Natural history of hyperphagia and other eating changes in dementia

OBJECTIVE: To investigate the natural history of overeating (hyperphagia) and its elements during the course of dementia. DESIGN: Prospective longitudinal study of overeating (hyperphagia) in dementia. Two studies were carried out: (1) hyperphagia and associated eating changes were investigated as part of a larger prospective 10-year study into behaviour changes, using carers' reports; (2) an observational study to investigate hyperphagia quantitatively; this took place over the course of a year by means of direct observation of test meals in a normal environment. SETTING: Subjects with dementia living in Oxfordshire, UK. PARTICIPANTS: (1) 99 people with dementia, living at home with a carer, with data for more than 1 year. (2) Nine people with a diagnosis of Alzheimer's disease who were hyperphagic. MEASURES: (1) The Present Behavioural Examination was used at 4-monthly intervals to assess the subjects' behaviour and psychological functioning. (2) Food intake, macronutrient choice and the microstructure of eating were measured using a standardized test meal. RESULTS: (1) Severe or persistent hyperphagia was reported in 23% of the sample and carers reported a clear onset to hyperphagia with a median duration of 16 months. (2) From direct observation, each person who was hyperphagic was seen to maintain a constant eating rate in test meals during the course of a year but meals ended earlier as hyperphagia decreased. CONCLUSIONS: Hyperphagia is common in dementia, it occurs over a single restricted period, mainly during the middle stages of dementia, and is not significantly related to age, sex, diagnosis, medication or activity.