The three parameters (yawing: Y, sliding: S, and rolling or “wipering”: W) of calorically induced head movements (vestibulo-collic reflex, VCR) were measured by a method using three rotary photosensors.
The subjects were 38 normal volunteers and 373 neurological patients, including 63 with spino-cerebellar degeneration (SCD). To elicit VCR, the external auditory canal was irrigated with 2 ml of 20°C water within 20 seconds.
[RESULTS]
1. The VCR parameters moved to the side of cold water irrigation in normal volunteers, patients with SCD and patients with other neurological diseases.
2. In normal volunteers, Y and W showed a statistically significant positive relationship with the maximum slow phase velocity of caloric nystagmus (SPVmax). Bilateral Y, left S and bilateral W showed a weak but statistically significant positive relationship with SPVmax, except in SCD patients, who showed no relationship between VCR parameters and SPVmax.
3. Both normal volunteers and SCD patients showed almost the same time course of VCR parameters, but the duration of caloric nystagmus in SCD patients was significantly shorter (rt: 153±21 sec, lt: 170±41 sec) than in normal volunteers (rt: 181±38 sec, lt: 188±35 sec). Several patients with SCD showed absent or diminished caloric nystagmus although they showed virtually normal VCR.
4. These results suggest that the vestibulo-ocular system and the VCR system are damaged in different ways in the central nervous system of patients with SCD.