Estimation of the loudness of tinnitus from matching tests.

To correct for the influence of recruitment when the loudness of tinnitus is measured by a balance test in an ear with sensorineural hearing loss, an averaged loudness function was devised, which converts the sensation level (SL) of tinnitus into an estimate of the effective loudness level. This is essentially the same as a phon scale except for the difference in reference level, and is defined as the equivalent SL of the tinnitus as if measured in an ear with a bone-conduction threshold of 0 dB HL at a frequency between 500 Hz and 4000 Hz. Using this function, the median estimated loudness of tinnitus from 301 randomly selected patients was 15 dB 'effective loudness level' with a maximum of more than 60 dB. A nomogram was made for clinical use to determine the effective loudness level easily from the SL of tinnitus and the bone-conduction HTL of the test ear. Although somewhat approximate, the effective loudness level is considered to be an unbiased loudness estimate of tinnitus under the condition that only the SL of tinnitus and the bone-conduction HTL are available, and makes it easier to appreciate the actual loudness compared with a complex loudness unit such as on the sone scale.

Detection of the unilateral vestibular recruitment phenomenon using the rotation test.

The possibility of detecting unilateral vestibular recruitment using the rotation test was examined. According to the analogy model of cochlear recruitment, the directional difference of rotation nystagmus reaches its maximum at the threshold stimulus intensity of the affected ear when recruitment is present, and the predicted maximum directional difference remains within the normal variation range when the contribution from the spontaneous nystagmus is removed. Moreover, there was no difference in the positive ratio of recruitment in the rotation test between the two groups evaluated as having positive and negative recruitment on the caloric test. From these results, detection of the unilateral vestibular recruitment phenomenon, when similar to the cochlear recruitment, was concluded to be difficult using the rotation test.

[Biological characteristics and prognosis of supraglottic carcinoma--a multivariate correlation analysis of prognosis].

The biological characteristics of supraglottic carcinoma was studied with special reference to the correlations of various biological factors with the prognosis of the lesion. The study included 100 cases of supraglottic carcinoma treated by total laryngectomy in the First Hospital of China Medical University in the period from 1975 to 1978, and 7 factors including histopathological findings observed in serial sections of the whole larynx, clinical findings, clinical course, etc. These factors were statistically analyzed by multiple correlation analysis using the theory of quantification I to determine the relations of these factors to the prognosis, as well as their participations in post operative course. 1. Twenty-seven cases died within 5 years after surgery, and 4 cases could not be followed up. 3 and 5-year survival rates were 79.5% and 72.2%, respectively, as calculated in accordance with the UICC General Rule. 2. Histopathologically 5-year survival rate was 10.0% in cases with poorly differentiated carcinoma, 78.0% in cases with moderately differentiated type, and 83.5% in cases with well-differentiated type. It was remarkably lower in poorly differentiated carcinoma than that in moderately or well-differentiated carcinoma. 3. In cases having dense lymphocyte infiltration associated with lymph follicles in peripheral region of tumor, 5-year survival rate was higher (90.4%) than in the other cases. 4. It was found that, as tumor size increased, 5-year survival rate decreased and the risk of lymph node involvement increased in the neck region. 5. 5-year survival rate was lower (48.5%) in cases with lesion infiltrating the surrounding tissues than in cases with other growth patterns. 6. Multiple correlation coefficient between prognosis and the 7 factors analyzed was 0.766. The important factors were the degree of differentiation (0.735), the degree of lymphocyte infiltration (0.260), the size of primary tumor (0.215), the growth pattern of tumor (0.141) and neck metastasis (0.028).

The syndrome of posterior thalamic hemorrhage.

In six patients with CT evidence of posterior thalamic hemorrhage, we found the following signs: saccadic hypometria away from the lesion; defective pursuit toward the lesion with corresponding opticokinetic abnormalities; mild ipsilateral ptosis; ipsilateral miosis; unilateral sensory neglect; and sensorimotor hemiparesis. This distinct syndrome has a benign course and satisfactory recovery. It differs from the classic picture of thalamic hemorrhage, and can be called "the syndrome of posterior thalamic hemorrhage."

Comparative study by scanning electron microscopy on vestibular toxicities of dibekacin, ribostamycin, and other aminoglycoside antibiotics in guinea pigs.

The vestibular toxicities of dibekacin, ribostamycin, gentamicin, and streptomycin were compared in guinea pigs. The animals were given the drugs for 21 days, examined for functional disturbances by electronystagmography (ENG), and then killed to observe morphologic changes in the vestibular sensory hairs on scanning electron microscopy (SEM). The degree of functional impairment was rated according to the duration of the postrotatory nystagmus and classified into three categories: normal, slight impairment, and severe impairment. The results of the SEM examination were similarly classified into three categories by severity of the degenerative changes in the vestibular sensory hairs, i. e., bending, fusion, ballooning, giant hair formation, or disappearance. Under these experimental conditions, the results of ENG and SEM observations showed good correlation and indicated that the vestibular toxicity was highest in the streptomycin-treated animals and lowest in the dibekacin- or ribostamycin-treated animals.