Citation Nr: A25035270 Decision Date: 04/16/25 Archive Date: 04/16/25 DOCKET NO. 241021-484184 DATE: April 16, 2025 ORDER Entitlement to service connection for tinnitus is granted. Entitlement to service connection for a hearing loss disability is denied. REMANDED Entitlement to service connection for migraine headaches, to include as secondary to service-connected tinnitus and as due to toxic exposure risk activity (TERA), is remanded. Entitlement to service connection for anxiety disorder with insomnia, to include as secondary to service-connected tinnitus, is remanded. Entitlement to service connection for temporomandibular joint dysfunction (TMJ), to include as secondary to service-connected tinnitus, is remanded. FINDINGS OF FACT 1. The Veteran's tinnitus was incurred in or otherwise caused by service. 2. Although the Veteran has a current diagnosis of bilateral hearing loss, his auditory function does not qualify as a current disability. CONCLUSIONS OF LAW 1. The criteria for entitlement to service connection for tinnitus were met. 38 U.S.C. §§ 1110, 1112, 1113, 1131, 5107; 38 C.F.R. §§ 3.102, 3.303, 3.307, 3.309. 2. The criteria for entitlement to service connection for a hearing loss disability were not met. 38 U.S.C. §§ 1110, 5107(b); 38 C.F.R. §§ 3.102, 3.303(a), 3.304, 3.307, 3.309, 3.385. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran had active service in the United States Navy, to include from January 1976 to January 1978. His military occupational specialty was Personnelman. These matters come before the Board of Veterans' Appeals (Board) on appeal from March and April 2023 rating decisions issued by the Agency of Original Jurisdiction (AOJ), a Department of Veterans Affairs (VA) Regional Office (RO). In the October 2024 VA Form 10182, Decision Review Request: Board Appeal (Notice of Disagreement), the Veteran elected the Direct Review docket. With respect to the headache claim, the Board may only consider the evidence of record at the time of the April 2023 AOJ decision on appeal. As for the others, the Board may only consider the evidence of record at the time of the March 2023 AOJ decision on appeal. 38 C.F.R. § 20.301. Any evidence submitted after those decisions cannot be considered by the Board, respective to the issues on appeal. 38 C.F.R. §§ 20.300, 20.301, 20.801. However, because the Board is remanding the claims, any evidence the Board could not consider will be considered by the AOJ in the adjudication of those claims. 38 C.F.R. § 3.103(c)(2)(ii). Benefit of the Doubt VA is responsible for determining whether the evidence supports the claim or is in relative equipoise, with a claimant prevailing in either event. 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102. The claimant is entitled to the benefit of the doubt when there is an "approximate" (meaning nearly equal) balance of positive and negative evidence regarding any material determination. Lynch v. McDonough, 21 F.4th 776, 781 (Fed. Cir. 2021). 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. 38 C.F.R. § 3.102. In deciding claims, it is the Board's responsibility to evaluate the entire record on appeal. See 38 U.S.C. § 7104(a). Although the Board has an obligation to provide reasons and bases supporting this decision, there is no need to discuss each, and every piece of evidence submitted by the Veteran or on his behalf. See Gonzales v. West, 218 F.3d 1378, 1380-81 (Fed. Cir. 2000). Rather, the Board's analysis below will focus specifically on what evidence is needed to substantiate the claims and what the evidence in the claims file shows, or fails to show, with respect to them. See Timberlake v. Gober, 14 Vet. App. 122, 128-30 (2000). Service Connection Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active service. 38 U.S.C. §§ 1110, 1131, 5107; 38 C.F.R. § 3.303. The three-element test for direct service connection requires 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 the in-service disease or injury. Shedden v. Principi, 381 F.3d 1163, 1166-67 (Fed. Cir. 2004). Certain chronic diseases (e.g., tinnitus, hearing loss) will be presumed related to service, absent an intercurrent cause, if they were shown as chronic in service; or, if they manifested to a compensable degree within a presumptive period following separation from service; or, if they were noted in service (or within an applicable presumptive period) with continuity of symptomatology since service that is attributable to the chronic disease. 38 U.S.C. §§ 1101, 1112, 1113, 1137; 38 C.F.R. §§ 3.303, 3.307, 3.309. Walker v. Shinseki, 708 F.3d 1331, 1338 (Fed. Cir. 2013). Service connection may be granted for any disease diagnosed after discharge, when all the evidence, including that pertinent to service, establishes that the disease was incurred in service. Presumptive periods are not intended to limit service connection to diseases so diagnosed when the evidence warrants direct service connection. The presumptive provisions of the statute and Department of Veterans Affairs regulations implementing them are intended as liberalizations applicable when the evidence would not warrant service connection without their aid. 38 C.F.R. § 3.303(d). 1. Entitlement to service connection for tinnitus is granted. The Veteran contends that his current tinnitus is the result of in-service acoustic trauma. He reports that he experienced loud noise exposure during general quarters, live fire exercises, and while performing duties close to shipboard gunfire and rudder noise. He also asserts noise exposure while attached to a Naval Mobile Construction Battalion (Seabees) operating heavy construction equipment. The first element of service connection is met. The Veteran has a current diagnosis of tinnitus. The second element of service connection is also met. The AOJ conceded noise exposure during service based on his military occupational specialty. The Board is bound by these favorable findings. 38 C.F.R. § 3.104. The issue on appeal is whether the Veteran's tinnitus was incurred in or otherwise caused by service, to include presumed in-service exposure to hazardous noise. The Board concludes that it was. As noted, the Veteran had active service from January 1976 to January 1978. However, the claims file contains additional service records dating from 1973 through 1975. These records strongly suggest that the Veteran had additional qualifying service prior to the dates formally verified by the AOJ. Despite this, the AOJ made no effort to verify these earlier service periods or to clarify the nature of that duty. Moreover, the associated service records are incomplete, illegible in places, or too low in resolution to be meaningfully reviewed (i.e., at 300 percent resolution). The AOJ issued a formal finding of unavailability and concluded that further efforts to obtain the Veteran's STRs would be futile. In such instances, VA has a heightened duty to assist the Veteran in developing the record and to consider the benefit of the doubt doctrine with particular care. See O'Hare v. Derwinski, 1 Vet. App. 365, 367 (1991); Washington v. Nicholson, 19 Vet. App. 362, 370 (2005). One such example is that there is no separation examination of record. In such instances, VA's duty to assist becomes exceptionally critical. This obligation is "particularly great in light of unavailability of the veteran's exit examination and full [service] medical records." Moore v. Derwinski, 1 Vet. App. 401, 406 (1991). The Board therefore views the absence of a separation examination not as neutral, but as an affirmative factor weighing in the Veteran's favor under the benefit-of-the-doubt doctrine. The Veteran underwent a January 2024 VA audiological examination. The examiner confirmed a current diagnosis of tinnitus but concluded that it was less likely than not related to service. They cited the Veteran's military occupational specialty as being low-risk for acoustic trauma and noted the absence of documented complaints of tinnitus in service treatment records. They also emphasized that the Veteran first reported tinnitus decades after separation. The Board finds this opinion inadequate. It fails to address the Veteran's competent and credible reports of in-service noise exposure. It also improperly relies on the absence of corroborating service records that are demonstrably incomplete. A medical opinion that ignores credible lay evidence and rests solely on the absence of contemporaneous treatment records is of limited probative value. See Dalton v. Nicholson, 21 Vet. App. 23, 39 (2007). Moreover, the Veteran is competent to report tinnitus, which is readily observable without specialized medical knowledge. See Charles v. Principi, 16 Vet. App. 370, 374 (2002). There is no competent medical opinion of record that attributes the Veteran's tinnitus to any cause other than service. The fact that he did not seek treatment for tinnitus earlier does not weigh heavily against the claim. That is to say that tinnitus is not the type of condition that necessarily prompts immediate clinical attention, and it is often self-managed unless symptoms become severe. Each disabling condition shown by a veteran's service records, or for which he seeks a service connection must be considered on the basis of the places, types and circumstances of his service as shown by service records, the official history of each organization in which he served, his medical records and all pertinent medical and lay evidence. 38 C.F.R. § 3.303(a) (emphasis added). In this case, the Veteran's description of the onset and continuity of symptoms is both plausible and consistent with the circumstances of his service, to include his reported berthing assignment above a ship rudder and involvement in live-fire exercises. Although the record does not contain a favorable medical nexus opinion, the Board finds that a remand to obtain one is not warranted. The AOJ's failure to develop the claim thoroughly (e.g., not verifying earlier periods of service, failing to address the condition of STRs, inadequate VA opinion), leaves the Board with no reasonable basis to delay adjudication further. The development of evidence in connection with claims for service connection will be accomplished when deemed necessary but it should not be undertaken when evidence present is sufficient for this determination. 38 C.F.R. § 3.304(c). Remand is inappropriate where the predominant purpose is not to allow the Board to make a fully informed decision unencumbered by error but to allow VA to obtain more evidence so that it can properly deny the claim. Andrews v. McDonough, 34 Vet. App. 216, 225 (2021). While the Veteran's private treatment records reflect that pulsatile tinnitus was mentioned as vascular etiologies were being explored, no definitive alternative cause was identified. Moreover, these notations appear to reflect diagnostic uncertainty rather than a confirmed non-service-related etiology. On the other hand, the Veteran has competently and credibly reported symptoms of tinnitus beginning in and persisting since service, and this lay evidence is uncontradicted by any persuasive medical evidence. In any event, the evidence of record is sufficient to resolve reasonable doubt in the Veteran's favor. 38 U.S.C. § 5107(b); cf. Wise v. Shinseki, 26 Vet. App. 517, 532 (2014) (recognizing that the Board may resolve medical questions in the Veteran's favor under the benefit-of-the-doubt standard, even in the absence of scientific consensus). Accordingly, entitlement to service connection for tinnitus is warranted. 2. Entitlement to service connection for a hearing loss disability is denied. The Veteran contends that his hearing loss is related to service. Specifically, he asserts that it is related to his exposure to noise during general quarters and live fire exercises: "MY ASSIGNED STATION WAS A CREWMAN FOR CANNONS + CALIBER GUNS." October 2023 VA Form 21-526EZ. The issue for the Board is whether the Veteran has a current disability that began during service or is at least as likely as not related to an in-service injury, event, or disease. Although the Veteran has been diagnosed with bilateral sensorineural hearing loss, the Board concludes that he does not have a current hearing loss disability for VA purposes and has not had one at any time during the pendency of the claim or recent to the filing of the claim. Romanowsky v. Shinseki, 26 Vet. App. 289, 294 (2013); McClain v. Nicholson, 21 Vet. App. 319, 321 (2007). As pertinent here, impaired hearing will be considered to be a disability when the auditory threshold in any of the frequencies 500, 1000, 2000, 3000, or 4000 Hertz is 40 decibels or greater; or when the auditory thresholds for at least three of the above frequencies are 26 decibels or greater; or when speech recognition scores using the Maryland CNC test are less than 94 percent. 38 C.F.R. § 3.385. A January 2024 VA examination reveals where the Veteran reported that he very often stayed away from people because of a ringing noise. "They often alarm me that I did not hear them." 38 C.F.R. § 4.10; Martinak v. Nicholson, 21 Vet. App. 447 (2007). The Veteran's Maryland CNC Word List speech recognition score and pure tone thresholds, in decibels, were as follows: January 2024 HERTZ (Hz) 1000 2000 3000 4000 Avg CNC RIGHT 20 25 30 35 27.50 98 LEFT 20 25 25 30 25.00 98 The audiometric testing (above) did not meet the auditory thresholds or speech recognition scores for impaired hearing. Aside from that, there is no evidence in the Veteran's medical records of pure tone thresholds and speech recognition scores to support a current hearing loss disability for VA compensation purposes. The Board acknowledges a September 2023 private audiology report, which noted bilateral mild-moderate sensorineural hearing loss. While comprehensive from a clinical standpoint, it fails to provide the necessary information required for VA rating purposes. Specifically, the report does not include detailed pure tone audiometric thresholds at crucial frequencies (i.e., 1000, 2000, 3000, 4000 Hz). These frequencies are essential for calculating the numeric designation of hearing impairment, which is a critical component to determine the presence of disability under the rating criteria. Additionally, the speech recognition scores reported in the examination were not obtained using the Maryland CNC word list, which is the standardized method mandated by the VA for evaluating speech discrimination. See 38 C.F.R. § 3.385. The absence of this standardized testing means that the results cannot be reliably compared to VA rating criteria. Without these specific pure tone thresholds and standardized speech recognition scores, the Board cannot accurately assess the extent of the Veteran's hearing loss. Consequently, the Board finds the September 2023 audiology report inadequate and nonprobative. While the Board also acknowledges the Veteran's reports of hearing problems, those statements are not sufficient to establish a hearing loss disability by themselves. See Jandreau v. Nicholson, 492 F.3d 1372, 1377, 1377 n.4 (Fed. Cir. 2007). On that point, the Board finds the competent and credible medical evidence more probative. In sum, the evidence more persuasively weighs against finding that the Veteran had a current hearing loss disability at any point during the appeal. Accordingly, entitlement to service connection for hearing loss is denied. REASONS FOR REMAND 1. Entitlement to service connection for migraine headaches, to include as secondary to service-connected tinnitus and as due to TERA, is remanded. The Veteran contends that his migraine headaches are caused or aggravated by his service-connected tinnitus. The issue raised during the course of this appeal is whether the Veteran's migraine headaches are related to service, to include as due to TERA (e.g., asbestos exposure); or otherwise, secondary to service-connected tinnitus. In an April 2024 rating decision, the AOJ denied service connection for migraine headaches on direct, secondary, and TERA bases. The Veteran has a current diagnosis of migraine including migraine variants, and verified in-service exposure, specifically to asbestos. See April 2024 Rating Decision. The Board is bound by these favorable findings. 38 C.F.R. § 3.104. Despite the denial on multiple theories, the Board finds that VA did not obtain an adequate medical opinion to address the actual theories raised. The January 2024 VA examination confirmed a diagnosis of tinnitus but did not address whether his migraine headaches are related to it. Nor did it adequately address whether the Veteran's migraines may be attributable to in-service TERA. The April 2014 opinion acknowledged the Veteran's presumptive asbestos exposure but characterized it as "minimal" without further clarification. While the examiner recited general scientific findings that asbestos exposure has not been specifically linked to migraine pathology, the opinion failed to account for the individualized exposure profile of the Veteran or the possible cumulative effects of other TERA-related exposures. In fact, accompanying exposure worksheets reflect that critical information (i.e., place, level, and duration of exposure; use of PPE; and any additional exposure types beyond asbestos) could not be located or was not reviewed. Accordingly, the Board finds that the opinion does not substantially resolve whether the Veteran's migraine headaches may be etiologically related to his known TERA exposures. The rationale is therefore inadequate for adjudicative purposes. The Board also finds that the McLendon factors are satisfied. See McLendon v. Nicholson, 20 Vet. App. 79, 83 (2006). There is evidence of a current disability, credible lay assertions of symptom interaction with a service-connected disability, and insufficient medical evidence to resolve the claim. Additionally, once VA undertakes development of the record, it is obligated to ensure that any medical opinion obtained is adequate. See Barr v. Nicholson, 21 Vet. App. 303, 311, (2007). The failure to obtain a medical opinion that addresses the full scope of the Veteran's claim amounts to a pre-decisional duty to assist error that must be corrected. 38 C.F.R. § 20.802(a). To this end, remand is required to obtain a VA medical opinion that addresses all raised theories of entitlement, to include direct service connection, secondary service connection (to tinnitus), and service connection based on TERA. 2. Entitlement to service connection for anxiety disorder with insomnia, to include as secondary to service-connected tinnitus, is remanded. The Veteran contends that he experiences an anxiety disorder with associated insomnia that is related to his military service or, alternatively, is caused or aggravated by his service-connected tinnitus. The Veteran has consistently described prolonged exposure to shipboard noise and operational duties aboard the USS THEODORE E. CHANDLER from approximately July 1973 to April 1975. He reported frequent sleep disturbances during this time due to intense machinery noise, proximity to naval weaponry during practice bombardments, and general operational activity during "General Quarters" and underway periods. In October 2023, the Veteran stated that these sleep disturbances persisted and were observed by shipmates. He also described grinding his teeth at night, which he associated with tension and the development of headaches. Private treatment records reflect that a diagnosis of anxiety disorder was added in February 2003, along with documented complaints of insomnia. In an April 2024 rating decision, the AOJ denied entitlement to service connection on a direct basis, to include as due to TERA and as secondary to (now service-connected) tinnitus. The Veteran has confirmed exposure to TERA (while the AOJ did not specify the nature of exposure) and a diagnosis of anxiety disorder with complaints of insomnia. See April 2024 Rating Decision. The Board is bound by these favorable findings. 38 C.F.R. § 3.104. Despite these findings and the theories raised by the record, the AOJ did not obtain a VA medical examination or opinion that addressed the Veteran's acquired psychiatric disorder under any theory of entitlement. At no point during development was the Veteran afforded a VA psychiatric examination, and there is no clear indication in the record that he was asked to provide further evidence in support of the psychiatric aspect of his claim. The record also indicates that his complete service treatment records have not been associated with the file, and several documents are illegible or inaccessible. The absence of a separation examination further complicates the evidentiary picture. In cases involving incomplete records, the Board must take particular care to ensure the benefit-of-the-doubt is fairly applied. See Moore v. Derwinski, 1 Vet. App. 401, 406 (1991). While the Veteran's reported experiences aboard the USS THEODORE E. CHANDLER are credible and consistent with the general conditions of Navy service, the Board is unable to fully characterize these as confirmed psychiatric "stressors" given the current evidentiary gaps and uncertainty regarding verified service dates. It is also unclear from the record whether the Veteran qualifies as a Vietnam War Veteran based on potential service in "Southeast Asia" waters. See October 2023 VA Form 21-4138. In sum, complete service verification is required. The Board finds that the McLendon factors are satisfied. See McLendon v. Nicholson, 20 Vet. App. 79, 83 (2006). The Veteran was diagnosed with anxiety disorder with insomnia; he has provided competent lay reports of symptoms and experiences during service that may be related to that issue; and there is insufficient medical evidence to decide the claim. In this case, the absence of an adequately responsive VA examination and medical opinion in the claims file amounts to a pre-decisional duty to assist error that must be corrected. 38 C.F.R. § 20.802(a). To this end, entitlement to service connection for anxiety disorder with insomnia, to include as secondary to service-connected tinnitus, is remanded. 3. Entitlement to service connection for TMJ, to include as secondary to service-connected tinnitus, is remanded. The Veteran contends that his current TMJ dysfunction is related to his service or, alternatively, was caused or aggravated by his service-connected tinnitus. Private treatment records reflect that a diagnosis of TMJ disorder was added in August 2003. In October 2023, the Veteran submitted a lay statement describing persistent mechanical noise exposure and sleep disruption during his assignment aboard the USS THEODORE E. CHANDLER from approximately July 1973 to April 1975. He associated these service-related experiences with recurring physical symptoms, to include the development of headaches. To date, the AOJ has not obtained a VA examination or medical opinion addressing the nature or etiology of the Veteran's TMJ dysfunction under any theory of entitlement. There is no indication that the Veteran was afforded an opportunity to clarify the basis of the claim, nor was development undertaken to assess whether TMJ dysfunction may be directly related to service or secondary to a service-connected disability. Again, the Veteran has been granted service-connection for tinnitus and the lay statements submitted raise the possibility of an association between these issues. The failure to obtain a medical opinion in the face of a current diagnosis, a plausible secondary theory, and facially credible lay evidence amounts to a pre-decisional duty to assist error that must be corrected. In its April 2024 decision, the AOJ denied service connection for TMJ dysfunction as due to TERA. However, the Board finds that this theory was not reasonably raised by the record. Neither the Veteran nor any medical evidence as suggested that his TMJ dysfunction may be related to environmental or chemical exposures during service. As such, no further development or discussion of that theory is warranted. As noted before, the Veteran's service treatment records are incomplete. Again, portions of the file are illegible, and a separation examination is not of record; consequently, VA's duty to assist is heightened. See O'Hare v. Derwinski, 1 Vet. App. 365, 367 (1991); Moore v. Derwinski, 1 Vet. App. 401, 406 (1991); Washington v. Nicholson, 19 Vet. App. 362, 370 (2005). Hence, the full scope of the Veteran's service must be verified, complete service records must be obtained, and then medical development of the claim must be undertaken. The Board finds that the McLendon factors are satisfied. See McLendon v. Nicholson, 20 Vet. App. 79, 83 (2006). The Veteran was diagnosed with TMJ dysfunction; he has provided competent lay descriptions of in-service experiences, to include prolonged noise exposure and disrupted sleep aboard the ship; post-service symptom progression; and there is insufficient medical evidence to decide the claim. In this case, the absence of an adequately responsive VA examination and medical opinion in the claims file amounts to a pre-decisional duty to assist error that must be corrected. 38 C.F.R. § 20.802(a). Accordingly, entitlement to service connection for TMJ, to include as secondary to service-connected tinnitus, is remanded. The matters are REMANDED for the following action: 1. Verify the Veteran's service. Obtain his complete service records, to include all documents pertaining to active service in the United States Navy, to include periods of ADT and IDT in the Navy Reserve. Verify all periods of active service, ADT and IDT. Make a direct request for such records from the appropriate records repositories, to include all prior Navy Reserve units and respective state or U.S. territory Adjutant(s) General. Conduct any necessary development to determine whether service records are complete. If necessary, make a request to the Defense Finance and Accounting Service. Document all requests for information and responses in the claims file. If found that such records do not exist or that further efforts to obtain them would be futile, notify the Veteran. 2. Obtain deck logs relevant to the Veteran's service aboard the USS PASSUMPSIC (AO 107); and USS THEODORE E. CHANDLER (DD717). Document all requests for information and responses in the claims file. If found that such records do not exist or that further efforts to obtain them would be futile, notify the Veteran. 3. The AOJ must take appropriate action to address the incomplete and partially illegible service records associated with the claims file. This includes requesting clearer copies from appropriate federal records custodians, reconstructing relevant service records where possible and documenting all efforts undertaken. If records cannot be obtained or reconstructed, a formal finding of unavailability must be issued and placed in the claims file. 4. Obtain a VA medical opinion from an appropriate clinician to address the etiology of the Veteran's diagnosed migraine including migraine variants. The need for a VA examination to elicit information from the Veteran in providing the opinions requested is left to the discretion of the clinician. The clinician must review the claims file. The clinician is asked to provide a response to the following: (a.) Is the Veteran's migraine including migraine variants related to service, including the indicated toxic exposure risk activities (TERAs)? In providing the requested opinion, the clinician must consider the total potential exposure through all of the Veteran's applicable military deployments and the synergistic, combined effect of all TERAs. (b.) Is the Veteran's migraine including migraine variants due to his service-connected tinnitus? (c.) Is the Veteran's migraine including migraine variants aggravated (i.e., made worse) by his service-connected tinnitus? The but-for causation standard is not limited to a single cause and effect, but rather contemplates multi-causal links, including action and inaction. Spicer v. McDonough, 61 F.4th 1360, 1364 (Fed. Cir. 2023). The examiner is advised that aggravation is different from causation in that it did not cause the disability but rather caused an increase in severity that is not due to the natural progress of the disability. Aggravation does not require that there be permanent worsening; rather, secondary service connection is warranted for "any incremental increase in disability above the degree of disability existing before the increase regardless of its permanence." Ward v. Wilkie, 31 Vet. App. 233, 239 (2019). Provide a rationale to support the opinions. If any opinion cannot be rendered without resorting to speculation, the clinician must explain why, and what (if any) additional evidence would be useful. 5. Schedule the Veteran for a VA examination to determine the nature and etiology of his anxiety disorder with insomnia. The examiner must review the claims file. (a.) The examiner is asked to provide a response to the following: (b.) Is the Veteran's anxiety disorder with insomnia related to service, including his reported experiences aboard the USS THEODORE E. CHANDLER between July 1973 and April 1975? In providing the requested opinion, the examiner must consider the Veteran's descriptions of sleep disturbance related to mechanical noise, weapons drills, and operational shipboard activity. In so doing, consider the Veteran's description of the in-service injury and symptoms as well as post-service symptoms. If there is any medical reason to accept or reject the proposition that his reported injury and symptoms in service and thereafter represented the onset of the current disability, this should be noted. Stated another way, do his reports about the symptoms align with how the currently diagnosed disability is known to develop or are they generally inconsistent with medical knowledge or implausible? (c.) Is the Veteran's anxiety disorder with insomnia due to his service-connected tinnitus? (d.) Is the Veteran's anxiety disorder with insomnia aggravated (i.e., made worse) by his service-connected tinnitus? The but-for causation standard is not limited to a single cause and effect, but rather contemplates multi-causal links, including action and inaction. Spicer v. McDonough, 61 F.4th 1360, 1364 (Fed. Cir. 2023). The examiner is advised that aggravation is different from causation in that it did not cause the disability but rather caused an increase in severity that is not due to the natural progress of the disability. Aggravation does not require that there be permanent worsening; rather, secondary service connection is warranted for "any incremental increase in disability above the degree of disability existing before the increase regardless of its permanence." Ward v. Wilkie, 31 Vet. App. 233, 239 (2019). Provide a rationale to support the opinions. If any opinion cannot be rendered without resorting to speculation, the clinician must explain why, and what (if any) additional evidence would be useful. 6. Schedule the Veteran for a VA examination to determine the nature and etiology of his TMJ dysfunction. The examiner must review the claims file. The examiner is asked to provide a response to the following: (a.) Is the Veteran's TMJ dysfunction related to service, including prolonged noise exposure and disrupted sleep aboard the ship, as reported in an October 2023 VA Form 21-4138? In providing the requested opinion, consider the Veteran's description of the in-service injury and symptoms as well as post-service symptoms. If there is any medical reason to accept or reject the proposition that his reported injury and symptoms in service and thereafter represented the onset of the current disability, this should be noted. Stated another way, do his reports about the symptoms align with how the currently diagnosed disability is known to develop or are his reports generally inconsistent with medical knowledge or implausible? (b.) Is the Veteran's TMJ dysfunction due to his service-connected tinnitus? (c.) Is the Veteran's TMJ dysfunction aggravated (i.e., made worse) by his service-connected tinnitus? The but-for causation standard is not limited to a single cause and effect, but rather contemplates multi-causal links, including action and inaction. Spicer v. McDonough, 61 F.4th 1360, 1364 (Fed. Cir. 2023). The examiner is advised that aggravation is different from causation in that it did not cause the disability but rather caused an increase in severity that is not due to the natural progress of the disability. Aggravation does not require that there be permanent worsening; rather, secondary service connection is warranted for "any incremental increase in disability above the degree of disability existing before the increase regardless of its permanence." Ward v. Wilkie, 31 Vet. App. 233, 239 (2019). Provide a rationale to support the opinions. If any opinion cannot be rendered without resorting to speculation, the clinician must explain why, and what (if any) additional evidence would be useful. Cory M. Picton Veterans Law Judge Board of Veterans' Appeals Attorney for the Board R. Skinner 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.