The affect of motor and cognitive fatigue on high quality of life in MS sufferers

Decreases in physical and mental quality of life (QoL) as a result of increased motor and cognitive fatigue in patients with multiple sclerosis (MS) underscores the importance of effectively managing these symptoms, according to study results published in the Multiple Sclerosis Journal.

The varying degrees of MS disability encouraged the study’s researchers to determine whether motor or cognitive fatigue would affect patients’ quality of life regardless of their physical disability. From November 2017 to May 2018, a total of 79 patients from Aalborg University Hospital in Denmark were included in this cross-sectional observational study. Only patients 18 years of age or older who were diagnosed with MS by McDonald’s 2010 criteria and able to communicate in Danish were selected.

The study researchers instructed patients to fill out the questionnaires on the Fatigue Scale for Motor and Cognitive Functions (FSMC), the Modified Fatigue Impact Scale (MFIS), and the Abbreviated 36 (SF-36) to measure fatigue in relation to cognitive, motor, psychosocial and assess health aspects status (physical function, pain, role restrictions, vitality, etc.). They received data on the duration and course of the disease as well as EDSS values ​​(Expanded Disability Status Scale), which were taken from patient files within 6 months.

Among the 79 patients, a majority (90%) had a diagnosis of relapsing-remitting MS (RRMS) with a mean age of 44 years, a mean disease duration of 9 years, and a mean EDSS score of 2.5. Data from the FSMC questionnaire showed that most patients (84%) were reportedly tired, with a majority (63%) reporting fatigue based on MFIS data.

When assessing the relationship between fatigue and quality of life, all fatigue scores showed a significant correlation with all quality of life scores (P <0.05). This remained significant after adjusting for age, duration of illness and EDSS score. The most striking correlations concerned the patient's vitality (r = -0.80, FSMCmot), the social functioning (r = -0.73, MFISps) and the role restrictions caused by physical problems (r = -0.70, MFIStot).

The results showed that the patient’s motor fatigue was most closely related to the QoL dimensions when compared to the cognitive fatigue scores. In addition, disability status (EDSS score) was important for all aspects of quality of life, with the exception of limitations due to emotional problems and mental health, with the strongest correlation with physical functioning.

The limitations of the study include the cross-sectional design and the misclassification due to interobserver deviations in the EDSS assessment as well as deviations in the interval between EDSS and fatigue / QoL assessment. In addition, the study researchers did not further investigate the role of depression in MS patients, as fatigue may be more due to depression than MS. They did not rate the comorbidities and medications that could change fatigue and sleep quality.

The study researchers concluded that the significant and varied correlation between motor and cognitive fatigue and reduced quality of life indicated the need for an appropriate assessment of fatigue in patients with MS. They added that the use of patient-reported interventions is necessary in order to “gain a holistic view of the effects of the disease that will form the basis for developing appropriate and specific treatment interventions”.


Ruben SD, Hilt CC, Petersen T. Quality of life in multiple sclerosis: The different effects of motor and cognitive fatigue. Multiple Sclerosis Journal ETC. Published online February 24, 2021. doi: 10.1177 / 2055217321996040

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