Functional focal retrograde amnesia: lost access to abstract autobiographical knowledge?

We describe three patients exhibiting an acute reversible amnesia characterised by an impaired recollection of past events with preserved anterograde memory, thus consistent with a focal retrograde amnesia (FRA). This occurred after variable events: state of fugue, road accident, post-traumatic headache. Retrograde amnesia affected autobiographical memory so severely as to cover all of the patients' lives and to erase knowledge of their own identity. The retrieval of public events was variably affected, ranging from normality to severe impairment. No lesions were found on neuroimaging, and neurophysiological findings were unimpressive. FRA subsided in a few days, leaving a gap for the onset. The hypothesis of a psychogenic amnesia is considered, but overcoming the organic/psychogenic dichotomy the episodes appear as examples of "functional" memory inhibition, potentially triggered by different conditions, including events classifiable as psychic trauma. The clinical and neuropsychological traits of functional FRA are discussed. According to a current theory of autobiographical memory, the memory profile may be explained by a lost access to abstract autobiographical knowledge. Given some analogies with the more common transient global amnesia, a mechanism of spreading depression may also be hypothesised for functional FRA.