Retrograde memory deficits in severe closed-head injury patients

A battery of tests evaluating different aspects of retrograde memory (autobiographical, public events, semantic knowledge) was administered to a group of 20 patients who had suffered from a severe closed-head injury (CHI) and who had recovered from the posttraumatic amnesia period and to a group of sex-, age- and education-matched normal controls. Results document a high prevalence of retrograde memory deficits among CHI individuals. The deficit involves both autobiographical and public events memories and extends to early acquired basic and cultural knowledge. The severity of the deficit does not vary according to some kind of temporal gradient or according to a presumed hierarchical or modality organization of the semantic system. However, in the domain of basic knowledge it more severely affects information pertaining to living than nonliving categories of objects. With the exception of a more severe deficit in retrieving autobiographical events occurred in the last year before trauma in a subgroup of patients with focal lesions restricted to the right hemisphere as compared to left lesioned patients, no clear relationship emerges between severity of the retrograde memory deficit and locus of focal cerebral lesions as demonstrated by neuroradiological exams.