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.

Background: Some previous research has hypothesized that executive dysfunction in patients with early Alzheimer's disease (AD) occurs as a result of a disconnection between different cerebral areas. The aim of the present study was to evaluate how the hippocampal volume influences executive function as a non-memory cognitive function.

Methods: From 157 consecutive patients with AD or amnestic mild cognitive impairment (A-MCI), we recruited 107 subjects who had a global Clinical Dementia Rating (CDR) of 0.5 or 1.0 and whose degree of hippocampal atrophy had been measured using magnetic resonance imaging (MRI); the severity of atrophy was assessed using the voxel-based specific regional analysis for Alzheimer's disease (VSRAD) system. We divided the subjects into three groups: mild atrophy, 0 < Z-score < 1.0 (N = 21); moderate atrophy, 1.0 ≤ Z-score < 2.0 (N = 46); or severe atrophy, 2.0 ≤ Z-score < 4.0 (N = 40) according to the Z-score and compared the Frontal Assessment Battery (FAB) and its subtest scores between each atrophy group.

Results: The results demonstrated that age, sex ratio, duration of illness, education years, MMSE score, Behave-AD score, and proportion of atrophy area in total brain (%) were not significantly different among the three groups. Only the go/no-go score among the six subtests was significantly lower for increasing atrophy severity (P < 0.05). Furthermore, hippocampal atrophy significantly influenced the go/no-go score independently of interactions from whether the diagnosis was early AD or A-MCI (P < 0.05).

Conclusion: These results support a significant association between hippocampal atrophy and executive dysfunction as a non-memory cognitive impairment in patients with early AD and A-MCI.

Background: Apathy and depression may be strongly associated with executive dysfunction in Alzheimer's disease (AD). The Frontal Assessment Battery (FAB) is an instrument for assessing executive function. The dual task paradigm is also useful for assessing divided attention. However, the association between apathy/depression and these tasks is unclear.

Methods: Both the FAB and the dual task were used to evaluate AD patients. A two-way analysis of variance was then conducted between the FAB and dual task results and the absence versus the presence of depression or the absence versus the presence of apathy.

Results: Of 88 patients with AD, 26 had both apathy and depression, 26 had depression only, 18 had apathy only, and 18 had neither. Total FAB scores and dual task scores differed significantly between the AD patients with depression and those without depression; the scores were also different between those with apathy and those without apathy. Also, a significant interaction between depression and apathy was noted for the total FAB and dual task scores.

Conclusions: The deficits in the total FAB and dual task scores were larger in AD patients with both apathy and depression compared with patients with either apathy or depression alone. AD patients with both symptoms may have greater deficits in frontal lobe function relative to AD patients with either apathy or depression alone.