When the amnestic mild cognitive impairment disappears: characterisation of the memory profile.

BACKGROUND/OBJECTIVES: Subjects affected by mild cognitive impairment (MCI) may improve during the observation period. This is the first study investigating qualitative features of memory deficits in subjects affected by reversible MCI [reversible cognitive impairment (RCI)].

METHODS: Baseline cognitive and memory performances of 18 subjects affected by amnestic MCI who had normalized cognitive performances at follow-ups were compared with those of 76 amnestic MCI subjects who still showed impaired cognitive performances at the 24-month follow-up (MCI) and with those of a group of 87 matched control subjects (normal controls).

RESULTS: Compared with normal controls the memory deficit in the MCI group affected all aspects of explicit long-term memory functioning; in the RCI group, instead, the memory deficit only affected the free recall of verbal material, particularly when the encoding could be improved by the use of semantic strategies.

CONCLUSIONS: These results are consistent with the view that the memory deficit in the MCI group is due to a very early degenerative pathology; in the RCI group, instead, a transitory reduction of processing resources, resulting a poor encoding of incoming material, is likely at the origin of the reversible memory disorder.