To investigate the detailed characteristics of 10-word recall test of ADAS-cog in patients with different levels of cognitive impairment.

One hundred and twenty-seven elder individuals were enrolled in this study from May 2012 to May 2016. According to the level of cognitive impairment, they were divided into three groups: normal group (NC group, n = 56), mild cognitive impairment group (MCI group, n = 49), and dementia group (D group, n = 22). Referring to the California vocabulary leaning test (CVLT), we set some new parameters which reflect the detailed characteristics of the 10-word learning test of ADAS-cog. The parameters included list all (sum of the words which were recalled just after learning), recall total (sum of words which were recalled after an 5-minute interval), primacy (sum of the recalled words which were in front of the list), learning 3nd (sum of words which were recalled just after the 3nd learning), consistency (consistency between the recalled words and the learning words), 3nd consistency (consistency between the recalled words and the 3nd learning words), and so on. We compared the diversity of the parameters in three groups. At the same time, we also completed some other neuropsychological tests such as MoCA and MMSE. Measurement data among the three groups were compared using one-way analysis of variance, and the LSD test was used for multiple comparisons. Categorical data were analyzed using chi-square test. The cutoff values of the scales were determined by ROC curve analysis. The areas under the ROC curves of indexes were calculated to compare their sensitivity and specificity.

As the cognitive function declined, the age increased in the three groups [(78.88 ± 9.55) years vs (82.16 ± 9.69) years vs (85.91 ± 5.65) years, P = 0.008]. The proportion of patients complaining subjective cognitive decline was the highest in the MCI group (51.8% vs 77.6% vs 59.1%). Compared with the total score of MoCA, the parameters such as list total, recall total, primacy, and 3nd consistency performed similarly in distinguishing MCI patients. Recall total had a sensitivity of 84.4% and a specificity of 86. 0% in judging MCI patients. Parameters like list all, recall total, learning 3nd, primacy, consistency, and 3nd consistency had high sensitivity and specificity in distinguishing dementia patients.

The detailed characteristics of neuropsychological tests can help achieve a more accurate diagnosis. Therefore, attention should be paid to the detailed characteristics of the tests as well as the total score.