Association Between Fatigue and Motor Exertion in Patients With Multiple Sclerosis - a Prospective Study

Background: Fatigue in multiple sclerosis (MS) is conceived as a multidimensional construct. Objectives: This study aims to describe the changes of balance and gait parameters after 6 min of walking (6 MW) as potential quantitative markers for perceptions of state fatigue and trait fatigue in MS. Methods: A total of 19 patients with MS (17 with fatigue) and 24 healthy subjects underwent static posturography, gait analysis, and ratings of perceived exertion before and after 6 MW. Results: 6 MW was perceived as exhaustive, but both groups featured more dynamic comfortable speed walking after 6 MW. Shorter stride length at maximum speed and increased postural sway after 6 MW indicated fatigability of balance and gait in MS group only. While most changes were related to higher levels of perceived exertion after 6 MW (state fatigue), higher fatigue ratings (trait fatigue) were only associated with less increase in arm swing at comfortable speed. Further analysis revealed different associations of trait fatigue and performance fatigability with disability and motor functions. Performance fatigability was most closely related to the Expanded Disability Status Scale, while for trait fatigue, the strongest correlations were seen with balance function and handgrip strength. Conclusions: Fatigability of performance was closely related to perceptions of exertion after 6 MW (state fatigue) and disability in MS but distinct from fatigue ratings, conceived as trait fatigue. Our study identified postural sway, arm swing during gait, and hand grip strength as unexpected potential motor indicators of fatigue ratings in MS

Cognitive-motor interference in multiple sclerosis and healthy controls: results from single, dual, and triple task posturography

Aim: This article is based on our previous research, which was presented as a poster at the ECTRIMS Congress 2018 and published as a conference abstract (https://www.professionalabstracts.com/ectrims2018/iplanner/#/presentation/1698). Cognitive-motor interference (CMI) has been observed in both healthy controls (HC) and persons with multiple sclerosis (pwMS), but limited and contradictory data is making it difficult to assess the impact of motor and cognitive functioning levels on CMI. The aim of this study was to investigate CMI in pwMS and HC by means of a dual task postural paradigm, to compare them between groups and to analyse the influence of motor and cognitive functioning levels assessed with complementary instruments on observed CMI. Methods: The dual task posturography paradigm serves to quantify the impact of a cognitive (i.e., performing serial subtractions), a motor challenge (closing eyes), or both challenges combined (triple task) on body sway during standing in an upright position feet closed. The data analysed were acquired in one interventional and four observational studies and selected based on predefined criteria and by systematic quality control. A total of 113 pwMS and 42 HC were selected for analysis. Results: Comparable changes in motor and cognitive performance due to cognitive or combined cognitive-motor challenges were observed in both HC and pwMS. Combining both tasks did not result in further changes in motor performance but resulted in a decrease in cognitive performance. This reduction in cognitive performance with an additional motor challenge correlated with lower levels of cognitive and motor functioning in pwMS. Unexpectedly, an increase in body sway due to a cognitive or combined cognitive-motor challenges was primarily observed in pwMS and HC with better cognitive and motor functioning. Conclusions: The results suggest that dual-task effects are not disease-specific but rather reflect individually different adaptation strategies depending on the specific motor and cognitive functioning levels

Associations between Fatigue and motor parameters in Multiple Sclerosis – a prospective study

Einleitung: Fatigue ist bei Patienten mit Multipler Sklerose (PwMS) eines der häufigsten Symptome, welches schon in der frühen Krankheitsphase auftreten kann und regelhaft zur Beeinträchtigung von Alltagsfunktionen führt. Der Begriff Fatigue umfasst unterschiedliche Komponenten. Häufig differenziert man die Wahrnehmung einer länger bestehenden Erschöpfung von einer erhöhten Erschöpfbarkeit, jeweils in kognitiver und körperlicher Ausprägung. Ein Zusammenhang zwischen den unterschiedlichen Komponenten von Fatigue ist Gegenstand aktueller Forschung. Fragestellung: Ziel dieser Arbeit war es, Veränderungen von quantitativen motorischen Gang- und Standparametern zu untersuchen, hervorgerufen durch einen 6-Minuten-Gehtest (6MW), und diese als mögliche Parameter für das objektive Erfassen von kurzzeitiger (State) und zugrundeliegender (Trait) Erschöpfung bei PwMS zu beschreiben. Methodik: In dieser Arbeit wurden Daten von 19 PwMS und 24 gesunden Probanden in einer prospektiven klinischen Studie erhoben und analysiert. Der Studieneinschluss erfolgte auf Größe, BMI, Geschlecht und Alter kontrolliert. Unter den PwMS wurde Trait Fatigue mittels eines validierten Fragebogens (FSMC) erhoben. Basisparameter der motorischen Funktion waren die 6MW Gehstrecke, Handgreifkraft und Posturographie. Alle Teilnehmer durchliefen Gangmessungen in normaler und schneller Ganggeschwindigkeit, sowie einer statischen Posturographie, jeweils vor und nach dem 6MW als Auslöser für Erschöpfbarkeit. Zusätzlich wurde der Grad der State Fatigue direkt vor und nach dem 6MW auf einer Borg-Skala erfasst. Ergebnisse: Die Analyse zeigte Unterschiede zwischen beiden Gruppen hinsichtlich der Handgreifkraft, der Balance und der 6MW Gehstrecke. Der 6MW wurde von beiden Gruppen gleichermaßen als anstrengend empfunden, dennoch war gruppenübergreifend das normale Gangtempo nach dem 6MW beschleunigt. Ausschließlich bei den PwMS nahm, als Zeichen einer Erschöpfbarkeit, nach 6MW die Schrittlänge im schnellen Gang ab und das Schwanken in der Posturographie zu. Obwohl ein Großteil der gemessenen Veränderungen im Zusammenhang mit der State Fatigue nach dem 6MW standen, war nur eine geringere Zunahme des Armschwunges im normalen Gangtempo mit stärkerer Trait Fatigue assoziiert. In der weiteren Analyse zeigten sich vielfältige Korrelationen zwischen der Trait Fatigue, sowie der motorischen Performance mit der Krankheitsschwere (EDSS) und motorischen Basisparametern. Dabei korrelierte die motorische Performance am stärksten mit dem EDSS. Die Trait Fatigue stand hingegen mit der Handgreifkraft und der Posturographie in Verbindung. Schlussfolgerung: Bei PwMS steht die körperliche Erschöpfbarkeit infolge eines 6MW im Zusammenhang mit State Fatigue und der Krankheitsschwere, ist aber weitestgehend unabhängig von Trait Fatigue. Als potentielle objektive Parameter zur Erfassung der Trait Fatigue konnten die Posturographie, Veränderung des Armschwungs im normalen Gangtempo und die Handgreifkraft identifiziert werden.Background: Fatigue is one of the most frequent and burdensome complaints in patients with multiple sclerosis (PwMS) with impact on daily functioning, even in early disease stages. It is conceived as a multidimensional construct related to patient’s perception of fatigue and fatigability in relation to exertion in the motor or cognitive domain. Immediate changes on perceptional level are conceived as state fatigue, while prolonged or constant sensations are considered as trait fatigue. The association between the different dimensions of fatigue is therefore subject of current research. Aim: The objective of this work was to describe changes of balance and gait parameters after 6-minute walking (6MW) as potential quantitative markers for perceptions of state and trait fatigue in PwMS. Methods: Data of 19 PwMS and 24 healthy subjects who were controlled for height, BMI, age and gender were collected and analyzed in a prospective clinical study. In PwMS trait fatigue was measured by the Fatigue Scale for Motor and Cognitive Functions (FSMC). Walking capacity, balance and hand grip strength were measured as baseline motor function parameters. All participants underwent an instrumental motor assessment that comprised walks in comfortable and maximum speed and static posturography. This, and participant ratings of perceived exertion, were taken directly before and after 6MW with the Borg Scale. Results: Analysis of baseline motor functions showed differences between the groups for balance, hand grip strength and walking capacity. The 6MW increased ratings of perceived exertion (state fatigue) to the same extent in both groups, however, both groups featured a more dynamic walking pattern in comfortable speed after 6MW. Increased postural sway and shorter stride length in maximum speed after 6MW exertion was only seen among PwMS and may indicate fatigability of balance and gait. Most of the observed changes were related to higher levels of perceived exertion (state fatigue) after 6MW. In contrast, only a lesser increase in arm swing at comfortable speed after 6MW was associated to higher fatigue ratings (trait fatigue). Further analysis revealed different associations of trait fatigue and performance fatigability with disability and motor function. The Expanded Disability Status Scale (EDSS) was most closely related to performance fatigability and ratings of state fatigue after exertion, while the strongest correlations for trait fatigue were observed with balance function and handgrip strength. Conclusion: Performance fatigability is closely related to perceived exertion after the 6MW (state fatigue) and disability scores in PwMS, but rather distinct from trait fatigue ratings. In this study we identified balance, arm swing during comfortable speed walking, and hand grip strength as potential motor indicators of fatigue ratings in PwMS