Validation of Perceived Mental Fatigability Using the Pittsburgh Fatigability Scale

Area of Science:

• Gerontology
• Psychology
• Neuroscience

Background:

• Mental fatigability is a significant concern in older adults, impacting daily functioning and quality of life.
• The Pittsburgh Fatigability Scale (PFS) is a widely used measure, but its mental subscale requires further validation.

Purpose of the Study:

• To establish the reliability, concurrent validity, and convergent validity of the Pittsburgh Fatigability Scale (PFS) Mental subscale in older adults.
• To assess the psychometric properties of the PFS Mental subscale across diverse cohorts.

Main Methods:

• A cross-sectional study design was employed, utilizing three cohorts of older adults from established aging research registries.
• The PFS Mental subscale was administered, alongside measures of cognition, depressive symptoms, and global fatigue for validity assessments.
• Confirmatory factor analysis, internal consistency (Cronbach's α), and test-retest reliability (ICC) were calculated.

Main Results:

• The PFS Mental subscale demonstrated strong internal consistency (Cronbach's α = 0.85) and good test-retest reliability (ICC = 0.78).
• Concurrent and construct validity were supported by moderate correlations with measures of cognition (r = 0.14-0.17), depressive symptoms (r = 0.31), and global fatigue (ρ = 0.21).
• Strong convergent validity was observed, with significant differences in PFS Mental scores across clinical and cognitive cut points (P < .001).

Conclusions:

• The validated PFS Mental subscale is a sensitive, one-page, self-administered tool for assessing perceived mental fatigability in older adults.
• This validated instrument is suitable for use in both clinical practice and research settings to evaluate mental fatigue.