Positive affect and regional cerebral blood flow in Alzheimer's disease

Quality of life (QOL) has been recently recognized as the central purpose of healthcare, and positive affect is one of the core dimension of QOL. However, positive affect among patients with dementia or Alzheimer's disease (AD) has not received much attention in the medical research field. One hundred sixteen consecutive patients with AD were recruited from the outpatient units of the Memory Clinic of Okayama University Hospital. The positive affect score was evaluated using the positive affect domain of the Quality of Life questionnaire for Dementia (QOL-D). Patients underwent brain SPECT with 99mTc-ethylcysteinate dimer. Positive affect scores were inversely related to apathy scores, subjective depressive scores, and delusion scores. After removing the effects of age, sex, duration of education, and cognitive function, positive affect scores showed a significant correlation with regional cerebral blood flow in the left premotor and superior frontal gyri. The left premotor and superior frontal area is significantly involved in the pathogenesis of the decrease of positive affect in AD. Apathy and depression are closely related to the prefrontal area in AD, and they may affect the relationship between positive affect and the left prefrontal area.