THE MICROSTRUCTURE OF EATING IN PEOPLE WITH DEMENTIA WHO ARE HYPERPHAGIC

Objectives. To describe (a) the nature of eating abnormalities and (b) mechanisms of hunger and satiation in hyperphagic subjects with demen tia. Design. Case-control study. Three groups of subjects were compare d: people with dementia, reported by their carers to be hyperphagic an d who overate under experimental conditions; people with dementia who ate normally; normal elderly. Subjects were individually matched acros s groups. Setting. Subjects with dementia: living either in the commun ity or in long-stay, psychogeriatric wards; the normal elderly control s lived at home. All lived in the UK. Participants. Participants with dementia fulfilled criteria for Alzheimer's disease. Hyperphagic group (n = 18): aged 54-91, MMSE scores 0-20. Normal elderly controls (n = 14) were individually matched for age and sex. Non-hyperphagic demente d controls (n = 14) were also matched for cognitive impairment. Measur es. Two standardised test meals were given: a single food meal and a m ixed food meal. Eating microstructure (latency period before eating; l oading rate; chewing rate; rate of energy consumption and behaviour pa tterns during meal), were measured from videorecordings. Present Behav ioural Examination was used to assess eating behaviour and MMSE to tes t cognitive impairment. Results. The hyperphagic group started to eat much more rapidly than non-hyperphagic demented controls, (W = 59.0; p = 0.006) and had a significantly higher initial eating rate (t = 2.28 , p < 0.0005). Unlike the normal elderly, neither group with dementia showed a significant deceleration during the meal. Conclusions. People with dementia have impaired satiation mechanisms. Hyperphagic subject s with dementia have more marked impairment of satiation and increased hunger compared with non-hyperphagic demented subjects.