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This report bears on the behavior of 188 unilateral stroke subjects when administered an aphasia screening test comprising a short interview as well as naming, repetition, word-picture matching and sentence-picture matching tasks. All subjects were unilingual lusophone adult (40 yr of age or older) right-handers. Furthermore, they were either totally unschooled illiterates or they had received school education and thereafter retained writing skills and reading habits. Subjects were tested less than 2 months after a first unilateral stroke. In all tasks, global error scores were greater among left and right brain-damaged illiterate and literate subjects than among their controls. In repetition and matching, these differences were statistically significant for the left but not for the right-stroke groups, irrespective of the literacy factor. In naming, on the other hand, significant differences were found not only for the two left-stroke groups but also for the right-stroke illiterate group although not for the right-stroke literate one. Likewise, some degree of word-finding difficulty and of reduction in speech output as well as sizeable production of phonemic paraphasias were observed in the interviews of several right-stroke illiterates, clearly less in those of right-stroke literates. These findings lead us to suggest that cerebral representation of language is more ambilateral in illiterates than it is in school educated subjects although left cerebral "dominance" remains the rule in both.

One hundred neurologically healthy adults were tested for their pointing (choosing one of four or six line drawings as the match to an auditorily presented linguistic stimulus), naming (from line drawings), and repetition abilities. All subjects were unilingual adult right-handers. Fifty-seven subjects were totally unschooled illiterates and 43 were fluent readers. Statistically significant differences were found to exist between the scores of the illiterate and literate subpopulations across all tasks. With the focus being placed on these cultural differences, the discussion bears on: (a) the interaction between linguistic and iconographic factors in certain types of naming and pointing tasks currently used in clinical and research aphasiology, (b) some of the linguistic parameters which are apparently at stake in repetition behavior, and (c) the circumstances in which aphasiological research dealing with groups of patients cannot yield reliable data without reference to neurologically healthy controls. It is argued that, when testing brain-damaged patients of different cultural backgrounds, one runs the risk of over- or underestimating the frequency of aphasia if one does not refer to norms which explicitly take educational level into account.