Development of a simplified Short-Term Memory recall Test (STMT) and its clinical evaluation

The early detection and prevention of dementia is attracting attention. We therefore developed an easily performed protocol to identify patients with memory impairment which may progress to dementia, and evaluated its validity.

We focused on short-term memory impairment alone, and named the test, consisting of 3 tasks, the simplified Short-Term Memory recall Test (STMT; with a maximum score of 8). Patients were classified into a memory impairment group of 26 subjects and a control group of 23 subjects. At the first examination, subjects underwent the STMT, MMSE and ADAS-Jcog. as cognitive function tests. Follow-up observations were performed for 2 years at 6-month intervals.

There were significant differences in the mean scores for all tests, except for MMSE memory items between the 2 groups. When the cut-off value of STMT was established as 4 points, and scores lower than this value were defined as memory impairment, the sensitivity and specificity were highest, 73.1% and 82.6%, respectively. Sensitivity and specificity also rose to 92.3% and 95.7%, respectively, when STMT scores were added together with those of ADAS-Jcog. Results of logistic regression analysis indicated that development into Alzheimer's disease 2 years later was significantly correlated with STMT scores at first examination. The incidence of progression to Alzheimer's disease in patients with scores < or =4 (cut-off value) was about 5 times higher than that of patients with scores > or =5.

This study suggests the usefulness of the STMT for identifying memory impairment as a pre-dementia state.