[Isolated autobiographical amnesia: a neurological basis?]

The term "autobiographical memory" (AuM) refers to contextually bound experiences that occurred in a specific time, place, and affective setting. AuM is a component of memory commonly impaired in amnestic disorders. Alteration occurs rarely in isolation but rather in the setting of a larger memory impairment. Isolated AuM deficit is a controversial clinical entity, however, recently reported in the context of temporal lobe epilepsy. This study aims at characterizing this poorly documented clinical syndrome and at discussing its potential pathophysiological basis.

We studied a group of three subjects with a history of pharmacosensitive epilepsy and severe AuM complaints. They all were submitted to a neuropsychological evaluation that included an extensive episodic memory assessment, along with wake/sleep electroencephalogram (EEG) and brain magnetic resonance imaging (MRI).

We observed the following findings: preserved autonomy and intact global cognitive functioning; normal performance to standardized episodic memory assessment, contrasting with decreased performance to specific AuM evaluation; frontal and/or temporal epileptic activity on EEG; and normal structural brain MRI.

We reported on a group of patients exhibiting selective impairment of some components of personal memory, associated with interictal frontal and/or temporal abnormalities on EEG. To account for these findings, we hypothesise that interictal epileptic-related activity is impeding long-term consolidation or storage of autobiographical material.