We read the recent article of Cappa et alwith great interest.1Using HMPAO SPECT, the authors studied 24 patients diagnosed as having (probable) Alzheimer's disease (AD) on the basis of DSM-III-R and the NINCDS-ADRDA criteria. According to Butters et al, they distinguished, on the basis of neuropsychological tests, patients with a diffuse pattern of cognitive deficits (dAD) from those with focal temporal lobe dysfunction (FTLD).2Patients with FTLD are reported by both studies as having a better cognitive prognosis. Whereas the dAD group had diffuse perfusion deficits, the patients with FTLD showed a circumscribed reduction of tracer uptake in the left or right, or both temporal lobes.

We comment on the problem of suggesting AD in these patients with dementia. In the study of Butters et al, seven of the patients of the FTLD group underwent necropsy. Six had the typical histopathological signs of AD. One patient, however, showed the features of hippocampal sclerosis (HS) and not those of AD (Cappaet al wrongly state that all necropsied cases of Butters et al had AD). Two major groups of patients with the histopathological signs of HS have been described in the literature: (1) HS is the most common morphological substrate of medial temporal lobe epilepsy (MTLE). The affected patients are known to show characteristic memory impairment, which correlates well with the degree of pathological changes. Progress of memory impairment in MTLE is very slow and other cognitive functions are …

Dr G Villa iclnp{at}unicatt.rm.it