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Confabulations on Episodic and Semantic Memory Questions Are Associated With Different Neurologic Backgrounds in Alzheimer Disease

Lee, Eunjoo PhD*; Kinomura, Shigeo MD, PhD; Meguro, Kenichi MD, PhD; Akanuma, Kyoko MSc; Meguro, Mitsue MSc; Fukuda, Hiroshi MD, PhD

Cognitive and Behavioral Neurology: June 2009 - Volume 22 - Issue 2 - p 81-88
doi: 10.1097/WNN.0b013e3181a7226c
Original Studies

Background The neurologic background of confabulations with reference to delusions or cognitive functions has not been clarified in Alzheimer disease (AD).

Methods Confabulations of 41 AD patients and 12 healthy controls were studied using the Modified Confabulation Battery. The mini-mental state examination and Cognitive Abilities Screening Instrument were used for cognitive evaluations. Cerebral atrophy was assessed by voxel-based–morphometry of magnetic resonance imaging and the correlations with confabulations were analyzed by statistical parametric mapping 2. For the relations with delusion, the AD patients were divided into the delusion and nondelusion groups. The single photon emission computed tomography was performed to evaluate cerebral blood flow and the group difference was analyzed by statistical nonparametric mapping 3.

Results The AD patients exhibited more confabulations on episodic memory questions compared with semantic questions. The semantic confabulation scores correlated with mini-mental state examination and most Cognitive Abilities Screening Instrument domains scores, and correlated with atrophy in the anterior cingulate, bilateral medial temporal, and right middle temporal gyrus. The delusion group exhibited more episodic confabulations and had lower prefrontal blood flow than the nondelusion group.

Conclusions Different mechanisms are involved in confabulations between semantic and episodic memories in AD. Episodic confabulation is affected by delusion related to frontal dysfunction, and semantic confabulation is associated with cognitive dysfunction.

*Osaki-Tajiri SKIP Center, Osaki

Department of Nuclear Medicine and Radiology, Institute of Development, Aging, and Cancer, Tohoku University

Department of Geriatric Behavioral Neurology, Tohoku University Graduate School of Medicine, Sendai, Japan

Reprints: Kenichi Meguro, MD, PhD, Department of Geriatric Behavioral Neurology, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan (e-mail:

Received for publication May 27, 2008; accepted February 15, 2009

Present Address of Eunjoo Lee, PhD: School of Health and Welfare, Woosong University, Daejeon, Korea.

© 2009 Lippincott Williams & Wilkins, Inc.