1991 Volume 1991 Issue Supplement51 Pages 38-43
Frenzel's spectacles and an infrared CCD camera were used to investigate head shaking nystagmus (HSN) while the subjects had their eyes open in the dark. The tests were performed on 30 normal subjects and 62 patients with peripheral or central vestibular dysfunction.
Head shaking tests were conducted during 30 cycles of horizontal head shaking with excursions of approximately +/- 45 degrees and a frequency of about 2 Hz (Kamei's method). HSN was recorded on ENG and a video recorder simultaneously. The slow phase velocity, the fast phase amplitude and duration of nystagmus were quantatively analyzed with a computer.
The HSN was observed in seven out of 30 normal subjects (23.3%) by an infrared CCD camera. On the other hand, in 40 out of 62 patients (64.5%), the HSN was observed with the infrared CCD camera. In our series, the rotatory factor of HSN was demonstated by the infrared CCD camera in 24 out of 40 patients (60%).
In conclusion, a high ratio of HSN is detectable with an infrared CCD camera. This camera should therefore be useful for diagnosing patients with vestibular disorders.
