Repetitive behaviour in Alzheimer's disease: description, correlates and functions

Background Repetitive behaviour is among the most common and burdensome of the behavioural and psychological symptoms of Alzheimer's disease (AD), yet little research has been done to investigate its nature or correlates. Memory impairment may account for repetitive questioning, but its possible role in other repetitive behaviours is unclear. Attention and executive dysfunction may account for both repetitive speech and actions. The role of mood also merits investigation. Objectives To investigate cognitive and affective differences between patients with and without repetitive behaviours, and to identify themes and carer attributions for the function of such behaviours. Methods Fifty-four participants aged >= 65, meeting NINCDS-ADRDA criteria for probable AD, were assessed using the MMSE, WMS-III word list, Trailmaking test, Stroop, Modified WCST, Cornell Scale for Depression, DEX and a repetitive behaviour questionnaire. Regression analyses were used to identify significant predictors of repetitive behaviour. Results Repetitive behaviours were manifest in 87% of the sample, with questions (68.5%) and statements/stories (61.1%) the most common types. Repetitive questions were predicted by high MMSE score (p=0.013), low immediate list recall score (p=0.013) and female gender (p=0.004). Repetitive statements/stories were predicted by dysexecutiveness (p=0.003) and younger age (p=0.016). Repetitive actions were predicted by longer illness duration (p=0.041), depressive symptoms (p=0.035) and dysexecutiveness (p < 0.001). Themes and patterns were evident in repetitive behaviour. Conclusions Repetitive behaviours were common in a sample of patients with AD referred to hospital clinics. Vocal and motor repetitive behaviours were predicted by different cognitive, demographic and mood variables. Copyright (c) 2005 John Wiley & Sons, Ltd.