Fatigue is one of main symptoms in multiple sclerosis, amyotrophic lateral sclerosis and other diseases with profound effect on quality of life and professional and social functioning. Not infrequent it is misdiagnosed as sleepiness or other symptom. Fatigue severity scale is a time efficient and easy to apply instrument to assess the impact of fatigue on patient's life. The aim of this study is to validate the Polish-language version of the 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.

Inclusion Criteria:

• Diagnosis of definite multiple sclerosis or definite, laboratory-supported multiple sclerosis, or definite amyotrophic lateral sclerosis, or probable amyotrophic lateral sclerosis or probable, laboratory supported amyotrophic lateral sclerosis or ischemic stroke or - for healthy controls - lack of diseases, pharmacotherapy or habits, which could induce abnormal tiredness

Exclusion Criteria:

• Presence of cognitive deficits or behavioral disorder, which could disturb participation in the study.

Participants will be recruited from the neurologic ambulatories and neurologic clinics of Jagiellonian University Medical College in Cracow and of Institute of Psychiatry and Neurology in Warsaw. Healthy controls will be recruited from personel of those facitlites as well as from the relatives of members of research team.

After the study is completed, the scans of collected questionnaires will be available upon request sent to the e-mail: jakub.antczak@uj.edu.pl

After the study is completed for the period of ten years.

Researchers affiliated in institutions listed on clinicaltrials.gov.