Content validity of the Extended ICF Core Set for stroke: an international Delphi survey of physical therapists

The "Extended ICF Core Set for stroke" is an application of the International Classification of Functioning, Disability and Health (ICF) and represents the typical spectrum of problems in functioning of people with stroke.

The objective of this study was to validate this ICF Core Set from the perspective of physical therapists.

Physical therapists experienced in stroke intervention were asked about their patients' problems and resources and about aspects of the environment that physical therapists treat in people with stroke in a 3-round electronic-mail survey using the Delphi technique. The responses were linked to the ICF. The degree of agreement was calculated using the kappa statistic.

One hundred twenty-five physical therapists from 24 countries named 4,793 problems treated by physical therapists in people with stroke. They identified 10 second-level ICF categories that currently are not represented in the Extended ICF Core Set for stroke. Twelve responses of the participants were linked to the ICF component personal factors, and 15 responses were not covered by the current version of the classification. The kappa coefficient for the linking agreement was 0.39 (95% bootstrapped confidence interval=0.34-0.41).

Two World Health Organization regions were not represented in the sample of physical therapists.

According to the physical therapists, the current version of the Extended ICF Core Set for stroke largely covers the types of problems that their interventions address. However, some aspects of functioning emerged that are not yet covered and may need further investigation.