Citation Nr: 21006125 Decision Date: 02/03/21 Archive Date: 02/03/21 DOCKET NO. 09-00 827 DATE: February 3, 2021 ORDER A higher 20 percent initial rating is granted for radiculopathy of the right lower extremity (sciatic nerve) from November 10, 2008 to February 7, 2013, and an even higher 40 percent rating is granted since February 8, 2013. A separate 10 percent rating also is granted as of December 11, 2020, for radiculopathy of an additional nerve (anterior crural femoral nerve) in the right lower extremity. An initial rating higher than 20 percent for degenerative disease (arthritis) of the lumbar spine prior to November 7, 2019 and since January 1, 2020 is denied. (In the interim, the Veteran had a temporary 100 percent convalescent rating under 38 C.F.R. § 4.30) Entitlement to service connection for a cervical spine disability, to include spondylosis, degenerative disc disease (DDD), and stenosis, is granted. Entitlement to service connection for obstructive sleep apnea (OSA) is denied. Entitlement to service connection for memory loss, fatigue, and loss of energy, to include as due to undiagnosed illness or other qualifying chronic disability pursuant to 38 C.F.R. § 3.317, is denied. REMANDED Entitlement to a total disability based on individual unemployability (TDIU) is remanded. FINDINGS OF FACT 1. The evidence of record supports finding that the radiculopathy of the Veteran’s right lower extremity (sciatic nerve) was caused moderate paralysis prior to October 25, 2017 and moderately severe paralysis since. 2. However, the evidence of record also supports finding the radiculopathy of his right lower extremity (anterior crural femoral nerve) has caused mild paralysis of this other nerve since December 11, 2020. 3. With the exception of the period from November 7, 2019 to January 1, 2020 during which the Veteran had a temporary 100 percent convalescent rating, the severity of his lumbar spine disability, with consideration of additional functional loss due to pain, most closely approximates forward flexion of his thoracolumbar spine to less than 60 degrees but to greater than 30 degrees. There is no evidence of ankylosis of his entire thoracolumbar spine or evidence of incapacitating episodes due to intervertebral disc syndrome (IVDS). 4. It is just as likely as not his cervical spine disability began during his service. 5. The preponderance of the evidence conversely is against finding that his OSA began during his service or is otherwise related or attributable to his service. 6. As well, the preponderance of the evidence is against finding that he has had memory loss, fatigue or energy loss, also claimed as due to an undiagnosed illness or medically unexplained chronic multisystem illness (MUCMI), that began during his service or is otherwise caused by an injury or a disease or an event during his service. The evidence of record, instead, reflects that his reported memory loss, fatigue and loss of energy are, in part, symptoms of his service-connected posttraumatic stress disorder (PTSD) and owing to chronic pain from his low back (lumbar spine) and neck (cervical spine) disabilities. CONCLUSIONS OF LAW 1. The criteria are met for entitlement to a higher 20 percent initial rating for radiculopathy of the right lower extremity (sciatic nerve) prior to October 25, 2017 and to an even higher 40 percent since. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. § 4.124a, Diagnostic Code (DC/Code) 8520. 2. The criteria also are met for a separate 10 percent rating for radiculopathy of the right lower extremity (anterior crural femoral nerve) since December 11, 2020. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.3, 4.7, 4.124a, DC 8526. 3. Aside from the temporary 100 percent convalescent rating already granted from November 7, 2019 to January 1, 2020, the criteria are not met for a rating higher than 20 percent for the degenerative disease (arthritis) of the lumbar spine. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.7, 4.40, 4.45, 4.59, 4.71a, DC 5242. 4. But the criteria are met for entitlement to service connection for cervical spondylosis, DDD, and stenosis. 38 U.S.C. §§ 1101, 1110, 1112, 1113, 5107; 38 C.F.R. §§ 3.303, 3.307, 3.309. 5. The criteria are not met for entitlement to service connection for OSA. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303. 6. The criteria are not met for entitlement to service connection for memory loss, fatigue or energy loss, including as due to an undiagnosed illness or MUCMI. 38 U.S.C. §§ 1110, 1117, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.317. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty from February 1994 to September 1997 and from December 2003 to March 2005, including in the Southwest Asia theater of operations during the Persian Gulf War. This appeal to the Board of Veterans’ Appeals (Board) is from rating decisions of a Department of Veterans Affairs (VA) Regional Office (RO). An October 2007 rating decision confirmed and continued the 20 percent rating for the Veteran’s low back disability – degenerative disease (arthritis) of his lumbar spine. An August 2010 rating decision denied his claim of entitlement to service connection for OSA. A May 2013 rating decision, in pertinent part, denied his claims of entitlement to service connection for a cervical spine condition, memory loss, and loss of energy/fatigue. A March 2009 rating decision conversely granted service connection for his right lower extremity radiculopathy and rated it initially 10-percent disabling. In October 2015, the Board, in pertinent part, remanded the claims of entitlement to service connection for a cervical spine condition and for loss of energy so a Statement of the Case (SOC) could be provided concerning these claims. See Manlincon v. West, 12 Vet. App. 238 (1999). The OSA claim also was remanded for further development. In May 2016, the directed SOC was issued, and in response the Veteran completed the steps necessary to “perfect” his appeal of the claims addressed in that SOC. Meanwhile, also in the October 2015 decision, the Board denied the Veteran’s claim of entitlement to a rating higher than 20 percent for his low back disability, and he appealed the Board’s decision concerning this claim to the higher U. S. Court of Appeals for Veterans Claims (Court). In a May 2016 Order, the Court granted a Joint Motion for Partial Vacatur and Remand (Joint Motion), vacating the portion of the Board’s October 2015 decision that had denied entitlement to a rating higher than 20 percent for the Veteran’s service-connected low back disability and remanding this claim back to the Board for further development and readjudication pursuant to agreement in the Joint Motion. In April 2017, the claim was decided in part and remanded in part for additional evidentiary development. The claim was remanded again for still more development in November 2018. All claims are again before the Board. Increased Ratings 1. Entitlement to an increased evaluation of 20 percent for radiculopathy of the right lower extremity (sciatic nerve) is granted prior to February 8, 2013 and an evaluation of 40 percent is warranted thereafter. 2. Entitlement to a separate evaluation of 10 percent also is granted for radiculopathy of the right lower extremity (anterior crural femoral nerve) beginning on December 11, 2020. The Veteran contends he is entitled to a rating higher than 10 percent prior to October 25, 2017 and higher than 20 percent thereafter. These ratings for the radiculopathy affecting his right lower extremity are under DC 8520. Paralysis of the sciatic nerve is evaluated in accordance with the criteria set forth in 38 C.F.R. § 4.124a, DC 8520. (Neuritis and neuralgia of that group are evaluated under DCs 8620 and 8720.). Under these criteria, mild incomplete paralysis is rated as 10-percent disabling. Moderate incomplete paralysis is rated as 20-percent disabling. Moderately severe incomplete paralysis is rated as 40-percent disabling. Severe incomplete paralysis, with marked muscular atrophy is rated as 60-percent disabling. Complete paralysis, with the foot dangles and drops, no active movement possible of muscles below the knee, flexion of knee weakened or (very rarely) lost is rated as 80-percent disabling. 38 C.F.R. § 4.124a. Under DC 8526, mild incomplete paralysis of the anterior crural (femoral) nerve warrants a 10 percent rating; moderate incomplete paralysis warrants 20 percent; and severe incomplete paralysis warrants 30 percent. With complete paralysis of the femoral nerve, which warrants a 40 percent rating, there is paralysis of the quadriceps extensor muscles. These descriptive words “mild,” “moderate,” “moderately severe” and “severe”, as used in the various DCs are not defined in the Rating Schedule. Regulations provide that ratings for peripheral neurological disorders are to be assigned based the relative impairment of motor function, trophic changes, or sensory disturbance. 38 C.F.R. § 4.120. Consideration is also given for loss of reflexes, pain, and muscle atrophy. See 38 C.F.R. §§ 4.123, 4.124. The term “incomplete paralysis” indicates a degree of lost or impaired function substantially less than the type picture for complete paralysis given with each nerve, whether due to varied level of the nerve lesion or to partial regeneration. When the involvement is wholly sensory, the rating is for the mild, or at most, the moderate degree. The disability ratings for the peripheral nerves are for unilateral involvement; when bilateral, the ratings combine with application of the bilateral factor. 38 C.F.R. § 4.124a, Note at “Diseases of the Peripheral Nerves.” The Note to 38 C.F.R. § 4.124a establishes a maximum disability rating for conditions that are wholly sensory, as opposed to a minimum disability rating for conditions that are more than wholly sensory. See Miller v. Shulkin, 28 Vet. App. 376 (2017). The maximum rating that may be assigned for neuritis not characterized by organic changes will be moderately severe incomplete paralysis for sciatic nerve involvement. See 38 C.F.R. § 4.123. In his July 2013 Notice of Disagreement (NOD), the Veteran contended that his radiculopathy symptoms had worsened. Similarly, in an earlier written statement submitted in February 2013, he also had reported that his radicular symptoms affected his ability to put his shoes on, drive, and perform other various activities of daily life. He indicated that an earlier October 2012 examination did not encompass his then current radiculopathy symptoms. The Board sees that October 2012 examination referenced was primarily for his underlying thoracolumbar spine disability but also included reports from him concerning his associated radicular symptoms since Note (1) of the General Rating Formula for Diseases and Injuries of the Spine – so including as pertaining to evaluation of the Veteran’s lumbar spine disability under DC 5242, indicates to rate all consequent neurological impairment owing to the spine disability under the appropriate DC, so in this instance DC 8520. In an October 2013 VA examination, partial paralysis of the Veteran’s foot was noted and attributed to his sciatic nerve. In an April 2015 VA treatment note, he was also noted to have lumbar radiculopathy with chronic symptoms (to include pain), worsening with overuse. Radicular pain, decreased sensation, and cold sensation were further noted during an October 2017 VA examination with the Veteran reporting experiencing difficulty with performing occupational tasks that would require standing, sitting, or walking for extended periods of time, using stairs, running, bending, sudden motion, lifting, carrying, pushing, or pulling any object. Specifically, he indicated he was experiencing more intense episodes of radiculopathy, to include leg pain and weakness, in both lower extremities. Also, in October 2017, he explained that, if he is on his feet walking or standing for extended periods of time or sitting/driving, he "will have no feeling in [his] legs." His deep tendon reflexes at this time were noted to be hypoactive (meaning less than average). The Veteran also complained of chronic pain referable to his low back and indicated the consequent effects of the associated radiculopathy were greatly affecting his quality of life. He reported intermittent pain radiating into both lower extremities from his lower back, into his buttocks and upper thighs, then down his lower legs to his toes. He reported the pain can be dull and aching or sharp and stabbing and was not dependent on activity and can occur with "doing nothing." He denied any swelling or discoloration of his lower extremities, but he did report his feet are cold all the time. In December 2018, the Veteran again reported experiencing pain in his right leg preventing him from sleeping at night and preventing him from “working a full day.” In December 2020, the Veteran again stated his condition had worsened and that he was having even more frequent flare-ups of pain, numbness, tingling, and burning in his feet and legs, making it difficult to sit, stand and walk long distances. No trophic changes or atrophy were noted and at the time of the examination the Veteran appeared to have a normal gait, although it was noted he used a cane occasionally. Deep tendon reflexes were noted to be normal at this time. Notably, however, the examiner indicated the Veteran was also experiencing mild incomplete paralysis of the anterior crural femoral nerve. Consequently, the Board finds a separate rating of 10 percent warranted for this separate neurologic condition. Based on the above, the Board finds that the Veteran’s disability is primarily manifest by sensory disturbance, intermittent loss of reflexes, and chronic pain. The Board also finds that the most probative evidence of record is against a finding that the disability is manifest by trophic changes, muscle atrophy, or complete paralysis that might warrant a higher rating. The Board thus finds that the level of impairment is most analogous to moderate incomplete paralysis of the sciatic nerve prior to February 8, 2013, the time in which the Veteran indicated his radicular symptoms has worsened, and moderately severe incomplete paralysis thereafter. The Board also finds a separate 10 percent rating warranted for the Veteran’s mild partial paralysis of the anterior crural femoral nerve under DC 8526, beginning December 2020, the first time in which a separate evaluation is ascertainable for this condition. In addition to DC 8526, the Board has considered all other potentially applicable Diagnostic Codes, but there is no evidence showing the Veteran has neurological impairment associated with any other peripheral nerves that have not already been service-connected. In conclusion, the Board finds that the preponderance of the evidence supports an increased evaluation of 20 percent for radiculopathy of the right lower extremity (sciatic nerve) is granted prior to February 8, 2013 and an evaluation of 40 percent is warranted thereafter. The Board also finds entitlement to a separate evaluation of 10 percent for radiculopathy of the anterior crural femoral nerve is warranted beginning December 2020. 3. Entitlement to an increased initial evaluation in excess of 20 percent for degenerative disease (arthritis) of the lumbar spine prior to November 7, 2019 and since January 1, 2020 is denied. The Veteran contends that he is entitled to an initial rating in excess of 20 percent for the degenerative arthritis of his lumbar spine. As already alluded to, he had a temporary 100 percent convalescent rating for his low back disability from November 7, 2019 to January 1, 2020 under 38 C.F.R. § 4.30, so that intervening period is not at issue and, therefore, will not be discussed. The Veteran’s lumbar spine disability is rated under 38 C.F.R. § 4.71a, DC 5242, which specifically concerns arthritis (see also DC 5003) but also is part of a General Rating Formula for Diseases and Injuries of the Spine. Under this General Rating Formula for Diseases and Injuries of the Spine, a 10 percent rating is warranted for forward flexion of the thoracolumbar spine greater than 60 degrees but not greater than 85 degrees; or, combined range of motion of the thoracolumbar spine greater than 120 degrees but not greater than 235 degrees; or, muscle spasm, guarding, or localized tenderness not resulting in abnormal gait or abnormal spinal contour; or, vertebral body fracture with loss of 50 percent or more of the height. A 20 percent rating is warranted for forward flexion of the thoracolumbar spine greater than 30 degrees but not greater than 60 degrees; or the combined range of motion of the thoracolumbar spine not greater than 120 degrees; or, muscle spasm or guarding severe enough to result in an abnormal gait or abnormal spinal contour such as scoliosis, reversed lordosis, or abnormal kyphosis. A 40 percent rating is warranted for forward flexion of the thoracolumbar spine to 30 degrees or less; or, favorable ankylosis of the entire thoracolumbar spine. A 50 percent rating is warranted for unfavorable ankylosis of the entire thoracolumbar spine. A 100 percent evaluation is warranted for unfavorable ankylosis of the entire spine, meaning when additionally considering the adjacent cervical segment. Any associated objective neurological abnormalities, including, but not limited to, bowel or bladder impairment, are to be evaluated separately under an appropriate diagnostic code. Id. at Note (1). As already discussed, this was the impetus for assigning the additional rating under DC 8520 for the right lower extremity radiculopathy since a complication of the lumbar spine disability. Ankylosis is defined as “immobility and consolidation of a joint due to disease, injury, or surgical procedure.” Dorland’s Illustrated Medical Dictionary, 94 (32nd ed. 2012). Fixation of a spinal segment in neutral position (zero degrees) always represents favorable ankylosis. See Note (5) in the General Rating Formula. When evaluating musculoskeletal disabilities based on limitation of motion, 38 C.F.R. § 4.40 requires consideration of functional loss caused by pain or other factors listed in that section that could occur during flare-ups or after repeated use and, therefore, not be reflected on range-of-motion testing. 38 C.F.R. § 4.45 requires consideration also be given to less movement than normal, more movement than normal, weakened movement, excess fatigability, incoordination, and pain on movement. See DeLuca v. Brown, 8 Vet. App. 202 (1995); see also Mitchell v. Shinseki, 25 Vet. App. 32, 44 (2011). Nonetheless, even when the background factors listed in § 4.40 or 4.45 are relevant when evaluating a disability, the rating is assigned based on the extent to which motion is limited, pursuant to 38 C.F.R. § 4.71a; a separate or higher rating under § 4.40 or 4.45 itself is not appropriate. See Thompson v. McDonald, 815 F.3d 781, 785 (Fed. Cir. 2016) (“[I]t is clear that the guidance of § 4.40 is intended to be used in understanding the nature of the veteran’s disability, after which a rating is determined based on the § 4.71a criteria.”). Under 38 C.F.R. § 4.59, painful motion is a factor to be considered with any form of arthritis; however, 38 C.F.R. § 4.59 is not limited to disabilities involving arthritis. See Burton v. Shinseki, 25 Vet. App. 1 (2011).   In Correia v. McDonald, 28 Vet. App. 158 (2016), the Court held that the final sentence of 38 C.F.R. § 4.59 requires that the examiner record the results of range of motion testing “for pain on both active and passive motion [and] in weight-bearing and non-weight-bearing and, if possible, with range of motion measurements of the opposite undamaged joint.” The spine has no opposite joint. In Sharp v. Shulkin, 29 Vet. App. 26 (2017), the Court held that VA examiners must obtain information about the severity, frequency, duration, precipitating and alleviating factors, and extent of functional impairment of flares from the veterans themselves, when a flare-up is not observable at the time of examination. The record indicates that, during the entirety of the review period, the Veteran’s range of motion (ROM) measurements have fallen squarely in the 20 percent rating criteria, with neither IVDS-related incapacitating episodes nor ankylosis noted on any examination. An October 2006 and October 2012 VA examinations showed flexion to 60 degrees and a diagnosis of IVDS (noted in October 2012), with the Veteran also reporting in 2006 that he had difficulty bending over at his job as a mechanic. In April 2006, the Veteran reported to his treatment providers that his back pain prevented him from playing with his children. In August 2007, the Veteran indicated his back pain had grown worse. In October 2017, the Veteran’s forward flexion was noted to be reduced to 50 degrees. The examiner also noted guarding and muscle spasm resulting in abnormal gait. The Veteran also reported his back-muscle spasms were severe and tightened up his back, causing abnormal spinal contour. The examiner also reported the Veteran guarded his back during motion to avoid potential of increased pain. The Veteran was not noted to have IVDS during this examination. During a May 2019 VA examination, the Veteran’s forward flexion was found to be 45 degrees, with this restricted flexion affecting his ability to walk, stand and bend down. Repetitive use was not performed due to the Veteran’s back being too tender to complete. Pain, fatigue, weakness, lack of endurance and incoordination were also noted and reported by the Veteran to be intensified during flare-ups, with no additional ROM reported. The Board finds that the preponderance of the evidence is against a rating in excess of 20 percent for the Veteran’s degenerative arthritis of the lumbar spine. The Board acknowledges the Veteran’s lay reports of symptoms and that there was functional loss due to pain, fatigue, weakness, lack of endurance and incoordination affecting his ability to sit, stand and walk. The Board also acknowledges the Veteran’s reports of flare-ups “with minimal activity at home much less work activity.” However, even considering the Veteran’s lay reports of symptoms and noted functional loss, the degree of additional limitation reflected by the statements, particularly the Veteran’s statements indicating his back flare-ups had significantly incapacitated him, would not result in limitation of motion more nearly approximating forward flexion of the thoracolumbar spine to 30 degrees or less; or, favorable ankylosis of the entire thoracolumbar spine. With regards to the Veteran’s reports of experiencing what he characterized as incapacitating episodes, consideration also resultantly has been given to assigning a rating under the Formula for Rating IVDS Based on Incapacitating Episodes. While he was noted during his October 2012 examination to have IVDS, the evidence of record is against finding that he was ever prescribed bed rest by a physician and for a duration meeting the criteria for a higher rating under DC 5243. If, as an example, he has remained in bed or returned to bed to rest and recuperate owing to his low back disability, this is not tantamount or equivalent to an incapacitating episode because Note (1) in DC 5243 specifies it must be physician prescribed, not just at the Veteran’s own election or whim. That said, the report of the Veteran’s December 2020 VA examination shows he has mild partial paralysis of the anterior crural femoral nerve also associated with the degenerative arthritis of his lumbar spine (meaning aside from the neurological impairment he already has a rating for to the extent affecting the sciatic nerve). Thus, he is being granted an additional (so separate) 10 percent rating under DC 8526, apart from the rating he already has instead under DC 8520. But, for the reasons and bases discussed, the preponderance of the evidence is against the Veteran’s claim for a rating higher than 20 percent for the degenerative disease (arthritis) of his lumbar spine. In denying any higher rating, the Board finds the benefit of the doubt doctrine is inapplicable. 38 U.S.C. § 5107; 38 C.F.R. §§ 4.3, 4.7. Service Connection 4. Entitlement to service connection for cervical spondylosis, DDD, and stenosis. The Veteran contends that his currently diagnosed cervical spine disability, like his lumbar spine disability, is related to his service. Specifically, he indicates this disability is from the “wear and tear” on his spine more generally that he experienced during his deployments to Iraq, as well as a motor vehicle accident he also was in during his deployment. Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active military service in the line of duty. 38 U.S.C. § 1110; 38 C.F.R. § 3.303. The three-element test for service connection requires evidence of: (1) a current disability; (2) in-service incurrence or aggravation of a relevant disease or an injury; and (3) a causal relationship (“nexus”) between the current disability and the disease or injury in service. See Shedden v. Principi, 381 F.3d 1163, 1166-67 (Fed. Cir. 2004). Certain diseases – including notably arthritis – will be presumed related to service, absent an intercurrent cause, if they were shown as chronic in service or if they manifested to a compensable degree (meaning to at least 10-percent disabling) within a presumptive period following separation from service (which is one year for arthritis), or if they were noted in service (or within an applicable presumptive period) with continuity of symptomatology since service that is attributable to the chronic disease. 38 U.S.C. §§ 1101, 1112, 1113; 38 C.F.R. §§ 3.307, 3.309(a). See also Walker v. Shinseki, 708 F.3d 1331, 1338 (Fed. Cir. 2013). In this case at hand, there is no disputing the Veteran has arthritis in his neck (cervical spine), not just in his low back (lumbar spine). Therefore, the Board turns its attention instead to determining whether there also is the required attribution of his neck arthritis to his service. See, e.g., Watson v. Brown, 4 Vet. App. 309, 314 (1993) ("A determination of service connection requires a finding of the existence of a current disability and a determination of a relationship between that disability and an injury or a disease incurred in service."). The Veteran specifically attributes the arthritis he now has in his neck to the sheer “wear and tear” he experienced during his training and combat service in Iraq and specifically mentions strain caused by having to wear “battle gear” for extended periods of time. There is a lesser burden of proof of establishing relevant injury in service if, as here, it is shown to have been sustained in combat. 38 U.S.C. § 1154(b); 38 C.F.R. § 3.304(d); see also Reeves v. Shinseki, 682 F.3d 988, 999 (Fed. Cir. 2012).  There is credible evidence of continuity of symptomatology (most notably, chronic neck pain), as contemplated by 38 C.F.R. § 3.303(b), during the several years since the Veteran’s service in the form of his written statements, corroborated by his treatment records and statements to VA examiners that his neck pain began during his service and has persisted ever since. However, the Board notes that a positive medical nexus opinion was proffered in July 2013 by the Veteran’s primary care provider, thereby negating the need to establish continuity of symptomatology as a means of etiologically linking the arthritis in the Veteran’s cervical spine (neck) back to the physical and combat activity in service he cites as the source or cause of it. The Board is mindful of the medical opinions since provided in October 2017 and February 2018, August 2019, and January 2020 disassociating (at least in part) the Veteran’s disability from his service. But those VA examiners did not entirely consider his supporting lay testimony or reconcile it with the other relevant evidence in the file (most notably the supporting nexus opinion that had previously been submitted) and, at least seemingly, impermissibly equated the absence of treatment with the notion he also had not experienced any relevant symptoms at some earlier points in time and continuously during the several years since. See, e.g., Dalton v. Nicholson, 21 Vet. App. 23 (2007) (examination was inadequate where the examiner did not comment on the appellant's report of in-service injury and instead relied on the absence of evidence in the service treatment records (STRs) to provide a negative opinion). The more recent January 2020 VA examiner’s opinion also is inadequate in that he simply indicated, impermissibly, that he could not opine on whether the Veteran’s helmet use during combat affected his cervical spine without resorting to speculation. This same examiner, however, simultaneously also indicated that helmet weight could indeed influence cervical spine injury. See Jones v. Shinseki, 23 Vet. App. 382 (2010) (discussing when versus when not permissible to reject equivocal opinions and when they invoke an obligation to obtain additional explanation if not apparent from the opinion). Contrary to those VA medical examiners’ findings, given the Veteran’s credible reports of continuity of symptomology since his service and eventual diagnosis of arthritis, in combination with the supporting medical nexus opinion submitted by his primary care provider in July 2013, the evidence is at least in relative equipoise regarding whether the symptoms and manifestations (i.e., pain) referable to the Veteran’s cervical spine (neck) originated during his service and resulted in the eventual diagnosis of arthritis or other degenerative disease (DDD, spondylosis). In this circumstance of relative balance of evidence for versus against the claim, this reasonable doubt is resolved in his favor and the claim granted rather than contrarily denied. 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102; see also Alemany v. Brown, 9 Vet. App. 518, 519 (1996) (An “absolutely accurate” determination of etiology is not a condition precedent to granting service connection, nor is “definite” or “obvious” etiology). Rather, this need only be an “as likely as not” proposition – which in this instance it is for the reasons and bases discussed. Accordingly, service connection for a cervical spine disability (to include cervical spondylosis, DDD, and stenosis) is granted. 5. Entitlement to service connection for OSA. The Veteran contends that his OSA also is attributable to his time in service. Alternatively, he contends that his OSA is secondarily related to his service by way of his service-connected PTSD, meaning it causes or aggravates it. 38 C.F.R. § 3.310(a) and (b); see also Allen v. Brown, 7 Vet. App. 439 (1995). The question for the Board, therefore, is whether his current disability began during service or is at least as likely as not related to an in-service injury, event, or disease. Specifically, the Board must determine whether his reports of experiencing sleep impairment during his service are related to his eventual diagnosis of OSA, i.e., were early indications or manifestations of this condition, even if not until later diagnosed. 38 C.F.R. § 3.303(d).  However, the Board concludes that, while the Veteran has a current diagnosis of OSA based on the results of a sleep study, and evidence recounts him experiencing restless sleeping and loud snoring during his service, the preponderance of the evidence weighs against finding that his OSA began during his service or is otherwise related to an in-service injury, event, or disease or is caused or aggravated by his service-connected PTSD. A January 2012 VA examination noted the Veteran’s OSA was unrelated to Gulf War exposures, but rather was related to his obesity. In April 2010, the Veteran’s wife submitted written testimony attesting that he had experienced restless sleep and loud snoring during his service, beginning in the mid-1990s and continuing through the then present. In May 2016, however, an additional examination was provided, and this additional examiner (like the one prior) concluded the Veteran’s OSA is unrelated to his service and that his lay statements were inconclusive as to whether his OSA began during his service A still additional examination was also more recently provided in May 2019 clarifying that it additionally is less likely than not the Veteran’s OSA is related to his PTSD (caused or aggravated by it) – particularly since he has other more pertinent risk factors such as his age, gender and weight. This additional examiner pointed out the Veteran’s obesity, alone, placed him in a higher risk category for OSA. Indeed, VA treatment records show the Veteran was not first diagnosed with OSA until February 2010 – well over a decade after his separation from service. While he and his wife are competent to report him having experienced symptoms suggestive of OSA (such as snoring) during and since service, they are not competent to diagnose this condition or determine that his symptoms were, in fact, prodromal manifestations of the OSA later diagnosed. This issue is medically complex, especially since an official OSA diagnosis usually requires specialized medical knowledge and, in the case of a sleep study, interpretation of the results of complicated diagnostic medical testing. Jandreau v. Nicholson, 492 F.3d 1372, 1377, 1377 n.4 (Fed. Cir. 2007).   Taken together, the several VA opinions of record from January 2012, May 2016, and May 2019 establish that the Veteran’s OSA is not at least as likely as not related to an in-service injury, event, or disease, including secondary to (again, meaning caused or being aggravated by) his service connected PTSD. 38 C.F.R. § 3.310. Specifically, the May 2016 VA examiner opined that the Veteran’s OSA was not at least as likely as not related to the sleep problems he reported experiencing during service because there was no objective medical evidence (as opposed to subjective accounts from the Veteran and his wife) to confirm the diagnosis during his military service. Moreover, the May 2019 examiner indicated the Veteran, instead, had more likely developed OSA secondary to other notable risk factors such as his age, excessive weight, and gender and explained that “PTSD has no direct effect on the muscles of the airway resulting in sleep apnea.” This examiner added that, “[w]hile there have been several articles referencing the presence of sleep apnea in individuals with PTSD, there is still no medical evidence showing that PTSD actually causes sleep apnea.” The Board acknowledges that various individual aspects of the several above -mentioned VA examinations and opinions were considered inadequate for lack of sufficient rationale or consideration of the Veteran’s and his wife’s lay statements as well as the Veteran’s contentions that his OSA was related to his PTSD through aggravation, even if not necessarily through causation. However, when viewed holistically, these opinions nonetheless do not support a finding of entitlement to service connection for the OSA – either as directly incurred in service or alternatively as secondary to the PTSD. The opinions, when considered collectively, so in the aggregate, provide the required level of explanation (rationale) to disassociate the Veteran’s OSA from his service by all possible means, so when considering all potential bases of entitlement, irrespective of whether raised expressly or, instead, by the record. Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 304 (2008).   The Board sincerely thanks the Veteran for his service but finds the preponderance of the evidence is against finding entitlement to service connection for his OSA. Therefore, in this circumstance the benefit-of-the-doubt doctrine does not apply. 38 U.S.C. § 5107 (b); 38 C.F.R. § 3.102. See also Gilbert v. Derwinski, 1 Vet. App. 49, 55 (1990). Because the evidence does not establish the required nexus between his reported symptoms in service and this eventual diagnosis, the Board finds the granting of service connection unwarranted. 6. Entitlement to service connection for memory loss, loss of energy and fatigue to include as due to undiagnosed illness or other qualifying chronic disability (MUCMI) pursuant to 38 C.F.R. § 3.317, is denied. The Veteran is seeking to establish service connection, as well, for memory loss, loss of energy, and fatigue, contending that he believes these ailments potentially are related to a MUCMI. In this regard, he has reported symptoms of poor attention, an inability to concentrate, and forgetfulness. He also has reported a history of fatigue, difficulty sleeping, and a lack of energy leading to a lack of motivation. For the following reasons and bases, however, the Board finds that he does not have memory loss, fatigue, or loss of energy as distinct conditions separate from his service-connected PTSD and non-service-connected disabilities (for example, his OSA). Service connection may be granted for a Persian Gulf War 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 multi-symptom illness (MUCMI). 38 C.F.R. § 3.317(a)(2)(i). The term MUCMI refers to a diagnosed illness without conclusive pathophysiology or etiology, that is characterized by overlapping symptoms and signs and has features such as fatigue, pain, disability out of proportion to physical findings, and inconsistent demonstration of laboratory abnormalities. 38 C.F.R. § 3.317(a)(2)(ii). A multi-symptom illness is a MUCMI where either the etiology or pathophysiology of the illness is inconclusive. Stewart v. Wilkie, 30 Vet. App. 383, 389-90 (2018). A multi-symptom illness is not a MUCMI where both the etiology and the pathophysiology of the illness are partially understood. Id. The determination of whether a MUCMI is “medically unexplained,” that is, the etiology and pathophysiology of the multi-symptom illness, must be particular to the claimant’s case. Id. at 291. Here, the Veteran had active service in the Southwest Asia theater of operations during the Persian Gulf War. Therefore, he is considered a Persian Gulf War veteran. 38 C.F.R. § 3.317(e). The Veteran was afforded a comprehensive Persian Gulf War General Examination in January 2013. The examiner noted that the Veteran’s report of fatigue and loss of energy was more likely explained by his diagnosed OSA and insomnia. He did not meet the criteria for chronic fatigue syndrome (CFS). He also reported experiencing fatigue since 2006 (in other words, upon his return from deployment to Iraq). As well, he reported at the time of this examination that he had been experiencing nightmares and chronic pain related to his service-connected ankle, back, and neck pain. He denied that his fatigue interfered with his job. The examiner observed, however, that the Veteran’s then current diagnoses of PTSD and OSA caused similar symptoms to those he described during the examination. Cognitive impairment was not noted. In January 2013, specific neuropsychological testing was performed, but the results were found to be inconclusive, with the examiner pointing out they indicated signs of malingering. In January 2018, an additional neuropsychological evaluation was provided that determined the Veteran’s performance on the evaluation was “globally indicative of a normal profile” – meaning he did not meet the criteria for a separate neurocognitive disorder. With regards to his self-reported symptoms, the examiner opined that the Veteran’s OSA, pain, and PTSD symptoms could be contributing to his subjective cognitive impairment. In May 2019, an addendum opinion was provided affirming that the Veteran’s reported symptoms of fatigue and loss of energy are less likely than not a separate condition apart from his diagnosed PTSD and OSA. The examiner specifically noted that the Veteran had no other diagnoses that would produce fatigue, loss of energy, as well as memory loss. The Veteran has a 50 percent rating for his PTSD, which contemplates he has associated sleep impairment. 38 C.F.R. § 4.130, DC 9411. Moreover, since his OSA has not been determined to be related to his service (i.e., a service-connected disability), the sleep impairment he has owing to it is not compensated in the way of a VA disability rating. Taken together, the several VA opinions of record from January 2013, January 2018, and May 2019 establish that the Veteran’s reported symptoms of memory loss, fatigue, and energy loss are not at least as likely as not related to an in-service injury, event, or disease, including consideration as a MUCMI (a diagnosed illness without conclusive pathophysiology or etiology), apart from that has been attributed to his service connected PTSD that he already is being compensated for. 38 C.F.R. § 3.310. Instead, all three examiners in January 2013, January 2018, and May 2019 have explained that the Veteran's symptoms are more likely attributable to other diagnosed conditions. In this regard, the January 2013 and May 2019 examiners reported that the Veteran is currently diagnosed with PTSD (for which he is service connected), as well as OSA, and obesity. The January 2013 and January 2018 examiners also indicated the Veteran’s chronic pain associated with his low back (and thus also his associated radiculopathy) likely played a role in causing fatigue, memory problems, and a loss of energy in that they also interfered with his ability to get a full night of sleep. He already is being separately compensated for those service-connected disabilities. In addition, the Board finds that the January 2013 VA examiner's opinion that the Veteran's reported symptoms are due to other diagnosed disorders rather than CFS or any other condition that would be considered a MUCMI is clear and unequivocal and is based on the relevant information of record, including the Veteran's statements, STRs, post-service treatment records, and diagnostic testing. Moreover, the examiner's explanation is logical and follows from the facts and information given. See Monzingo v. Shinseki, 26 Vet. App. 97, 105-06 (2012); Nieves-Rodriguez v. Peake, 22 Vet. App. 295, 304 (2008). Thus, the examiner’s conclusion that the Veteran's does not have a MUCMI is highly persuasive and probative evidence. While the Veteran believes that he has a MCUMI due to his military service, this is a complex medical question outside the competence of a non-medical expert to determine whether such a cause-and-effect relationship exists in this particular case or whether a specific diagnosis exists. In this regard, such questions involve complex medical matters requiring expert consideration of the nature of the Veteran's in-service symptoms, his post-service symptomatology, and his other diagnosed conditions. These medical questions cannot be considered within the competence of a non-expert lay witness. 38 C.F.R. § 3.159(a)(1) and (a)(2). Thus, the Veteran, as a layman, has not established the competence needed to rebut the expert medical opinion. See Fountain v. Shinseki, 27 Vet. App. 258, 274-75; Monzingo, 26 Vet. App. at 106. As such, his opinion is not adequate to rebut the VA examiners’ opinions, nor is it otherwise sufficiently probative to be considered competence evidence in regard to the present claim. See Fountain, 27 Vet. App. at 274-75. Therefore, the Board finds that the Veteran does not have a current diagnosis that would be considered an undiagnosed illness or MUCMI of the type contemplated by 38 U.S.C. § 1117 and 38 C.F.R. § 3.317. Additionally, while an undiagnosed illness consisting of the Veteran's symptoms may also be presumptively service connected to that service, the January 2013, January 2018, and May 2019 examiners persuasively explained that the symptoms attributed by the Veteran to a MUCMI are instead caused by other diagnosed conditions. Thus, they are not part of an undiagnosed illness. Moreover, the Veteran is already service connected for a psychiatric disorder (PTSD) and several conditions contributing to his chronic pain (including his low back disability, associated radiculopathy and now, as a result of this decision, his neck disability). Thus, he is already compensated for the symptoms claimed or certainly will be once the RO additionally rates his now service-connected cervical spine disability.   The Board sincerely thanks the Veteran for his service but finds the preponderance of the evidence is against finding service connection for his claimed memory loss, fatigue, and loss of energy as a MUCMI. Therefore, in this circumstance the benefit-of-the-doubt doctrine does not apply. 38 U.S.C. § 5107 (b); 38 C.F.R. § 3.102. See also Gilbert v. Derwinski, 1 Vet. App. 49, 55 (1990). REASONS FOR REMAND Entitlement to a TDIU is remanded. The Board finds this claim has been raised by the record since derivative of the claims for higher ratings for the service-connected disabilities and because the Veteran has at least suggested he may be unemployable on account of these same disabilities. See Rice v. Shinseki, 22 Vet. App. 447 (2009) (a claim for a TDIU due to service-connected disability is part and parcel of an increased-rating claim when such claim is raised by the record). This claim must be further developed before being decided, however, including by having the Veteran complete and return a TDIU application (VA Form 21-8940) and by providing any other needed information.   Accordingly, this claim is REMANDED for the following action: Provide the Veteran all necessary forms concerning his derivative claim of entitlement to a TDIU, including the application (VA Form 21-8940). Have him complete and return all forms needed to assess his level of education, prior training and work experience, salary, etc., to in turn assist in determining whether he is unemployable owing to his service-connected disabilities. KEITH W. ALLEN Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board C. B. Kucera 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.