Cognitive findings after transient global amnesia: role of prefrontal cortex.

The aim of this study is to verify, after recovery, the presence of specific patterns of cognitive dysfunctions in Transient Global Amnesia (TGA). Fourteen patients with the diagnosis of TGA were submitted to a battery of neuropsychological tests and compared to a matched control group. We found significant qualitative and quantitative differences between TGA patients and controls in the California Verbal Learning Test (CLVT) and Rey-Osterrieth Complex Figure Test. Our data support the presence of selective cognitive dysfunctions after the clinical recovery. Moreover, for Verbal Fluency, Digit Span Backward, and Number of Clusters in the CVLT short-term memory test, the relation resulted as positively related with the temporal interval from the TGA episode. Reduction of categorical learning, attention, and qualitative alterations of spatial strategy seem to postulate a planning defect due to a prefrontal impairment.

Cognitive functions after transient topographical amnesia.

Twelve consecutive patients having previously experienced one or more episodes of isolated transient topographical amnesia (TTA) underwent neuropsychological examination 6-12 months after the last episode to detect signs of global cognitive decline and to assess, in particular, cognitive functions deemed critical for topographical orientation. The test scores were compared with those of 12 normal subjects matched for age, sex, educational level and place of residence. Both patients and controls showed normal performances in all tasks. The comparison between the two groups revealed a significantly lower performance of the patient group in a task of geographical orientation, namely 'Map of Italy'. We conclude that isolated episodes of TTA in the elderly per se do not represent a sign of mental deterioration, but can be associated with frailty on survey components of spatial orientation. It remains to be explained whether this feature is a pre-existing condition favouring the occurrence of the episodes of topographical amnesia or represents a sequela.