A historic case of visual agnosia revisited after 40 years.

In one of the seminal works on visual agnosia, Adler (1944, 1950) presented the case of a 22-yr-old woman who sustained carbon monoxide cerebral toxicity in the Cocoanut Grove nightclub diaster of 1942. We located this patient 40 yrs after injury and performed a detailed reevaluation. The patient demonstrated persistent deficits in visual recognition, characterized most prominently by defective recognition of elemental shape and form, associated with alexia, prosopagnosia, visuospatial disorientation and impaired visual imagery. Visual acuity, colour recognition, writing ability and verbal intelligence were relatively preserved. Isolated bilateral occipital injury was demonstrated by CT and MRI scanning. On comparison with previously reported cases, our results support the hypothesis that carbon monoxide toxicity can induce a visual agnosia of the apperceptive type with well defined characteristics, seldom seen with other types of cerebral injury. Prognosis for long-term recovery is poor.