Age-stratified validation of the performance index (P-Index) as a metric for dual-task cost in functional mobility across the adult lifespan

Area of Science:

• Gerontology
• Neuroscience
• Rehabilitation Medicine

Background:

• Cognitive decline is a growing concern across the adult lifespan.
• Assessing cognitive-motor interference during dual-task (DT) activities is crucial.
• The instrumented Timed Up and Go (iTUG) test offers a platform for such assessments.

Purpose of the Study:

• To evaluate the predictive validity of the Performance Index (P-Index) for cognitive outcomes.
• To determine the P-Index's ability to quantify dual-task performance across the adult lifespan.
• To assess the P-Index's relationship with Mini-Mental State Examination (MMSE) scores.

Main Methods:

• A cross-sectional study included 247 participants of diverse age groups.
• Participants completed single-task (ST) and dual-task (DT) iTUG tests.
• The P-Index was calculated using iTUG times and cognitive task accuracy.

Main Results:

• An optimal P-Index weighting (W1=0.6, W2=0.4) identified a threshold of 0.90 for detecting MMSE scores ≥26 (sensitivity=0.69, specificity=0.64).
• Depressive symptoms were associated with lower MMSE scores (OR=1.19).
• Increased medication use (OR=1.04) and higher P-Index values (OR=3.89) predicted better cognitive performance.

Conclusions:

• The P-Index reliably quantifies dual-task interference and predicts cognitive performance across adulthood.
• The P-Index demonstrates potential as a practical tool for cognitive-motor assessments.
• This metric may aid in the early detection of cognitive decline.