[Two cases of fronto-temporal dementia without remarkable lobar atrophy].

Front-temporal dementia (FTD), advocated by Lund and Manchester groups, includes Pick type corresponding to the conventional frontal Pick's disease, motor-neuron type associated with neural symptoms, and frontal lobe degeneration type. In Japan, however, there have been few case reports of the frontal lobe degeneration type. Here we examined clinical characteristics and imaging findings of 2 cases of FTD frontal lobe degeneration type. Neurological examinations were normal. CT and MRI scans revealed no obvious frontal lobar atrophy, while HMPAO-SPECT scans demonstrated remarkable hypoperfusion in anterior hemisphere. Neuropsychological examination revealed frontal symptoms, including personality change, stereotypes, and disinhibition. These symptoms can not be distinguished from the cases of FTD Pick type, because those cases of FTD Pick type have obvious lobar atrophy.