Relationship of frontal lobe dysfunction and aberrant motor behaviors in patients with Alzheimer's disease.

BACKGROUND

In order to address the neuropsychological pathogenesis of aberrant motor behaviors in Alzheimer's disease (AD), we used a cross-sectional study design to investigate the association between frontal lobe function, including executive function, and activity disturbances (wandering, purposeless activities and inappropriate activities).

METHODS

Among 75 consecutive outpatients with AD, 50 subjects with a Clinical Dementia Rating (CDR) score of 1 or 2 were selected and divided into two groups based on data obtained from interviews with their caregivers: an aberrant motor behaviors (AMB) group (n = 22), and a non-aberrant motor behaviors (NAMB) group (n = 28). Aberrant motor behavior was defined according to whether the "activity disturbance" score (ranging from 0 to 9) of the Behavioral Pathology in Alzheimer Disease (Behave-AD) scale was 0 or >or=1. The total and subtest scores of the Frontal Assessment Battery (FAB) were then compared between the two groups.

RESULTS

Significant differences were found between the FAB total (P < 0.05) and the subtest scores (lexical fluency, conflicting instructions; P < 0.05) in the two groups. The FAB score was significantly associated with the activity disturbance score (r = -0.49; P<0.001). A stepwise multiple regression analysis showed that only the FAB score significantly influenced the activity disturbance score (P < 0.001).

CONCLUSIONS

This finding suggested that in addition to episodic memory disturbance, frontal lobe dysfunctions might lead patients with AD to develop aberrant motor behavior.