[Sleepiness and fatigue in multiple sclerosis - comparison of different measuring instruments]

Abstract

Introduction: Patients suffering from multiple sclerosis often complain of fatigue and sleepiness. Patients often cannot distinguish between these symptoms. Daytime sleepiness, attention and concentration deficits affect life quality severely. Usually symptoms of MS are characterized by the Expanded Disability Status Scale (EDSS). In new studies the MSFC proves to be a more sensitive method especially estimating the cognitive deficits.

Methods: 31 RRMS patients (18 women, 13 men, mean age 35.6 +/- 8.3 years) and 19 healthy controls (9 men, 1 woman, age: 55.1 +/- 7.8 years) were assessed by: 1) morning and evening protocols of the German Sleep Society, 2) Epworth Sleepiness Scale (ESS), 3) Extended Disability Status Scale (EDSS), 4) MS Functional Composite (MSFC) based on arm function, ambulation and cognition (paced auditory serial addition test, PASAT), 5) Fatigue Severity Scale (FSS).

Results: The EDSS-Score ranged from 1.0 to 6.5 (2.8 +/- 1.4). Mean Z-Score of MSFC was -0.19 +/- 0.63. Most deficits could be shown in the PASAT. Total sleep time correlated with recovery capacity of sleep (r = 0.42, P < 0.05). The ESS-Score was 6.1 +/- 2.9 (1 - 14). FSS-Score was raised with intraindividual variability (4,33 +/- 1.62, 1.4 - 7). The EDSS failed to correlate with the ESS- or FSS-Score. FSS correlated significantly with arm function (r = 0.465) und ambulation (r = 0.436) in the MSFC (P < 0.05).

Discussion: MS-Patients are often not able to distinguish between fatigue and sleepiness. By using different scales judging sleepiness and fatigue significant differences could be evaluated. Fatigue is mainly linked to motoric deficits scored by the MSFC. Therefore medication with stimulants seems not to be useful in fatigue therapy.