Idiom comprehension of 15 patients with mild probable Alzheimer's disease was examined by means of a sentence-to-picture matching task. Patients had to choose between two pictures, one representing the figurative and the other the literal interpretation. They were also submitted to a literal sentence comprehension test and to a pencil-and-paper dual task. Whereas literal comprehension was normal in seven subjects and mildly impaired in the others, idiom comprehension was very poor in all of them and correlated with the performance on the dual task. When the idiom test was repeated using an unrelated situation as an alternative to the picture representing the figurative meaning, performance significantly improved. It was hypothesized that the response in the sentence-to-picture matching task in the case of idioms requires sentence processing followed by the suppression of the literal interpretation. Alzheimer's disease patients proved to be unable to inhibit the literal meaning, although they had not lost the idiomatic meaning. In a second experiment, 15 Alzheimer's disease patients with a comparable level of cognitive impairment were submitted to the same idiom comprehension test, and to a test of verbal explanation of the idioms. The results showed significantly better performance in the oral task than in the sentence-to-picture matching task. In oral explanation, however, Alzheimer's disease patients also produced some literal interpretation whenever this represented a possible situation in the real world. We suggest that, during idiom interpretation, the literal meaning needs to be suppressed in order to activate the figurative meaning, and we stress the fact that both linguistic and extralinguistic factors must be taken into account to explain idiom interpretation.

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Tests of famous face recognition and naming, and tasks assessing semantic knowledge about famous people after presentation either of their faces or their names are often used in the neuropsychological examination of aphasic, amnesic and demented patients. A total of 187 normal subjects took part in this study. The aim was to collect normative data for a newly devised test including five subtests: famous face naming, fame judgement after face presentation and after name presentation, semantic knowledge about famous people after face presentation and after name presentation. Norms were calculated taking into account demographic variables such as age, sex and education and adjusted scores were used to determine inferential cut-off scores and to compute equivalent scores. Multiple regression analyses showed that age and education influenced significantly the performance on most subtests, but sex had no effect on any of them. Scores of the subtest evaluating fame judgements after name presentation were significantly influenced only by education. The only subtest whose scores were not influenced by any demographic variable was fame judgement after face presentation.

Nonambiguous idiom comprehension was assessed in 15 right brain-damaged (RBD) and 12 left brain-damaged (LBD) aphasic patients by means of a string-to-picture matching task. Idiom comprehension was found to be severely impaired with a bias toward literal interpretation. The RBD patients, though impaired, performed significantly better than LBD patients; their performance was correlated with visuospatial abilities and was significantly affected by lesion site. The results of this study suggest that the performance of RBD patients in the comprehension of idiomatic sentences may be affected by (a) an involvement of the frontal lobe and/or (b) visuospatial deficits that may impair their performance on the picture-matching task.