Objective: Many people present to health services with concern about cognitive symptoms. In a significant proportion those symptoms are not the result of pathologically defined brain disease. In some they are part of a functional cognitive disorder (FCD). We assessed the frequency of cognitive lapses in a non-clinical sample in order to consider the utility of frequency of cognitive lapses in diagnosing cognitive disorders.
Methods: Healthy adults, who had never sought help for cognitive symptoms, completed a questionnaire, distributed via social media, about self-evaluation of cognitive function, frequency of cognitive lapses, and use of memory aids, including Schmitdke and Metternich's functional memory disorder (FMD) inventory.
Results: One hundred and twenty-four adults, aged 18-59 (median 23), most with further or higher education, responded. Thirty-one (25%) reported "fair" or "poor" memory. Forty-eight (39%) reported memory worse than 5 years ago, and 30 (24%) reported memory worse than others the same age. Participants endorsed a mean 13/18 specific cognitive lapses at least monthly. One hundred and eleven (89%) scored ≥4, the suggested cutoff for the FMD inventory.
Conclusions: Cognitive lapses described in FCDs are common in highly educated adults. The high frequency of lapses in this healthy population suggests self-reported frequency of lapses alone cannot discriminate FCDs from "normal" experiences. Further research is required to clarify the role of abnormal metacognition in FCD. Better understanding of the factors moderating subjective interpretation of cognitive failures will also aid development of better clinical risk-stratification methods in people concerned about future dementia.
Keywords: Cognition; cognitive dysfunction; memory; memory disorders; metacognition; reference values.