Psychometric properties of the modified reaching performance scale in persons with multiple sclerosis

Area of Science:

• Neurology
• Rehabilitation Science
• Movement Science

Background:

• Assessing motor performance deficits in persons with MS (pwMS) requires valid and reliable tools.
• The Reaching Performance Scale (RPS), adapted for MS (mRPS), shows promise for evaluating reaching movement quality.
• The psychometric properties of the mRPS in pwMS were previously unestablished.

Purpose of the Study:

• To determine the content validity of the modified Reaching Performance Scale (mRPS) for patients with MS.
• To evaluate the psychometric properties, including within- and between-session reliability and concurrent validity, of the mRPS in pwMS.

Main Methods:

• Forty-five pwMS performed the mRPS, rating movement quality and compensations during reaching tasks.
• Content validity was assessed by an expert panel; reliability was tested via multiple repetitions within and between days.
• Concurrent validity was examined by correlating mRPS scores with established measures of upper limb function, hand strength, trunk control, and perceived performance.

Main Results:

• The mRPS demonstrated excellent within-session (Kappa 0.85-0.98) and moderate-to-excellent between-session reliability (Kappa 0.66-1.00).
• The mRPS showed high correlation with the Action Research Arm Test (ARAT; rho=0.74) and moderate correlations with measures of trunk performance, hand function, and perceived performance.

Conclusions:

• The mRPS is a reliable instrument for assessing the quality of reaching movement patterns and motor compensations in pwMS.
• The mRPS exhibits partial but significant concurrent validity with other measures of upper limb and trunk function in individuals with MS.