Citation Nr: 18155809 Decision Date: 12/06/18 Archive Date: 12/06/18 DOCKET NO. 13-17 540 DATE: December 6, 2018 ORDER Entitlement to service connection for a sinus condition is granted. Entitlement to service connection for bilateral hearing loss is denied. Entitlement to service connection for tinnitus is denied. FINDINGS OF FACT 1. Resolving reasonable doubt in the Veteran’s favor, his sinus condition is at least as likely as not related to service. 2. The preponderance of the evidence is against finding that the Veteran has bilateral hearing loss and tinnitus due to a disease or injury in service, to include combat noise exposure in Vietnam. CONCLUSIONS OF LAW 1. The criteria for service connection for a sinus condition are met. 38 U.S.C. §§ 1110, 5107(b); 38 C.F.R. §§ 3.102, 3.303(d). 2. The criteria for service connection for bilateral hearing loss and tinnitus are not met. 38 U.S.C. §§ 1110, 5107(b); 38 C.F.R. §§ 3.102, 3.303(a), 3.385. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty from February 1966 to March 1970, with service in the Republic of Vietnam from February 1969 to November 1969. The Veteran was awarded the Combat Infantry Badge. This matter comes before the Board on appeal from January 2011 and November 2011 rating decisions of the Department of Veterans Affairs (VA) Regional Office (RO) in St. Petersburg, Florida. A Travel Board hearing was held in February 2017 before the undersigned Veterans Law Judge. The Board remanded the appeal for further development in December 2017. Service Connection Service connection is warranted where the evidence of record establishes that a particular injury or disease resulting in disability was incurred in the line of duty in active military service or, if preexisting such service, was aggravated thereby. 38 U.S.C. §§ 1131, 5107(b); 38 C.F.R. §§ 3.102, 3.303(a). Generally, to establish entitlement to service connection, a veteran must show evidence of (1) a current disability, (2) in-service incurrence or aggravation of a disease or injury, and (3) a causal relationship between the current disability and an in-service injury or disease. All three elements must be proved. See generally Davidson v. Shinseki, 581 F.3d 1313 (Fed. Cir. 2009). Alternatively, under 38 C.F.R. § 3.303 (b), service connection may be established for certain chronic diseases listed under 38 C.F.R. § 3.309 (a) by either (1) the existence of such a chronic disease noted during service, or during an applicable presumption period under 38 C.F.R. § 3.307, and present manifestations of that same chronic disease; or (2) where the condition noted during service is not in fact shown to be chronic or where the diagnosis of chronicity can be legitimately questioned, then a showing of continuity of symptomatology after discharge is required to support the claim of service connection. 38 C.F.R. § 3.303 (b); see also Walker v. Shinseki, 708 F.3d 1331 (Fed. Cir. 2013). Where a Veteran served for at least 90 days during a period of war or after December 31, 1946, and manifests certain chronic diseases, including other organic diseases of the nervous system, to a degree of 10 percent within one year from the date of termination of such service, such disease shall be presumed to have been incurred or aggravated in service, even though there is no evidence of such disease during the period of service. 38 U.S.C. §§ 1101, 1112, 1137; 38 C.F.R. §§ 3.307, 3.309. For the purposes of applying the laws administered by VA, impaired hearing will be considered to be a disability when the auditory threshold in any of the frequencies 500, 1000, 2000, 3000, 4000 Hertz (Hz) is 40 decibels (dB) or greater; or when the auditory thresholds for at least three of the frequencies 500, 1000, 2000, 3000, or 4000 Hertz are 26 decibels (dB) or greater; or when speech recognition scores using the Maryland CNC Test are less than 94 percent. 38 C.F.R. § 3.385. Tinnitus is a noise in the ears, such as ringing, buzzing, roaring, or clicking. See YT v. Brown, 9 Vet. App. 195, 196 (1996); See also Kelly v. Brown, 7 Vet. App. 471, 472. When there is an approximate balance of positive and negative evidence regarding any issue material to the determination of a matter, the Secretary shall give the benefit of the doubt to the Veteran. 38 U.S.C.§ 5107 (b); 38 C.F.R. §3.102; see also Gilbert v. Derwinski, 1 Vet. App. 49, 53 (1990). 1. Entitlement to service connection for a sinus condition The Veteran contends that his sinus condition is the result of his military service. Resolving doubt in the Veteran’s favor, the Board concludes that the Veteran has a diagnosed sinus condition that is related to service. 38 U.S.C. §§ 1110, 1131, 5107(b); Holton v. Shinseki, 557 F.3d 1363, 1366 (Fed. Cir. 2009); 38 C.F.R. § 3.303(a). The Veteran’s service treatment records (STRs) indicated that in November 1966, he was treated in the emergency department for what was described as “flu like” symptoms and was diagnosed with “possible viral infection.” His February 1970 separation Report of Medical Examination did not indicate that the Veteran had a sinus condition. On the Report of Medical History, he endorsed “no” for “ear, nose or throat trouble”, “sinusitis”, “hay fever” and “chronic or frequent colds”. Within a month of separation, however, an April 1970 VA treatment letter from the Buffalo VA Medical Center (VAMC) indicated that the Veteran was approved for treatment for a sinus condition; however, if the RO determined that the Veteran’s sinus condition was not related to service, treatment would stop. In a November 1970 Memorandum Rating for Hospitalization and/or Treatment Purposes Only, the RO found that there was no evidence of record of the Veteran’s claimed sinus condition. The rating specialist related that in response to the RO’s request the Veteran indicated that he was treated for the claimed condition at Dispensary #6, Fort Dix, New Jersey during February and March of 1970. The rating specialist maintained that a request for these records was sent to the Walson Army Hospital, Fort Dix, New Jersey and in their reply of November 2, 1970 they indicated they had no records of alleged treatment pertaining to the Veteran and that a thorough search failed to disclose any information. The rating specialist concluded that the claimed condition was not shown by the evidence of record. Post-service clinical evidence indicated that the Veteran has received treatment for his sinus condition since January 2005 through the present. The Veteran was afforded a VA Nose, Sinus, Larynx, and Pharynx examination in November 2010. The Veteran’s diagnosed sinusitis was noted. The Veteran reported a history of chronic sinus problems since 1970. The examiner opined that he/she could not render a nexus opinion without resulting to speculation, as the Veteran’s claims file was not available for review. In a February 2011 addendum medical opinion, the VA examiner opined that it is less likely as not that the Veteran’s sinus condition is a result of his military service. The examiner noted that the Veteran claimed that he has had a sinus problem since June 1970; however, there is no evidence of the Veteran being treated for a sinus condition from 1967 to 1970. The examiner reviewed the claims file and concluded that there is no indication that the Veteran was diagnosed with and/or treated for a chronic sinus condition while in the military. A November 2011 Report of General Information indicated that the RO requested the Veteran’s treatment records for his claimed sinus condition from the Buffalo VAMC and received a negative response. In June 2013, in support of his claim, the Veteran submitted an article entitled, “Thousands of Records May Have Been Lost or Damaged at VA Hospitals in Buffalo, Batavia”, www.buffalonews.com, (May 23, 2015). The article detailed four whistle-blowers’ accounts of “shoddy record-keeping” at the Buffalo VA Medical Center. In essence, the author reported that allegedly “thousands of patient records at [the Buffalo VAMC] have likely been misplaced or damaged” as records were “randomly thrown in boxes. . . Social Security numbers were not properly attributed to the correct veteran name, and that mold-infested files were not handled properly”. In a July 2016 private treatment note, Dr. M. B., an ear, nose and throat specialist, rendered the clinical assessment that the Veteran’s sinus symptoms began during service and his history of chronic rhinosinusitis could have been a result of Agent Orange exposure. In statements and during the February 2017 hearing, the Veteran contended that he was treated for a sinus condition and diagnosed with “simple allergies” during active duty at Fort Dix Army base. The Veteran testified that he was also treated for sinusitis within 12 months of separation from service. An April 2018 VA addendum medical opinion indicated that there is no objective evidence of a sinus condition in the Veteran’s STRs. Despite specific requests made in a December 2017 Board Remand, the VA examiner failed to address the Veteran’s lay assertions regarding his in-service diagnosis of “simple allergies” or the fact that in April 1970, the Veteran sought treatment for a sinus condition at the Buffalo VAMC and was tentatively approved for treatment. In light of the foregoing, the Board resolves reasonable doubt in the Veteran’s favor and finds that service connection for a sinus condition is warranted. The Board acknowledges the negative and positive nexus opinions and that the opinions neither prove or disprove that the Veteran’s sinus condition was incurred in or is a result of his service. The Board notes that the Veteran complained of “flu like” symptoms during active duty and sought treatment for a sinus condition within one month of separation. As such, the Board is satisfied that the criteria for establishing service connection for a sinus condition are met. 38 U.S.C. 1110, 1113, 5107(b); 38 C.F.R. §§ 3.102, 3.303(d). 2. Entitlement to service connection for bilateral hearing loss and tinnitus The Veteran contends that his bilateral hearing loss and tinnitus are a result of his service. The existence of a present disability is established through the Veteran’s medical examination reports produced during the course of his appeal. The records contain diagnoses of bilateral hearing loss and recurrent tinnitus, which establish that the Veteran has a bilateral hearing disability within VA standards. See 38 C.F.R. § 3.385. The Veteran had in-service audiological evaluations during service in February 1966 (enlistment examination), June 1966 (Office Candidate School (OCS) examination), and February 1970 (separation examination) at which time auditory thresholds were recorded. It is unclear whether such thresholds were recorded using American Standards (ASA) units or International Standards Organization-American National Standards Institute (ISO-ANSI) units. For service audiological evaluations conducted prior to January 1, 1967, VA protocol is to assume that ASA standard was used. For service audiological evaluations conducted between January 1, 1967 and December 31, 1970, VA protocol is to consider the data under both ASA and ISO-ANSI standards, whichever is more beneficial to the Veteran. Audiometric data originally recorded using ASA standards will be converted to ISO-ANSI standard by adding between 5 and 15 decibels to the recorded data as follows: Hertz 250 500 1000 2000 3000 4000 6000 8000 add 15 15 10 10 10 5 10 10 The Veteran’s February 1966 enlistment audiogram revealed normal bilateral hearing and the Report of Medical Examination did not indicate any reported tinnitus. On the Report of Medical History, the Veteran endorsed “yes” for “ear, nose or throat trouble” and “no” for “running ears”. The audiogram findings, in decibels, read: HERTZ 500 1000 2000 3000 4000 RIGHT 0 (15) 0 (10) 0 (10) \ 5 (10) LEFT 5 (20) 0 (10) 0 (10) \ 5 (10) The June 1996 OCS audiogram revealed normal bilateral hearing and the Report of Medical Examination did not indicate any reported tinnitus. On the Report of Medical History, the Veteran endorsed “no” for “hearing loss”, “ear, nose or throat trouble” and “running ears”. The Veteran remarked that “there has been no significant change in my health since my last physical.” The audiogram findings, in decibels, read: HERTZ 500 1000 2000 3000 4000 RIGHT -5 (10) -5 (5) -5 (5) \ 0 (5) LEFT -5 (10) -5 (5) 0 (10) \ -5 (0) The February 1970 separation examination revealed normal bilateral hearing and the Report of Medical Examination did not indicate any reported tinnitus. On the Report of Medical History, the Veteran endorsed “no” for “hearing loss”, “ear, nose or throat trouble” and “running ears”. The audiogram findings, in decibels, read: HERTZ 500 1000 2000 3000 4000 RIGHT 0 (15) 0 (10) 0 (10) 10 (20) 20 (25) LEFT 0 (15) 0 (10) 0 (10) 0 (10) 20 (25) As an initial matter, the Board notes that the Veteran’s STRs show normal bilateral hearing both at entrance and at separation from service and no complaints related to bilateral hearing loss. However, the Board points out that the absence of in-service evidence of hearing loss is not fatal to a claim for service connection. Ledford v. Derwinski, 3 Vet. App. 87, 89 (1992). Evidence of a current hearing loss disability (i.e., one meeting the requirements of 38 C.F.R. § 3.385, as noted above) and a medically sound basis for attributing such disability to service may serve as a basis for a grant of service connection for hearing loss. See Hensley at 159; see also Godfrey v. Derwinski, 2 Vet. App. 352 (1992). As such, the remaining inquiry is whether the evidence demonstrates the incurrence of bilateral hearing loss and tinnitus in service or as a result of service. Upon review of the evidence, the Board concludes that the evidence of record is against a finding that the Veteran’s bilateral hearing loss and tinnitus is related to his service. Post-service, the Veteran underwent private audiograms in December 2008, July 2015, and January 2018. At the outset, the Board notes that the Veteran’s private audiograms of record did not indicate specifically that the Maryland CNC was utilized in accordance with 38 C.F.R. § 3.85(a). As such, the examinations would be deemed inadequate for determining the Veteran’s auditory acuity according to VA standards. The September 2010 VA audiometry examination revealed bilateral hearing loss with threshold shifts in decibels as follows: HERTZ 500 1000 2000 3000 4000 RIGHT 10 30 60 60 65 LEFT 10 20 30 60 60 Speech recognition scores indicated 68 percent for the right ear and 94 percent for the left ear. The Veteran reported that he experienced a gradual hearing loss over the past 7 years. He reported the onset of tinnitus in the preceding 2-3 to years, which was not constant but rather occurred twice a month and lasted 10-20 minutes. The VA audiologist indicated that the only in-service audiogram of record was the February 1970 separation examination. The audiologist opined that it is less likely as not that the Veteran’s bilateral hearing loss and tinnitus were caused by, or are a result of, his in-service noise exposure while serving as a parachutist during service. The audiologist explained that the Veteran’s acoustic trauma is conceded; however, the February 1970 separation audiogram indicated that the Veteran’s hearing was within normal limits for all frequencies tested in both ears. According to the audiologist, the speech recognition score in the right ear is poorer than expected from acoustic trauma, with the degree of hearing loss. The audiologist based her rationale, in part, on current medical research, including research produced by the Institute of Medicine (IOM). The audiologist opined that the IOM concluded that based on current knowledge of cochlear physiology, there is no sufficient scientific basis for the existence of delayed-onset hearing loss and tinnitus. As such, the Veteran’s hearing loss and tinnitus are not attributed to his military service. A July 2015 private medical opinion noted a diagnosis of bilateral hearing loss with tinnitus. The private physician noted that the Veteran had a history of severe acoustic trauma, including combat in Vietnam, which the physician felt was “a significant contributing factor” to his hearing loss with tinnitus. In February 2017, the Veteran testified at a Travel Board hearing and contended in several statements that his hearing loss and tinnitus are related to acoustic trauma he suffered during combat in Vietnam. The Veteran testified that he was exposed to “unbelievable” sounds in airplanes as part of the 101st Airborne division and when he tested/fired tanks. The Veteran testified that his physician informed him of the nexus/link between his hearing loss and service. The Veteran testified that he experienced shifts in his auditory threshold as documented in a 1966 OCS audiogram. After the hearing, the Veteran submitted a medical article entitled, “Adding Insult to Injury: Cochlear Nerve Degeneration after ‘Temporary’ Noise-Induced Hearing Loss,” The Journal of Neuroscience, S. Kujawa and M.C. Lieberman, (November 11, 2009). The authors asserted that: overexposure to intense sound can cause temporary or permanent hearing loss; acoustic overexposures caused moderate, but completely reversible, threshold elevation that leave cochlear sensory cells intact, but cause acute loss of afferent nerve terminals and delayed degeneration of cochlear nerve; noise-induced damage to the ear has progressive consequences; noise induced loss of spiral ganglion cells (SGCs), the cell bodies of the cochlear afferent neurons contacting [ear] hair cell, is delayed by months and can progress for years; and that reversibility of noise-induced threshold shifts masks progressive underlying neuropathology that likely has profound long term consequences on auditory processing. In an April 2018 addendum medical opinion, a VA audiologist rendered the clinical assessment that the Veteran’s bilateral hearing loss and tinnitus are not attributable to service, namely, any exposure to noise during combat in Vietnam. The stated rationale was that although it is documented and conceded that the Veteran was exposed to noise in service, no evidence exists that this exposure caused hearing loss during service, within one year of discharge from the service, or that it was causally or etiologically related to noise exposure during service. The audiologist explained that although there were shifts in hearing from the Veteran’s entrance to separation examinations from 1966 to 1970 on ASA and ISO conversions, his hearing was still within normal limits at separation from service. Therefore, in the audiologist’s judgment, the Veteran’s current hearing loss had to begin after he was discharged from the service. The audiologist expounded on the fact that the first evidence of hearing loss in the Veteran’s claims file is on hearing examination in 2008; 38 years after separation. The audiologist emphasized that the 2005 IOM study, “Noise and Military Service: Implications for Hearing Loss and Tinnitus” states: there is not sufficient evidence from longitudinal studies in laboratory animals or humans to determine whether permanent noise-induced hearing loss can develop much later in one’s lifetime, long after the cessation of that noise exposure. Although the definitive studies to address this issue have not been performed, based on the anatomical and physiological data available on the recovery process following noise exposure, it is unlikely that such delayed effects occur.” Therefore, according to the audiologist, based on the objective evidence (audiograms), there is no evidence on which to conclude that the Veteran’s current hearing loss was caused by or a result of the Veteran’s military service, including noise exposure. Regarding the Veteran’s claimed tinnitus, the audiologist noted that on VA examination in 2010, the Veteran reported onset of tinnitus 2-3 years prior to the examination. The audiologist further noted that other medical evidence of record indicated that the Veteran reported onset during service. The audiologist opined that either way, in the absence of objectively verifiable noise injury, the association between claimed tinnitus and noise exposure cannot be assumed to exist. The audiologist explained that tinnitus may occur following a single exposure to high-intensity impulse noise, long-term exposure to repetitive impulses, long-term exposure to continuous noise, or exposure to a combination of impulses and continuous noise. However, in the audiologist’s judgment, you would have to accept the scientifically unsubstantiated theory that tinnitus occurred as a result of some latent, undiagnosed noise injury. The audiologist emphasized that IOM never stated that tinnitus could result from undiagnosed noise injuries. The audiologist noted that in most cases, tinnitus is accompanied by measurable hearing loss. The audiologist added that “we recognize that the audiogram is an imperfect measurement. Nevertheless, it is accepted as the objective basis for determining noise injuries.” With respect to the Kujawa and Liberman article, the VA audiologist noted that the authors posited that a 2-hour exposure to 100 decibels (dB) sound pressure level (SPL) noise-band produced a 40dB elevation of neural response thresholds (auditory brainstem response (ABRs), compound action potential (CAPs)) and smaller threshold elevations in distortion product otoacoustic emissions (DPOAEs) suggesting outer hair cell (OHC) dysfunction and neural damage. By 2 weeks post-exposure, DPOAE thresholds had returned to normal pre-exposure values and remained stable after 8-16 weeks. Although threshold sensitivity recovered, the decrease in suprathreshold ABR and CAP responses suggested loss of neurons in some cochlear regions. At 32 kHz, where acute threshold shifts were large, ABR amplitudes recovered to only about 40 percent of pre-exposure values, whereas at 12 kHz, where initial shifts were small, amplitude recovery was more complete (about 80 percent). DPOAEs recovered completely at all test frequencies. This decrease in neural responses associated with full recovery of DPOAE amplitudes suggested neuronal loss with complete OHC recovery. The authors noted that DPOAE and ABR thresholds were sensitive to hair cell damage, but they were insensitive to “primary” neuronal degeneration, i.e., loss of cochlear neurons without loss of hair cells. They argued that using behavioral thresholds failed to provide evidence of underlying neuropathy. The traditional view is that hair cell loss is seen in minutes to hours, whereas spiral SGC loss is not seen for weeks to months leading to the conclusion that acoustic over-exposure targets hair cells primarily, whereas noise-induced SGC death is a secondary event to the loss of hair cells. The present study showed that noise-induced SGC death can be extensive even in the presence of normal hair cells. The authors hypothesized that the same primary neural degeneration occurs in noise-exposed human ears because (1) acute noise-induced swelling of cochlear-nerve terminals has been observed in every mammal studied, including cat, guinea pig and mouse; (2) the CBA/CAJ mouse has noise vulnerability typical of other mammals; and (3) the same synaptic loss without hair cell damage is seen in guinea pigs. Since inner hair cell (IHC) sensory fibers constitute 95 percent of the cochlear nerve, neuropathy of this neural population must have important consequences for hearing, even when threshold sensitivity recovers. The effects of this damage are not known, but the authors theorized that loss of cochlear neurons should decrease stimulus coding in low signal-to-noise conditions. Peripheral neuropathy may also lead to changes in brainstem circuitry and cortical reorganization, with overrepresentation of surviving cochlear regions thought to be the basis physiologic cause of tinnitus and hyperacusis. The VA audiologist opined that the authors bemoaned the fact that threshold sensitivity is the gold standard for quantifying noise damage in humans. The authors cited the IOM’s conclusion that delayed threshold shifts after noise was evidence that delayed effects of noise do not occur (Humes et al., 2005). The authors concluded that reversibility of noise-induced threshold shifts masked progressive underlying neuropathology. The VA audiologist noted that the authors specifically questioned the conclusions of the IOM Report noting that the lack of delayed threshold shifts after noise exposure “has been taken as evidence that delayed effects of noise do not occur”. In fact, IOM stated “there was insufficient evidence in laboratory animals or humans to determine whether permanent noise-induced hearing loss can develop much later in one’s lifetime, long after the cessation of that noise exposure. Although the definitive studies to address this issue have not been performed, based on anatomical and physiological data available on the recovery process following noise exposure, it is unlikely that such delayed effects occur.” The VA audiologist emphasized that the delayed effect to which IOM was referring was delayed hearing loss. Therefore, in the VA audiologist’s judgment, the authors, Kujawa and Liberman, misquoted the IOM report. The VA audiologist explained that IOM did look at animal studies and discussed Mills et al., (1997) at length since it addressed hearing sensitivity in exposed and non-exposed animals, and found no difference over time. Furthermore, IOM cited human population studies (ISO-1999) that showed hearing thresholds asymptote at 20 years of exposure. They concluded that “continued noise exposure for an additional 2 decades (from 20 to 40 years of exposure) results in little additional noise-related hearing loss following the initial 10-20 years of exposure, it is hard [sic] to imagine that removal from the noise after 10-20 years of exposure would result in further declines in hearing”. Therefore, according to the VA audiologist, these studies, while important and elegant, do not overturn the conclusions of the IOM. The premise that delayed hearing loss occurs even with apparent recovery of hearing thresholds simply misstates the legal basis for disability and the conclusions of the Kujawa articles. The audiologist explained that disability is result of permanent impairment. Temporary threshold changes may indicate noise injury, and in light of the Kujawa papers, may indicate progressive neuropathy. Nevertheless, these papers did not state that animals suffered delayed-onset hearing loss. In fact, hearing thresholds returned to normal. Ultimately, the VA audiologist emphasized that it should be noted that while the Veteran obtained medical opinions linking his hearing loss and tinnitus to noise exposure in service, the medical professionals who provided these opinions did not have access to the Veteran’s complete military medical records and formed their opinions based only on the evidence available to them, not the complete medical file, including the Veteran’s STRs. After carefully reviewing the evidence of record, the Board finds that the preponderance of the evidence is against a finding of service connection for bilateral hearing loss and tinnitus. In so finding, the Board considers the June 1966 OCS examination audiogram and the February 1970 separation audiogram which indicated that the Veteran had normal hearing and no reported tinnitus both during service and at separation. The Board also considers the April 2018 VA medical opinion, which indicated that the Veteran’s bilateral hearing loss and tinnitus were not caused by or related to the Veteran’s service, including any delayed onset hearing loss. The April 2018 VA examiner opined that although it is documented and conceded that the Veteran was exposed to noise in service, there is no evidence of record that his noise exposure caused any hearing loss during service, within one year of discharge from the service, or that it was causally or etiologically related to noise exposure during service. The VA audiologist noted that although the Veteran experienced threshold shifts from entrance to separation from service, he had normal bilateral hearing at separation. Regarding the Veteran’s claimed tinnitus, the audiologist noted that the Veteran’s contentions regarding the onset of his tinnitus were inconsistent. On VA examination in 2010, the Veteran reported that his tinnitus began 2-3 years prior to the examination and at other times, he reported that it began during service. Ultimately, the audiologist determined that in the absence of objectively verifiable noise injury, the association between claimed tinnitus and noise exposure cannot be assumed. The VA audiologist asserted that one would have to accept the scientifically unsubstantiated theory that tinnitus occurred as a result of some latent, undiagnosed noise injury. The audiologist noted that IOM never stated that tinnitus could result from undiagnosed noise injuries. In the same manner, the VA examiner discussed the Veteran’s contention that his bilateral hearing loss and tinnitus could have had a delayed-onset after his in-service noise exposure. Notably, the audiologist expounded on the fact that the 2005 IOM study indicates that “there is insufficient evidence . . . to determine whether permanent noise-induced hearing loss can develop much later in one’s lifetime, long after the cessation of . . . noise exposure”. The VA audiologist noted that the IOM cited human population studies that showed hearing thresholds asymptote at 20 years of exposure. IOM concluded that “continued noise exposure for an additional 2 decades (from 20 to 40 years of exposure) results in little additional noise-related hearing loss following the initial 10-20 years of exposure”. The IOM study also suggested that “it is hard to imagine that removal from the noise after 10-20 years of exposure would result in further declines in hearing.” In discussing the Kujawa and Liberman article, the VA audiologist opined that the authors’ theory regarding delayed-onset hearing loss is at variance with the conclusion of the IOM. The VA audiologist explained that the premise that delayed hearing loss occurs even with apparent recovery of hearing threshold is inconsistent with the diagnosis of a hearing disability; notably, that disability is a result of permanent impairment. The VA audiologist noted that temporary threshold changes may indicate noise injury, and in light of the Kujawa article, may indicate progressive neuropathy. Nevertheless, Kujawa and Liberman did not aver that animals tested suffered any delayed-onset hearing loss. Most crucially, the study showed that by 2 weeks post-exposure, DPOAE thresholds returned to normal pre-exposure levels and remained stable after 8-16 weeks, and recovered completely at all test frequencies. It is well established that a medical opinion “must support its conclusion with an analysis that the Board can consider and weigh against contrary opinions.” See Stefl v. Nicholson, 21 Vet. App. 120, 124 (2007). As such, when reviewing medical opinions, the Board may appropriately favor the opinion of one competent medical authority over another. See Owens v. Brown, 7 Vet. App. 429, 433 (1995). However, the Board may not reject medical opinions based on its own medical judgment. Obert v. Brown, 5 Vet. App. 30 (1993); see Colvin v. Derwinski, 1 Vet. App. 171 (1991). The probative value of a medical opinion is generally based on the scope of the examination or review, as well as the relative merits of the expert’s qualifications and analytical findings, and the probative weight of a medical opinion may be reduced if the examiner fails to explain the basis for an opinion. Sklar v. Brown, 5 Vet. App. 140 (1993). As such, the Board affords significant probative value to the April 2018 VA medical opinion in that the audiologist reviewed the Veteran’s claims file and provided a very thorough explanation for the medical opinion based on sound medical principles. The medical opinion speaks to the issue at hand, whether the Veteran’s bilateral hearing loss and tinnitus are attributable to his service. Conversely, the Board finds the July 2015 medical opinion inadequate as the physician did not provide an adequate explanation of his clinical findings. See Stefl; see also Sklar, supra. The physician provided a positive nexus opinion but did not indicate the scope of his review of the Veteran’s medical records, including the Veteran’s claims file, which did not indicate complaints and/or a diagnosis of bilateral hearing loss and tinnitus during active duty. The claims file revealed a normal separation audiogram and clinical evidence that the Veteran was diagnosed with bilateral hearing loss decades after separation. As such, the July 2015 private medical opinion is not probative to the issue at hand, the nexus/relationship between the Veteran’s bilateral hearing loss and tinnitus and his military service. Furthermore, the Board considers that the Veteran was diagnosed with bilateral hearing loss and endorsed recurrent tinnitus, decades after separation. In sum, the Veteran was not diagnosed with bilateral hearing loss or tinnitus until approximately 40 years after his separation from service. The evidence indicates that the Veteran’s bilateral hearing loss and tinnitus did not manifest to a compensable degree within the one-year presumptive period after separation from service. There is no persuasive medical evidence or persuasive credible lay evidence that the Veteran's claimed disorders had their onset in service and continued ever since service. Therefore, the Board finds that the evidence of record preponderates against a finding of service connection for bilateral hearing loss or tinnitus on a presumptive or continuity of symptomatology basis. Additionally, there is clear and convincing evidence that bilateral hearing loss and tinnitus were not incurred in service and persisted in the years following service. Cf. Reeves v. Shinseki, 682 F.3d 988 (2012). The Board recognizes the Veteran’s assertion that his bilateral hearing loss and tinnitus are related to service-related acoustic trauma, specifically, encountered during combat in Vietnam. The Veteran is considered competent to report the observable manifestations of his claimed disability. In this regard, while the Veteran can competently report symptoms, an actual diagnosis of bilateral sensorineural hearing loss requires objective testing to determine whether it is severe enough to be considered a disability for VA compensation purposes, and can have many causes. In any event, to the extent the Veteran may be competent to opine as to etiology in certain situations, the Board finds that the Veteran’s lay assertions in the present case are clearly outweighed by the April 2018 VA medical opinion. The audiologist has the training, knowledge, and expertise on which the examiner relied to form the opinion, and provided a persuasive rationale for the clinical assessment. Thus, after reviewing the evidence of record, the Board finds there is no causal connection between the Veteran’s current bilateral hearing loss, tinnitus and his service. Although the Veteran is entitled to the benefit of the doubt where the evidence is in approximate balance, the benefit of the doubt doctrine is inapplicable where, as here, the preponderance of the evidence is against the claim for service connection for bilateral hearing loss and tinnitus. The claim is therefore denied. See 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102; see also Gilbert. TANYA SMITH Veterans Law Judge Board of Veterans’ Appeals ATTORNEY FOR THE BOARD C. Taylor, Associate Counsel