Limited evidence was found for the psychometric properties and clinical usability of these instruments .
However , the CFS-activities and participation question naire ( APQ ) is a disease-specific instrument with moderate content and construct validity .
PURPOSE To summarize measurement instruments used to evaluate activity limitations and participation restrictions in patients with chronic fatigue syndrome ( CFS ) and review the psychometric properties of these instruments .
Chronic fatigue syndrome causes activity limitations and participation restrictions in one or more areas of life .
Functional Incapacity and Physical and Psychological Symptoms: How They Interconnect in Chronic Fatigue Syndrome
Background : It has been argued that perceived functional incapacity might be a primary characteristic of chronic fatigue syndrome ( CFS ) and could be explained by physical symptoms . If so , it could be expected to be closely associated with physical , but not psychological symptoms . The study tests this hypothesis . Sampling and Methods : The sample consisted of 73 patients , with a diagnosis of CFS according to the Oxford criteria , r and omly selected from clinics in the Departments of Immunology and Psychiatry at St. Bartholomew ’s Hospital , London . The degree of fatigue experienced by patients was assessed using the  Chalder Fatigue Question naire and a visual analogue scale . Self-rated instruments were used to measure physical and social functioning , quality of life , and physical and psychological symptoms . Results : Principal-component analysis of all scale scores revealed 2 distinct components , explaining 53 % of the total variance . One component was characterized by psychological symptoms and generic quality of life indicators , whilst the other component was made up of physical symptoms , social and physical functioning and indicators of fatigue . Conclusions : The findings suggest that perceived functional incapacity is a primary characteristic of CFS , which is manifested and /or explained by physical symptoms
Limited evidence was found for the psychometric properties and clinical usability of these instruments .
However , the CFS-activities and participation question naire ( APQ ) is a disease-specific instrument with moderate content and construct validity .
PURPOSE To summarize measurement instruments used to evaluate activity limitations and participation restrictions in patients with chronic fatigue syndrome ( CFS ) and review the psychometric properties of these instruments .
Chronic fatigue syndrome causes activity limitations and participation restrictions in one or more areas of life .