PATIENTS: Thirty-seven individuals with tinnitus and 38 without tinnitus, with ages ranging from 20 to 45 years and pure-tone thresholds of 25 dB or better at frequencies between 500 and 8000 Hz. The aim of our investigation was to compare the BAEP results of this group with those of healthy controls with presbycusis and to look for possible correlations between alteration of the auditory brainstem function and the aging of elderly diabetic patients. In the Meniere’s disease Recruitment could be demonstrated at auditory brainstem evoked responses as well as retrocochlear lesion could be ruled out by studying the interpeak latency values which greatly helped to differentiate a unilateral Meniere’s disease from an acoustic neuroma. We measured the effects of locally applied forskolin on spontaneous firing rate of isolated neurons in the peri-olivary region of the superior olive complex in anesthetized adult Long Evan rats. In the two cases in which vecto-electronystagmography showed central vestibular alteration, there were no changes to the evoked potential parameters. We then administered vigabatrin, a GABA transaminase inhibitor, in the animals to suppress NaSal-induced tinnitus. The BAER is also helpful in the diagnosis of demyelinating diseases (multiple sclerosis) of the brain, tumors of the hearing and balance nerve (acoustic neuroma), and brain stem strokes.
Synchronized discharges of the auditory nerve fibers and inhibition of the abnormal activity of the cochlear nerve by AES may play important roles associated with RI. This group is further divided into three subgroups according to tinnitus laterality: GIIa (20 subjects with bilateral tinnitus), GIIb (20 subjects with right ear tinnitus and GIIc (20 subjects with left ear tinnitus). Both groups were submitted to full audiological history taking, otological examination, basic audiologic evaluation and Auditory brainstem response audiometry (ABR) which was recorded in both groups followed by calculation of the absolute latencies of wave I, III and V, interpeak latencies as well as the interaural latency difference of wave V.Generally, there was no significant difference between both groups, however, some tinnitus patients showed abnormal prolonged absolute latencies, interpeak latencies and increased interaural latency difference of wave V. When hearing loss was asymmetrical and on the tinnitus-affected side, there was also lengthening of 0–1 latencies on the tinnitus-affected side in both sexes and of ipsi and contralateral I–V latencies in women. Some cases have normal results while others showed prolonged absolute or interpeak latencies or increased ILD-V difference.