Validation of Polish Language Version of Fatigue Severity Scale

Fatigue is one of main symptoms in multiple sclerosis, amyotrophic lateral sclerosis, post-polio syndrome, stroke, parkinsonism as well as in the chronic fatigue syndrome. It has profound effect on quality of life and professional and social functioning and in multiple sclerosis it is described as the worst symptoms by the 50% of patients. It is defined as the difficulty in initiating and maintaining a sustained mental or physical activity. Not infrequent it is misdiagnosed as sleepiness or other symptom. Fatigue severity scale (FSS) is a time efficient and easy to apply instrument to assess the impact of fatigue on patient's life. It has been translated and validated in Turkish, Russian, Hindi, Portuguese, and many other languages. FSS is a short, nine-item self-report questionnaire. Each item is a Likert scale, scored from one to seven, where seven refers to the most severely expressed aspect of fatigue. The aim of this study is to validate the Polish-language version of the Fatigue Severity Scale (pFSS). This version has been created according to widely accepted, respective standards, including translation by two independent native Polish-language speakers with acquired knowledge of English and backward translation by two independent native English-language speakers with acquired knowledge of Polish as well as with the pretesting on ten patients.