Frontal assessment battery and brain perfusion imaging in Alzheimer's disease

Background: The frontal assessment battery (FAB) is reported to be a useful tool for assessing frontal dysfunction. However, the neural substrates involved in patients with Alzheimer's disease (AD) remain to be elucidated. The aim of the present study was to identify the regional perfusion patterns of the brain associated with performance scores on the FAB of patients with AD using brain perfusion assessed by single photon emission computed tomography (SPECT). Methods: Twenty-four AD patients with high scores and 24 age-and sex-matched AD patients with low scores on the FAB were selected from 470 consecutive Japanese patients of the Memory Clinic of Okayama University Hospital. All 48 participants underwent brain SPECT with 99mTc-ethylcysteinate dimer, and the SPECT images were analyzed by statistical parametric mapping. Results: No significant differences were found between high and low FAB scoring groups with respect to Addenbrooke's Cognitive Examination scores, Mini-Mental State Examination scores, or the depression score of the Neuropsychiatric Inventory subscale. Compared with patients with high scores on the FAB, AD patients with low scores showed significant hypoperfusion in the left middle frontal gyrus (MFG) and the right superior frontal gyrus (SFG) extending to the left SFG. Conclusion: Our results suggest that functional activity of the SFG and MFG is closely related to the FAB score. The FAB might be a promising strategy to detect early stages of AD with low SFG and MFG function.