Normal and pathological saccadic dysmetria
Abstract
Initial saccades to visual targets are generally not precise in either normal subjects or patients with saccadic dysmetria. Quantitative criteria have to be applied to clearly distinguish between normal and pathological saccadic dysmetria, which is often found in patients with cerebellar lesions. To establish these criteria, the accuracy of visually guided horizontal saccades (10 degrees and 20 degrees target steps) was studied in a group of 24 patients with lesions affecting the cerebellum or its connections, and compared with data from 17 normal subjects. Eye movements were recorded with infrared oculography. Saccades of normal subjects had an average gain of 0.92-0.95 depending on the stimulus condition. Centripetal saccades were significantly larger than centrifugal saccades, for 20 degrees target steps. Most patients (n = 15) had significantly larger saccadic amplitudes than normal subjects (hypermetria), at least in one direction. Saccades in the opposite direction could be either hypometric, hypermetric or normal. Two patients had hypometric saccades in both directions. For one of the patients with hypermetria, in addition, the amplitude difference between centrifugal and centripetal saccades was significantly larger tha...Continue Reading
Citations
Related Concepts
Related Feeds
Ataxias
Ataxia is a neurological condition characterized by lack of voluntary coordination of muscle movements including loss of coordination, balance, and speech. Discover the latest research on different types of ataxias here.
Ataxia telangiectasia (MDS)
Ataxia telangiectasia is a rare neurodegenerative diseases caused by defects in the ATM gene, which is involved in DNA damage recognition and repair pathways. Here is the latest research on this autosomal recessive disease.