APPERCEPTIVE BLINDNESS IN LISSAUER'S DEMENTIA PARALYTICA.

PICK (1898) described as apperceptive blindness the inability to see resulting from loss of visual attention. He observed that symptom in cases of circumscribed atrophy of the occipital lobes. According to Pick the loss of visual attention resulted in an inability to focus and in a loss of visual apperception, i.e. of the capacity for conscious perception of visual stimuli. Potzl (1928) who studied the symptom in the same kind of case material expressed the opinion that apperceptive blindness belonged to the visual agnosias, the basic disorder being an inability to synthesize visual impressions. Observations made by Horn and Stengel (1930) in a case of Pick's disease corroborated Potzl's view. The literature does not contain further reports on that symptom which obviously occurs only under a specific set of conditions of which little is known. We have observed a patient who to our knowledge is the first reported case of apperceptive blindness in general paralysis; it allows us to carry the analysis of that symptom further than has been possible hitherto.