The impact of stimuli on affect in persons with dementia

To examine how presentation of different stimuli impacts affect in nursing home residents with dementia.

Participants were 193 residents aged 60 to 101 years from 7 Maryland nursing homes who had a diagnosis of dementia (derived from the medical chart or obtained from the attending physician). Cognitive functioning was assessed via the Mini-Mental State Examination (MMSE), and data pertaining to activities of daily living were obtained through the Minimum Data Set. Affect was assessed using observations of the 5 moods from Lawton's Modified Behavior Stream. Baseline observations of affect were performed for comparisons. During the study, each participant was presented with 25 predetermined engagement stimuli in random order over a period of 3 weeks. Stimuli were categorized as live social, simulated social, manipulative, work/task-related, music, reading, or individualized to the participant's self-identity. The dates of data collection were 2005-2007.

Differences between stimulus categories were significant for pleasure (F(6,144) = 25.137, P < .001) and interest (F(6,144) = 18.792, P < .001) but not for negative affect. Pleasure and interest were highest for the live social category, followed by self-identity and simulated social stimuli for pleasure, and for manipulative stimuli in terms of the effect on interest. The lowest levels of pleasure and interest were observed for music. Participants with higher cognitive function had significantly higher pleasure (F(1,97) = 6.27, P < .05). Although the general trend of the impact of the different categories was similar for different levels of cognitive function, there were significant differences in pleasure in response to specific stimuli (interaction effect: F(6,92) = 2.31, P < .05). Overall, social stimuli have the highest impact on affect in persons with dementia.

The findings of the present study are important, as affect is a major indicator of quality of life and this study is the first to systematically examine the impact of specific types of stimuli on affect. As live social stimuli are not always readily available, particularly in busy nursing home environments, simulated social stimuli can serve as an effective substitute, and other stimuli should have a role in the activity tool kit in the nursing home. The relative ranking of stimuli was different for interest and pleasure. The findings demonstrate the differential effect of presentation of different types of stimuli on the affect of persons with dementia, and that, while the impact is greater on persons with higher levels of cognitive function, there is a different effect of varying stimuli even in persons with MMSE scores of 3 or lower. Future research should attempt to ascertain a person's degree of interest in stimuli prior to developing an intervention.