Frontal neurodegeneration associated with Frontal Assessment Battery in early Alzheimer's disease.

BACKGROUND

The Frontal Assessment Battery (FAB) is widely used to assess executive dysfunction in patients with amnestic mild cognitive impairments due to Alzheimer's disease (aMCI-AD), but its neurobiological meaning is unclear. To elucidate this, we examined the relationship between the FAB score and three key imaging biomarkers: gray matter volume, amyloid-beta (Aβ) deposition, and glucose metabolism.

METHODS

Twenty Aβ- and tau-positive aMCI-AD patients and age-matched controls underwent structural magnetic resonance imaging and positron emission tomography with [11C]PiB and [18F]FDG. Voxel-based morphometry and statistical parametric mapping analyses were performed to elucidate the relationships between FAB scores and regional gray matter volume, [11C]PiB uptake for Aβ deposition, and [18F]FDG uptake for glucose metabolism.

RESULTS

FAB scores were significantly lower in aMCI-AD than in controls (p < 0.001). In aMCI-AD, FAB was significantly correlated with right inferior frontal gray matter volume and right medial and left middle frontal glucose metabolism (family-wise error p < 0.05). However, there was no correlation between Aβ deposition and FAB (family-wise error p < 0.05).

CONCLUSIONS

The decreased FAB score is linked more with frontal-lobe neurodegeneration than with Aβ pathology in aMCI-AD. The FAB could be an early marker for neurodegeneration related to frontal-lobe executive dysfunction.