Participants

The characteristics of AD group and control group participants are presented in Table 1. The AD patient group consisted of nine women and eight men who were referred to the psychiatric outpatient clinic of Kanazawa University Hospital or Kaga Kokoro Hospital. The patients fulfilled the National Institute of Neurological and Communicative Diseases and Stroke/Alzheimer’s disease and Related Disorders Association (NINCDS-ADRDA) work group criteria for probable AD [15]. Neurological, serological, and MRI studies of these patients were performed to eliminate any other medical condition potentially causing dementia. The period from the time the symptoms were noticed by the family was defined as the duration of illness. No patient was receiving any medication acting upon the central nervous system (i.e. antipsychotic, anticholinergic, antidepressant, anticonvulsant, benzodiazepine, cerebral metabolic activator, or cerebral vasodilator) except donepezil hydrochloride (9 patients were receiving 5 mg of donepezil hydrochloride per day). Each patient was assessed with the functional assessment stages (FAST) [16] (CDR) [17], and a Japanese version of the Mini-Mental State Examination (MMSE) [18]. The Wechsler Memory Scale-Revised (WMS-R) [19] was used to evaluate details of memory performance. The control group, which consisted of 17 healthy volunteers, was not significantly different from the AD group in age or gender. Control participants had no personal or family history of psychiatric or neurological disease. All were functioning normally and independently in daily life. None of their WMS-R subscores was below the 1.5 standard deviation of the normal range. All participants had normal color vision, visual acuity, pupil reaction, and visual fields. All participants agreed to participate in the study with full knowledge of the experiment characteristics of the research. Written informed consent was obtained from all participants before their enrollment. The Ethics Committees of Kanazawa University Hospital approved this study.

CDR, Clinical Dementia Rating; FAST, Function Assessment Staging; MMSE, Mini-Mental State Examination; WMS-R, Wechsler Memory Scale–Revised

^a Immediate memory (retention of information in immediate awareness).^b Capacity to acquire and recall information over brief time periods.

^c Ability to recall information after 30 min of intervening activity. Significance was inferred from results of un-paired t-tests.

* P < 0.05.