ISOLATED AMNESIA WITH SLOW ONSET AND STABLE COURSE, WITHOUT ENSUING DEMENTIA - MRI AND PET DATA AND A 6-YEAR NEUROPSYCHOLOGICAL FOLLOW-UP

Patient EDS presented with an amnesic disorder of insidious onset (4 y ears) that remained stable and restricted to memory functions over a 1 0-year course. Repeated neuropsychological evaluations over 6 years sh owed a moderate-to-severe, stable impairment of long-term memory and o f memory for public events, and a milder, stable impairment of autobio graphic memory and of short-term memory. Language, perception, praxis and 'frontal' functions were fully preserved. MRI showed atrophy of th e right hippocampus, of the right mammillary body and of the sylvian f issure (bilaterally, but more marked on the left). On PET scan, metabo lic activity in the mesial temporal structures was significantly reduc ed on the right and was at lower normal levels on the left. The disord er observed in EDS is similar to that recently reported in other patie nts. Possible etiologies of the selective amnesia observed in EDS are considered and their implications discussed.