Absence of a relationship between subjective memory complaint and objective memory impairment in mild cognitive impairment (MCI): is it time to abandon subjective memory complaint as an MCI diagnostic criterion?

Background: Subjective memory complaints are a requirement in the diagnosis of mild cognitive impairment (MCI) as they are thought to indicate a decline in objective memory performance. However, recent research suggests that the relationship between subjective memory complaint and objective memory impairment is less clear. Thus, it is possible that many people without subjective memory complaints who develop Alzheimer's disease are precluded from a diagnosis of MCI. Methods: The present study examined the relationship between subjective memory complaint assessed using the Multifactorial Memory Questionnaire (MMQ) and objective memory impairment assessed using standard neuropsychological measures in cases of amnestic MCI (n = 48), non-amnestic MCI (n = 27), and unimpaired healthy participants (n = 64). Results: Correlational and regression analyses indicated that subjective memory complaints displayed a poor relationship with objective memory performance. A subsequent discriminant function analysis indicated that subjective memory complaints failed to improve the diagnostic accuracy of MCI and resulted in increased rates of false negative and false positive diagnoses. Conclusion: The results of the present study suggest that a diagnostic criterion of subjective memory complaint reduces the accuracy of MCI diagnosis, resulting in an elevated rate of false positive and false negative diagnoses. The results of this study in conjunction with recent research indicate that a criterion of subjective memory complaint should be discarded from emerging diagnostic criteria for MCI.