Astereopsis caused by traumatic brain injury

Impaired depth perception (astereopsis) has been observed in a variety of c erebral pathologies affecting the posterior parietal lobe. In the current s tudy of 93 consecutive head trauma admissions, 24% had complete astereopsis and 41% performed more than 2 SDs below the orthopedic control group mean. Degree of impairment was related to Glascow Coma Scale score, length of po sttraumatic amnesia, reduced visuospatial and memory abilities, and th-e pr esence of intracranial pathology of the parietal lobes. Impairment was also related to trauma severity in patients without any visualized intracranial pathology, presumably due to diffuse axonal sheaving. Clinically meaningfu l impairment was observed in 24% of this group; 10% had complete astereopsi s. Stereoacuity screening requires I to 2 minutes. Undetected astereopsis m ay increase risk for subsequent motor vehicle accidents or falls. (C) 1999 National Academy of Neuropsychology. Published by Elsevier Science Ltd.