Validity and Reliability of the Persian Version of Fatigue Scale for Motor and Cognitive Functions (FSMC) in Patients with Multiple Sclerosis (MS)

Maedica (Bucur). 2025 Dec;20(4):746-752. doi: 10.26574/maedica.2025.20.4.746.

ABSTRACT

BACKGROUND: Fatigue is one of the most common symptoms in patients with multiple sclerosis (MS), and the cognitive aspect of fatigue is not fully evaluated in these patients. After reviewing existing questionnaires and noting that the fatigue scale for motor and cognitive functions (FSMC) questionnaire has not been validated in Persian, we designed this study to assess the validity and reliability of the Persian version of the FSMC questionnaire in patients with MS.

METHODS: One hundred and forty patients and 63 healthy participants who met the inclusion criteria for healthy controls (age-matched with cases, no history of neurological or psychiatric disorders and not taking anti-depressant medications in the past three months) were enrolled in the present study. Both groups completed the FSMC questionnaire, while the patient group was asked to fill out the valid and reliable Persian version of the modified fatigue impact scale (MFIS), fatigue severity scale (FSS) and Beck depression inventory (BDI). Internal consistencies, content, convergent and discriminant validities were evaluated. We considered the MFIS score as the comparator with a cut-off value of 33 to dichotomize fatigued and non-fatigued individuals, then we plotted the ROC curves of total FSMC, cognitive and motor sub-scales to estimate the best cut-off value of FSMC.

RESULTS: The Cronbach’s alpha for the total FSMC was calculated as 0.95, for the FSMC cognitive subscale as 0.92, and the motor subscale as 0.94. The ICC for the motor subscale was 0.962, and for the cognitive subscale was 0.963. Content validity index (CVI) and content validity ratio (CVR) for all questions of FSMC questionnaire were 100% (content validity). There were significant positive correlations between FSMC and its subscales with MFIS, FSS, BDI and expanded disability status scale (EDSS) (convergent validity). The FSMC score and its subscales were significantly different between patients and healthy individuals (discriminant validity).

CONCLUSION: The Persian version of FSMC provides a valid and reliable tool for evaluating motor and cognitive aspects of MS fatigue, which could be applied in clinical practice and research purposes.

PMID:41537078 | PMC:PMC12767892 | DOI:10.26574/maedica.2025.20.4.746