[Left hemisphere lesion and visual recognition of single letters (author's transl)].

100 Controls and 200 left hemisphere-damaged patients were sub-divided by means of a Standard Language Battery in 35 non Aphasic patients, 51 Broca's aphasic patients, 85 Wernicke's aphasic patients and 29 global aphasics. They were all submitted to a single letter recognition test. From a parametric statistical work-out of the experimental data, it turned out that global aphasics are by far the most impaired experimental group, even if their performance had been adjusted by co-variance taking into account their more relevant aphasic and neurological disorders. Whilst age and length of illness do not play a significant role in the test performance, this was significant for the educational level (years of schooling) and for the severity of the aphasic disorders (Token Test). The relationship between the above-mentioned independent variables and the letter recognition scores did not change significantly across the experimental groups. The only exception was that the relation between the Token Test and the letter recognition scores proved to be significantly different between Broca's and Global Aphasics. No definite conclusion could be drawn about the outstandingly poor scores of global aphasics, as neither their performance or their I.Q. (W.A.I.S.) seemed to be related to the letter recognition scores (in contrast with Broca's and Wernicke's aphasics), nor to the presence of retro-geniculate visual field defects.