A CASE OF “ANTHISAN” POISONING

Early History. The patient, a male, now aged seventeen years, has the following family history. The mother is stated to be hysteroid. The father died when the patient was aged nine years. An identical twin brother of the patient was found to have an intelligence quotient of 80, and he has always been in advance of the patient developmentally. An elder sister is married, and is stated to be apparently dull. A younger sister is normal. At an institute for the blind the patient learned to weave and to take part in sports. Recognition of pictures was found to be inadequate. He could rarely identify anything in pictorial form. His colour vision was normal. His dark adaptation was abnormal, indicating probably defective peripheral vision. Depth perception and perspective perception in pictorial form were very defective. It was found that over the years his perception was improving. This was largely the result of learning to trace with his eyes. Electroencephalographic findings were as follows. The first report was that the electroencephalogram was nonepileptic in type. In view of Nielsen's assertion that visual verbal agnosia is invariably associated with a subcortical lesion below the major angular gyrus and separated from the calcarine area, a second electroencephalogram was taken. A grossly abnormal record with a dominant epileptic type of rhythm was noted. Photic response was entirely absent. No spike activity occurred. In visual agnosia tests almost all objects were correctly named. Tactile agnosia tests, with objects protected by a shield so that the patient could feel but not see the object, were passed successfully. His performance in the object-sorting test was abnormal, and consistent with that expected from an organic psychotic. The overall defective level of performance was associated with evidence of ability for high-level abstract conceptualation. From the foregoing and other tests it was considered that the patient was a moron and that he was an epileptic with a probable cortical or subcortical lesion in the area of the major angular gyrus. The absence of gross abnormalities in a consistently abnormal record in conjunction with the indications of a definite focus were suggestive of a subcortical lesion. The patient displayed visual verbal agnosia, but did not display object agnosia, at either visual or tactile level. He was unable to cope with the simplest organization of perspective; and he was unable to integrate a number of isolated percepts in pictorial form. He was, however, able to integrate percepts of real objects. His ability to recognize in general terms was apparently improving considerably with time.