Objective: Mild cognitive impairment (MCI) is an etiologically nonspecific diagnosis including a broad spectrum of cognitive decline between normal aging and dementia. Several large-scale cohort studies have found sex effects on neuropsychological test performance in MCI. The primary aim of the current project was to examine sex differences in neuropsychological profiles in a clinically diagnosed MCI sample using clinical and research diagnostic criteria.
Method: The current study includes archival data from 349 patients (age M = 74.7; SD = 7.7) who underwent an outpatient neuropsychological evaluation and were diagnosed with MCI. Raw scores were converted to z-scores using normative datasets. Sex differences in neurocognitive profiles including severity, domain-specific composites (memory, executive functioning/information processing speed, and language), and modality-specific learning curves (verbal, visual) were examined using Analysis of Variance, Chi-square analyses, and linear mixed models. Post hoc analyses examined whether sex effects were uniform across age and education brackets.
Results: Females exhibit worse non-memory domain and test-specific cognitive performances compared to males with otherwise comparable categorical MCI criteria and global cognition measured via screening and composite scores. Analysis of learning curves showed additional sex-specific advantages (visual Males>Females; verbal Females >Males) not captured by MCI subtypes.
Conclusions: Our results highlight sex differences in a clinical sample with MCI. The emphasis of verbal memory in the diagnosis of MCI may result in diagnosis at more advanced stages for females. Additional investigation is needed to determine whether these profiles confer greater risk for progressing to dementia or are confounded by other factors (e.g., delayed referral, medical comorbidities).
Keywords: MCI; criteria; dementia; diagnosis; female; verbal memory.