Appendix C to Part 227 - Audiometric Baseline Revision
49:4.1.1.1.21.4.15.1.44 : Appendix C
Appendix C to Part 227 - Audiometric Baseline Revision
This appendix is mandatory beginning on February 26, 2009.
I. General
A. A professional reviewer (audiologist, otolaryngologist, or
physician) shall use these procedures when revising baseline
audiograms.
B. Although these procedures can be programmed by a computer to
identify records for potential revision, the final decision for
revision rests with a human being. Because the goal of the
guidelines is to foster consistency among different professional
reviewers, human override of the guidelines must be justified by
specific concrete reasons.
C. These procedures do not apply to: The identification of
standard threshold shifts (STS) other than an FRA STS 1 or to the
calculation of the 25-dB average shifts that are reportable on the
Form FRA F 6180.55a.
1 OSHA and FRA use the same definition for Standard Threshold
Shift (STS). FRA's definition is located in § 227.5. OSHA's
definition is located in 29 CFR 1910.95(g)(10)(i).
D. Initially, the baseline is the latest audiogram obtained
before entry into the hearing conservation program. If no
appropriate pre-entry audiogram exists, the baseline is the first
audiogram obtained after entry into the hearing conservation
program. Each subsequent audiogram is reviewed to detect
improvement in the average (average of thresholds at 2, 3, and 4
kHz) and to detect an FRA STS. The two ears are examined separately
and independently for improvement and for worsening. If one ear
meets the criteria for revision of baseline, then the baseline is
revised for that ear only. Therefore, if the two ears show
different hearing trends, the baseline for the left ear may be from
one test date, while the baseline for the right ear may be from a
different test date.
E. Age corrections do not apply in considering revisions for
improvement (Rule 1). The FRA-allowed age corrections from appendix
F of Part 227 2 may be used, if desired, before considering
revision for persistent STS. Rule 2 operates in the same way,
whether age corrections are used or not.
2 FRA and OSHA use the same age-correction provisions. FRA's is
found in appendix F of part 227 and OSHA's in appendix F of 29 CFR
1910.95.
II. Rule 1: Revision for Persistent Improvement
If the average of the thresholds for 2, 3, and 4 kHz for either
ear shows an improvement of 5 dB or more from the baseline value,
and the improvement is present on one test and persistent on the
next test, then the record should be identified for review by the
audiologist, otolaryngologist, or physician for potential revision
of the baseline for persistent improvement. The baseline for that
ear should be revised to the test which shows the lower (more
sensitive) value for the average of thresholds at 2, 3, and 4 kHz
unless the audiologist, otolaryngologist, or physician determines
and documents specific reasons for not revising. If the values of
the three-frequency average are identical for the two tests, then
the earlier test becomes the revised baseline.
III. Rule 2: Revision for Persistent Standard Threshold Shift
A. If the average of thresholds for 2, 3, and 4 kHz for either
ear shows a worsening of 10 dB or more from the baseline value, and
the STS persists on the next periodic test (or the next test given
at least 6 months later), then the record should be identified for
review by the audiologist, otolaryngologist, or physician for
potential revision of the baseline for persistent worsening. Unless
the audiologist, otolaryngologist, or physician determines and
documents specific reasons for not revising, the baseline for that
ear should be revised to the test which shows the lower (more
sensitive) value for the average of thresholds at 2, 3, and 4 kHz.
If both tests show the same numerical value for the average of 2,
3, and 4 kHz, then the audiologist, otolaryngologist, or physician
should revise the baseline to the earlier of the two tests, unless
the later test shows better (more sensitive) thresholds for other
test frequencies.
B. Following an STS, a retest within 90 days of the periodic
test may be substituted for the periodic test if the retest shows
better (more sensitive) results for the average threshold at 2, 3,
and 4 kHz.
C. If the retest is used in place of the periodic test, then the
periodic test is retained in the record, but it is marked in such a
way that it is no longer considered in baseline revision
evaluations. If a retest within 90 days of periodic test confirms
an FRA STS shown on the periodic test, the baseline will not be
revised at that point because the required six-month interval
between tests showing STS persistence has not been met. The purpose
of the six-month requirement is to prevent premature baseline
revision when STS is the result of temporary medical conditions
affecting hearing.
D. Although a special retest after six months could be given, if
desired, to assess whether the STS is persistent, in most cases,
the next annual audiogram would be used to evaluate persistence of
the STS.