Correlation between a reduction in Frontal Assessment Battery scores and delusional thoughts in patients with Alzheimer's disease.
OBJECTIVE
The purpose of the present study was to investigate the relationship between delusional thoughts (delusional ideation or misidentification) and frontal lobe function using the Japanese version of the Frontal Assessment Battery (FAB) bedside screening neuropsychological test in early stage Alzheimer's disease (AD) patients.


METHODS
Forty-eight probable AD patients with Mini-Mental State Examination score >or=18 points and a clinical dementia rating score of either 0.5 or 1.0 were divided into two groups based on data obtained from interviews with their caregivers: a delusional thought group (n = 19) and a non-delusional thought group (n = 29). The FAB total and subtest scores were then compared for the two groups.


RESULTS
Significant differences were found between the FAB total (P < 0.01) and subtest scores (similarities, motor series, conflicting instructions; P < 0.05) for the two groups. Multiple regression analysis showed that delusional thought was significantly associated with the FAB total score.


CONCLUSIONS
In addition to episodic memory disorders, a reduction in the FAB score may reflect frontal lobe dysfunctions, including executive function, in patients with AD, leading to delusional ideation.
Nagata
Tomoyuki
T
Department of Psychiatry, Jikei University School of Medicine, Kashiwa Hospital, Kashiwa, Chiba, Japan. t.nagata@jikei.ac.jp
Ishii
Kazuhiro
K
Ito
Tatsuhiko
T
Aoki
Kimiyoshi
K
Ehara
Yoshito
Y
Kada
Hirohide
H
Kada
Hidehiro
H
Furukawa
Haruko
H
Tsumura
Maki
M
Shinagawa
Shunichiro
S
Kasahara
Hiroo
H
Nakayama
Kazuhiko
K
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology* / Q000523:psychology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000503:physiopathology* / Q000523:psychology; D003702:Delusions / Q000175:diagnosis / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data*; D011569:Psychiatric Status Rating Scales; D012044:Regression Analysis