Multiple Sclerosis Fatigue is Associated with Reduced Psychomotor Vigilance

Abstract

Fatigue is a common and disabling symptom in those who suffer from multiple sclerosis (MS). Studies indicate that more than 75% of MS patients suffer from fatigue. 1-3 Two-thirds of MS patients rank fatigue as one of their three most debilitating symptoms. 1 Multiple sclerosis fatigue is particularly aggravated by heat and can significantly impair physical activity. 1 It is one of the main causes of work absenteeism in individuals with MS. 4 Yet fatigue is a lay term that remains subjectively defined and assessment of fatigue is therefore dependent on self-report. Perhaps as a result, the physiologic substrates of MS fatigue are not well-described. The subjective experience of fatigue is multifactorial and has been correlated with factors such as disability, depression, and pain. [5][6][7] Interestingly, no clear association has been established between MS fatigue and demographic factors, such as age and gender; lesion burden; or the clinical form of MS. 1,[7][8][9] ABSTRACT: Background: Fatigue is common and disabling in multiple sclerosis, yet its physiologic substrates remain poorly defined. The aim of this study was to determine the relationship between fatigue and an objective measure of alertness in MS patients. Methods: This study enrolled 49 consecutive MS clinic patients at two academic hospitals in Toronto. Alertness was assessed with the psychomotor vigilance test (PVT), a ten-minute reaction-time test that measures attention and is sensitive to sleep loss. Patients with visual impairment or arm weakness were excluded. Validated tools were used to assess fatigue, disability, mood, and pain. Results: The average age was 43; 65% were women. Median EDSS was 2.0 (range 0-7.5). Fifty-five percent reported a high impact of fatigue on their lives. Psychomotor vigilance test performance was worse than in an age-and sex-matched population, with a mean reaction time of 315 msecs and 3.98 lapses >500 msec (p<0.001). In a multiple regression analysis, fatigue was the most significantly correlated factor with mean PVT reaction time (p<0.05), and disability was also significantly correlated (p<0.01). Mood and pain did not correlate with the PVT. Eighteen (37%) reported often experiencing restlessness in their legs at night. Conclusion: Subjective fatigue and disability were associated with poor performance on alertness testing in MS patients. This research highlights a potential role for psychomotor vigilance testing in providing a standardized assessment tool for an important aspect of MS-related fatigue.RÉSUMÉ: La fatigue dans la sclérose en plaques est associée à une diminution de la vigilance psychomotrice. Contexte : La fatigue est un symptôme fréquent et invalidant chez les patients atteints de la sclérose en plaques (SP) et sa cause physiologique demeure mal définie. Le but de cette étude était de déterminer la relation entre la fatigue et une mesure objective de vigilance chez des patients atteints de la SP. Méthode : Nous avons inclus 49 patients consécutifs de cliniques de SP situées dans deux hôpitaux ac...

Counteracting Fatigue in Multiple Sclerosis with Right Parietal Anodal Transcranial Direct Current Stimulation

“…Previous studies demonstrated that MS patients with fatigue present a larger vigilance decrement than healthy controls ( 2 , 16 ). Moreover, several studies found correlations between fatigue and vigilance decrement in MS patients ( 3 , 5 , 17 ). Therefore, vigilance tasks appear to be well suited to measure fatigue in MS.…”

“…Several studies on the relation between fatigue and cognitive performance in multiple sclerosis (MS) patients found evidence for a relation between fatigue and vigilance ( 1 – 5 ). Vigilance tasks require an individual to sustain attention during a repetitive monotonous task over a prolonged period of time ( 6 ).…”

Assessment of Fatigue in Multiple Sclerosis

“…These remarks concern only the direct application of relatively short tests for the objectification of fatigue as well as test batteries which provide frequent changes between short tests. Another strategy in the measurement of fatigue analyzes the effect on the test process, the so-called time-on task effect, and this could actually represent a central variable [33]. Fot the PASAT several research groups have shown (although not always reproducible) that the MS patients with fatigue show a stronger performance decline compared to non-fatigue groups at the end of the test [34].…”

Diagnostik der Fatigue bei Multipler Sklerose

“…Alle diese Ausführungen gelten nur für die unmittelbare Anwendung von relativ kurzen Tests zur Objektivierung von Fatigue und für Testbatterien, welche einen häufigen Wechsel zwischen kurzen Tests vorsehen. Eine andere Strategie in der Messung der Fatigue analysiert dagegen deren Auswirkung auf den Testverlauf, d. h. den sogenannten Time-on-Task-Effekt, und dieser könnte tatsächlich eine zentrale Variable darstellen [33]. Für den PASAT konnten mehrere Forschergruppen, wenn auch nicht immer replizierbar, zeigen, dass MS-Patienten mit Fatigue gegen Ende des Tests einen stärkeren Leistungseinbruch zeigen als Vergleichsgruppen ohne Fatigue [34] [35] (unter Ausschluss der somatischen Items), die Hospital Anxiety and Depression Scale (HADS) [36], den Pittsburgh Schlafqualitätsindex (PSQI) [37] und die Epworth-Schläfrigkeitsskala (ESS) [38] an.…”