Dementia in hippocampal sclerosis resembles frontotemporal dementia more than Alzheimer disease

Objective: To characterize the clinical course of pathologically diagnosed hippocampal sclerosis dementia (HSD). Background: Dementia associated with HSD is incompletely characterized. Previous studies suggest similarities to both Alzheimer disease (AD) and frontotemporal dementia (FTD). Methods: Case-control analysis of the clinical course of patients with HSD, FTD, and AD from a neuropathology autopsy series conducted by a university hospital. Case histories were reviewed. Cumulative prevalence of behavioral, cognitive, psychiatric, and language symptoms were compared between groups, as was time of symptom onset. Clinical diagnostic criteria for FTD and AD were applied to case histories. Sensitivity and specificity of clinical FTD diagnostic criteria (Report of the Work Group on FTD and Pick's disease) were computed. Results: Cumulative prevalence of symptoms in HSD was most similar to that of FTD and differed from AD. Behavioral abnormalities such as decreased grooming and inappropriate behavior were more prevalent in HSD and FTD than AD. Hyperorality, inappropriate behavior, and decreased interest had earlier onset in HSD and FTD. Cognitive symptoms of disorientation, dyscalculia, apraxia, and agnosia were more prevalent in AD, as were psychiatric symptoms of hallucinations, delusions, and aggression. Most HSD patients met diagnostic criteria for FTD. Criteria sensitivity was 64.0% and specificity was 73.7%. Conclusions: FTD is a clinical syndrome associated with heterogeneous neuropathology. The clinical course of HSD is more similar to that of FTD than AD. These findings, together with the neuropathologic data presented in the accompanying article, support expanding the scope of FTD (Pick complex) to include HSD.