Reducing false positive diagnoses in mild cognitive impairment: the importance of comprehensive neuropsychological assessment.

BACKGROUND AND PURPOSE: Longitudinal studies of mild cognitive impairment (MCI) report that a sizeable proportion of MCI cases revert to normal levels of functioning over time. The rate of recovery from MCI indicates that existing MCI diagnostic criteria result in an unacceptably high rate of false positive diagnoses and lack adequate sensitivity and specificity. METHODS: The aim of the present study was to identify a set of neuropsychological measures able to differentiate between true positive cases of MCI from those who were unimpaired at 11 months' follow-up. RESULTS: A discriminant function analysis identified that a combination of measures of complex sustained attention, semantic memory, working memory, episodic memory and selective attention correctly classified outcome in more than 80% of cases. The rate of false positive diagnoses (5.93%) was considerably lower than is evident in previously published MCI studies. CONCLUSIONS: The results of the present study indicate that the rate of false positive MCI diagnoses can be significantly reduced through the use of sensitive and specific neuropsychological measures of memory and non-memory functions.

The learning profile of persistent mild cognitive impairment (MCI): a potential diagnostic marker of persistent amnestic MCI.

BACKGROUND AND PURPOSE: Previous research examining mild cognitive impairment (MCI) has highlighted the heterogeneity of outcome in MCI sufferers. MCI is associated with greater risk of progression to dementia; however, a substantial proportion of those identified with MCI have alternative outcomes including recovery to unimpaired status. This heterogeneity may in part reflect insufficient sensitivity and specificity in identifying subclinical memory impairment. METHOD: The present study examined learning in a sample of 109 adults aged 61-91 years with persistent amnestic MCI, persistent non-amnestic MCI, recovered MCI and healthy controls. At the final assessment point, learning for words recalled across each trial of the Rey Auditory Verbal Learning Test was examined for each group. RESULTS: It was found that persistent amnestic MCI participants displayed significantly lower learning compared with recovered MCI and healthy control groups. DISCUSSION: The results of this study indicated that poor learning across trials may be a defining feature of persistent amnestic MCI. Further research is required to establish the predictive utility of within trial list learning performance to identify individuals with persistent and progressive variants of MCI.