Smooth pursuit eye movements in chronic schizophrenics and healthy volunteers using a quantitative objective measure for detecting saccadic intrusions
✍ Scribed by D. J. King; P. J. Mills; M. F. Mannion; J. F. Green
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 100 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0885-6222
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✦ Synopsis
An electro-oculogram based eye tracking system (the Cardi System for the Generation and Analysis of Saccades) was used to quantify smooth pursuit eye movements (SPEM) and saccadic intrusions in 20 chronic schizophrenic patients and 16 normal, healthy controls. Statistically signi®cant dierences were found between the two groups at all four target frequencies tested (0 . 2, 0 . 25, 0 . 33 and 0 . 5 Hz) in three measures of SPEM dysfunction ( position error, velocity error and saccadic intrusions). Of the patients' position errors, 50±70 per cent were greater than the 95th percentile for controls. Velocity errors gave a similar range of SPEM dysfunction (50±65 per cent) but the frequency of saccadic intrusion abnormality was more variable (20±60 per cent). Position error and saccadic intrusions, at the fastest target speed, correlated with total BPRS scores. Extrapyramidal symptoms (Simpson and Angus) and abnormal involuntary movements also correlated with saccadic intrusions at 0 . 5 Hz. There were no signi®cant correlations between SPEM dysfunction and age, duration of illness, negative symptoms (total SANS score) or current dose of antipsychotic drug treatment.