Sex Differences for Verbal Fluency Decline in Progressive Supranuclear Palsy
Leonardino Digma1, Teodoro del Ser2, Irene Litvan1, Ece Bayram1
1Parkinson and Other Movement Disorders Center, Department of Neurosciences, UCSD School of Medicine, 2Alzheimer's Disease Investigation Research Unit, CIEN Foundation, Queen Sofia Foundation, Alzheimer Research Centre, Carlos III Institute of Health
Objective:
To assess for sex differences in longitudinal change in verbal fluency performance in people with progressive supranuclear palsy (PSP).
Background:
Cognitive impairment is a core feature of PSP; executive dysfunction and reduced phonemic verbal fluency are included in the diagnostic criteria. Sex differences in other neurodegenerative disorders, such as Alzheimer’s and Parkinson’s diseases, have been extensively studied with reports consistently showing cognition is differentially impacted in men and women. In PSP, however, the sex differences in cognitive decline have yet to be fully characterized.
Design/Methods:
We included 139 participants with PSP (62 women, 77 men) that underwent cognitive testing as part of the Tauros trial. Baseline sex differences in demographics and verbal fluency performance were assessed using Mann-Whitney U tests. Then, sex differences in longitudinal change in verbal fluency performance were evaluated with linear mixed models, including interactions of time and baseline score, age, and education as covariates.
Results:
There were no significant differences in baseline age, disease duration, and disease severity between women and men. Men had significantly more education than women (p=0.03). Baseline verbal fluency performance was similar across the sexes. However, compared to women, men had more severe decline in semantic fluency (β=-3.95土0.98; p=7.26e-5) and lexical fluency over time (β=-1.64土0.76; p=0.031).
Conclusions:
We found that men with PSP had worse decline in verbal fluency performance than women, suggesting PSP may affect cognition differently between sexes. Although studies in healthy elderly show a more pronounced decline in category fluency than letter fluency, our findings were likely not due to aging as these studies in healthy elderly report no sex differences for category fluency performance or rate of decline. As cognitive impairment is common and burdensome in PSP, sex-specific approaches may be needed to address the needs of people with PSP.