Part 2. Identification of problems in functioning of persons with sleep disorders from the health professional perspective using the International Classification of Functioning, Disability and Health (ICF) as a reference: a worldwide expert survey.

OBJECTIVES: The objective of this study is to identify relevant aspects of functioning as well as related environmental factors from the perspective of health professionals worldwide experienced in treating persons with any kind of (primary) sleep disorder.
METHODS: A structured email survey was sent to 174 selected international experts. Using six open-ended questions, physicians, nurses, therapists, technicians, biologists and psychologists were asked to indicate the problems in functioning experienced by individuals with (primary) sleep disorders including contextual factors like environmental and personal factors which influence functioning. The International Classification of Functioning, Disability and Health (ICF) was used as a frame of reference to analyse the data. All answers were translated ("linked") to the ICF based on established coding rules. Absolute and relative frequencies of the linked ICF categories were reported.
RESULTS: One hundred and twenty-three experts (70.7%) from six World Health Organization (WHO) regions (54 countries) mentioned 5200 themes which were linked to 7256 ICF categories. The majority of these linkings (33.3%) were attributed to 58 different ICF categories of the ICF component body functions, followed by 21.8% of linkings to 52 categories of environmental factors, 16.1% of linkings to 49 different categories in activities and participation, and 9.7% of linkings to 29 categories of body structures.
CONCLUSION: Health professionals addressed a large variety of functional problems reflecting the complexity of sleep disorders. The ICF provided a comprehensive framework in order to integrate answers from different professional backgrounds and different world regions.