optic ataxia
Difficulty with visually guided reaching and grasping movements, typically affecting the hand contralateral to a posterior parietal lesion.
Full Definition
Optic ataxia is a visuomotor disorder characterized by inaccurate reaching and pointing movements toward visual targets, despite normal visual acuity, visual field, and basic motor function. The condition most commonly results from damage to the superior parietal lobule, particularly the parietal reach region, and is often unilateral, affecting movements of the hand contralateral to the lesion. Patients demonstrate difficulty with depth perception and spatial localization when reaching, but can perform the same movements accurately when guided by proprioception or when the target is placed in their hand. This dissociation helps distinguish optic ataxia from other movement disorders.
Usage
Usage note: Two words, not hyphenated. Distinct from cerebellar ataxia.
In Context
- "The patient's optic ataxia was evident when attempting to reach for objects in her left visual field following the right parietal stroke." — Occupational therapy evaluation
- "Testing revealed optic ataxia with accurate movements when the patient's eyes were closed, suggesting preserved proprioceptive guidance." — Neuropsychological report