The relation between the symbol digit modalities test, fatigue, depression, and anxiety symptoms in a Belgian MS cohort.

BACKGROUND

Multiple sclerosis (MS) is associated with high prevalence of cognitive impairment, ranging from 40 to 80%. The purpose of this single-center retrospective study was to examine the relation between cognitive function, as measured by Symbol Digit Modalities Test (SDMT), with fatigue, anxiety, and depression symptoms in a Belgian cohort of patients with MS.

METHODS

Sociodemographic and clinical data were analyzed in 66 (F:40, M:26) Belgian patients with a diagnosis of MS. The cognitive function was assessed with the oral version of SDMT, depression and anxiety symptoms with the Hospital Anxiety and Depression scale (HAD), fatigue symptoms with the French valid version of the Fatigue Impact Scale in MS (EMIF-SEP), which is a scale composed of four dimensions (cognitive, physical, social, and psychological) allowing a multidimensional evaluation of fatigue.

RESULTS

The multivariate linear regression analysis demonstrated that lower SDMT scores were associated with higher EDSS score and psychological dimension of fatigue symptoms. No association were found between SDMT and anxiety or depression symptoms. Conversely, higher depression and anxiety symptoms were associated with higher total fatigue symptoms, but lower physical dimension of fatigue symptoms. Higher anxiety symptoms were also independently associated with higher social dimension of fatigue symptoms.

CONCLUSION

A complex relationship exists between cognitive performance, fatigue, and neuropsychiatric symptoms in Belgian people with MS. The level of disability and fatigue adversely affects the cognitive function in MS, whereas depression and anxiety seem to not have a significant effect. A more complex relationship exists between fatigue and neuropsychiatric symptoms, with a divergent interplay between the different dimensions of fatigue that supports the multidimensional approach to assessing fatigue in MS.