Primary auditory neuropathy - an enigma.
OBJECTIVE
To report audiological and neuroradiological findings in patients with primary auditory neuropathy (PAN) from a tertiary institution in south India.


METHODS
The auditory profiles in 24 patients were analyzed along with neurological and radiological findings.


RESULTS
Puretone audiometry showed varied hearing acuity and configuration. The syllable recognition score (n=15) was above 80% except in three. The dichotic digit test (n=11) showed bilateral suppression except in two who showed unilateral suppression. The auditory brainstem responses and the acoustic stapedius reflex were absent with distortion product otoacoustic emission (DPOAE) present in all. The neurological and radiological studies were normal.


CONCLUSIONS
The audiological profile is consistent with the presence of DPOAE and absence of acoustic stapedius reflex and auditory brainstem responses. In patients with adequately preserved syllable recognition in quiet conditions, there was a significantly poor performance on dichotic digit test. As these patients had no neurological deficits and absence of specific etiological factors, we propose to use the term PAN for this entity.
Shivashankar
N
N
Department of Speech Pathology and Audiology, National Institute of Mental Health and Neuro Sciences, Bangalore, India. shiv@nimhans.kar.nic.in
Satishchandra
P
P
Shashikala
H R
HR
Gore
M
M
D000161:Acoustic Stimulation; D000328:Adult; D017668:Age of Onset; D001299:Audiometry; D001933:Brain Stem / Q000503:physiopathology*; D005260:Female; D006311:Hearing Disorders / Q000503:physiopathology*; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D012018:Reflex; D012189:Retrospective Studies; D012737:Sex Factors; D013198:Stapedius / Q000503:physiopathology