The Challenge of Subjective Cognitive Complaints and Executive Functions in Middle-Aged Adults as a Preclinical Stage of Dementia: A Systematic Review

Subjective cognitive complaints correspond to a heterogeneous construct that frequently occurs in the early stages of older adult life. Despite being a common source of worry for middle-aged people, it can be underestimated when clinical and neuropsychological assessments discard any underlying pathological processes. Negative age stereotyping but also self-stereotyping can contribute to doing so. Although its diagnosis is a challenge, its implication as a possible predictor of mild cognitive impairment or dementia increases the interest in its early diagnosis and intervention. The present systematic review analyzes the empirical data on the relationship between these complaints and early executive dysfunction with possible predictive value for preclinical stages of dementia. The sixteen papers obtained from the PubMed and Embase databases were exploratory, cross-sectional and prospective in scope. The studies corroborated the relationship between subjective cognitive complaints and some executive processes, which is noteworthy since many people with subjective executive complaints progress to dementia. The relational studies confirmed that impaired executive performance is associated with CSF biomarkers and reduced cortical volume in specific brain regions. However, the heterogeneity of reports in these studies demands stronger efforts in future research with specific tools applied in clinical and neuropsychological assessments and analyzed under a gender perspective.