Validity of performance scales for disability assessment in multiple sclerosis

Area of Science:

• Neurology
• Rehabilitation Medicine
• Health Outcomes Research

Background:

• Self-reported health status assessments are increasingly used but require validation.
• The Performance Scales (PS) is a self-report measure for multiple sclerosis (MS)-associated disability.
• Previous studies validated the total PS score but not individual subscales.

Purpose of the Study:

• To assess the criterion and construct validity of individual Performance Scales (PS) subscales in patients with multiple sclerosis (MS).

Main Methods:

• Forty-four MS patients completed the PS and criterion measures including neurological examination (EDSS), MS Functional Composite (MSFC), contrast acuity testing, and MS Quality of Life Inventory.
• Criterion and construct validity were assessed using Spearman rank correlations between PS subscales and other measurements.

Main Results:

• The overall PS score correlated with the MSFC (r=-0.58, P<0.0001).
• Mobility, hand, vision, fatigue, and bladder subscales demonstrated significant correlations with their respective criterion measures (r=0.59-0.77, P<0.0001).
• The sensory subscale showed a weak correlation with the sensory functional system score (r=0.39, P=0.01), and the cognitive subscale did not correlate with the PASAT (r=-0.17, P=0.26).

Conclusions:

• The study supports the criterion and construct validity of the overall PS and its mobility, hand, vision, fatigue, and bladder subscales.
• Further assessment is required for the cognitive, sensory, and spasticity subscales of the Performance Scales.