Assessment of disabilities in stroke patients with apraxia: Internal consistency and inter-observer reliability

In this paper the internal consistency and inter-observer reliability of the assessment of disabilities in stroke patients with apraxia is presented. Disabilities were assessed by means of observation of activities of daily living (ADL). The study was conducted at occupational therapy departments in general hospitals, rehabilitation centers and nursing homes in the Netherlands. Patients (n=42) diagnosed to have had a stroke in the left hemisphere and to have apraxia as well, participated in the study (48% male, aged 39-91). Guidelines were offered for the ADL-observation and the assessment of disabilities in these activities. The internal consistency of the scales is expressed by means of Cronbach's alpha and Mokken-scale analysis. The inter-observer reliability is expressed by means of percentage of agreement between two observers, Cohen's kappa and the intra-class correlation coefficient (ICC). The internal consistency of the observations is good: alpha is high (0.94). The Mokken-analysis confirms this finding: an H-coefficient of 0.58 and corresponding rho of 0.94 indicate a strong and reliable scale composed of the set of all ADL-observations. Results indicate that the inter-observer reliability can be considered fair to good: all kappa values were higher than 0.44; the maximum kappa was 0.95. Percentages of agreement vary between 60% and 96%. The ICC range from 0.62 to 0.98. The results of this study imply that the ADL-observations can be considered an internally consistent and reliable instrument for the assessment of disabilities in stroke patients with apraxia.