Dyspraxia of speech and of eye motility.

Five patients with a disturbance of their preprogramming of speech (dyspraxia of speech) were exposed to a comprehensive eye-motor test-battery. The saccades were found hypometric and inaccurate with irregular intervening pauses. The finding was interpreted as due to an extension of lesions from frontal cortical speech areas into visual motor cortex disturbing the normal preprogramming of voluntary saccades. The results were interpreted as supporting the assumption that voluntary saccades are initiated in the frontal cortex. An increase of vestibular nystagmus in these cases was related to a release of vestibular nystagmus due to the disappearance of cortical inhibition on brain stem acitivty.