A SPECT study of wandering behavior in Alzheimer's disease

Among behavior disturbance during Alzheimer's disease (AD), wandering is one of the most common. Different psychological processes have been suggested to explain the wandering behavior. The aim of this study was to examine whether wandering during AD was associated with cerebral perfusion patterns measured by (99 m)Tc-labeled bicisate (ECD) brain SPECT.

We compared SPECT scans of 13 AD subjects with wandering behavior (sex ratio M/F, 4/9; age, 73.1 years, SD 7.4; Mini Mental Status Examination score, median 20 interquartile range [16-23]), 13 AD subjects without wandering behavior (matched for age [ +/- 2 years], sex and MMSE score [ +/- 2 points]) and 13 healthy controls (matched for age [ +/- 2 years] and sex) without cognitive impairment. Wandering was defined on the Neuro-Psychiatric Inventory. Score of leukoaraiosis, assessed with the scale of Blennow and number of lacuna infarction were compared on CT scan. SPECT imaging was compared using statistical parametric mapping (SPM 2).

There were no significant differences between the groups in term of educational level and CT scan analysis. SPECT imaging was consistent with the diagnosis of AD in both wanderers and AD subjects without wandering behavior. Despite similar clinical dementia severity, wanderers had more severely reduced regional cerebral blood flow (rCBF) in the left parietal-temporal lobe than AD subjects without wandering behavior.

Wandering behavior could be facilitated by a specific patterns of cerebral blood flow. Wandering, as a physical activity, could also enhance the recruitment of the cortical network.