Changes in appetite, food preference, and eating habits in frontotemporal dementia and Alzheimer's disease

Background: Despite numerous reports of changes in satiety, food preference, and eating habits in patients with frontotemporal dementia, there have been few systematic studies. Objectives: To investigate the frequency of changes in eating behaviours and the sequence of development of eating behaviours in frontotemporal dementia and Alzheimer's disease, using a caregiver questionnaire. Methods: Three groups of patients were studied: frontal variant frontotemporal dementia (fv-FTD) (n = 23), semantic dementia (n = 25), and Alzheimer's disease (n = 43). Level of education and dementia severity was similar in the three groups. The questionnaire consisted of 36 questions investigating five domains: swallowing problems, appetite change, food preference, eating habits, and other oral behaviours. Results: The frequencies of symptoms in all five domains, except swallowing problems, were higher in fv-FTD than in Alzheimer's disease, and changes in food preference and eating habits were greater in semantic dementia than in Alzheimer's disease. In semantic dementia, the developmental pattern was very clear: a change in food preference developed initially, followed by appetite increase and altered eating habits, other oral behaviours, and finally swallowing problems. In fv-FTD, the first symptom was altered eating habits or appetite increase. In Alzheimer's disease, the pattern was not clear although swallowing problems developed in relatively early stages. Conclusions: Change in eating behaviour was significantly more common in both of the frontotemporal dementia groups than in Alzheimer's disease. It is likely that the changing in eating behaviours reflects the involvement of a common network in both variants of frontotemporal dementia-namely, the ventral (orbitobasal) frontal lobe, temporal pole, and amygdala.