Changes in click characteristics during ABR recording.
Manipulation of auditory stimuli affect the ABR evoked potentials and aid the diagnosis, particularly in auditory neuropathy patients. Some patients with auditory neuropathy lose evoked otoacoustic emissions over time; in these cases, comparing responses to rarefaction and condensation clicks, and decreasing the stimulus rate can show an extended cochlear microphonism or yield an improved electric potential record.


OBJECTIVE
To analyze the effect of these click manipulations on the records of potentials of patients with hearing loss as a form of improving the diagnosis.


METHODS
A clinical prospective study.


METHODS
59 patients with hearing loss underwent ABR recording using rarefaction and condensation clicks at a stimulus rate of 27.7/sec, and rarefaction clicks at a stimulus rate of 3.3/sec. The records were compared to the otoacoustic evoked emission.


RESULTS
Eight (13.53%) patients showed changes in the recorded ABR potentials as a result of manipulating the characteristics of clicks, such as extended cochlear microphonism or an improved record of electric potentials. Five patients had no otoacoustic evoked emissions.


CONCLUSIONS
Manipulation of click stimuli can improve the topographic diagnosis of hearing loss, particularly in the group of auditory neuropathy patients with no otoacoustic evoked emissions, where usually, the diagnosis is only possible through the method described above.
Fávero
Mariana Lopes
ML
FM, USP, Sao Paulo SP, Brazil. lopessquare@ig.com.br
Silva
Fernando L Carvalho
FL
Tabith Junior
Alfredo
A
Nicastro
Fernanda S
FS
Gudmond
Monica C
MC
Spinelli
Mauro
M
D000328:Adult; D002648:Child; D002675:Child, Preschool; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D034381:Hearing Loss / Q000175:diagnosis* / Q000503:physiopathology; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011446:Prospective Studies; D012720:Severity of Illness Index