Spatial memory impairments in amnestic mild cognitive impairment in a virtual radial arm maze.
OBJECTIVE
This study aims to apply the virtual radial arm maze (VRAM) task to find spatial working memory and reference memory impairments in patients of amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). Spatial memory functions between aMCI converters and nonconverters are also compared using VRAM results.


METHODS
We assessed the spatial memory in 20 normal controls, 20 aMCI, and 20 mild AD subjects using VRAM. The Mini-Mental State Examination, Clinical Dementia Rating scale, and other neuropsychological tests were given to the subjects in conjunction with the VRAM test. Scores in working memory errors and reference memory errors were compared among the three groups using repeated measures analysis of variance. In addition, aMCI patients were followed-up after 5 years and surveyed for AD conversion rate.


RESULTS
In AD patients, both spatial working and reference memory were impaired. However, in aMCI subjects, only spatial reference memory was impaired. Significant spatial reference memory impairment was found in the aMCI converter group when compared to the nonconverter group.


CONCLUSIONS
Spatial working memory is less impaired in aMCI while reference memory is similarly damaged in AD. In aMCI patients, more severe spatial reference memory deficit is a neuropsychological marker for AD conversion. VRAM may be well utilized in humans to assess spatial memory in normal aging, in aMCI, and in AD.
Department of Psychiatry, Seoul National University, Seoul, South Korea ; Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, South Korea.
Jun-Young
JY
Lee
Department of Psychiatry, Seoul National University, Seoul, South Korea ; Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, South Korea.
Sooyeon
S
Kho
Department of Psychiatry, Seoul National University, Seoul, South Korea ; Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, South Korea.
Hye Bin
HB
Yoo
Department of Psychiatry, Seoul National University, Seoul, South Korea ; Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, South Korea.
Soowon
S
Park
Department of Psychiatry, Seoul National University, Seoul, South Korea ; Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, South Korea.
Jung-Seok
JS
Choi
Department of Psychiatry, Seoul National University College of Medicine, Seoul, South Korea.
Jun Soo
JS
Kwon
Department of Psychiatry, Osan Mental Hospital, Gyeonggi, South Korea.
Kyung Ryeol
KR
Cha
Department of Psychiatry, Seoul National University, Seoul, South Korea ; Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Seoul, South Korea.
Hee-Yeon
HY
Jung
Alzheimer’s disease; cognition; spatial behavior; user computer interface