**UNITED STATES COURT OF VETERANS APPEALS**

No. 91-1179

[Danny J. Hensley, Appellant]{.smallcaps},

[v.]{.smallcaps}

[Jesse Brown,]{.smallcaps}

[Secretary of Veterans Affairs, Appellee.]{.smallcaps}

On Appeal from the Board of Veterans\' Appeals

and

On Appellee\'s Motion for Summary Affirmance

(Decided May 18, 1993 )

*Danny J. Hensley, pro se*.

*James A. Endicott, Jr.,* General Counsel, *David T. Landers*, Acting
Assistant General Counsel, *R. Randall Campbell,* Deputy Assistant
General Counsel, and *Jacqueline M. Sims* were on the pleadings for
appellee.

Before NEBEKER, *Chief Judge*, and MANKIN and STEINBERG, *Associate
Judges*.

STEINBERG, *Associate Judge*: The appellant, Vietnam veteran Danny J.
Hensley, appeals from a March 13, 1991, Board of Veterans\' Appeals (BVA
or Board) decision denying service-connected disability compensation for
bilateral hearing loss. The Secretary of Veterans Affairs (Secretary)
has moved for summary affirmance. For the reasons set forth below, the
Court will vacate the BVA decision and remand the matter for
readjudication.

**I. Background**

The veteran served in the U.S. Navy from October 10, 1969, to August 17,
1973. R. at 13. On his applications to the Department of Veterans
Affairs (VA) for service-connected disability benefits, he reported
having served on an aircraft carrier and having incurred hearing loss as
the result of working on and around jet aircraft in service. R. at 16,
22. Although the service records before the Court do not specifically
mention service on an aircraft carrier, his service separation report
states that his last duty assignment was with an attack squadron and
that he had nearly three years of foreign and/or sea service during the
Vietnam Conflict. R. at 35.

At his August 1969 examination for entrance onto active duty, the
following threshold hearing levels were reported on audiometric testing:

[500]{.underline} [1000]{.underline} [2000]{.underline}
[3000]{.underline} [4000]{.underline} (Hertz)

RIGHT: 10 -5 -10 \-- -5 (decibels)

LEFT: 10 -5 -10 \-- 60

R. at 2. The examiner diagnosed \"Def\[ective\] hearing\". *Ibid*.
Audiometric testing measures threshold hearing levels (in decibels (dB))
over a range of frequencies (in Hertz (Hz)); the threshold for normal
hearing is from 0 to 20 dB, and higher threshold levels indicate some
degree of hearing loss. [current medical diagnosis &
treatment]{.smallcaps} 110-11 (Stephen A. Schroeder et al. eds., 1988).
As explained in part I.A., below, however, hearing loss does not
constitute a disability for VA purposes when the threshold levels at
500, 1000, 2000, 3000, and 4000 Hz are all less than 40 dB and at least
three are 25 dB or less. *See* 38 C.F.R. § 3.385 (1992). The record does
not contain any records of treatment for hearing problems in service. At
his August 1973 separation examination, the veteran\'s hearing levels
were measured on audiometric testing as follows:

[500]{.underline} [1000]{.underline} [2000]{.underline}
[3000]{.underline} [4000]{.underline} (Hz)

RIGHT: 35 25 15 5 10 (dB)

LEFT: 5 0 0 20 70

R. at 10. With the exception of the left-ear result at 500 Hz, all of
the scores showed a worsening of hearing at separation when compared
with the scores at entrance. The examiner diagnosed \"HFHL
\[high-frequency hearing loss\] both ears.\" *Ibid.*

In January 1990, the veteran filed with a VA regional office (RO) an
application for service-connected disability compensation for hearing
loss. R. at 16. On his application, he reported having received
treatment for his hearing loss since December 1989. R. at 17. The RO
received reports of a December 1989 private physical examination and of
December 1989 and January 1990 private audiometric testing. R. at 19-20,
34. In the report of the physical examination, the examiner diagnosed
\"bilateral \[HFHL\]\" due to \"probable noise trauma\". R. at 34. The
audiometric test reports recorded threshold hearing levels of 75 and 85
dB at 4000 Hz and 65 and 40 dB at 3000 Hz in the right ear; none of the
other recorded thresholds was above 30 dB. R. at 19-20. On the January
1990 report of audiometric testing, the examiner noted that the
veteran\'s noise exposure had included \"military \-- jet aircraft\[,\]
some equipment/machinery\[, and\] hunting\", and that his last exposure
had been in October 1989. R. at 20. In a January 1990 letter to VA, the
examiner indicated that the veteran had bilateral sensorineural hearing
loss, and stated: \"patient to wear ear protection in noise \-- high
risk for noise damage because of years with jet aircraft, machinery . .
. .\" R. at 31.

The veteran was given a VA audiometric examination in April 1990, at
which time his hearing levels were reported as follows:

[500]{.underline} [1000]{.underline} [2000]{.underline}
[3000]{.underline} [4000]{.underline} (Hz)

RIGHT: 25 20 15 5 40 (dB)

LEFT: 5 10 0 45 90

R. at 25-26. Except for the scores at 4000 Hz in both ears and 3000 Hz
in the left ear, the veteran\'s hearing was generally not worse than it
had been at separation in 1973. His score on a \"speech recognition\"
test was 96%. *Ibid*. He was diagnosed with \"bilateral, high-frequency,
sensorineural hearing loss.\" R. at 25. The examiner noted that he had
had an 18-to-19-year history of unilateral loss in the left ear. R. at
26.

In a June 1990 decision, the RO denied service connection for bilateral
HFHL, concluding that hearing in the right ear had been within normal
limits at separation, and that, although there was hearing loss in the
left ear at separation, the record of the entrance examination showed
that such hearing loss was present at entry and that the condition was
not aggravated beyond the normal progression of the condition. R. at
36-37. The veteran filed a Notice of Disagreement in June 1990 in which
he stated that the examination at separation from service did not
sufficiently evaluate whether his hearing loss may have been related to
his exposure to jet engine noise and that the examiner had told him then
that his discharge would be delayed if he wanted to pursue that issue.
R. at 42-43. After the RO issued a Statement of the Case, he submitted a
Form 1-9 (Appeal to the BVA), again asserting that his in-service noise
exposure had caused hearing loss. R. at 50-51.

In the March 13, 1991, BVA decision here on appeal, the Board denied
service connection for hearing loss. *Hensley*, BVA 91-\_\_\_\_\_ (Mar.
13, 1991). With respect to the right ear, the Board concluded that \"the
veteran\'s hearing acuity in his right ear was within normal limits
during service, and \[HFHL\] in the right ear was not present until many
years after service.\" *Id.* at 5. With respect to the left ear, the
Board noted that the threshold levels of 60 dB and 70 dB in the 4000 Hz
range recorded on the entrance and separation audiometric tests,
respectively, were outside of normal limits and represented a 10-decibel
diminishment in hearing acuity at that level during service. *Id.* at 4.
The Board concluded, however, that the recorded diminishment in hearing
during service was \"of minimal significance in demonstrating an
increase in the severity of any preservice hearing deficit\" and that
the evidence, therefore, did not demonstrate that the veteran\'s
preexisting right-ear hearing disability had been aggravated during
service. *Ibid.*

On appeal to this Court, the appellant asserts that the BVA erred in
concluding that his hearing was \"within normal limits\" upon separation
from service and in failing to consider whether any hearing loss
becoming manifest after his separation from service was related to his
exposure to noise trauma during service. In August 1992, after the
Secretary had filed a motion for summary affirmance, the Court ordered
the Secretary to file a supplemental memorandum of law; the Court also
permitted appellant to file a response to that memorandum. The Secretary
filed his memorandum in October 1992, and the appellant filed a response
in December 1992. The Court appreciates the contributions of both
parties.

**I. Analysis**

***A. Requirements for Establishing Service Connection for Hearing
Loss***

Service connection for VA disability compensation purposes will be
awarded for any disease or injury that was incurred or aggravated during
the veteran\'s active service or was initially manifested to a degree of
10% or more within an applicable presumption period. *See* 38 U.S.C.A.
§§ 1110, 1112 (West 1991); 38 C.F.R. §§ 3.303, 3.307 (1992).
Furthermore, when a disease was not initially manifested during service
or within the applicable presumption period, \"direct\" service
connection may nevertheless be established by evidence demonstrating
that the disease was in fact incurred or aggravated during the
veteran\'s service. *See* 38 U.S.C.A. § 1113(b) (West 1991); 38 C.F.R.
§ 3.303(d) (1992); *Cosman v. Principi*, 3 Vet.App. 503, 505 (1992);
*Triplette v. Principi*, 3 Vet.App. 370, 375 (1992); *Godfrey v.
Derwinski*, 2 Vet.App. 352, 356 (1992); *Douglas v. Derwinski*, 2
Vet.App. 103, 108-09 (1992).

Entitlement to service connection for impaired hearing is subject to the
additional requirements of 38 C.F.R. § 3.385 (1992), which provides:

> Service connection for impaired hearing shall not be established when
> hearing status meets pure tone and speech recognition criteria.
> Hearing status shall not be considered service-connected when the
> thresholds for the frequencies of 500, 1000, 2000, 3000, and 4000
> Hertz are all less than 40 decibels; the thresholds for at least three
> of these frequencies are 25 decibels or less; and the speech
> recognition scores using the Maryland CNC Test are 94 percent or
> better.

In *Ledford v. Derwinski*, 3 Vet.App. 87, 89 (1992), the Court held that
the regulation, although prohibiting an award of service connection
where audiometric test scores are within the established limits, does
not prevent a veteran from establishing service connection on the basis
of post-service evidence of hearing loss related to service when there
were no audiometric scores reported at separation from service. The
Court noted there that the Secretary\'s stated purpose in promulgating
section 3.385 in 1990 was \"to establish criteria for the purpose of
determining the levels at which hearing loss becomes disabling\" and to
establish \"a department-wide rule for making determinations regarding
service connection for impaired hearing\". *Id.* at 89 (quoting 55
Fed.Reg. 12348-02 (1990)). The Court stated: \"In one sense, the
regulation mixes apples and oranges in that it uses criteria for hearing
loss to determine service connection and not degree of disability\".
*Ibid.*

In its August 1992 order in this case, the Court directed the Secretary
to file a memorandum addressing, inter alia, the following issue:

> Does 38 C.F.R. § 3.385 (1991) establish that service connection for
> hearing loss may be awarded ***only*** when the level of hearing loss
> evidenced by audiometric and speech recognition testing meets that
> regulation\'s threshold criteria ***at the time of separation from
> service***; or may a veteran establish service connection where, as
> here, there is evidence of worsening of hearing in service (but not
> meeting the regulation\'s threshold criteria) and some years after
> service the veteran\'s hearing loss meets the regulation\'s threshold
> criteria? If it is the latter, the Secretary should further address
> the issue of the evidence required to establish service connection of
> a hearing loss meeting the regulatory criteria several years after
> separation from service. *See* 38 C.F.R. § 3.303(a), (b), and (d).

In his response, the Secretary states that section 3.385 does not
preclude an award of service connection for a hearing disability
established by post-service audiometric and speech-recognition scores,
even though hearing was found to be within normal limits on audiometric
and speech-recognition testing at the time of separation from service.
He asserts that the purpose of section 3.385 is to establish guidelines
for determining when a hearing \"disability\" is present within the
meaning of 38 U.S.C.A. § 1110 (West 1991), so that service-connected
disability compensation may be awarded, and that, \"\[r\]egardless of
when the regulation\'s threshold criteria are met, a determination must
be made as to whether the \'disability\' was incurred in or aggravated
by service.\" In describing the evidence necessary to establish service
connection when hearing disability is not demonstrated on testing at
separation from service, the Secretary states:

> \[W\]here the regulatory threshold requirements for hearing disability
> are not met until several years after separation from service, the
> record must include evidence of exposure to disease or injury in
> service that would adversely affect the auditory system and
> post-service test results meeting the criteria of 38 C.F.R. § 3.385.
> VA rating authorities must evaluate available testimony, clinical
> data, diagnoses, and any medical opinions relevant to the issue. *See*
> 38 C.F.R. § 3.303 (principles of service connection) . . . . For
> example, if the record shows (a) acoustic trauma due to significant
> noise exposure in service and audiometric test results reflecting an
> upward shift in tested thresholds in service, though still not meeting
> the requirements for a \"disability\" under 38 C.F.R. § 3.385, and (b)
> post-service audiometric testing produces findings meeting the
> requirements of 38 C.F.R. § 3.385, rating authorities must consider
> whether there is a medically sound basis to attribute the post-service
> findings to the injury in service, or whether they are more properly
> attributable to intercurrent causes.

Appellee\'s Response at 7-8.

The Court agrees with the Secretary\'s assertion that section 3.385 does
not preclude service connection for a current hearing disability where
hearing was within normal limits on audiometric testing at separation
from service. Although that regulation speaks in terms of \"service
connection\", it operates to establish when a measured hearing loss is
(or, more accurately, is ***not***) a \"disability\" for which
compensation may be paid, provided that the requirements for service
connection are otherwise met under 38 U.S.C.A. §§ 1110, 1112 and 38
C.F.R. §§ 3.303, 3.307. *Cf. Cuevas v. Principi*, 3 Vet.App. 542, 548
(1992) (\"establishing service connection requires a finding of the
existence of a current disability and a determination of a relationship
between that disability and an injury or disease incurred in service or
some other manifestation of the disability during service\"); *Rabideau
v. Derwinski*, 2 Vet.App. 141, 143 (1992) (\"there must be evidence both
of a service-connected disease or injury and a present disability which
is attributable to such disease or injury\"). Therefore, when
audiometric test results at a veteran\'s separation from service do not
meet the regulatory requirements for establishing a \"disability\" at
that time, he or she may nevertheless establish service connection for a
current hearing disability by submitting evidence that the current
disability is causally related to service. As the Court stated in
*Godfrey, supra*, where there was no evidence of the veteran\'s hearing
disability until many years after separation from service, \"\[i\]f
evidence should sufficiently demonstrate a medical relationship between
the veteran\'s in-service exposure to loud noise and his current
disability, it would follow that the veteran incurred an injury in
service; the requirements of section 1110 would be satisfied.\" *See
also Cosman, supra* (service connection may be established for
psychiatric disorder manifest many years after separation); *Triplette,
supra* (same); *Douglas, supra* (same as to carcinoma manifest many
years after separation).

Applying this analysis to the instant case, it is clear that section
3.385 does not prohibit an award of service-connected disability
compensation for the veteran\'s bilateral hearing loss. An April 1990 VA
audiometric examination revealed threshold hearing levels of 40 dB or
more at 4000 Hz in both ears. Section 3.385, as relevant here, prohibits
a finding of a hearing disability only where threshold hearing levels at
500, 1000, 2000, 3000, and 4000 Hz \"are ***all less than*** 40
decibels\" and at least three of those threshold levels are 25 db or
less. 38 C.F.R. § 3.385 (1992) (emphasis added). Where, as here,
***any*** of the relevant threshold hearing levels are 40 dB or more, a
determination as to whether the hearing loss is service connected must
be made under the statutory and regulatory provisions governing service
connection generally, and the determination of the level of disability
due to any such service-connected hearing loss will be made under 38
C.F.R. § 4.85 (1992) (\"Evaluation of hearing impairment\"). Because
application of the governing law and regulation pertaining to service
connection yields different analyses with respect to the veteran\'s
left-ear and right-ear hearing losses, it is necessary to discuss those
claims separately.

***B. Service Connection for Left-Ear Hearing Loss***

Pursuant to the standards in section 3.385, the veteran\'s hearing in
his left ear was outside of normal limits both upon his entrance into
and his separation from service, as evidenced by threshold hearing
levels of 60 and 70 dB, respectively, at 4000 Hz. Section 3.385
establishes that a \"disability\" will ***not*** be found to exist when
audiometric scores are within the established limits; it does not by its
terms require that a \"disability\" be ***found*** to exist whenever
audiometric scores are outside of those limits. However, 38 C.F.R.
§ 4.85, which establishes criteria for evaluating the severity of a
service-connected hearing disability, provides for a service-connected
disability rating for ***any*** amount of hearing loss, including where
average puretone decibel loss on audiometric examination is between 0-41
dB. 38 C.F.R. § 4.85, Tables VI, VIa, VII (1992). It is thus apparent,
in view of sections 3.385 and 4.85, that the veteran\'s left-ear hearing
loss constituted a \"disability\" at both entrance and separation.

Therefore, because the veteran had a hearing disability upon entry into
service, his entitlement to service connection for that condition must
be predicated on a finding that that condition was aggravated during
active service so as to warrant disability compensation under 38
U.S.C.A. §§ 1110 and 1153 (West 1991). *See also* 38 C.F.R. § 3.306(b)
(1992). Section 1153 provides:

> A preexisting injury or disease will be considered to have been
> aggravated by active military, naval, or air service, where there is
> an increase in disability during such service, unless there is a
> specific finding that the increase in disability is due to the natural
> progress of the disease.

38 U.S.C.A. § 1153 (West 1991). Section 3.306(b) further provides, with
respect to veterans of wartime service:

> Clear and unmistakable evidence (obvious or manifest) is required to
> rebut the presumption of aggravation where the preservice disability
> underwent an increase in severity during service. This includes
> medical facts and principles which may be considered to determine
> whether the increase is due to the natural progress of the condition.

38 C.F.R. § 3.306(b) (1992). Ratings for disabilities aggravated by
service are determined by \"deduct\[ing\] from the present degree of
disability the degree, if ascertainable, of the disability existing at
the time of entrance into active service, in terms of the rating
schedule\". 38 C.F.R. § 4.22 (1992). If the degree of disability at the
time of entry is not ascertainable in terms of the schedule, \"no
deduction will be made.\" *Ibid.*

The veteran\'s audiometric test results at entrance and separation
indicate a 10-decibel decrease in hearing capacity at 4000 Hz during
service. R. at 2, 10. In denying service connection for left-ear hearing
loss on the basis of aggravation, the BVA stated:

> In acknowledging a reported diminishment of 10 decibels at 4000 Hz in
> the left ear from testing performed upon induction and at separation
> from service, this variance is found to be of minimal significance in
> demonstrating an increase in the severity of any preservice hearing
> deficit. Moreover, normal findings were noted at the other hertz
> levels of pertinence to demonstrating hearing loss. Accordingly, the
> evidence does not reflect an ascertainable hearing loss upon
> separation from service that could adequately be characterized as
> reflecting an aggravation, or worsening, of the veterans \[sic\]
> preservice hearing capabilities.

*Hensley*, BVA 91-\_\_\_\_\_, at 4. Although this statement is fraught
with ambiguity, it appears that the Board concluded that the recorded
decrease in hearing ability did not constitute an \"increase in
disability\" during service so as to create a presumption of aggravation
under the applicable statutory and regulatory provisions set forth
above.

Pursuant to 38 U.S.C.A. § 7104(d)(1) (West 1991), the Board is required
to provide a written statement of the reasons or bases for its findings
and conclusions on all material issues of fact and law presented on the
record; the statement must be adequate to enable a claimant to
understand the precise basis for the Board\'s decision, as well as to
facilitate review in this Court. *See* *Masors v. Derwinski*, 2 Vet.App.
181, 188 (1992); *Hatlestad v. Derwinski*, 1 Vet.App. 164, 169 (1991)
(*Hatlestad I*); *Gilbert v. Derwinski*, 1 Vet.App. 49, 57 (1990). To
comply with this requirement, the Board must analyze the credibility and
probative value of the evidence, account for the evidence which it finds
to be persuasive or unpersuasive, and provide the reasons for rejecting
any evidence favorable to the veteran. *See Simon v. Derwinski*, 2
Vet.App. 621, 622 (1992); *Abernathy v. Derwinski*, 2 Vet.App. 391, 394
(1992); *Hatlestad I, supra*; *Gilbert, supra*. Moreover, the Board may
not base a decision on its own unsubstantiated medical conclusions but,
rather, may reach a medical conclusion only on the basis of independent
medical evidence in the record or adequate quotation from recognized
medical treatises. *See Hatlestad v. Derwinski*, 3 Vet.App. 213, 217
(1992) (*Hatlestad II*); *Colvin v. Derwinski*, 1 Vet.App. 171, 174
(1991); *see also Thurber v. Brown*, \_\_ Vet.App. \_\_, \_\_, No.
92-172, slip op. at 9 (U.S. Vet. App. May 14, 1993) (where BVA intends
to rely on medical evidence, it must give claimant notice of such intent
and opportunity to respond).

In the instant case, the Board failed to provide any reasons or bases to
support the conclusion that the objectively measured worsening of
left-ear hearing capacity during service did not constitute an
\"increase in disability\" requiring application of the statutory
presumption of aggravation. Specifically, in reaching that cursory
conclusion, the Board did not discuss the criteria it used, in terms of
the applicable law and regulation, for determining whether there had
been an \"increase in disability\" during service. Because the
veteran\'s service medical records clearly reflect an objectively
measurable and measured worsening of hearing during service, the Board
was required to determine whether that worsening constituted an
in-service \"increase in disability\" within the meaning of section
1153, and to provide a statement of reasons or bases, explaining the
Board\'s analysis of all pertinent evidence in the context of all
pertinent law and regulation, sufficient to enable the claimant and the
Court to understand the \"precise basis\" for the Board\'s decision.
*Gilbert*, 1 Vet.App. at 56.

Neither the statute nor the regulations set forth the criteria for
determining whether a measured worsening of a disease or injury
constitutes an \"increase in disability\" within the meaning of section
1153. In *Hunt v. Derwinski*, this Court held that \"\[t\]he term
\'disability\' \[in section 1153\], as contemplated by VA regulations
\[(38 C.F.R. § 4.1)\], means \'impairment in earning capacity resulting
from such diseases and injuries and their residual conditions\'\", and
that the ratings in VA\'s rating schedule in part 4, title 38, U.S. Code
of Federal Regulations, \"\'represent as far as can practicably be
determined the average impairment in earning capacity resulting from
such diseases and injuries and their residual conditions in civil
occupations\'.\" *See Hunt v. Derwinski*, 1 Vet.App. 292, 296 (1991)
(quoting 38 C.F.R. § 4.1 (1990)). Presumably, then, in instances where
VA\'s rating schedule provides a sufficiently comprehensive basis for
determining when any measured worsening of a condition causes a
measurable \"impairment in earning capacity\", application of the
rating-schedule provisions to the veteran\'s measured level of
disability at entrance onto and separation from service will determine
whether there was an \"increase in disability\".

However, in *Browder v. Derwinski*, 1 Vet.App. 204, 207 (1991), the
Court pointed out that VA\'s schedule of ratings is designed to
establish disability ratings for purposes of paying compensation for
disabilities that have already been shown to be service connected, and
that the schedule thus may not in all cases provide an adequate basis
for determining when a disability has increased in severity for purposes
of establishing service connection under section 1153. *See* 38 U.S.C.A.
§ 1155 (West 1991) (instructing Secretary to establish a schedule for
rating disabilities providing \"ten grades of disability, and no more,
upon which payments of compensation shall be based\"). The *Browder*
Court thus held that the presumption of aggravation may apply \"where
there was a worsening of the disability regardless of whether the degree
of worsening was enough to warrant compensation\", and remanded to the
BVA a claim where evidence demonstrated a decrease in the veteran\'s
right-eye visual acuity in service without discussing whether that
increase would have been cognizable under VA\'s rating schedule.
*Browder*, 1 Vet.App. at 207.

As noted above, VA\'s rating schedule is constructed for the purpose of
establishing levels of disability for compensation purposes based upon
\"average impairment in earning capacity\" resulting from particular
injuries or diseases. 38 U.S.C.A. § 1155 (West 1991). Moreover, although
section 1155 directs the Secretary to establish in the rating schedule
\"ten grades of disability\" for evaluating the severity of such
conditions, the Secretary has provided less than ten levels of
disability for most of the conditions listed in the schedule. *See
generally* 38 C.F.R. §§ 4.71a - 4.150 (1992). Therefore, the schedular
ratings established by the Secretary for compensation purposes may not
in all cases provide a sufficiently comprehensive basis for determining
when a measured worsening of a particular veteran\'s condition in
service constitutes an \"increase in disability\" for purposes of
establishing service connection through aggravation under section 1153.
This would seem to be so where the next higher rating is more than one
decile greater.

Furthermore, the rating-schedule provisions may not in all cases provide
the most accurate or most logical basis for determining whether there
has been an \"increase in disability\" during service. For example, with
respect to organic mental disorders and psychoneurotic disorders, the
rating schedule provides for disability ratings based on a finding that
the condition causes \"total\", \"severe\", \"considerable\",
\"definite\", or \"mild\" social and industrial impairment. *See* 38
C.F.R. § 4.132, Diagnostic Codes 9300-9411 (1992). In determining
whether an organic mental disorder or psychoneurotic disorder was
aggravated during a veteran\'s active service many years before, it is
certainly reasonable to suppose that evidence may clearly establish that
the disability increased in severity during service and caused a
decrease in the veteran\'s earning capacity, although the application of
the above-listed adjectives at entry and at separation from service may
not be as clear.

Based upon the foregoing analysis and the Court\'s opinions in *Hunt*
and *Browder*, the Court holds that the presence of a ratable increase
in disability at separation would be conclusive of an in-service
increase in disability, but the obverse would not be true; that is, the
absence of a ratable in-service increase would not rule out a
determination of an increase in disability. Where the rating schedule
does not provide a comprehensive basis for a BVA determination as to
whether a measured worsening of a preexisting condition ***in a
particular case*** constitutes an \"increase in disability\" under
section 1153, evidence of record might clearly establish that there has
been an \"increase in disability\" for purposes of establishing a
presumption of aggravation under section 1153 even though it is not
clear that such increase would have resulted in an increased rating
under the rating-schedule provisions for that particular disability.

Therefore, in adjudicating a claim such as the present one for service
connection based on aggravation under section 1153, the Board\'s reasons
or bases must include an explanation of the criteria used by the Board
to determine whether a measured worsening of the disability during
service constituted an \"increase in disability\", and an explanation of
how those criteria apply to the facts of the particular claim being
decided. If the Board determines that application of the rating-schedule
criteria is conclusive as to that determination, the Board must explain
why it views those rating-schedule criteria as the only adequate basis
for making that determination and must explain how those criteria apply
to the veteran\'s disability as noted at entrance onto and separation
from service. If the Board concludes that the rating-schedule provisions
do not provide the only adequate basis for determining whether there has
been an in-service increase in disability under section 1153 from a
particular disease or injury during service, the Board must explain the
criteria used to determine whether there has been an \"increase in
disability\" with respect to that condition as well as the resulting
evaluation of the evidence under such criteria.

In the instant case, the Board did not explain the criteria it used to
determine whether there was an increase in disability from the
veteran\'s left-ear hearing condition during service, and how, pursuant
to such criteria, it concluded that the measured decrease in left-ear
hearing acuity during service did not demonstrate an \"increase in
disability\" under section 1153. Therefore, remand is required for
prompt readjudication and issuance of a decision supported by reasons or
bases consistent with this opinion. If on remand the Board concludes
that the veteran\'s left-ear hearing condition did increase in severity
during service, the Board must apply the presumption of aggravation and
explain whether or not that presumption has been rebutted by clear and
unmistakable evidence. *See* 38 U.S.C.A. § 1153; 38 C.F.R. § 3.306(b).
If the Board concludes that the presumption is rebutted because the
in-service increase in disability was due to the natural progress of the
disease, it must point to independent medical evidence or quote
recognized medical treatises to provide adequate support for that
medical conclusion. *See* 38 U.S.C.A. § 7104(d)(1) (West 1991);
*Thurber, supra;* *Hatlestad II, supra*; *Colvin, supra*.

***C. Service Connection for Right-Ear Hearing Loss***

With respect to the veteran\'s right-ear hearing ability, all reported
hearing thresholds were less than 40 dB on audiometric testing at entry
and separation and all but one were 25 or less at separation. Therefore,
under the standards established by section 3.385, there was no
indication of a right-ear hearing \"disability\" during service.
However, the entrance and separation audiometric scores revealed a
decrease in hearing ability of 15-30 dB at all reported Hz levels during
service (R. at 2, 10), although audiometric scores sufficient to
establish a right-ear hearing disability for which service connection
may be awarded consistent with section 3.385 were not reported until the
April 1990 VA examination. R. at 25-26.

On the basis of this evidence, the Court finds a plausible basis for the
BVA\'s conclusion that a right-ear hearing disability was not manifested
during service or to a 10% degree during the one-year presumption period
following service, and, therefore, that conclusion is not subject to
reversal as a clearly erroneous finding of fact. *See* 38 U.S.C.A.
§ 7261(a)(4) (West 1991); *Gilbert*, 1 Vet.App. at 53. However, that
finding does not end the inquiry. As noted in part II.A., above, a
claimant may establish direct service connection for a hearing
disability initially manifest several years after separation from
service on the basis of evidence showing that the current hearing loss
is causally related to injury or disease suffered in service. *See* 38
U.S.C.A. § 1113(b); 38 C.F.R. § 3.303(d); *Godfrey, supra*; *see also
Cosman, supra*; *Triplette, supra*; *Douglas, supra*.

In the present case, the evidence supporting a claim of direct service
connection for a right-ear hearing disability manifested many years
after service includes audiometric test scores showing a 15-30-decibel
decline in all recorded threshold hearing levels during service (R. at
2, 10); the veteran\'s statements that he suffered significant noise
exposure working on an aircraft carrier during service (R. at 16, 22,
43, 50-51); the veteran\'s service separation report indicating his
service with an attack squadron (R. at 13, 35); and private physicians\'
reports stating that the veteran\'s hearing loss was probably due to
noise trauma, including exposure to jet-aircraft noise during service
(R. at 31, 34). In light of this evidence, the Board was required to
determine whether the veteran\'s current right-ear hearing disability
was causally related to in-service noise exposure. Because the Board
failed to address that question, remand is required for adjudication of
that direct service connection claim. Moreover, because the veteran has
submitted \"significant evidence\" supporting his claim of service
connection for a right-ear hearing disability, the Board must consider
and discuss the applicability of the \"benefit-of-the-doubt\" rule in 38
U.S.C.A. § 5107(b) (West 1991) in determining whether the evidence
establishes entitlement to service-connected disability compensation.
*See Williams (Willie) v. Brown*, \_\_ Vet.App. \_\_, \_\_, No. 91-901,
slip op. at 6 (U.S. Vet. App. Feb. 18, 1993) (\"where there is
significant evidence in support of an appellant\'s claim, as there is
here, the Board must provide a satisfactory explanation as to why the
evidence was not in equipoise\"); *Gilbert*, 1 Vet.App. at 54.

**III. Conclusion**

Based upon the foregoing opinion, the Court denies the Secretary\'s
ill-advised motion for summary affirmance, vacates the March 13, 1991,
BVA decision, and remands the matter to the Board for prompt
readjudication, consistent with this opinion, on the basis of all
evidence of record and all applicable provisions of law and regulation.
*See* 38 U.S.C.A. § 7104(a) (West 1991); *Fletcher v. Derwinski*, 1
Vet.App. 394, 397 (1991). \"On remand, the appellant will be free to
submit additional evidence and argument\". *Quarles v. Derwinski*, 3
Vet.App. 129, 141 (1992). A final decision by the Board following the
remand herein ordered will constitute a new decision which, if adverse,
may be appealed to this Court only upon the filing of a new Notice of
Appeal with the Court not later than 120 days after the date on which
notice of that new decision is mailed to the appellant.

VACATED AND REMANDED.