Kouji Hachikawa

Evoked otoacoustic emissions from ears with idiopathic sudden deafness.

Evoked otoacoustic emissions (EOEs) were examined in ears with idiopathic sudden deafness (ISD) at an early stage after onset and were compared with those in ears with long-standing sensorineural hearing losses of unknown etiology (SHLUE). In ears with SHLUE, EOEs were not recordable from ears with a hearing loss exceeding 35 dB at minimum hearing level of 4 audiometric frequencies: 500, 1,000, 2,000 and 4,000 Hz (4 MHL). On the other hand, although 4 MHLs were greater than 35 dB in most of the ears, EOEs could be detected in about one-half of the ears with ISD, and, moreover, the majority of these EOE detectable ears showed a good hearing prognosis in spite of the degree of hearing loss. There was, however, no correlation between EOE threshold and degree of hearing recovery. From these results it seems that EOE testing might be clinically applicable for predicting whether or not hearing loss due to ISD can be recovered.

Frequency Analysis of Evoked Otoacoustic Emissions

Evoked otoacoustic emissions (EOEs) were examined in 8 normal hearing ears without spontaneous otoacoustic emissions (SOEs), and the frequency of the first 10 ms after appearance of the EOE response wave was analyzed, dividing it into the first 5 ms half (First half A) and the last 5 ms half (Last half B). In the First half A, the peak frequency of the power spectrum tended to match the stimulus frequency, but in the Last half B, the peak frequency tended to be constant and moreover, it tended to match the frequency at which EOE can best be recorded. These findings suggest that each ear has its own characteristic EOE frequency.

Clinical effect of bifemelane hydrochloride in patients with vertigo.

The therapeutic effect of Bifemerane Hydrochloride was studied in 43 patients with vertigo. The patients were given a 50mg tablet of Bifemelane Hydrochloride three times daily for over 8 weeks.Evaluation of the final global improvement showed it to be very effective in 7 patients (16.3%), moderately effective in 15 (34.9%) and slightly effective in 13 (30.2%), giving a total efficacy rate of 81.4%.No side effects were noted.Bifemerane Hydrochloride tablets were considered to be useful for patients with vertigo.