Clinical profiles of late‐onset semantic dementia, compared with early‐onset semantic dementia and late‐onset Alzheimer's disease

Abstract

Semantic dementia (SD) has been recognized as a representative of dementia with presenile onset; however, recent epidemiological studies have shown that SD also occurs in the elderly. There have been few studies about the differences of clinical profiles between early-onset SD (EO-SD) and late-onset SD (LO-SD). Age-associated changes in the brain might cause some additional cognitive and behavioural profiles of LO-SD in contrast to the typical EO-SD cases. The aim of the present study was to clarify the characteristics of neuropsychological, and behavioural and psychological symptoms of dementia (BPSD) profiles of LO-SD patients observed in screening tests in comparison with EO-SD patients and late-onset Alzheimer's disease (LO-AD) patients as controls. Study participants were LO-SD (n = 10), EO-SD (n = 15) and LO-AD (n = 47). We examined the Mini-Mental State Examination (MMSE), the Raven's Coloured Progressive Matrices (RCPM), the Short-Memory Questionnaire (SMQ), the Neuropsychiatric Inventory (NPI) and the Stereotypy Rating Inventory (SRI). Both SD groups scored significantly lower than the LO-AD patients in 'naming' of the MMSE. In the 'construction' score of the MMSE and the RCPM score, however, the LO-SD patients as well as the LO-AD patients were significantly lower than the EO-SD patients. In the SMQ score, 'euphoria' and 'disinhibition' scores of the NPI, the SRI total and subscale scores, both SD groups were significantly higher, whereas in the 'delusion' score of the NPI, both SD groups were significantly lower than the LO-AD patients. Visuospatial and constructive skills of LO-SD patients might be mildly deteriorated compared with EO-SD patients, whereas other cognitive and behavioural profiles of LO-SD are similar to EO-SD. Age-associated changes in the brain should be considered when we diagnose SD in elderly patients.