Synopsis
This is the report of the Inter-Society Working Group on Hearing Disability, which was founded in 1986 and completed its work in 1991. The report proposes a method for the quantification of hearing disability resulting from hearing impairment for the purposes of description and compensation, with particular reference to noise-induced hearing deficit. The book will be of interest to medical specialists concerned with the assessment of hearing disability as well as to legal professionals dealing with compensation claims in this area and to those with an academic interest in disability assessment.

Part 1 Introduction: historical background and terms of reference
rationale and philosophy
scope and report. Part 2 Definitions particular to this report. Part 3 Technical background: general
surrogate measures of disability
characterization of the concept of hearing disability
scale relation between autiometric impairment and disability
the low fence and the high fence
differential weighting of the two ears
age-associated hearing loss. Part 4 Audiometric equipment: equipment for air-conduction audiometry
equipment for bone-conduction audiometry
additional equipment
equipment required for calibration of audiometers
quality assurance
quality assurance - general
principles of calibration
procedures
background noise requirements for the test room
specific recommendations applicable to audiometry for disability assessment. Part 5 Determining hearing threshold levels in usual cases: audiometric procedure - procedure for air conduction testing
procedure for bone conduction testing
reporting of results
sources of error in audiometry - sources of objective error
systematic and random uncertainties associated with audiometric techniques
uncertainties associated with the subject
normal expectation of audiometric reliability
abnormal performance or unusual occurrences
uncertainties associated with audiometric techniques
uncertainties associated with the subject
normal expectation of audiometric reliability
abnormal performance or unusual occurrences
uncertainties associated with the audiometrician and the interpretation or responses
qualifications and training of personnel. Part 6Determination of hearing threshold levels in abnormal cases: detection of spurious hearing threshold level (SHTL)
estimation of genuine hearing threshold levels (GHTL). Part 7 Evaluation of compensable hearing loss: mandatory requirements
conditional and discretionary tests
principles of evaluation
age-associated hearing loss (AAHL)
evaluation of a conductive component of hearing loss
relevant conductive hearing loss
evaluation of the decibel value of the CHL. Part 8 Tables for calculating percentage disability: source material and derivation
basic relation between hearing threshold level and percentage disability
binaural evaluation
tables of percentage disability. Part 9 Assessment of disability: general plan
diagnosis of noise-induced hearing loss
assessment of overall and noise-induced hearing disability
apportionment
how to use the tables
general procedure
procedure when there is a constitutional element. Part 10 Additional assessment procedures: retrospective assessment and rules for apportionment
prognostic assessment
other considerations
tinnitus
noise-induced vestibular malfunction
use of hearing aids. Part 11 Contents of the medicolegal report. Part 12 Summary of recommendations.