Impact of MCI on testing performance in different cognitive domains

Abstract

AbstractBackgroundImpaired memory affects cognitive testing performance. This study examined in elderly adults the impact of mild cognitive impairment (MCI) on testing performance in different cognitive domains.MethodAfter giving their IRB‐approved written consent, 10 cognitively normal subjects (65±2 years old) and 10 patients with amnestic MCI (68±2 years old) completed the Mini‐Mental State Examination (MMSE), Digit‐Span test, California Verbal Leaning Test –2nd edition (CVLT‐II), and Trail Making Test – B version (TMT‐B). Cognitive performances of the MCI and normal groups were compared by standard t tests. ANOVA was applied to evaluate the impacts of the group and trial‐number factors on immediate Free‐Recall (FR) performance in CVLT‐II.ResultThe group MMSE scores were 24.8±0.4 in the MCI group vs 29.2±0.3 in the normal subjects (P<0.0001). The time to complete TMT‐B was prolonged markedly in the MCI (154±28 s) vs. normal (56±6 s) subjects (P = 0.007). Forward performance score in the Digit‐Span test did not differ between the groups (MCI 9.0±0.6 vs normal 8.5±0.9), although backward Digit‐Span performance was superior (P = 0.021) in the normal (7.0±0.6) vs. MCI (5.1±0.4) groups. CVLT‐II immediate FR scores improved with successive trials in both MCI and normal subjects (trial‐number factor P<0.0001). Although the FR scores from the first 2 trials did not differ between the groups, there was a significant difference appeared in the FR scores of the 3rd and the overall FR scores were appreciably lower in the MCI subjects (group factor P = 0.006). Moreover, 30‐sec Short‐Delay (S‐D) and 10‐min Long‐Delay (L‐D) FR scores were significantly lower in the MCI subjects (Table).ConclusionBoth short‐term memory and visuospatial‐executive function were significantly impaired in the MCI patients as compared with the age‐matched cognitively normal cohort. Repeated trials improve the immediate Free‐Recall in both groups. The backward Digit‐Span test was more sensitive than the forward test to detect the impairment of short‐term memory and attention in the elderly adults with MCI.