PARKINSON'S DISEASE

Summary

The veteran, who served in the United States Army from February 1968 to February 1971, appeals the denial of service connection for obstructive sleep apnea and the denial of service connection for parkinsonism. The veteran also sought an increased rating for tremors, which the Board found to be part of the parkinsonism claim. The veteran asserted that his parkinsonism and tremors were secondary to his service-connected hypertension and tinnitus. The Board found that the evidence was approximately balanced regarding a current diagnosis of parkinsonism, and therefore, resolving doubt in the veteran's favor, service connection for parkinsonism was granted. This was based on a combination of VA examinations and treatment records that indicated a diagnosis of Parkinson's disease or parkinsonism, despite some conflicting reports. The Board also noted the veteran's presumed exposure to herbicides due to his service in Vietnam. For obstructive sleep apnea, the Board found that while the veteran had a current diagnosis and presumed herbicide exposure, the condition was not listed as a presumptive illness. Furthermore, the evidence persuasively weighed against a service connection, as the condition manifested over 45 years after service, and VA examinations opined it was less likely than not related to service-connected hypertension, tinnitus, or toxic exposure. The veteran's lay opinion regarding the cause was not considered competent.

Rationale

Presumed herbicide exposure in Vietnam; Approximately balanced evidence regarding current diagnosis; Benefit of the doubt resolved in veteran's favor

Full Decision Text

Citation Nr: A26023252
Decision Date: 03/16/26	Archive Date: 03/16/26

DOCKET NO. 251222-625972
DATE: March 16, 2026

ORDER

Service connection for parkinsonism is granted.

Service connection for obstructive sleep apnea is denied.

FINDINGS OF FACT

1. The Veteran is presumed to have been exposed to herbicides during his active service in the Republic of Vietnam.

2. The evidence is approximately balanced as to whether the Veteran has a current diagnosis of parkinsonism.

3. The evidence of record persuasively weighs against finding that the Veteran's obstructive sleep apnea began during active service; is related to an in-service disease or injury; or was caused or aggravated by his service-connected hypertension and/or tinnitus.

CONCLUSIONS OF LAW

1. Resolving all reasonable doubt in the Veteran's favor, the criteria for service connection for parkinsonism have been met.  38 U.S.C. §§ 1110, 1116, 5107; 38 C.F.R. §§ 3.102, 3.307, 3.309.

2. The criteria for service connection for obstructive sleep apnea have not been met.  38 U.S.C. §§ 1110, 1168, 5107; 38 C.F.R. § 3.102.  

REASONS AND BASES FOR FINDINGS AND CONCLUSIONS

The Veteran served on active duty in the United States Army from February 1968 to February 1971.  

This matter comes before the Board of Veterans' Appeals (Board) on appeal from December 2025 rating decisions issued by a Department of Veterans Affairs (VA) Regional Office (RO), which is an agency of original jurisdiction (AOJ).  A December 10, 2025, rating decision confirmed and continued a July 2025 rating decision's denial of service connection for a tremor disability.  A December 19, 2025, rating decision denied service connection for obstructive sleep apnea.

In a December 2025 VA Form 10182, Decision Review Request: Board Appeal (Notice of Disagreement), the Veteran disagreed with the denial of service connection for "tremors" and "sleep apnea;" he also elected the Direct Review docket.  Therefore, the Board may only consider the evidence of record at the time of the December 2025 rating decisions, regarding their respective issues on appeal.  38 C.F.R. § 20.301.  Any evidence submitted after the AOJ decisions on appeal cannot be considered by the Board.  38 C.F.R. §§ 20.300, 20.301, 20.801. 

If the Veteran would like VA to consider any evidence that was submitted that the Board could not consider, the Veteran may file a Supplemental Claim (VA Form 20-0995) and submit or identify this evidence.  38 C.F.R. § 3.2501.  If the evidence is new and relevant, VA will issue another decision on the claims, considering the new evidence in addition to the evidence previously considered.  Id.  Specific instructions for filing a Supplemental Claim are included with this decision.

Service Connection

Service connection may be granted for a disability resulting from a disease or injury incurred in or aggravated by active service.  38 U.S.C. §§ 1110, 1131; 38 C.F.R. § 3.303.  The three-element test for service connection requires evidence of: (1) a current disability; (2) an in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the current disability and the in-service disease or injury.  Shedden v. Principi, 381 F.3d 1163, 1166 -67 (Fed. Cir. 2004).  

Service connection may be established on a presumptive basis for certain diseases, such parkinsonism, if a veteran was exposed to an herbicide agent during active military, naval, or air service.  38 U.S.C. § 1116(a).  A veteran will be presumed to have been exposed to an herbicide agent during such service, unless there is affirmative evidence to establish that the veteran was not exposed to any such agent during that service, if the veteran served in the Republic of Vietnam or its off-shore waters within 12 nautical miles, during the period beginning on January 9, 1962, and ending on May 7, 1975.  38 U.S.C. § 1116(c)-(d); 38 C.F.R. § 3.307(a)(6)(iii).  

Even when a
 to an herbicide agent during active military, naval, or air service.  38 U.S.C. § 1116(a).  A veteran will be presumed to have been exposed to an herbicide agent during such service, unless there is affirmative evidence to establish that the veteran was not exposed to any such agent during that service, if the veteran served in the Republic of Vietnam or its off-shore waters within 12 nautical miles, during the period beginning on January 9, 1962, and ending on May 7, 1975.  38 U.S.C. § 1116(c)-(d); 38 C.F.R. § 3.307(a)(6)(iii).  

Even when a veteran is not entitled to the presumption of service connection, he or she may nonetheless establish service connection based with proof of actual direct causation.  See generally Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994).

Service connection may also be established on a secondary basis for a disability that is due to or the result of service-connected disease or injury.  38 C.F.R. § 3.310(a).  Establishing service connection on a secondary basis 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.  See 38 C.F.R. § 3.310; see also Spicer v. McDonough, 61 F.4th 1360, 1364 (Fed. Cir. 2023) (all that is needed is a "but for" causation or aggravation to show entitlement to secondary service connection).

In determining whether service connection may be granted, a review of the entire evidence of record is warranted.  38 C.F.R. § 3.303(a).  It is the defined and consistently applied policy of the Department of Veterans Affairs to administer the law under a broad interpretation, consistent, however, with the facts shown in every case.  When, after careful consideration of all procurable and assembled data, a reasonable doubt arises regarding service origin, the degree of disability, or any other point, such doubt will be resolved in favor of the claimant.  By reasonable doubt is meant one which exists because of an approximate balance of positive and negative evidence which does not satisfactorily prove or disprove the claim.  38 C.F.R. § 3.102.  Where there is an "approximate balance" of positive and negative evidence to support a claim, the claimant will receive the "benefit of the doubt".  Lynch v. McDonough, 21 F.4th 776, 781 (Fed. Cir. 2021).

1. Entitlement to service connection for parkinsonism 

The Veteran seeks service connection for Parkinson's-like symptoms, shakes, and tremors, which he asserts is related to his active service in the Republic of Vietnam.  See March 2021 VA Form 21-526EZ, Fully Developed Claim (Compensation); see also March 2021 VA Form 21-4138, Statement in Support of Claim.  The Veteran also asserts that his parkinsonism and/or tremors are secondary to his service-connected hypertension.  See October 2025 VA Form 21-4138.  

As an initial matter, the AOJ made a favorable finding in the December 10, 2025, decision on appeal that the Veteran was diagnosed with a current essential tremors disability.  The AOJ also conceded in-service participation in a toxic exposure risk activity (TERA) based on the Veteran's active service in the Republic of Vietnam and his military occupational specialty (MOS) of wheeled vehicle mechanic.  See also August 2021 VA Memorandum to the File (indicating exposure to herbicides was conceded based on the Veteran's duty or visitation (boots on ground) in the Republic of Vietnam).  The Board is bound by the AOJ's favorable finding absent evidence of a clear and unmistakable error in the finding.  38 C.F.R. § 3.104.  

As discussed in further detail below, the evidence is approximately balanced as to whether the Veteran has been diagnosed with parkinsonism during the relevant period of review.  

The evidence of record that persuasively weighs against finding that the Veteran has a current diagnosis of parkinsonism includes a May 2021 VA central nervous system examination report wherein the Veteran was diagnosed with "Essential Tremors" and the "Presence of neurostimulator (DBS) [deep brain stimulator]".  See also May 2021 VA medical opinion (stating there is "No hx [history] of Parkinson's or Parkinsonism noted in [the Veteran's]
 error in the finding.  38 C.F.R. § 3.104.  

As discussed in further detail below, the evidence is approximately balanced as to whether the Veteran has been diagnosed with parkinsonism during the relevant period of review.  

The evidence of record that persuasively weighs against finding that the Veteran has a current diagnosis of parkinsonism includes a May 2021 VA central nervous system examination report wherein the Veteran was diagnosed with "Essential Tremors" and the "Presence of neurostimulator (DBS) [deep brain stimulator]".  See also May 2021 VA medical opinion (stating there is "No hx [history] of Parkinson's or Parkinsonism noted in [the Veteran's] records").  

Also weighing against whether the Veteran has parkinsonism is a May 16, 2025 VA medical opinion in which the VA examiner opines that the Veteran "does not have Parkinson's Disease or Parkinsonism."  Rather, the VA examiner opines that the Veteran has "essential tremor (ET)," which "is a neurological disorder that causes your hands, head, trunk, voice or legs to shake rhythmically," and "is often confused with Parkinson's disease."  See also May 16, 2025, VA Parkinson's disease examination report (indicating that the Veteran does not have Parkinson's disease or parkinsonism).  

A November 18, 2025, VA Parkinson's disease examination report is further evidence that weighs against finding the Veteran has a current diagnosis of parkinsonism.  Notably, the report indicates the Veteran did not have a diagnosis of Parkinson's disease or parkinsonism.  In a corresponding November 2025 VA medical opinion report, the same VA examiner did not render an etiology opinion as she concluded the Veteran did not have a current Parkinson's disease nor parkinsonism diagnosis. 

The evidence of record that persuasively weighs in favor of finding that the Veteran has a current diagnosis of parkinsonism includes a May 28, 2025 VA central nervous system examination report.  Significantly, the VA examiner indicates that the Veteran was diagnosed with a central nervous system condition, specifically "Parkinson's disease."  The VA examiner further indicates that when the Veteran's DBS is "turned off," he experiences "Head twitches," "Parkinson like tremors" an antalgic gait, and shaking in his legs.  In a May 28, 2025, VA medical opinion, the same VA examiner opined that the Veteran's parkinsonism is related to in-service exposure to herbicide agents, which also persuasively weighs in favor of finding that the Veteran has a current diagnosis of Parkinsonism.  As a rationale, the VA examiner explained that "Parkinsonism is a broad term comprising a clinical syndrome and presenting with various neurodegenerative diseases, which manifest with motor symptoms such as rigidity, tremors, bradykinesia, and unstable posture, leading to profound gait impairment."

Additionally, a December 2025 VA TERA opinion also suggests the Veteran has a current diagnosis of parkinsonism.  While the December 2025 VA examiner opined that the Veteran's tremor disability was unrelated to his in-service TERA, the VA examiner nevertheless identified the Veteran's tremor disability "to include essential tremors (parkinsonism)."

Post-service VA treatment records also include conflicting evidence as to whether the Veteran has been diagnosed with parkinsonism.  For example, an October 12, 2017, VA primary care note shows the Veteran reported a "worsening hand tremor," unsteady gait, and balance issues.  At that time, the impression was that the Veteran's symptoms were indicative of "tremor, ataxia consistent w/parkinsonism - progressive."  On October 16, 2017, a VA neurologist indicated that the Veteran's symptoms were "unlikely... an emerging atypical parkinsonism."  A September 2018 VA community care-coordination note shows the Veteran was admitted on September 11, 2018, for "Phase I" of "Deep Brain Stimulator for Parkinson's disease."  Significantly, the Veteran was specifically noted to have "Primary Diagnosis: Parkinson's disease."

A July 18, 2022, VA preoperative note specifically indicates that the Veteran had "Parkinson's disease s/p [status post] DBS."  A July 25, 2022, VA neurology note indicates the Veteran did not "exhibit parkinsonian features," even though the Veteran complained of "problems with balance" and "occasional falls."  See also July 26, 2022, VA neurology note (showing the "parkinsonism" was absent on physical examination).  

In light of the foregoing, the evidence of record is approximately
 "Deep Brain Stimulator for Parkinson's disease."  Significantly, the Veteran was specifically noted to have "Primary Diagnosis: Parkinson's disease."

A July 18, 2022, VA preoperative note specifically indicates that the Veteran had "Parkinson's disease s/p [status post] DBS."  A July 25, 2022, VA neurology note indicates the Veteran did not "exhibit parkinsonian features," even though the Veteran complained of "problems with balance" and "occasional falls."  See also July 26, 2022, VA neurology note (showing the "parkinsonism" was absent on physical examination).  

In light of the foregoing, the evidence of record is approximately balanced as to whether the Veteran has a current parkinsonism disability.  Where there is an "approximate balance" of positive and negative evidence to support a claim, the claimant will receive the "benefit of the doubt".  Lynch, 21 F.4th at 781.  Thus, resolving all reasonable doubt in the Veteran's favor, it is at least as likely as not that the Veteran has a current parkinsonism disability.  

Given it is already established that the Veteran was exposed to herbicide agents in service, without any evidence to the contrary, the Veteran's current parkinsonism is presumed to be the result of in-service herbicide agent exposure.  Accordingly, with all reasonable doubt resolved in the Veteran's favor, service connection for parkinsonism is warranted.  See 38 U.S.C §§ 1116, 5107; 38 C.F.R. §§ 3.102; Lynch, supra.

2. Entitlement to service connection for obstructive sleep apnea

The Veteran seeks service connection for obstructive sleep apnea, which he contends is related to his active service.  See February 2026 Appellate Brief.  The Veteran also asserts his obstructive sleep apnea is due to his service-connected hypertension and tinnitus.  See October 2025 VA Form 21-526EZ; see also October 2025 VA Form 21-4138 (indicating, the Veteran's physician advised him that sleep apnea can be due to hypertension and/or tinnitus because "research shows this is recognized in the medical world as such link").  

As an initial matter, the AOJ made a favorable finding in the December 19, 2025 decision on appeal that the Veteran has a current obstructive sleep apnea disability based on a November 2025 VA medical examination report.  The AOJ also conceded in-service exposure to herbicide agents.  The Board is bound by the AOJ's favorable finding absent evidence of a clear and unmistakable error in the finding.  38 C.F.R. § 3.104.  

While it is established that the Veteran served in Vietnam during the Vietnam War era, and he is presumed to have been exposed to herbicide agents during service, obstructive sleep apnea is not among the diseases listed under 38 C.F.R. § 3.309(e)(5), for which presumptive service connection based on herbicide exposure is available.  As such, presumptive service connection for the Veteran's obstructive sleep apnea based on exposure to herbicides in service is not warranted.  Nevertheless, even though the Veteran is not entitled to the presumption of service connection, he may nonetheless establish service connection with proof of actual direct causation.  See generally Combee v. Brown, 34 F.3d 1039 (Fed. Cir. 1994).   

For the reasons set forth below, the evidence of record persuasively weighs against finding that the Veteran's obstructive sleep apnea began during active service; is related to an in-service disease or injury; or was caused or aggravated by his service-connected hypertension and/or tinnitus.

A review of the Veteran's service treatment records does not reveal any complaints of, or treatment for obstructive sleep apnea in service.  In a January1971 Report of Medical Examination, conducted at service separation, the evaluation did not indicate any sleep or respiratory disorders.  Similarly, in a January 1971 Report of Medical History, completed by the Veteran at service separation, he specifically checked "NO" as to "frequent trouble sleeping."  

In addition, the objective evidence of record indicates that the Veteran's current sleep disorder did not manifest until many years after service.  See November 2025 VA medical examination report (showing the date of onset for obstructive sleep apnea as 2018); see also January 2016 VA primary care note (noting the Veteran "denies sleep apnea symptoms and does not use [a] cpap [continuous positive airway pressure machine]).  Significantly, the Veteran's sleep apnea symptoms did not manifest for more than 45 years after separation
 Similarly, in a January 1971 Report of Medical History, completed by the Veteran at service separation, he specifically checked "NO" as to "frequent trouble sleeping."  

In addition, the objective evidence of record indicates that the Veteran's current sleep disorder did not manifest until many years after service.  See November 2025 VA medical examination report (showing the date of onset for obstructive sleep apnea as 2018); see also January 2016 VA primary care note (noting the Veteran "denies sleep apnea symptoms and does not use [a] cpap [continuous positive airway pressure machine]).  Significantly, the Veteran's sleep apnea symptoms did not manifest for more than 45 years after separation.  See Maxson v. Gober, 230 F.3d 1330, 1333 (Fed. Cir. 2000) (explaining that the Board may consider "evidence of a prolonged period without medical complaint," along with other factors in resolving a claim).

The Veteran was afforded a VA medical opinion in connection with his claim in November 2025, wherein the VA examiner opined that the Veteran's obstructive sleep apnea was less likely than not due to his service-connected hypertension and tinnitus.  As a rationale, the VA examiner explained that, according to recent medical literature, hypertension and tinnitus did not lead to the development of obstructive sleep apnea.  The VA examiner further explained that obstructive sleep apnea is a sleep-related breathing disorder caused by repeated upper airway collapse during sleep due to anatomical narrowing, loss of muscle tone, or obesity-related factors.  In contrast, the examiner indicated that hypertension involves elevated arterial blood pressure resulting from vascular, renal, or neurohormonal changes.  The examiner also noted that tinnitus is a perception of ringing or noise in the ears caused by dysfunction within the auditory system.  Therefore, the examiner opined that neither hypertension nor tinnitus directly impair the upper airway in a way that would make it more prone to collapse and cause onset of obstructive sleep apnea.  

As it pertains to the Veteran's in-service exposure to toxins, including herbicide agents, VA obtained a second medical opinion in December 2025.  The VA examiner opined that the Veteran's obstructive sleep apnea was not related to his in-service toxic exposure risk activities (TERAs).  In support of the opinion, the examiner explained that there is no medical or scientific evidence available that provided any indication of a relationship between the development of sleep apnea and the TERA.  In addition, the examiner noted that there were risk factors outside of military service, such as "hereditary, congenital, smoking history, weight, lab findings, multifactorial, etc." that far outweighed the factors associated with the TERA.  

The November 2025 and December 2025 VA medical opinions are persuasive as they contain sufficient rationales that are supported by the objective evidence of record.  See Prejean v. West, 13 Vet. App. 444, 448-49 (2000); see also Stefl, 21 Vet. App. at 123 ("An opinion is adequate where it is based upon consideration of the veteran's prior medical history and examinations and also describes the disability, if any, in sufficient detail so that the Board's evaluation of the claimed disability will be a fully informed one") (internal citations omitted); Nieves-Rodriguez v. Peake, 22 Vet. App. at 301 ("A medical examination report must contain not only clear conclusions with supporting data, but also a reasoned medical explanation connecting the two") (internal citations omitted).  

While the Veteran may believe that his obstructive sleep apnea is the result of his active duty, or his service-connected disabilities, he is not competent to provide such an opinion.   Such a determination is medically complex, requiring knowledge of the interaction between multiple systems in the body and interpretation of complicated diagnostic medical testing, such that it is outside the competence of the Veteran, who has not been shown to possess the medical training or credentials to make such determinations.  See Jandreau v. Nicholson, 492 F.3d 1372, 1377 n.4 (Fed. Cir. 2007); Kahana v. Shinseki, 24 Vet. App. 428 (2011).  Furthermore, the Veteran has asserted that a physician opined that his obstructive sleep apnea is due to his service-connected hypertension and/or tinnitus, but to date, the Veteran has provided no such opinion.  See generally, October 2025 VA Form 21-4138.  

Consideration has also been given to the Veteran's private and VA treatment records; however, there is no additional opinion of record that addresses the likely etiology of the Veteran's obstruct
  See Jandreau v. Nicholson, 492 F.3d 1372, 1377 n.4 (Fed. Cir. 2007); Kahana v. Shinseki, 24 Vet. App. 428 (2011).  Furthermore, the Veteran has asserted that a physician opined that his obstructive sleep apnea is due to his service-connected hypertension and/or tinnitus, but to date, the Veteran has provided no such opinion.  See generally, October 2025 VA Form 21-4138.  

Consideration has also been given to the Veteran's private and VA treatment records; however, there is no additional opinion of record that addresses the likely etiology of the Veteran's obstructive sleep apnea, or that would otherwise diminish the probative value of the November 2025 and December 2025 VA medical opinions.  Notably, the Veteran has not provided any competent evidence that would show his obstructive sleep apnea is related to his active service or service-connected disabilities.  Based on the foregoing, the competent and probative evidence of record persuasively weighs against finding that the Veteran's obstructive sleep apnea began during active service; is related to an in-service disease or injury; or was caused or aggravated by his service-connected hypertension and/or tinnitus.  

Accordingly, service connection for obstructive sleep apnea is not warranted, and the benefit of the doubt doctrine is inapplicable.  38 U.S.C. § 5107(b); Lynch, 21 F.4th at 781.

 

L. B. CRYAN

Veterans Law Judge

Board of Veterans' Appeals

Attorney for the Board	Jenkins Moody, Morgan B.

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.