Wave I in brain-stem response audiometry arises from-

Ans. is 'a' i.e., Cochlear nerveBrain Stem Response Audiometry (BERA)o It is a non-invasive procedure which objectively helps to find the integrity of central auditory pathway through the VIII nerve, pons and mid brain. It is accurate to within 10 or 15 dB of the psychoacoustic thereshold. It is the most reliable audiological method of differentiating between cochlear and Retrocochlear hearing losses. It is anobjective test and can be done under sedation.o It is used both as a screening test and as a definative hearing assessment test in children. Best test to detect deafness in infants (reliably recorded even from premature infants of 30 weeks gestational age) and mentally retarded or malingering subjects. It is also used for Identification of the site of lesion in Retrocochlear pathologies and to diagnose brainstem pathology e.g. multiple sclerosis or pontine tumor.Waves of BERAo In a normal person, 7 waves are produced in first 10 miliseconds. The first, third and fifth waves are most stable and are used in measurements. Site of origin of waves areWave I-Distal part of Eighth nerveWave II-Proximal part of Eighth cranial nerveWave III-Cochlear nucleusWave IV-Superior olivary complexWaveV-Lateral leminiscusWave VI & VII-Inferior colliculus