Ocular microtremor in patients with idiopathic Parkinson’s disease
- aDepartment of Neurosurgery, Frenchay Hospital, Bristol, UK, bMercer’s Institute for Research on Ageing, St James’s Hospital, Dublin, Ireland
- Miss S Bojanic, Room 1, Academic Centre, Frenchay Hospital, Bristol BS16 1LE, UK. Telephone 0044 117 970 1212 ext 3584; fax 0044 117 975 3979; email sbojanic{at}neurosurgery.demon.co.uk
- Received 25 March 1998
- Revised 23 October 1998
- Accepted 3 November 1998
Abstract
Abnormalities in the oculomotor control mechanism of patients with idiopathic Parkinson’s disease are well recognised. In this study the effect of Parkinson’s disease on tonic output from oculomotor nuclei was studied by using oculomicrotremor as an index of such output. Oculomicrotremor readings were taken from 22 parkinsonian patients and 22 normal healthy volunteers using the piezoelectric strain gauge technique. There was a slower overall tremor frequency, baseline, and burst frequency in the parkinsonian group. There was also a significant increase in the duration of baseline, with a decrease in the number of bursts a second and a decrease in average duration of bursts in the patient group compared with the normal group. One patient, whose medication was withdrawn, showed a marked decrease in mean frequency and baseline frequency with a decrease in number of bursts and increase in baseline duration compared with readings taken when treatment recommenced. These results suggest that variables measured in oculomicrotremor are altered compared with normal subjects, reflecting altered tonic output from oculomotor nuclei in patients with idiopathic Parkinson’s disease.
