Citation Nr: 21063798 Decision Date: 10/18/21 Archive Date: 10/18/21 DOCKET NO. 07-06 319 DATE: October 18, 2021 ORDER Service connection for left cerebellar infarction (stroke) is denied. Service connection for a disability manifesting as chronic motor and sensory problems of the upper and lower extremities (chronic motor/sensory problems) is denied. A total disability rating based on individual unemployability due to service-connected disabilities (TDIU) is denied. FINDINGS OF FACT 1. The Veteran had service in the Southwest Asia Theater of operations during the Persian Gulf War from August to December 1990. 2. The Veteran's post-service stroke was caused by a post-service vertebral artery dissection. 3. Symptoms of stroke were not chronic in service, not continuous since service, and did not manifest to a compensable degree within one year of service. 4. The Veteran's stroke was not incurred in service and is not etiologically related to active service, to include a period of active or inactive duty for training. 5. The Veteran's chronic motor/sensory problems are secondary to the non-service-connected stroke. 6. The Veteran was not rendered unable to obtain or maintain substantial gainful employment as a result of service-connected disabilities. CONCLUSIONS OF LAW 1. The criteria for service connection stroke have not been met. 38 U.S.C. §§ 1110, 1112, 1117, 1131, 5103, 5103A, 5107; 38 C.F.R. §§ 3.102, 3.159, 3.303, 3.307, 3.309, 3.317. 2. The criteria for service connection for chronic motor/sensory problems have not been met. 38 U.S.C. §§ 1110, 1112, 1117, 1131, 5103, 5103A, 5107; 38 C.F.R. §§ 3.102, 3.159, 3.303, 3.310, 3.317. 3. The criteria for TDIU have not been met. 38 U.S.C. §§ 1155, 5103, 5103A, 5107; 38 C.F.R. §§ 3.102, 3.340, 3.341, 4.15, 4.16, 4.18, 4.19. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty in the United States Air Force from September 1980 to April 1986, and from August to December 1990. The Veteran had additional service in the Air National Guard, including periods of active and inactive duty for training (ACDUTRA and INACDUTRA). These matters come before the Board of Veterans' Appeals (Board) on appeal from a February 2007 rating decision of a Department of Veterans Affairs (VA) Regional Office (RO). These matters were previously remanded for further development in November 2011, September 2015, and September 2016. In October 2019, the Board denied the claims for service connection for left cerebellar infarction (stroke), a disability manifesting as chronic motor and sensory problems of the bilateral upper and lower extremities (chronic motor/sensory problems), and TDIU. The Veteran appealed the decision to the United States Court of Appeals for Veterans Claims (Court). In November 2020, the Court granted a Joint Motion for Remand (JMR), vacating the October 2019 Board decision. The JMR agreed that the Board's October 2019 decision relied on an inadequate medical opinion, and that the Board did not ensure substantial compliance with its prior remand directives related to the medical opinion. In March 2021 and August 2021, the Board remanded the matters for VA examinations and medical opinions. The Board finds that the Agency of Original Jurisdiction (AOJ) substantially complied with the Board Remand directives. See Dyment v. West, 13 Vet. App. 141, 146-47 (1999) (remand not required under Stegall v. West, 11 Vet. App. 268 (1998), where the Board's remand instructions were substantially complied with), aff'd, Dyment v. Principi, 287 F.3d 1377 (Fed. Cir. 2002). The Board finds that the duties to notify and assist in this case have been fulfilled. Neither the Veteran nor the evidence has raised any specific contentions regarding the duties to notify or assist. Service Connection Under the relevant laws and regulations, service connection may be granted for a disability resulting from disease or injury incurred in or aggravated by active service. 38 U.S.C. §§ 1110, 1131; 38 C.F.R. § 3.303(a). Generally, service connection for a disability requires evidence of: (1) the existence of a present disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the present disability and the disease or injury incurred in or aggravated by service. In addition to direct service connection (discussed above), service connection may also be established on a secondary basis for disability which is proximately due to, or the result of, a service-connected disease or injury. 38 C.F.R. § 3.310(a). Secondary service connection may also be established for a disorder which is aggravated by a service-connected disability; compensation may be provided for the degree of disability (but only that degree) over and above the degree of disability existing prior to the aggravation. 38 C.F.R. § 3.310(c). Establishing service connection on a secondary basis essentially requires evidence sufficient to show (1) that a current disability exists and (2) that the current disability was either (a) caused by or (b) aggravated by a service-connected disability. 38 C.F.R. § 3.310(c). Active military, naval, or air service includes any period of ACDUTRA during which the individual concerned was disabled or died from a disease or injury incurred in or aggravated in the line of duty, or any period of INACDUTRA during which the individual concerned was disabled or died from injury, not diseases, incurred in or aggravated in the line of duty, or an acute myocardial infarction, cardiac arrest, or cerebrovascular accident during INACDUTRA. 38 U.S.C. § 101(21), (24); 38 C.F.R. § 3.6(a), (d); Biggins v. Derwinski, 1 Vet. App. 474, 477-78 (1991). ACDUTRA is, generally, full-time duty in the Armed Forces performed by reserves for training purposes. 38 C.F.R. § 3.6(c)(1). VA's General Counsel has interpreted that it was the intention of Congress when it defined active service in 38 U.S.C. § 101(24) to exclude inactive duty training during which a member was disabled or died due to nontraumatic incurrence or aggravation of a disease process. See VAOPGCPREC 86-90. Accordingly, service connection may be granted for disability resulting from disease or injury incurred in, or aggravated, while performing ACDUTRA, or from injury incurred or aggravated while performing INACDUTRA. The presumptive provisions of "chronic" in-service symptoms and "continuous" post service symptoms do not apply to periods of ACDUTRA or INACDUTRA. See Biggins, 1 Vet. App. at 477-78; Smith v. Shinseki, 24 Vet. App. 40 (2010); see also Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2013). Therefore, consideration of the provisions of 38 C.F.R. §§ 3.303(b), 3.307 and 3.309 (presumption of service incurrence for certain diseases) for any periods of ACDUTRA and/or INACDUTRA is not appropriate. The Veteran is currently diagnosed with stroke, which is considered an "brain thrombosis" recognized as a "chronic disease" under 38 C.F.R. § 3.309(a); therefore, the presumptive provisions of 38 C.F.R. §§ 3.303(b), 3.307, and 3.309 apply to the claim for service connection for stroke. Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2013). Service connection may be granted on a presumptive basis for a Persian Gulf veteran who exhibits objective indications of qualifying chronic disability, including resulting from undiagnosed illness, that became manifest either during active service in the Southwest Asia theater of operations during the Persian Gulf War, or to a degree of 10 percent or more not later than December 31, 2021, and which by history, physical examination, and laboratory tests cannot be attributed to any known clinical diagnosis. 38 U.S.C. § 1117; 38 C.F.R. § 3.317(a)(1). In claims based on qualifying chronic disability, unlike those for direct service connection, there is no requirement that there be competent evidence of a nexus between the claimed illness and service. Gutierrez v. Principi, 19 Vet. App. 1, 8-9 (2004). Lay persons are competent to report objective signs of illness. The term "Persian Gulf veteran" means a veteran who served on active military, naval, or air service in the Southwest Asia Theater of operations during the Persian Gulf War. 38 C.F.R. § 3.317(e)(1). The DD Form 214 and service treatment records reflect that the Veteran served in Southwest Asia from August to December 1990; therefore, this Veteran is a Persian Gulf veteran as defined by 38 C.F.R. § 3.317. A "qualifying chronic disability" for VA purposes is a chronic disability resulting from (A) an undiagnosed illness, (B) a medically unexplained chronic multi-symptom illness (such as chronic fatigue syndrome (CFS), fibromyalgia, or IBS) that is defined by a cluster of signs or symptoms, or (C) any diagnosed illness that the Secretary determines in regulation prescribed under 38 U.S.C. § 1117(d) warrants a presumption of service connection. 38 U.S.C. § 1117(a)(2); 38 C.F.R. § 3.317(a)(2)(i)(B). "Objective indications of chronic disability" include both "signs," in the medical sense of objective evidence perceptible to a physician, and other, non-medical indicators that are capable of independent verification. To fulfill the requirement of chronicity, the illness must have persisted for a period of six months. 38 C.F.R. § 3.317(a)(2), (3). Signs or symptoms that may be manifestations of undiagnosed illness include, but are not limited to, the following: (1) fatigue; (2) signs or symptoms involving skin; (3) headache; (4) muscle pain; (5) joint pain; (6) neurologic signs or symptoms; (7) neuropsychological signs or symptoms; (8) signs or symptoms involving the respiratory system (upper or lower); (9) sleep disturbances; (10) gastrointestinal signs or symptoms; (11) cardiovascular signs or symptoms; and (12) abnormal weight loss. 38 C.F.R. § 3.317 (b). 1. Service Connection for a Stroke The Veteran asserts that service connection is warranted for a stroke. Specifically, the Veteran asserts that he was either on active duty or inactive duty training when he had a stroke in September 2001. Alternatively, the Veteran asserts that he had a hypertensive condition and that his body was exposed to varying air pressure during flight missions during active service, either of which could have caused his stroke. See February 2005, April 2007 correspondence, October 2009 representative brief. Private treatment records and VA examination reports show a current disability of stroke due to a vertebral artery dissection. See September 2001, February 2015 private treatment records; April 2021, August 2021 VA examination reports. At the outset, the Board finds that that neither the stroke nor the underlying cause of the stroke, the vertebral artery dissection, is a congenital defect or pre-existing condition. See 38 C.F.R. § 3.303(c). While the VA examiners in December 2008, January 2014, May 2014, and December 2015 opined that the stroke was caused by a congenital defect, the opinions did not clearly address the relevant medical principles or literature that supported the opinion that the stroke was caused by a congenital defect versus an acquired disease. As such, the Board has found these opinions to be of little probative value as it related to the etiology of the stroke. The Board obtained a medical opinion from a private neurologist in February 2015. After reviewing the claims file and the relevant medical literature, the private neurologist opined that the cause of the stroke was not congenital in nature. The examiner noted that, while some studies hypothesized that spontaneous dissection patients may have a congenital disorder of connective tissue, no congenital disorder has been clearly established as a cause of dissection. The neurologist explained that most of the studies regarding the putative congenital nature of dissections were relatively small and many employed "a case-control design a study methodology that makes it hard to eliminate bias," weakening the strength of the conclusions that can be drawn from them. Additionally, the private neurologist noted that even the more encouraging studies support the view that a congenital cause for dissection has not yet been firmly established. As such, the Veteran's stroke cannot be attributed to a congenital cause by a probability of at least 50 percent or greater. See February 2015 private treatment record. Additionally, the VA examiner in August 2021 also opined that the Veteran's stroke due to vertebral artery dissection was not a congenital or pre-existing disorder. Upon reviewing the claims file and the relevant medical literature, the VA examiner explained that, while certain congenital conditions (such as Ehlers-Danlos syndrome) may predispose to vertebral artery dissection, there is no objective evidence of any such pre-existing conditions in this case. The Board finds these opinions to be highly probative, as the examiners reviewed the record for an accurate factual history and provided thorough rationales based on the medical literature and accepted medical principles. Next, the Board has considered whether service connection is warranted for stroke under the Persian Gulf War (qualifying chronic disability) presumptions. See 38 U.S.C. § 1117 and 38 C.F.R. § 3.317. The Board finds that the stroke is not an undiagnosed illness or MUCMI, as the disability does, in fact, carry a diagnosis and clear etiology. For the stroke to be due to an undiagnosed illness or MUCMI, the symptoms would have to be not attributable to another, specific cause. Only if such symptoms are not related to a diagnosed disability with clear etiology, i.e., a brain clot or hemorrhage not due to stroke, may it be found to be due to an undiagnosed illness or MUCMI. Both the private neurologist and the VA examiners have indicated that the stroke was caused by the vertebral artery dissection, so the stroke is a diagnosable condition with a clear etiology. See February 2015 private treatment record, August 2021 VA examination report. As such, the stroke is not an undiagnosed illness or medically unexplained chronic multi symptom illnesses (MUCMI). As the disability has been clinically diagnosed, the Persian Gulf presumptive service connection provisions pertaining to undiagnosed illnesses and MUCMI are not applicable. See U.S.C. § 1117; 38 C.F.R. § 3.317. After a review of all the evidence of record, lay and medical, the Board finds that the weight of the evidence is against a finding that symptoms of stroke were chronic in service, were continuous since service, or manifested to a compensable degree within one year of service to warrant presumptive service connection on the basis of a "chronic" disease under 38 U.S.C. § 1112 and 3.303(b), 3.307, and 3.309. The service treatment records are silent as to symptoms, diagnosis, or treatment of a stroke during active service. Symptoms of stroke first manifested in September 2001, 15 years after service separation, when the Veteran noted symptoms of tingling and weakness on the left side of his body, headache, and vertigo after running on a treadmill and lifting weights at the gym. A left cerebellar stroke due to a left vertebral dissection was confirmed via diagnostic work up, which included a magnetic resonance imaging (MRI) and angiogram. See September 2001 private treatment record. This same evidence also shows that symptoms of stroke did not manifest within one year of active service, as symptoms of the stroke were not reported until 15 years after service separation. As to the question of direct service connection, the weight of the lay and medical evidence also shows that the current stroke was not incurred in or etiologically related to service, to include any period of ACDUTRA or INACDUTRA. The evidence of record shows that the Veteran had a stroke on September 4, 2001. The Veteran alleges that he was on active or inactive duty training in the Air Force Reserves in September 2001 when the stroke occurred. In support of this contention the Veteran submitted his active and inactive duty training orders from 2000 to 2004. The Veteran indicated that periods of INACDUTRA are annotated by the number "22" on the orders and periods of ACDUTRA are annotated by the number "50" on the orders. A review of the Air Force Reserve training orders the Veteran submitted shows that the Veteran was not on ACDUTRA or INACDUTRA for the entire month of September 2001. The service personnel records show that, prior to onset of stroke on September 4, 2001, the most recent prior period of INACDUTRA or ACDUTRA was August 4 to August 5, 2001. As such, the stroke did not occur during a period of ACDUTRA or INACDUTRA. In an October 2003 letter, a treating private physician also noted that the blood clot that caused the Veteran's stroke could have happened at any time during the Veteran's Reserve technician career. The Board finds this statement to be of no probative value, as an assertion that the blood clot "could have" occurred during any time in the Veteran's Air Force Reserve career is a statement of mere possibility rather than probability. Moreover, the physician did not indicate that the claims file was reviewed for an accurate history of the condition as it related to the Veteran's active service, or even show recognition of what periods the service were. Additionally, the statement is of no probative value as it is conclusory, and is not supported by any rationale. See Tirpak v. Derwinski, 2 Vet. App. 609, 611 (1992) (a letter from a physician indicating that the veteran's death "may or may not" have been averted if medical personnel could have effectively intubated the veteran was held to be speculative); Bloom v. West, 12 Vet. App. 185, 186-187 (treating physician's opinion that service "could have" precipitated a disability found too speculative); Stegman v. Derwinski, 3 Vet. App. 228, 230 (1992) (the Court found evidence favorable to the veteran's claim that does little more than suggest a possibility that his illnesses might have been caused by service radiation exposure is insufficient to establish service connection); Obert v. Brown, 5 Vet. App. 30, 33 (1993) (a physician's statement that the veteran may have been having some symptoms of multiple sclerosis for many years prior to the date of diagnosis also implied "may or may not" and was deemed speculative); and Bostain v. West, 11 Vet. App. 124, 128 (1998) (the Court held that a physician's opinion that an unspecified preexisting service-related condition "may have" contributed to the veteran's death was too speculative to be new and material evidence). For the above-mentioned reasons, the Board finds this purported opinion to be a speculative statement is of no probative value, as it is a statement of possibility that is speculative in nature. 38 C.F.R. § 3.102 (evidence involving speculation or remote possibility does not show probability). Moreover, competent and credible medical evidence of record indicates that it is unlikely that the dissection that caused the stroke was present for some indefinite period during the Veteran's Air Force Reserve service, to include during a preceding period of ACDUTRA or INACDUTRA one moth prior to the Veteran's September 2001 stroke. In February 2015, the private neurologist considered the private treating physician's October 2003 statement that the blood clot that caused the Veteran's stroke could have occurred at any time during the Veteran's Reserve service and rejected this assertion. The February 2015 private neurologist noted that the Veteran's stroke almost certainly developed very close in temporal association with both his dissection and his clinical presentation on September 4, 2001. The private neurologist noted that medical studies show that the risk for stroke is greatest one to two weeks after a dissection, making it extremely unlikely that the Veteran was harboring a vertebral dissection for some indefinite period of time prior to September 4, 2001. As such, the examiner noted that it is most like that the Veteran's blood clot formation developed one to two weeks before the stroke on September 4, 2001 at most, and that the blood clot most like occurred on the date of the actual stroke a time when the Veteran was not in service status. The Board finds this opinion highly probative as the private neurologist provided a thorough rationale based on a review of medical studies and accepted medical principles. This competent evidence weighs against finding that the stroke or the vertebral dissection that caused the stroke began during a period of ACDUTRA or INACDUTRA, as the competent and credible medical evidence of record indicates that the blood clot that caused the stroked likely occurred no more than two weeks prior to the September 4, 2001 stroke. Service personnel records shows that the Veteran's most recent period of active or inactive duty training prior to the stroke was August 4th to 5th, 2001, one month prior to the Veteran's clinical presentation of a stroke, and in no way suggest a stroke during a service period. See September 2001 private treatment records; see also service personnel records received May 2007. The Board has considered the Veteran's lay assertion that the stroke is related to elevated blood pressure readings or exposure to changes in pressure due to participating in flight missions during service. As a lay person, the Veteran is competent to report any stroke symptoms the Veteran experienced at any given time; however, under the specific facts of the case that show no in-service stroke symptoms, no symptoms of stroke until almost 15 years after service, and no symptoms of stroke during a period of ACDUTRA or INACDTRA, the Veteran does not have the requisite medical training or credentials to be able to render a competent medical opinion regarding the onset and diagnosis of the stroke that was caused by vertebral dissection in this case. The etiology of stroke and vertebral dissection requires medical expertise that falls outside the realm of common knowledge of a lay person and involves complex medical etiological question dealing with the origin and progression of the stroke, and is diagnosed primarily on clinical findings and physiological testing. For these reasons, the Veteran's unsupported lay opinion under the specific facts of this case that include no in-service injury, diagnosis, or symptoms of stroke; and no stroke symptoms until years after service is of no probative value. The private neurologist in February 2015 opined that the stroke is not related to any elevated blood pressure reading during active service. The private neurologist reviewed the service treatment records and noted that service treatment records only show two elevated blood pressure readings over the years, that is, an elevated reading of 136/92 in January1983 during service, and an elevated reading of 142/82 in August 2002 after active service, about one year after the Veteran's stroke, as the January 1985 reading of 140/90 mentioned in the representative brief is actually at the upper limit of normal. The private neurologist also noted that the record does not support diagnosis of a chronic hypertensive condition during active service. Moreover, even if the evidence showed a hypertensive condition prior to stroke, the association between hypertension and arterial dissection has not been clearly established by medical studies; as such, an elevated blood pressure reading or hypertensive condition could not be said to be the cause of the Veteran's stroke. See February 2015 private treatment record. The neurologist also opined that it is unlikely that the September 2001 stroke is related to an October 1982 concussion or a September 1990 appendectomy, as it is extremely unlikely that a concussion sustained in 1982 or an appendectomy procedure in 1990 caused a stroke in 2001, as medical studies indicate that stroke manifest within one to two weeks of an arterial dissection. Additionally, the neurologist also considered the Veteran's assertion that his stroke could be related to changes in pressure during flight mission, as well as the service treatment records showing that the Veteran was exposed to weather radar in February 2000. The private neurologist could think of no biomechanical mechanism by which flying in a pressurized cabin or a single, low dose, radiation exposure would cause a stroke. A VA examination and medical opinion was provided in April 2021. The VA examiner could not provide an opinion as to the etiology of the stroke caused by vertebral artery dissection without resorting to mere speculation as to cause of the vertebral dissection. As such, the Board has afforded no probative value to the attempted April 2021 VA medical opinion. In August 2021, a different VA examiner opined that the (post-service) stroke, which was caused by the vertebral artery dissection, is not related to service, to include any exposures during service. Upon review of the claims file and the medical literature, the VA examiner reasoned that there is no evidence of related complaints or treatments for stroke or vertebral dissection during service. Furthermore, there are no exposures or events occurring during service that are established primary etiologies of the condition. The VA examiner noted that, while trauma to the neck and spinal manipulation can represent risk factors for vertebral artery dissection, there is no evidence of either of these having occurred during service. Moreover, the VA examiner further reasoned that according to medical literature vertebral artery dissection that caused the stroke often occurs spontaneously and without any pre-existing conditions or events. As such, the examiner assessed that there was no relationship between the Veteran's post-service stroke, which was cause by a post-service event of the vertebral artery dissection, and active service. See August 2021 VA examination report. Based on the evidence of record, the weight of the competent and credible evidence demonstrates no relationship between the Veteran's current stroke and active service. For these reasons, the Board finds that a preponderance of the evidence is against the claim for service connection for stroke on a direct, presumptive, or any other basis, and the claim must be denied. 2. Service Connection for Chronic Motor/Sensory Problems The Veteran seeks service connection for chronic motor/sensory problems. The evidence of record indicates that the Veteran has reported multiple residuals symptoms since the September 2001 stroke including numbness, tingling, and weakness in the hands and feet, tremors, imbalance, heat intolerance, and spatial disorientation. See October 2003 private treatment record, December 2008, January 2014, April 2021 VA examination reports. At the outset, the Board has considered whether service connection is warranted for chronic motor/sensory problems under the Persian Gulf War (qualifying chronic disability) presumptions. See 38 U.S.C. § 1117 and 38 C.F.R. § 3.317. The Board finds that the chronic motor/sensory problems are not an undiagnosed illness or MUCMI, as the residual disability does, in fact, carry a clear etiology. The August 2021 VA examiner opined that the medical literature indicates that the Veteran's stroke is a well-established primary etiology of his chronic motor or sensory problems in this case, specifically tremors, imbalance, spatial disorientation, heat intolerance, intermittent tingling and numbness in the hands and feet, and weakness in the upper and lower extremities. See August 2021 VA examination report. For a chronic motor/sensory condition to be due to an undiagnosed illness or MUCMI, the symptoms would have to be not attributable to another, specific cause. Only if such symptoms are not related to a diagnosed disability with clear etiology, i.e., chronic motor/sensory condition not due to stroke may it be found to be due to an undiagnosed illness or MUCMI. As such, the chronic motor/sensory problems, which are residuals of the stoke, are not an undiagnosed illness or medically unexplained chronic multi symptom illnesses and the provisions pertaining to undiagnosed illnesses and MUCMI are not applicable. See U.S.C. § 1117; 38 C.F.R. § 3.317. As to the question of direct service connection, the weight of the lay and medical evidence also shows that the chronic motor/sensory problems were not otherwise incurred in or etiologically related to service, to include exposure to toxin in the Southwest Asia Theater of operations. The service treatment records are silent for any complaints, symptoms, diagnosis, for any motor or sensory disturbances during service or for many years after service separation. Chronic motor/sensory problems are first reported in 2003, 17 years after service separation, and three years after the post-service stroke. During the January 2014 VA examination, the Veteran reported that his motor/sensory problems began after the post-service September 2001 stroke. This same evidence shows that the chronic motor/sensory problems, were not chronic in service, and did not manifest withing one year of service, as the lay and medical evidence of record shows that the chronic motor/sensory problems first manifested after the post-service stroke to warrant presumptive service connection for "chronic" disease. Moreover, the treating and examining physicians of records have opined that the Veteran's residual motor and sensory conditions were caused by the non-service-connected stroke. The examiner in August 2021 noted that there are no more likely alternate etiologies as there is no evidence of related complaints or treatments during service, and there are no exposures or events occurring during service which are established primary etiologies of the condition. See October 2003 private treatment records, January 2014, December 2016, August 2021 VA examination reports. The Veteran has not provided any competent medical evidence relating his motor/sensory residuals to active service, including to any exposures to service in the Southwest Asian theater of operations. Based on the evidence of record, the weight of the competent and credible evidence is against a relationship between the current chronic motor/sensory problems and active service. For these reasons, the Board finds that a preponderance of the evidence is against the claim for service connection for chronic motor/sensory problems on a direct, presumptive, or any other basis, and the claim must be denied. 3. TDIU Disability ratings are determined by applying the criteria set forth in VA's Rating Schedule, which is based on the average impairment of earning capacity. 38 U.S.C. § 1155. Total disability is considered to exist when there is any impairment which is sufficient to render it impossible for the average person to follow a substantially gainful occupation. Total disability may or may not be permanent. 38 C.F.R. § 3.340(a)(1). Total ratings are authorized for any disability or combination of disabilities for which the Rating Schedule prescribes a 100 percent evaluation. 38 C.F.R. § 3.340(a)(2). TDIU may be assigned when the disabled person is, in the judgment of the rating agency, unable to secure or follow a substantially gainful occupation as a result of service-connected disabilities. The service-connected disabilities, employment history, educational and vocational attainment, and all other factors having a bearing on the issue will be addressed in both instances. 38 C.F.R. § 4.16(a), (b). If there is only one such disability, it must be rated at 60 percent or more; if there are two or more disabilities, at least one disability must be rated at 40 percent or more, with sufficient additional disability to bring the combined rating to 70 percent or more. 38 C.F.R. § 4.16(a). For the above purpose of one 60 percent disability, or one 40 percent disability in combination, the following will be considered as one disability: (1) disabilities of one or both upper extremities, or of one or both lower extremities, including the bilateral factor, if applicable, (2) disabilities resulting from common etiology or a single accident, (3) disabilities affecting a single body system, e.g. orthopedic, digestive, respiratory, cardiovascular-renal, neuropsychiatric, (4) multiple injuries incurred in action, or (5) multiple disabilities incurred as a prisoner of war. 38 C.F.R. § 4.16(a). If a veteran's disabilities do not meet the objective combined rating percentage criteria of 38 C.F.R. § 4.16(a), it then becomes necessary to consider whether the criteria for referral for extraschedular consideration are met under § 4.16(b) criteria. It is the established policy of VA that all veterans who are unable to secure and follow a substantially gainful occupation by reason of service-connected disabilities shall be rated totally disabled. Submission to the Director, Compensation and Pension Service, for extraschedular consideration is warranted in all cases of veterans who are unemployable by reason of service-connected disabilities, but who fail to meet the percentage standards set forth in § 4.16(a). 38 C.F.R. § 4.16(b). See Wages v. McDonald, 27 Vet. App. 233 (2015) (holding that a decision of TDIU under 38 C.F.R. § 4.16(b) by the Director of C&P is not evidence, and is not a policy decision, but is simply a decision or adjudication that is adopted by the RO and reviewed de novo by the Board). Cf. Kuppamala v. McDonald, 27 Vet. App. 447 (2015) (applying principles announced in Wages to 38 C.F.R. § 3.321(b) extraschedular adjudication, namely, Director of C&P decision is not evidence, and is not a policy decision, but is simply a decision or adjudication that is adopted by the RO and reviewed de novo by the Board). Individual unemployability must be determined without regard to any non-service-connected disabilities or a veteran's advancing age. 38 C.F.R. §§ 3.341(a), 4.19; Van Hoose v. Brown, 4 Vet. App. 361 (1993). The sole fact that a veteran is unemployed or has difficulty obtaining employment is not enough. A high rating in itself is recognition that the impairment makes it difficult to obtain or keep employment, but the ultimate question is whether a veteran is capable of performing the physical and mental acts required by employment, not whether a veteran can find employment. Id. at 361. When reasonable doubt arises as to the degree of disability, such doubt will be resolved in a veteran's favor. 38 C.F.R. § 4.3. In Faust v. West, 13 Vet. App. 342 (2000), the U.S. Court of Appeals for Veterans Claims (Court) defined "substantially gainful employment" as an occupation that provides an annual income that exceeds the poverty threshold for one person, irrespective of the number of hours or days that a veteran actually works and without regard to a veteran's earned annual income. In Hatlestad v. Derwinski, 5 Vet. App. 524, 529 (1993), the Court held that the central inquiry in determining whether a veteran is entitled to a TDIU is whether a veteran's service-connected disabilities alone are of sufficient severity to produce unemployability. The determination as to whether a total disability is appropriate should not be based solely upon demonstrated difficulty in obtaining employment in one particular field, which could also potentially be due to external bases such as economic factors, but rather to all reasonably available sources of employment under the circumstances. See Ferraro v. Derwinski, 1 Vet. App. 326, 331-332 (1991). In evaluating a veteran's employability, consideration may be given to the level of education, special training, and previous work experience in arriving at a conclusion, but not to age or impairment caused by non-service-connected disabilities. 38 C.F.R. §§ 3.341, 4.16, 4.19. Marginal employment is not considered substantially gainful employment and generally is deemed to exist when a veteran's earned income does not exceed the amount established by the U.S. Department of Commerce, Bureau of the Census, as the poverty threshold for one person. Marginal employment may also be held to exist in certain cases when earned annual income exceeds the poverty threshold on a facts-found basis. Consideration shall be given in all claims to the nature of the employment and the reason for termination. 38 C.F.R. § 4.16(a). Marginal employment, odd-job employment, and employment at half the usual remuneration is not incompatible with a determination of unemployability if the restriction to securing or retaining better employment is due to disability. 38 C.F.R. § 4.17(a). The ultimate issue of whether a TDIU should be awarded is not a medical issue, but rather is a determination for the adjudicator. See Moore v. Nicholson, 21 Vet. App. 211, 218 (2007) (ultimate question of whether a veteran is capable of substantial gainful employment is not a medical one; that determination is for the adjudicator), rev'd on other grounds sub nom, Moore v. Shinseki, 555 F.3d 1369 (Fed. Cir. 2009). Although VA must give full consideration, per 38 C.F.R. § 4.15, to "the effect of combinations of disability," VA regulations place responsibility for the ultimate TDIU determination on VA, not a medical examiner's opinion. Geib v. Shinseki, 733 F.3d 1350, 1354 (Fed. Cir. 2013); 38 C.F.R. § 4.16(a); see also Smith v. Shinseki, 647 F.3d 1380, 1385-86 (Fed. Cir. 2011) (VA is not required to obtain an industrial survey from a vocational expert before making a TDIU determination but may choose to do so in an appropriate case). On the December 2005 VA Form 21-8940, Application for Increased Compensation based on Unemployability (TDIU Claim), the Veteran wrote that he has been rendered unemployable solely due to the (non-service-connected) stroke. The service-connected disabilities are left knee osteoarthritis (rated 10 percent), tinnitus (rated 10 percent), appendectomy scar (rated 0 percent), and headaches (rated 0 percent), for a combined disability rating of 20 percent. Because the Veteran does not have one service-connected disability rated at least 60 percent, or one service-connected disability rated at least 40 percent with a minimum combined rating of at least 70 percent for all service-connected disabilities, the service-connected disabilities do not satisfy the threshold combined rating percentage requirements for consideration of TDIU. 38 C.F.R. § 4.16(a). Further, having considered all the evidence of record, lay and medical, the Board finds that referral under 38 C.F.R. § 4.16(b) to the Compensation and Pension Director for TDIU adjudication is not warranted. While the evidence of record reflects that the service-connected disabilities caused some functional limitations and impairment, the service-connected disabilities did not render the Veteran unable to secure and maintain substantial gainful employment during the appeal period. In this case, the evidence of record shows that the service-connected left knee disability has manifested as functional limitations and impairment including painful limitation of motion of the left knee, with range of motion from 5 to 100 degrees. The evidence indicates that the left knee limits the ability for prolonged standing and walking, as well as full squatting, and that symptoms have been managed with a brace that the Veteran purchased. Nevertheless, the Veteran denied any flare ups of the left knee during the December 2018 VA examination, and there was no functional loss of motion on observed repetitive use of the left knee. See December 2018 VA examination report. The Veteran's tinnitus has manifested as constant, bilateral ringing in the ears, which impacts sleep. The Veteran reported that he uses a fan to mask the tinnitus so he can sleep at night, and the condition is not otherwise bothersome. See December 2008 VA treatment record, July 2015 VA examination report. As for the headaches, the Veteran reported that headaches have manifested as episodes of head pain, blurred vision, nausea, and light sensitivity about twice a week, which last less than one day in duration. Prostrating attacks of headaches occur on an infrequent basis, and the evidence does not support any very prostrating and prolonged attacks that have been productive of economic inadaptability. See December 2015, April 2021 VA examination reports. As for the appendectomy scar, status post September 1990 appendectomy, the evidence of record indicates the Veteran reported some discomfort that radiates from the scar down to his groin for the past five to 10 years during a July 2015 VA examination. The scar was neither painful nor unstable during examination, and the July 2015 VA examiner opined that it is less likely than not the discomfort the Veteran reported is related to the appendectomy scar, as the examiner was unable to assess any physiologic relationship between his symptoms reported and the physical findings. See July 2015 VA examination report. Although the service-connected disabilities have caused some functional limitations and impairment, the weight of the evidence does not suggest that they have rendered the Veteran unemployable. Notably, the Veteran asserted that he has been unemployable due to the non-service-connected stroke. See December 2005 TDIU Claim. As service connection for a stroke has not been established, the Board may not consider any functional limitations, impairment, or residuals attributable to the non-service-connected stroke. The latest and most probative evidence from the Veteran shows that the Veteran has been able to maintain employment despite the functional limitations of his service-connected disabilities, and that the temporary period of unemployment was due to circumstances unrelated to the service-connected disabilities. Specifically, the Veteran reported that he lost his civilian job as an aircraft mechanic for the Air Force due to the non-service-connected stroke. See December 2005 TDIU Claim. Nevertheless, the evidence of record indicates that the Veteran resumed employment thereafter and was subsequently laid off from his job at Olan Brass due to the work being outsourced to Mississippi, not due to the service-connected disabilities. To the extent that the Veteran asserted that his stroke made it difficult for him to perform some of his job duties prior to being laid off, such lay assertions do not relate to the Veteran's limitations in employment activities due to the service-connected disabilities. See December 2008 VA examination report; see also February 2009 VA Form 9. Additionally, subsequent lay reports made during VA examinations indicate that the Veteran has continued to work over the years, and has most recently been employed as a production manager in the aerospace assembly manufacturing field. Furthermore, the Veteran reported that he has lost no more than one to two weeks of work a year due to his service-connected disabilities. See January 2014, December 2018, April 2021 VA examination reports. Although the service-connected disabilities have caused some functional impairment commensurate with the degree of compensation granted, and the Board has noted and considered specific functional impairments caused by each disability, the weight of the evidence of record is against finding that the service-connected disabilities have precluded the Veteran from obtaining (securing) or following (maintaining) substantial gainful employment during the TDIU claim period. The more probative evidence of record shows that the Veteran remains employed as of 2021. There is no additional, subsequent evidence of record to contradict the Veteran's own, last reported employment as of April 2021, when the Veteran was reporting such history during a VA examination. For these reasons, the weight of the evidence of record shows that the Veteran was not rendered unable to obtain or maintain substantially gainful employment by virtue of the service-connected disabilities during the relevant period on appeal; therefore, the appeal for TDIU must be denied. J. PARKER Veterans Law Judge Board of Veterans' Appeals Attorney for the Board Moore, Shanna 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.