C.F.R. § 4.3; where there is a questions as to which of two evaluations apply, assigning a higher of the two where the disability pictures more nearly approximates the criteria for the next higher rating, 38 C.F.R. § 4.7; and, evaluating functional impairment on the basis of lack of usefulness, and the effects of the disability upon the person’s ordinary activity, 38 C.F.R. § 4.10. See Schafrath v. Derwinski, 1 Vet. App. 589 (1991). A claimant may experience multiple distinct degrees of disability that might result in different levels of compensation from the time the increased rating claim was filed until a final decision is made. Thus, separate ratings can be assigned for separate periods of time based on the facts found - a practice known as "staged" ratings. Fenderson v. West, 12 Vet. App. 119 (1999); Hart v. Mansfield, 21 Vet. App. 505 (2007). 1. Entitlement to a disability rating in excess of 70 percent prior to January 10, 2014, for PTSD, unspecified depressive disorder, and stimulant use disorder. The Veteran has been awarded a 70 percent disability rating prior to January 10, 2014, and a 100 percent disability rating effective January 10, 2014. As the 100 percent rating is the maximum schedular rating available for PTSD and the Veteran has not asserted entitlement to extraschedular rating or special monthly compensation, the period from January 10, 2014, forward is not for consideration by the Board in the decision below. The Veteran contends that his psychiatric disabilities warrant a disability rating in excess of 70 percent prior to January 10, 2014, due to the severity of his symptoms. Under the General Formula for Mental Disorders (General Formula), the Board must conduct a “holistic analysis” that considers all associated symptoms, regardless of whether they are listed as criteria. Bankhead v. Shulkin, 29 Vet. App. 10, 22 (2017); 38 C.F.R. § 4.130. The Board must determine whether unlisted symptoms are similar in severity, frequency, and duration to the listed symptoms associated with specific disability percentages. Then, the Board must determine whether the associated symptoms, both listed and unlisted, caused the level of impairment required for a higher disability rating. Vazquez-Claudio v. Shinseki, 713 F.3d 112, 114-118 (Fed. Cir. 2013). The issue in this appeal is whether the Veteran’s associated symptoms caused the level of impairment required for a disability rating of 100 percent. The Board concludes that the Veteran’s symptoms did not cause the level of impairment required for a disability rating of 100 percent. The Veteran’s symptoms more closely approximated the symptoms associated with a 70 percent rating, and resulted in a level of impairment that most closely approximated the level of impairment associated with a 70 percent rating. A noncompensable rating is assigned when a mental condition has been formally diagnosed, but symptoms are not severe enough to either require continuous medication, or to interfere with occupational and social functioning. A 10 percent rating is assigned when mild or transient symptoms which decrease work efficiency and ability to perform occupational tasks only during periods of occasional stress, or symptoms controlled by medication cause occupational and social impairment. A 30 percent rating is assigned when symptoms such as depressed mood, anxiety, suspiciousness, panic attacks (weekly or less often), chronic sleep impairment, or mild memory loss (such as forgetting names, directions, or recent events), cause occupational and social impairment with occasional decrease in work efficiency and intermittent periods of inability to perform occupational tasks (although generally functioning satisfactorily, with routine behavior, self-care, and normal conversation). A 50 percent rating is assigned when symptoms such as flattened affect; circumstantial, circumlocutory, or stereotyped speech; panic attacks more than once a week; difficulty in understanding complex commands; impairment of short and long-term memory (e.g., retention of only highly learned material, forgetting to complete tasks); impaired judgment; impaired abstract thinking; disturbances of motivation and mood; or difficulty in establishing and maintaining effective work and social relationships cause occupational and social impairment with reduced reliability and productivity. A 70 percent rating is assigned when symptoms such as suicidal ideation; obsessional rituals which interfere with routine activities; intermittently illogical, obscure, or irrelevant speech; near-continuous panic or depression affecting the ability to function independently, appropriately and effectively; impaired impulse control (such as unprovoked irritability with periods of violence); spatial disorientation; neglect of personal appearance and hygiene; difficulty in adapting to stressful circumstances (including work or a worklike setting); or inability to establish and maintain effective relationships cause occupational and social impairment with deficiencies in most areas, such as work, school, family relations, judgment, thinking, or mood. A 100 percent rating is assigned for total occupational and social impairment, due to such symptoms as: gross impairment in thought processes or communication; persistent delusions or hallucinations; grossly inappropriate behavior; persistent danger of hurting self or others; intermittent inability to perform activities of daily living (including maintenance of minimal personal hygiene); disorientation to time or place; or memory loss for names of close relatives, own occupation or own name. The Veteran was afforded a VA examination in March 2012. The examiner reviewed the claims file and performed an examination. He noted occupational and social impairment with reduced reliability and productivity. He reported a good relationship with his children and his wife. He had two friends, but otherwise described himself as a loner. He worked as a contractor, but noted the jobs were few and far between. He had difficulty working with other people and being confined to a building. He was not receiving any treatment or any medication. The Veteran reported recurrent and distressing dreams and recollections, psychological distress and reactivity to cues, avoidance, diminished interest, feelings of detachment or estrangement, restricted range of affect, sleep impairment, irritability, and hypervigilance. The examiner specifically noted anxiety, sleep impairment, flattened affect, difficulty in adapting to stressful circumstances, including work or a worklike setting, and an inability to establish and maintain effective relationships. The Veteran’s treatment records indicate psychiatric diagnoses, but do not indicate consistent treatment or complaints of a psychiatric disability. The Board finds the severity, frequency, and duration of the Veteran’s unlisted symptoms more closely approximate the symptoms contemplated by a 70 percent rating, which are less severe, less frequent, and shorter in duration than those contemplated by a 100 percent rating. See 38 C.F.R. § 4.126. The Veteran’s symptoms of recurrent and distressing dreams and recollections, psychological distress and reactivity to cues, avoidance, diminished interest, feelings of detachment or estrangement, sleep impairment, and hypervigilance are similar to difficulty in adapting to stressful circumstances (including work or a worklike setting) and occupational and social impairment with deficiencies in most areas, such as work, school, family relations, judgment, thinking, or mood, which are contemplated by the assigned 70 percent rating. The Board also finds the level of impairment caused by the Veteran’s symptoms more closely approximates the level associated with a 70 percent rating. The Veteran experienced occupational and social impairment with reduced reliability and productivity with deficiencies in most areas. In short, the preponderance of the evidence weighs against finding that the severity, frequency, and duration of the Veteran’s symptoms resulted in the level of impairment required for a 100 percent rating. The criteria for a 100 percent or higher rating are not met and the appeal must be denied. Increased Rating for Tension Headaches The Veteran contends that he is entitled to a higher rating because due to the severity and frequency of his headaches. The Veteran has been awarded a noncompensable disability rating prior to February 1, 2017, and a 30 percent disability rating effective February 1, 2017. Tension headaches are rated pursuant to 38 C.F.R. § 4.124a, Diagnostic Code (DC) 8100, for migraine. Under DC 8100, a noncompensable rating is warranted for migraines with less frequent attacks. A 10 percent rating is warranted for migraines with characteristic prostrating attacks averaging one in 2 months over the last several months. The rating criteria of DC 8100 are considered successive, meaning that a claimant cannot fulfill the criteria of the higher rating without fulfilling those of the next lower rating. Johnson v. Wilkie, 30 Vet. App. 245, 252 (2018). This renders 38 C.F.R. §§ 4.7 and 4.21 inapplicable. Johnson, 30 Vet. App. at 252. The phrase “characteristic prostrating attacks” is used in the criteria corresponding to 10 percent and 30 percent ratings under DC 8100 to describe the nature and severity of migraines, but it is not defined in the regulation. Pursuant to Dorland’s Illustrated Medical Dictionary 1531 (32d ed. 2012), prostration is defined as “extreme exhaustion or powerlessness.” Thus, the phrase “characteristic prostrating attacks” is understood to describe migraine attacks that typically produce extreme exhaustion or powerlessness. The rating criteria for a 50 percent rating contains several undefined phrases. The descriptive phrase “very frequent” connotes a frequency at least greater than once a month, as is required by the rating criteria corresponding to a lesser 30 percent rating. Johnson, 30 Vet. App. at 253. The phrase “completely prostrating” generally means that the migraines attack must render the veteran entirely powerless. Id. The completely prostrating attacks must also be “prolonged,” which is defined as “to lengthen in time: extend duration: draw out: continue, protract.” Id. (internal citation omitted). Lastly, the 50 percent rating criteria requires that the very frequent completely prostrating and prolonged attacks be “productive of severe economic inadaptability.” Productive can be read as having either the meaning of “producing” or “capable of producing,” and, with regard to severe economic inadaptability, nothing in DC 8100 requires that the claimant be completely unable to work in order to qualify for a 50 percent rating. Pierce v. Principi, 18 Vet. App. 440, 445-46 (2004). 2. Entitlement to a compensable disability rating prior to February 1, 2017, for tension headaches. The Veteran was afforded a VA examination in May 2012. The examiner noted headaches. The Veteran had tension headaches. The Veteran had never diagnosed with or treated for headaches. He stated that he has headaches once every week or two. He did not require medication. He reported pressure on the right side of the head and sometimes across the entire frontal area. He noted no nausea, vomiting, sensitivity to light or sound, changes in vision, or sensory changes. The headaches last less than one day. The examiner noted no characteristic prostrating attacks of migraine or non-migraine headache pain. The Veteran also had no very frequent prostrating and prolonged attacks of migraine headache pain or non-migraine headache pain. The examiner noted no functional impact on the Veteran’s ability to work due to his headache condition. The Veteran submitted a disability benefits questionnaire in January 2016 regarding his headaches. The examiner noted that the Veteran was prescribed hydrocodone to treat his headaches. The Veteran reported pulsating or throbbing head pain on both sides of the head. He also reported nausea, vomiting, sensitivity to light, sensitivity to sound, and sensory changes. The pain lasts less than one day. The examiner noted prostrating attacks of non-migraine headache pain more frequently than once per month with very frequent prostrating and prolonged attacks of non-migraine headache pain. During a headache, the Veteran experienced nausea, light and sound sensitivity, reduced power of concentration, and dizziness. He must lie down in a dark quiet room. The Veteran is competent to report his readily observable symptoms. Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007). The Veteran is credible in his reported symptoms as noted in the January 2016 disability benefits questionnaire. Considering all relevant evidence of record, the Board finds that the January 2016 disability benefits questionnaire shows that the Veteran’s headaches did manifest with characteristic prostrating and prolonged attacks of non-migraine headache pain occurring on an average once a month over the prior several months. As such a 30 percent disability rating is warranted prior to February 1, 2017. Entitlement to a disability rating in excess of 30 percent is addressed in the section below. 3. Entitlement to a disability rating in excess of 30 percent for tension headaches from February 1, 2017, forward. As noted above, the Veteran submitted a disability benefits questionnaire in January 2016 regarding his headaches. The examiner noted that the Veteran was prescribed hydrocodone to treat his headaches. The Veteran reported pulsating or throbbing head pain on both sides of the head. He also reported nausea, vomiting, sensitivity to light, sensitivity to sound, and sensory changes. The pain lasts less than one day. The examiner noted prostrating attacks of non-migraine headache pain more frequently than once per month with very frequent prostrating and prolonged attacks of non-migraine headache pain. During a headache, the Veteran experienced nausea, light and sound sensitivity, reduced power of concentration, and dizziness. He must lie down in a dark quiet room. The examiner opined that the Veteran would miss several days of work and require frequent unscheduled breaks throughout the day. He would not be able to maintain gainful employment due to his headaches. The Veteran was afforded a VA examination in February 2017. The examiner diagnosed tension headaches. The Veteran noted headaches two to three times per week. The examiner noted characteristic prostrating attacks of migraine or non-migraine headache pain once every month on average. The examiner also noted very prostrating and prolonged attacks of migraine/non-migraine pain productive of severe economic inadaptability. The functional impact included limited concentration and limited activity level with severe headaches. The Board concludes that the Veteran has had migraines with very frequent completely prostrating and prolonged attacks productive of severe economic inadaptability, corresponding to the criteria for a 50 percent rating under DC 8100. Thus, a higher disability rating of 50 percent is warranted for the Veteran’s tension headaches. The Board notes that the 50 percent disability rating is the maximum schedular rating available under Diagnostic Code 8100 and no other diagnostic code is applicable. The Veteran has not asserted and the evidence does not indicate that referral for extraschedular consideration is warranted. 4. Entitlement to a compensable disability rating for left great ingrown toenail. The Veteran contends that he is entitled to a compensable disability rating due to the severity of his ingrown toenail. The Veteran’s ingrown toenail is rated by analogy under Diagnostic Code 7813, for onychomycosis of the nails. VA amended the criteria for rating skin disabilities effective from August 13, 2018. These new regulations apply to all applications for benefits received by VA or that are pending before the agency of original jurisdiction on or after August 13, 2018. Claims pending prior to the effective date will be considered under both old and new rating criteria, and whatever criteria is more favorable to the veteran will be applied. The Board may not apply a current regulation prior to its effective date, unless the regulation explicitly provides otherwise. Kuzma v. Principi, 341 F.3d 1327 (Fed. Cir. 2003). However, the Board is not precluded from applying prior versions of the applicable regulation to the period on or after the effective dates of the new regulation if the prior version was in effect during the pendency of the appeal. Prior to August 13, 2018, Diagnostic Code 7813, instructed to rate as disfigurement of the, face, or neck (DC 7800) or scars (DC’s 7801, 7802, 7803, 7804, or 7805), or dermatitis (7806) depending on the predominant disability. 38 C.F.R. § 4.118, Diagnostic Code 7813. Here, the evidence of record demonstrates that the predominant disability would be analogous to dermatitis (7806) as the Veteran’s toenail did not result in scarring. Prior to August 13, 2018, under Diagnostic Code 7806, a noncompensable rating is assigned for less than 5 percent of the entire body or less than 5 percent of exposed areas affected, and; no more than topical therapy required during the past 12 months. A 10 percent rating is assigned for at least 5 percent, but less than 20 percent, of the entire body, or at least 5 percent, but less than 20 percent, of exposed areas affected, or; intermittent systemic therapy such as corticosteroids or other immunosuppressive drugs required for a total duration of less than six weeks during the past 12-month period. A 30 percent rating is assigned for 20 to 40 percent of the entire body or 20 to 40 percent of exposed areas affected, or; systemic therapy such as corticosteroids or other immunosuppressive drugs required for a total duration of six weeks or more, but not constantly during the past 12-month period. A 60 percent rating is assigned for more than 40 percent of the entire body or more than 40 percent of exposed areas affected, or; constant or near- constant systemic therapy such as corticosteroids or other immunosuppressive drugs required during the past 12- month period. Or rate as disfigurement of the head, face, or neck (DC 7800) or scars (DC’s 7801, 7802, 7803, 7804, or 7805), depending on the predominant disability. 38 C.F.R. § 4.118, Diagnostic Code 7806. For claims filed prior to August 13, 2018, the Court held that a systematic therapy is one that that affects the entire body in its treatment of the condition at issue, and that the Board must determine (1) whether a topical treatment affects the body as a whole in treating a veteran’s skin condition; and (2) whether the given treatment is “like” a corticosteroid or other immunosuppressive drug.” Burton v. Wilkie, 30 Vet. App. 286 (2018). Only the second question need be addressed if the treatment is clearly systemic. Id. Effective August 31, 2018, VA regulations explicitly state that systemic therapy is treatment that is administered through any route other than the skin, and topical therapy is treatment that is administered through the skin. 38 C.F.R. § 4.118(a). Additionally, effective August 13, 2018, a new General Rating Formula for the Skin applies to Diagnostic Codes 7806, 7809, 7813 to 7816, 7820 to 7822, and 7824. See 38 C.F.R. § 4.118. Under this formula, a noncompensable rating is assigned for no more than topical therapy required over the past 12-month period and at least one of the following: characteristic lesions involving less than 5 percent of the entire body affected; or characteristic lesions involving less than 5 percent of exposed areas affected. A 10 percent rating is assigned for at least one of the following: characteristic lesions involving at least 5 percent, but less than 20 percent, of the entire body affected; or at least 5 percent, but less than 20 percent, of exposed areas affected; or intermittent systemic therapy including, but not limited to, corticosteroids, phototherapy, retinoids, biologics, photochemotherapy, PUVA, or other immunosuppressive drugs required for a total duration of less than 6 weeks over the past 12- month period. A 30 percent rating is assigned at least one of the following: characteristic lesions involving more than 20 to 40 percent of the entire body or 20 to 40 percent of exposed areas affected; or systemic therapy including, but not limited to, corticosteroids, phototherapy, retinoids, biologics, photochemotherapy, PUVA, or other immunosuppressive drugs required for a total duration of 6 weeks or more, but not constantly, over the past 12-month period. A 60 percent rating is assigned for at least one of the following: characteristic lesions involving more than 40 percent of the entire body or more than 40 percent of exposed areas affected; or constant or near-constant systemic therapy including, but not limited to, corticosteroids, phototherapy, retinoids, biologics, photochemotherapy, psoralen with long-wave ultraviolet-A light (PUVA), or other immunosuppressive drugs required over the past 12-month period. Or rate as disfigurement of the head, face, or neck (DC 7800) or scars (DC’s 7801, 7802, 7803, 7804, or 7805), depending on the predominant disability. 38 C.F.R. § 4.118, General Rating for the Skin for DCs 7806, 7809, 7813-7816, 7820-7822, and 7824. As noted above, in this case the predominant disability is analogous to dermatitis as the Veteran’s toenail did not result in scarring. In March 2012, the Veteran attended a VA examination of the foot. The examiner diagnosed an ingrown toenail. The Veteran had a surgical procedure to remove ingrown toenail in the Army and the toenail turned black and remained black. The examiner described it as moderate in severity. The examiner noted no functional impact on his ability to work due to his toenail. The Veteran was afforded a VA examination in February 2017. The Veteran described pain related to a partial toenail. He reported limited ability to stand, run, or wear certain types of shoes. No pain was noted on physical examination. The examiner did note pain on non weight-bearing, disturbance of locomotion, and interference with standing. The examiner noted no painful or unstable scars, scars equal to or greater than 39 square cm, or located on the head, face, or neck. The left great toe has partial debridement with no nail on approximately half of the nail bed. The remaining half of his left great toe is jagged and tender to manipulation. The nail bed was approximately 1.5 cm long and 2.0 cm wide. The clean/debrided nail bed goes from the top of the nail bed down to 0.6 cm to meet the remaining half of his jagged nail bed due to his dermatophytosis. The examiner noted limited standing and walking, and that the Veteran must wear certain types of footwear for comfort. The Veteran attended another VA examination in January 2019. The examiner noted that the Veteran had not been treated with medication in the prior 12 months for any skin condition. He had not had any other treatments or procedures. The disability covered less than 5 percent of total body area and no exposed area. The condition did not cause scarring or any functional impairment. The Board finds that the preponderance of the evidence is against the assignment of a compensable evaluation under the pre-August 13, 2018, regulations because the Veteran’s ingrown toenail does not more nearly approximate at least 5 percent, but less than 20 percent, of the entire body, or at least 5 percent, but less than 20 percent, of exposed areas affected, or; intermittent systemic therapy such as corticosteroids or other immunosuppressive drugs required for a total duration of less than six weeks during the past 12-month period. The Board finds that the preponderance of the evidence is against the assignment of a compensable evaluation under the August 13, 2018, regulations because the Veteran’s ingrown toenail does not more nearly approximate (1) characteristic lesions involving at least 5 percent, but less than 20 percent, of the entire body affected; or (2) at least 5 percent, but less than 20 percent, of exposed areas affected; or (3) intermittent systemic therapy required for a total duration of less than 6 weeks over the past 12- month period. The Board acknowledges that the Veteran believes that the disability on appeal has been more severe than the assigned disability rating reflects. Moreover, the Veteran is competent to report observable symptoms, to include pain and an inability to wear certain shoes, and his reports are credible. Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007). However, he does not assert, and medical treatment records do not show, that the Veteran’s disability more nearly approximates the criteria in the next higher rating. The Board has considered whether any other Diagnostic Codes related to disabilities of the skin would provide for a higher disability evaluation. However, the evidence does not reflect that he would warrant a higher rating under a different diagnostic code. See 38 C.F.R. § 4.118. In conclusion, the Board finds that the preponderance of the evidence is against the Veteran’s claim for a compensable rating for a left great ingrown toenail. In denying such a rating, the Board finds the benefit of the doubt doctrine is not applicable. 38 U.S.C. § 5107; 38 C.F.R. §§ 4.3, 4.7. Service Connection Service connection may be established for a disability resulting from disease or injury incurred in or aggravated by service. 38 U.S.C. §§ 1110, 1131; 38 C.F.R. § 3.303. Evidence of continuity of symptomatology from the time of service until the present is required where the chronicity of a chronic condition manifested during service either has not been established or might reasonably be questioned. 38 C.F.R. § 3.303(b); see also Walker v. Shinseki, 708 F.3d 1331, 1340 (Fed.Cir.2013) (holding that only conditions listed as chronic diseases in 38 C.F.R. § 3.309(a) may be considered for service connection under 38 C.F.R. § 3.303(b)). Regulations also provide that service connection may be granted for any disease diagnosed after discharge, when all the evidence, including that pertinent to service, establishes that the disability was incurred in service. 38 C.F.R. § 3.303(d). Generally, in order to prove service connection, there must be competent, credible evidence of (1) a current disability, (2) in-service incurrence or aggravation of an injury or disease, and (3) a nexus, or link, between the current disability and the in-service disease or injury. See, e.g., Davidson v. Shinseki, 581 F.3d 1313 (Fed. Cir. 2009); Pond v. West, 12 Vet. App. 341 (1999). The Board has reviewed all the evidence in the record. Although the Board has an obligation to provide adequate reasons and bases supporting this decision, there is no requirement that the evidence submitted by the appellant or obtained on his behalf be discussed in detail. Rather, the Board’s analysis below will focus specifically on what evidence is needed to substantiate each claim and what the evidence in the claims file shows, or fails to show, with respect to each claim. See Gonzales v. West, 218 F.3d 1378, 1380-81 (Fed. Cir. 2000) and Timberlake v. Gober, 14 Vet. App. 122, 128-30 (2000). Except as otherwise provided by law, a claimant has the responsibility to present and support a claim for benefits under the laws administered by VA. VA shall consider all information and medical and lay evidence of record. Where there is an approximate balance of positive and negative evidence regarding any issue material to the determination of a matter, VA shall give the benefit of the doubt to the claimant. 38 U.S.C. § 5107; 38 C.F.R. § 3.102; see also Gilbert v. Derwinski, 1 Vet. App. 49, 53 (1990). 5. Entitlement to service connection for a left leg disability to include as due to an undiagnosed illness. The Veteran contends that he has a left leg disability that is causally related to his active service, specifically his service in the Gulf War. He asserts that he has pain in his left leg due to chronic pain syndrome. Service connection may be granted for a Persian Gulf veteran with objective indications of a qualifying chronic disability that manifested either during active service in the Southwest Asia theater of operations or to a degree of 10 percent or more not later than December 31, 2021. 38 U.S.C. § 1117(a)(1); 38 C.F.R. § 3.317(a)(1). A qualifying chronic disability is a chronic disability that may result from an undiagnosed illness or a medically unexplained chronic multisymptom illness (MUCMI). 38 C.F.R. § 3.317(a)(2)(i). The term chronic means that the disability has existed for 6 months or more, to include intermittent episodes of improvement or worsening over that period. 38 C.F.R. § 3.317(a)(4). Here, the Veteran had active service in Southwest Asia from December 1990 to April 1991. Therefore, he is considered a Persian Gulf veteran. 38 C.F.R. § 3.317(e). Although the Veteran complained of left leg pain that he believes is due to chronic pain syndrome, during the May 2012 VA examination for Gulf War Illnesses, the Veteran actually indicated that his left leg pain was left hip pain. Upon examination, the examiner found degenerative joint disease (DJD) of the left hip. In a February 2017 VA examination, the examiner also noted a diagnosis of left knee strain. As the Veteran’s DJD and left knee strain are diagnosed conditions, they cannot be considered an undiagnosed illness. 38 C.F.R. § 3.317(a)(1)(ii), (a)(2)(ii). VA has also considered whether the Veteran’s DJD of the left hip or left knee strain may be considered a MUCMI. The Board notes that the diagnoses of DJD and left knee strain are specific diagnoses that are not medically unexplained. DJD and knee strain have specific etiologies that are medically known. Accordingly, presumptive service connection as a MUCMI is not warranted. The Board has also considered entitlement to service connection on a direct basis. The Veteran’s service treatment records are silent for any complaints, treatment, or diagnosis of a left leg disability. On the October 1991 separation report of medical examination, the examiner noted clinically normal lower extremities and other musculoskeletal. On the corresponding report of medical history, the Veteran reported no arthritis, rheumatism, bursitis, bone, joint, other deformity, trick or locked knee, or neuritis. Several years after separation from service, the Veteran attended a June 1995 periodic examination for the National Guard. Again, the Veteran’s normal lower extremities and other musculoskeletal system were normal. On the corresponding report of medical history, the Veteran again reported no arthritis, rheumatism, bursitis, bone, joint, other deformity, trick or locked knee, or neuritis. Post-service treatment records do not indicate that the Veteran’s current left leg complaints, diagnosed as left hip DJD and left knee strain, are causally related to the Veteran’s active service. Based on the evidence cited above, the Board finds that the preponderance of the evidence is against the claim of service connection for a left leg disability. As the preponderance of the evidence is against the claim for service connection for a left leg disability, the benefit of the doubt rule does not apply. 38 C.F.R. § 5107; 38 C.F.R. § 3.102. 6. Entitlement to service connection for OSA. The Veteran contends that he has OSA that is causally related to or aggravated by his service-connected PTSD. The Veteran has not raised, and the record does not reasonably raise, entitlement to direct service connection. The Veteran’s service treatment records are silent for any complaints, treatment, or diagnosis of OSA. The Veteran’s October 1991 report of medical history showed no current or past difficulty sleeping. A post-service May 2012 VA examination showed no sleep apnea. Therefore, the Board’s adjudication will consider only entitlement to secondary service connection. Service connection may be granted for a disability that is proximately due to, or aggravated by, service-connected disease or injury. 38 C.F.R. § 3.310. The question for the Board is whether the Veteran has a current disability that is proximately due to or the result of, or was aggravated beyond its natural progress by a service-connected disability. The Board concludes that the Veteran’s OSA is proximately due to or the result of, or aggravated beyond its natural progression by a service-connected disability. 38 U.S.C. §§ 1110, 1131; Allen v. Brown, 7 Vet. App. 439 (1995) (en banc); 38 C.F.R. § 3.310(a). The Veteran attended a VA examination in May 2012. The examiner diagnosed OSA. The examiner did not provide a nexus regarding the Veteran’s secondary service connection claim. The Veteran submitted a disability benefits questionnaire regarding his OSA claim in January 2016. The examiner noted that the Veteran is service-connected for PTSD. The Veteran reported that the CPAP caused him to feel trapped and claustrophobic. The examiner reported that based on his experience, interview with the Veteran, review of the medical records, and supporting medical literature, he disagreed with the OSA VA examiner and felt it was more likely than not that the Veteran’s service-connected PTSD aided in the development of and aggravated his OSA. Research has shown that PTSD and other psychiatric disorders are commonly associated with OSA. A recent study found an arousal-based mechanism initiated by posttraumatic stress that promotes the development of OSA in trauma survivors. Another study found that with CPAP treatment, both OSA and PTSD symptoms decreased providing further evidence of the co-morbidity of these conditions. The Veteran reported that he frequently cannot use his CPAP due to his PTSD. He has panic attacks weekly due to the mask. His inability to use his CPAP every night greatly aggravates the effects of his sleep apnea and the next day he is very tired and will fall asleep frequently. The examiner again noted that based on his experience, interview with the Veteran, review of the medical records, and supporting literature, it is as likely as not that the Veterans service-connected PTSD aided in the development of and permanently aggravates his OSA. The Veteran was afforded a VA examination in January 2019. The examiner diagnosed OSA and provided a nexus opinion. The examiner found that it is less likely than not that the Veteran’s OSA was caused or aggravated by his PTSD. The examiner noted that OSA is caused by an anatomical obstruction of the upper airways. While OSA and PTSD are often found in the same cohort of patients, medical literature does not support a causal relationship between OSA and PTSD. Upon review of the record, the Board finds the evidence to at least be in equipoise as to whether the Veteran’s current OSA is proximately due to and aggravated beyond its natural progression by his service-connected PTSD. Accordingly, after resolving all doubt in favor of the Veteran, the Board finds that service connection for OSA is warranted. 38 U.S.C. § 5107; 38 C.F.R. § 3.102. REASONS FOR REMAND 1. Entitlement to a TDIU due to service-connected disabilities prior to January 1, 2014, is remanded. The grant of entitlement to OSA may affect the disabilities considered under his TDIU claim; therefore, the service connection and TDIU claims are inextricably intertwined. Thus, a decision by the Board on the claim for TDIU would, at this point, be premature. Additionally, the Board notes that the Veteran has reported conflicting evidence regarding his employment. In January 2013, the Veteran qualified for Vocational Rehabilitation and Education (VR&E) assistance. Prior to that he had his own business, but was in the process of selling it due to the stress of being a business owner. In December 2013, the Veteran reported two separate jobs for two different companies with an average gross monthly salary of $4000 from March 2009 to October 2012 working full time and an average gross monthly salary of $2800 from March 2012 to December 2013 working full time on a contract or temporary assignment. In November 2019, the Veteran submitted an application for increased compensation based on unemployability that indicated that he became too disabled to work as of January 2011. The record contains an income statement from the Social Security Administration that appears incomplete as it does not list the companies or jobs reported by the Veteran during his application for VR&E. Therefore, the RO should request complete income statements from the Social Security Administration to determine if the Veteran was employed full time during that period. Additionally, the Veteran should be requested to submit an updated VA Form 21-8940 for employment information. The matters are REMANDED for the following action: 1. Request the Veteran submit an updated VA Form 21-8940. 2. Obtain the Veteran’s federal records from Social Security Administration, to include income statements. Document all requests for information as well as all responses in the claims file. (Continued on the next page)   3. After undertaking the development above and any additional development deemed necessary, the Veteran’s claim should be readjudicated. If the benefits sought on appeal remain denied, the appellant and his representative should be furnished a supplemental statement of the case and be given an appropriate period to respond thereto before the case is returned to the Board, if in order. Jennifer White Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board Patricia Veresink, Associate 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.