Part 1. International Classification of Functioning, Disability and Health (ICF) Core Sets for persons with sleep disorders: results of the consensus process integrating evidence from preparatory studies.

Background/objectives: The International Classification of Functioning, Disability and Health (ICF) provides a comprehensive and universally accepted framework to classify changes in functioning related to health conditions. Comprehensive and Brief Core Sets have been defined for various disorders but not for sleep disorders. Such a Core Set would greatly enhance the techniques available to describe the impact of sleep disorders on patients. The overarching purpose of this paper is to report on phase 1 of the international and World Health Organization (WHO) endorsed consensus process in identifying ICF Core Sets for sleep disorders.

Methods: A formal decision-making and consensus process which integrated evidence gathered from preparatory studies was carried out. Relevant ICF categories were selected by a sample of international experts from different backgrounds using the nominal group technique.

Results: Twenty-six experts from 22 countries and different professional backgrounds attended the consensus conference. Altogether 120 second- or third-level ICF categories were included in the Comprehensive ICF Core Set with the following ICF component split: 49 categories from body functions, 8 from body structures, 31 from activities and participation and 32 from environmental factors. The Brief ICF Core Set included a total of 15 second-level categories: 5 body functions (sleep, energy and drive, attention, consciousness, respiration functions); 3 body structures (brain, respiratory system, pharynx); 4 activities and participation (focusing attention, driving, handling stress and other psychological demands, carrying out daily routine); and 3 environmental factors (immediate family; health services, systems, and policies; and health professionals).

Conclusion: A formal consensus process integrating evidence and expert opinion led to the first version of the ICF Core Sets for persons with sleep disorders. Further validation of the Core Set is needed.