The Parkinson fatigue scale.

BACKGROUND In recent years several studies have highlighted the clinical significance of fatigue in Parkinson's disease. While we are becoming aware of its prevalence and impact on the lives of patient, little progress has been made in understanding its nature or aetiology, nor on finding ways to manage the problem clinically. One possible reason for the slow pace of progress is the lack of an appropriate instrument to measure fatigue in Parkinson's disease and related disorders. While assessment tools have been developed for assessing fatigue associated with other diseases, their use in patients with Parkinsonism can pose problems and their validity cannot be assumed. OBJECTIVES In an attempt to progress research and improve clinical management a new instrument is presented, the Parkinson Fatigue Scale. METHODS This 16-item self-report instrument (the PFS-16) arose from statements by individuals with Parkinsonism experiencing fatigue. Initially tested on a sample of almost 500 patients, and subsequently on an independent sample of over 100. RESULTS The PFS-16 scale was designed to tap a single construct encompassing the physical aspects fatigue and their impact on the patient's daily function. The scale deliberately excludes emotional and cognitive features that may occur as part of the fatigue experience but which may also occur independently in Parkinsonism. The scale has good intrinsic properties and satisfactory test-retest reliability. It shows reasonable associations with other measures of fatigue and is able to identify patients who self-report the presence of fatigue, and particularly those in whom fatigue is a problem. Cut-off scores are provided in both cases with good specificity and sensitivity. CONCLUSION While further evaluation is required, the scale is offered to facilitate clinical practice and future research. It is hoped that its use will enable the improved understanding and clinical management of this important problem.