Aphasia due to lesions confined to the right hemisphere in right handed patients: a review of the literature including the Italian cases.

We review most of the work published, to our knowledge, between 1880 and 1988 on aphasia due to right cerebral lesions in right-handed patients ("crossed aphasia"). We summarize the 87 cases found in chronological order within defined groups, dealing in greater detail with the less well-known cases in English-language publications and with the cases from other sources that we consider most representative and convincing. The 87 cases fall into three groups on the following criteria: right-handedness (on standardized tests), absence of left-handers in the family, left hemisphere integrity. Group 1 comprises cases that are unreliable because the handedness data are missing and/or because left hemisphere lesions were known to be present or probably were so. Group 2 comprises cases with full clinical data but no formal test of handedness, with familial cases of left-handedness and/or without satisfactory evidence of left hemisphere integrity. Groups 3 comprises the 26 reliable cases, that is those with proven right-handedness, no left-handers in the family and with proven hemisphere integrity. We discuss the implications of these cases.