Citation Nr: 21063807 Decision Date: 10/18/21 Archive Date: 10/18/21 DOCKET NO. 16-49 947A DATE: October 18, 2021 ORDER Service connection for primary lateral sclerosis (PLS) is denied. FINDING OF FACT The Veteran's PLS did not have its onset during service and is not otherwise related to service, including herbicide agent exposure. CONCLUSION OF LAW The criteria for service connection for PLS have not been met. 38 U.S.C. §§ 1110, 1112, 1113, 1116, 5103, 5103A, 5107; 38 C.F.R. §§ 3.102, 3.159, 3.303, 3.304, 3.307, 3.309. REASONS AND BASES FOR FINDING AND CONCLUSION The Veteran served on active duty in the Air Force from June 1971 to August 1974. These matters come before the Board of Veterans' Appeals (Board) from a January 2015 rating decision. The Veteran testified before the Board at a hearing in February 2021. A transcript of the hearing has been associated with the claims file. In May 2021, the Board remanded the Veteran's claim to afford him a VA examination regarding his claim of service connection for PLS. The claim has since been returned to the Board for review. For the reasons indicated in the discussion below, the examination conducted pursuant to the Board's remand instructions was adequate and the agency of original jurisdiction (AOJ) therefore complied with the Board's remand instructions. Stegall v. West, 11 Vet. App. 268 (1998). 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. Generally, the evidence must show the existence of (1) 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 or aggravated during service. Shedden v. Principi, 381 F.3d 1163, 1166-67 (Fed. Cir. 2004). Certain chronic diseases are subject to presumptive service connection if the disease manifests to a compensable degree within one year of separation from service even though there is no evidence of such disease during the period of service. This presumption is rebuttable by affirmative evidence to the contrary. 38 U.S.C. §§ 1112, 1113; 38 C.F.R. §§ 3.307(a)(3), 3.309(a). Moreover, for such chronic diseases, an alternative method of establishing the second and third Shedden element is through a demonstration of continuity of symptomatology if the disability claimed qualifies as a chronic disease listed in 38 C.F.R. § 3.309(a). 38 C.F.R. § 3.303(b); Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2014). Additionally, evidence of continuous symptoms since active duty is a factor for consideration as to whether a causal relationship exists between an in-service injury or incident and the current disorder as is contemplated under 38 C.F.R. § 3.303(a). Herbicide Agent Exposure VA regulations state that a Veteran who served in the Republic of Vietnam during the period beginning on January 9, 1962, and ending on May 7, 1975, shall be presumed to have been exposed during such service to an herbicide agent, which means a chemical in an herbicide used in support of the United States and allied military operations in the Republic of Vietnam, specifically: 2,4-Dichlorophenoxyacetic acid; 2,4,5-Trichlorophenoxy-acetic acid; cacodylic acid; and picloram. 38 U.S.C. § 1116; 38 C.F.R. § 3.307(a)(6). Service connection for the diseases noted below is warranted for a Veteran who has been exposed to an herbicide agent during active military service (subject to the requirements of 38 C.F.R. § 3.307(a)): AL amyloidosis; chloracne or other acneform diseases consistent with chloracne, diabetes mellitus, Hodgkin's disease, non-Hodgkin's lymphoma, acute and subacute peripheral neuropathy, porphyria cutanea tarda, multiple myeloma, prostate cancer, soft-tissue sarcomas, ischemic heart disease, diabetic neuropathy, Parkinson's disease, B-cell leukemias, and respiratory cancers (cancer of the lung, bronchus, larynx, and trachea). Service connection is warranted even if these disorders were not shown during active duty. 38 C.F.R. § 3.309(e). The Board notes that the list of diseases associated with exposure to certain herbicide agents does not include PLS. PLS The Board has reviewed the evidence of record and finds that service connection is not warranted for PLS. At the February 2021 Board hearing, the Veteran provided testimony regarding his claim of service connection for PLS. He asserted that his PLS is a form of amyotrophic lateral sclerosis (ALS), a disability for which presumptive service connection may be granted at any time following separation from service under 38 C.F.R. § 3.318. The Veteran stated that he had previously submitted medical literature supporting his assertion that PLS is a form of ALS. Further, the Veteran asserted that he believes that his PLS is caused by herbicide agent exposure during service in the Republic of Vietnam as no one in his family has ever had PLS. Subsequently, in May 2021 the Board remanded the issue of service connection for PLS for a VA examination and opinion. Additionally, in the May 2021 remand, the Board determined that the Veteran's service department records demonstrated service in the Republic of Vietnam, and in-service exposure to herbicide agents was therefore conceded. The Veteran's service treatment records (STRs) do not reflect complaints, treatment, or evidence of PLS. In March 1996, nearly 22 years after discharge from service, the first evidence of PLS is noted in his VA treatment records. In March 1996 VA treatment records, the Veteran is noted as having progressive gait abnormalities, including difficulty walking, running, and maintaining balance. He is noted as having probable multiple sclerosis (MS). In August 1996 VA treatment records, the Veteran is documented as being admitted to the hospital to undergo a course of medication. He was noted as having a 10-year history of gait disturbance involving spasticity in the lower extremities. He was diagnosed as having lower extremity spasticity, possible MS versus PLS. In December 2000 VA treatment records, the Veteran is documented as continuing medication for his diagnosis of PLS and that he is walking better with physical therapy. In November 2016 VA treatment records, the Veteran is documented as being homebound due to PLS, requiring help with activities of daily living, and requiring the use of a wheelchair and hospital bed. In May 2018 VA treatment records the Veteran reported worsening PLS symptoms with increased weakness and falls. In February 2021, one of the Veteran's treating VA physician provided a statement regarding his PLS. The physician stated that the Veteran's PLS was diagnosed in 1996 and that PLS is a slowly progressive condition that causes worsening weakness and spasticity in the body over time, which can involve the upper and lower extremities as well as the muscles of swallowing and breathing. The physician stated that the Veteran's PLS has caused him to be a paraplegic and has also affected his speech. The physician explained that PLS has many overlapping characteristics of ALS, as both may exhibit upper motor neuron dysfunction, which causes the increase in tone known as spasticity, and both are progressive, incurable, and have an unknown etiology. Further, the physician explained that PLS and ALS are not always easily distinguished from one another and it remains unclear whether they represent two distinct disease or whether PLS is simply a variant of ALS that tends to progress more slowly and affect the central nervous system to a greater degree; however, the physician clarified that he was not making a statement regarding whether PLS is a variant of ALS or not. The Board finds that the Veteran's VA treatment records and statement of his VA treating physician demonstrate he has a present diagnosis of PLS; however, his treating physicians do not provide an opinion regarding the etiology of his PLS, and the physicians do not provide an opinion stating that his PLS is caused by or related to service. Therefore, this evidence does not demonstrate a nexus relationship and it does not demonstrate continuity of symptoms based on the clinical evidence, it does not support the claim of service connection for PLS. Further, the evidence does not support the assertion that PLS is a form of ALS, for which presumptive service may be granted at any time following separation from service. In June 2014, the Veteran submitted medical literature indicating that there is an ongoing debate in the medical community regarding whether PLS and ALS are two separate diseases or simply two points on a continuum of motor neuron degeneration. Further, the medical literature indicated that PLS may be a slowly progressive form of ALS in which lower motor neurons (LMN) may be affected but the process is slower or different. In the submitted medical literature, a second study also found that PLS is a distinct clinical disease from ALS and third study found that transitions from PLS from ALS have been found. In July 2021, the Veteran underwent a VA examination regarding his PLS. He reported the onset of PLS symptoms in the early 1980s, including incoordination and tripping. The examiner documented that the Veteran was diagnosed as having PLS in 1996, that his PLS has progressively worsened, and that he is now a paraplegic residing in an assisted living facility. The examiner opined that PLS is a separate and distinct disease from ALS, as there are numerous studies that document the distinct differences that separate and distinguish the two diseases. The examiner opined that it is less likely than not that the Veteran's PLS is caused by service, including herbicide agent exposure during service in the Republic of Vietnam, as medical literature has shown that the cause of PLS is unknown, the diagnosis of PLS was not made until 1996, and the Veteran's service ended in 1974. In support of the finding that PLS is a separate and distinct disease from ALS, the examiner explained that disease duration is significantly longer in patients with PLS, the mortality rate is significantly lower in patients with PLS, in PLS the disease burden in the motor cortex is more medial than in ALS consistent with its lower limb symptom-predominance, and PLS is associated with considerable cerebellar white and grey matter degeneration. Further, the examiner stated that although PLS and ALS are closely related diseases, the fact that cases of PLS consistently show minimal involvement of LMN demonstrates that PLS represents a distinct entity rather than an early stage of ALS. Lastly, the examiner stated that PLS may be initially mistaken for ALS and that most neurologists follow an affected individual's clinical course for at least three to four years before making a diagnosis of PLS. In support of the finding that the Veteran's PLS is not caused by service, including herbicide agent exposure, the examiner explained that the underlying cause of adult PLS is currently unknown and that in most cases is occurs sporadically in people with no family diagnosis of the disease. The Board finds the results of the July 2021 VA examination to be highly probative in reaching its conclusion that that PLS is a separate and distinct disease from ALS and that the Veteran's PLS is not caused by service, including herbicide agent exposure. Regarding the conclusion that PLS is a separate and distinct disease from ALS, the VA examiner acknowledged the medical literature indicating that PLS and ALS are closely related diseases and that PLS may be initially mistaken for ALS. The examiner provided a thorough analysis of relevant medical literature regarding the characteristics of PLS and ALS and the distinctions between the two diseases. Moreover, the examiner's findings were supported by a well-reasoned medical rationale relying on the discussed medical literature. Lastly, the Board notes that the Veteran's treating VA physician also did not make a finding that PLS is a variant of ALS. Therefore, the Board finds that the probative evidence of record does not support the finding that PLS is a form of ALS. Regarding the conclusion that the Veteran's PLS is not caused by service, including herbicide agent exposure, the examiner explained that the etiology of PLS is currently unknown and that in most cases it occurs sporadically in people with no family diagnosis of the disease. The examiner further explained that the evidence does not support the finding that the Veteran's PLS is caused by herbicide agent exposure as the Veteran's service ended in 1974, which was nearly 22 years prior to his diagnosis of PLS. The Board acknowledges the Veteran's assertion that his PLS is caused by herbicide agent exposure during service in the Republic of Vietnam. Although the Veteran is competent to report his observations and to opine as to some medical matters, his contention that his PLS is caused by herbicide agent exposure or is otherwise related to service relates to an internal medical process, which extends beyond an immediately observable cause-and-effect relationship and is the type of evidence that the courts have found to be beyond the competence of lay witnesses. Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007). Thus, the Board finds that the probative evidence of record does not support a finding of continuity of symptoms or a nexus element between the Veteran's PLS and service, including herbicide agent exposure. Accordingly, the Board finds that the preponderance of the evidence is against the claim of service connection for PLS. Therefore, the appeal is denied. MICHAEL E. KILCOYNE Veterans Law Judge Board of Veterans' Appeals Attorney for the Board A. Page-Nelson, Associate Counsel The Board's decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.