Spatial memory impairments in amnestic mild cognitive impairment in a virtual radial arm maze

Abstract

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.

Conclusion

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.

Keywords:

• spatial behavior
• Alzheimer’s disease
• user computer interface
• cognition

Acknowledgments

The English in this document has been checked by at least two professional editors, both native speakers of English (http://textcheck.com). This study was supported by a grant from the Korea Healthcare technology R&D Project, Ministry for Health and Welfare, Republic of Korea (A070001). The study was conducted at the Seoul National University and Seoul Metropolitan Government – Seoul National University Boramae Medical Center.

Author contributions

Dr Jun-Young Lee conceived the study, acquired, and interpreted the data. Ms Sooyeon Kho and Ms Hye Bin Yoo analyzed the data and edited the article. Ms Soowon Park made major revisions to the Introduction section. Dr Jung-Seok Choi and Jun Soo Kwon acquired the patients and their clinical reports. The corresponding authors Dr Kyung Ryeol Cha and Dr Hee-Yeon Jung designed the research and the experiments. All authors made substantial contributions to conception and design of the paper, acquisition of data, or analysis and interpretation of data, and drafted the article or revised it for critically important content.

Disclosure

The authors report no conflict of interest in this work. No competing financial interests exist.