U. Proschel et U. Eysholdt, SPECIFITY AND SENSITIVITY OF TRANSIENT CL ICK-EVOKED OTOACOUSTIC EMISSIONS (TEOAE) IN CHILDREN, Laryngo-, Rhino-, Otologie, 74(8), 1995, pp. 481-488
Transient click evoked otoacoustic emissions (TEOAE) have been shown t
o be a good test of hearing impairment especially when used for infant
screening. However, occasional cases of false positive results - TEOA
Es in spite of severe hearing loss - have been reported. This study en
compasses 243 children whose hearing thresholds were known from subjec
tive hearing tests and - in questionable cases - derived from addition
al auditory evoked potentials. The TEOAEs proved to have a high sensit
ivity (93%) and a reasonable specifity (67%), if the margin between go
od and bad hearing was set at 30 dB. However, four ears showed good TE
OAEs in spite of poor hearing thresholds. In three cases, the children
proved to have a central auditory hearing loss due to a cerebral diso
rder. One child with bilaterally superb TEOAEs had a unilateral deafne
ss of unclear origin with no obvious retrocochlear or central disorder
. Possible explanations under discussion included the presence of a re
trocochlear lesion which was too small to show up in the tests used or
that the defect was located just between the outer hair cells and the
first neuron, for example in the inner hair cells. Additionally, effe
rent inhibition might cause a functional deafness as described by Raja
n (1989) for the guinea pig. The results also show that TEOAEs should
always be used in the differential diagnosis of hearing impairment in
generally disabled children. The need for hearing aids and especially
their adjustment has to be discussed in case of good TEOAEs, i.e., nor
mal peripheral hearing. The use of a hearing aid without any peak clip
ping and gain control on the basis of subjective hearing tests and ABR
only, as is sometimes suggested, may lead to severe hearing loss in t
hese cases due to the loudness of the hearing aid.