Rasch analysis in the development of a rating scale for assessment of mobility after stroke

The study describes the development of a rating scale for assessment of mobility after stroke. It was based on 74 first-stroke patients, 40 men and 34 women, each assessed three times during rehabilitation. Their median age was 69 years, and they represented all degrees of severity of paresis. Content, construct, criterion and convergent validity were examined, as well as the inter-rater reliability. The final rating scale has three special characteristics: 1) it reflects the regularity in the recovery of mobility after stroke; 2) the sum of item scores comprises the information contained in the 10-item subscores; 3) the score sum is independent of age, side of hemiparesis, and gender of the patient. Latent trait analysis (Rasch) was found to be an ideal model for statistical investigation of these properties.