Test-retest intra-rater reliability of grip force in patients with stroke.

Objective: Coefficients of repeatability and reproducibility can be guides in differentiating between real changes and measurement error. The aim was to evaluate test-retest intra-rater reliability of a clinical procedure measuring grip force with Grippit in stroke patients, to assess relationship between grip force of the hands and between sustained and peak grip force.

Patients And Methods: Eighteen patients were tested using the Grippit at two occasions one hour apart. Each occasion comprised three consecutive trials per hand.

Results: The paretic hand needs to score a 50 N change within and between occasions to exceed the measurement error in 95% of the observations, irrespective of calculation method. Expressed by CV(within) the measurement error was 10%. There was no learning or fatigue effect during measuring. There was a wide variation between subjects but the mean ratio between sides was 0.66. The mean ratio between sustained and peak grip force was 0.80-0.84.

Conclusion: The measurement errors were acceptable and the instrument can be recommended for the use in stroke patients at a department of rehabilitation medicine.