Observation of spontaneous nystagmus with an infrared CCD camera in patients with sudden deafness

Abstract

Using an infrared CCD camera we observed spontaneous nystagmus (SPN) chronologically in 19 patients with sudden deafness and vertigo (V₊group) and 25 patients with sudden deafness without vertigo (V_-group) who were hospitalized within 10 days after the onset of hearing loss. As a control group, 20 healthy volunteers were examined. The results were as follws: 1) SPN were recognized in 100% of the V₊group and in 96% of the V_-group. No SPN was recognized in the control group. 2) The average period of persisting SPN was 33.4 days in the V₊group and 29.7 days in the V_-group. The average period of persisting vertigo in the V₊group was 14.8 days. 3) The frequency of nystgmus was higher in the V₊group than in the V_- group. 4) Paralytic SPN was seen in 18 out of 19 cases in the V₊group and in 23 out of 25 cases in the V_-group. 5) Abnormal caloric responses were recognized in 6 cases (32%) in the V₊group and in 2 cases (8%) in the V_-group. 6) Average hearing level before and after the therapy were 95.3dB and 71.3dB, respectively, and hearing recovery more than 30dB was seen in 9 out of 19 cases (47%) in the V₊group. On the other hand, in the V_-group the average hearing level before and after the therapy were 77.2dB and 35.4 dB, respectively, and hearing recovery more than 30dB were seen in 18 out of 25 cases (72%). These results suggested that there were subclinical vestibular dysfunctions in most cases of the sudden deafness without vertigo, and these findings might reflect the extension and severity of the inner ear lesions.