Comparison of Memory Disorders in Amnestic Mild Cognitive Impairment and Alzheimer‘S Disease

Abstract

According to the literature, long-term memory disorders appear earliest as mild cognitive impairment progresses to Alzheimer’s disease. Other types of memory impairment are discussed sparcely in literature, most studies include general tests of memory performance. Objective: Compare memory disorders in amnestic mild cognitive impairment and Alzheimer’s disease. Subjects: 75 patients were tested twice in the period of one year, 44 of those with amnestic mild cognitive impairment and 12 with Alzheimer’s disease. Method: Memory disorders were tested using 10 Word Test, Backwards Digit Span, Associative Memory Test, and Rey- Osterrieth Complex Figure Test. Results: Estimate means of associative and visual memory corresponds the norm; disorders appear in domains of short-term memory, working memory, long-term memory, and maximal retrieval in amnestic mild cognitive impairment. All memory domains are below norm in Alzheimer’s disease. Statistically significant mean differences (p < 0,05) were obtained in such domains as short-term memory, maximal retrieval, associative and working memory when comparing the groups of amnestic mild cognitive impairment and Alzheimer’s disease. The level of disturbance is significantly lower in all memory domains in single-domain amnestic mild cognitive impairment than those of Alzheimer’s disease. In multiple-domain amnestic mild cognitive impairment, significantly lower memory disturbances appear only in maximal retrieval (p = 0,026) and working memory (p = 0,001) domains. Conclusions: Disorders in all memory domains – i.e., short-term, working, associative, long-term, visual memory, and maximal retrieval – are characteristic to Alzheimer’s disease. Disorders of short-term, working, long-term memory, and maximal retrieval are characteristic to amnestic mild cognitive impairment. Disorders of memory in multiple-domain amnestic mild cognitive impairment display similar pattern to those in Alzheimer’s disease. It can be assumed that single-domain amnestic mild cognitive impairment progresses to multiple-domain amnestic mild cognitive impairment, as mild cognitive impairment progresses to Alzheimer’s disease. Article in Lithuanian doi:10.5200/sm-hs.2012.114