Jun Yamaguchi

Relationship between Auditory Brainstem Response Waveform and Head Size

The relationship between the head size and the latency and amplitude of the auditory brainstem response (ABR) was investigated in 60 normal-hearing adults (30 males and 30 females). We found a strong positive correlation between the latency of ABR waves and the head size and a strong negative correlation surfaced between the ABR amplitude and head size. These results indicate that the head size is one of the most important factors influencing the waveform of the ABR.

Neurotological Findings in Bell's Palsy and Hunt's Syndrome

Neurotological findings were analysed in 23 patients with Bells palsy and in 25 patients with Hunts syndrome. The incidence and extent of the auditory and vestibular pathology was high in Hunts syndrome. Although patients had no subjective symptoms related to the auditory and/or vestibular pathology in the Bells palsy cases, about one-third of the patients showed abnormal findings upon neurotological examination. Differentiating these two diseases is therefore considered difficult by means of neurotological examination in the same way as by serological testing as has been reported by other investigators.

Changes in the auditory brain-stem response in comatose patients.

The auditory brain-stem response (ABR) was correlated with age, cause of coma and prognosis in 157 comatose patients. It was found that changes in the ABR could not be attributed to the age or cause of coma. In the patients who recovered and the persistent vegetative state the one to five inter wave latency became shorter. In the patients who later died, the one to five inter wave latency was prolonged. The patients who showed no response or only wave one from the beginning of coma and those in whom the wave form increased with the latency all died. These findings suggest that the ABR may be important test for judging the prognosis in comatose patients.

Postoperative observations following tympanoplasty.

Postoperative observations were reported after tympanoplasty of 478 patients during last 5 years and 9 months. Changes in hearing level, incidence of re-perforation of the tympanic membrane, presence of ear drainage, and development of cholesteatoma were the main items investigated.Hearing level reached a certain level about one year after tympanoplasty and maintained that level afterwards. The incidence of permanent re-perforation was .5% and that of ear drainage was 2.5%. The development of cholesteatoma was observed 28 patients, 17.2% of all cholesteatoma cases (163 cases). The recurrence of cholesteatoma was usually diagnosed one to three years after tympanoplasty under operation microscope. Therefore, postoperative observation should be carried out for at least three years after surgery. In our clinic, however, more than 10% of the patients who received tympanoplasty did not return for examination three years after surgery. It is important to strive to increase the postoperative observation rate to 100% after tympanoplasty.

Tinnitus measurement and treatment - Part. 3 Follow up study on the long-term use of band-noise masker.

A follow up study was carried out of 12 patients using band-noise masker for 6 months to 3 years.Various auditory tests and measurements of tinnitus were performed before and after the long-term use of band-noise tinnitus masker: loudness balance, masking and pitch match tests.None of the 12 patients showed any remarkable changes in hearing at the 7 frequencies tested, from 125 to 8000Hz. Tinnitus frequency obtained by the pitch match method demonstrated no changes after long-term listening to band-noise. The contralateral loudness balance method indicated changes of tinnitus loudness; however, both the ipsilateral loudness balance method and the masking method showed no remarkable changes of tinnitus loudness after the long-term use of a tinnitus masker.We conclude that the long-term use of a band-noise masker has no effect on the pure tone threshold as long as close follow-up examinations are performed.