Marisa Ferreira1, Paulo A Pereira2, Marta Parreira3, Inês Sousa4, José Figueiredo5, João J Cerqueira6, Antonio F Macedo7. 1. Vision Rehabilitation Lab.; Centre/Department of Physics and Optometry, University of Minho, Braga, Portugal; Association "Todos com a Esclerose Multipla (TEM)", Braga, Portugal. Electronic address: marisaborgesferreira@gmail.com. 2. Association "Todos com a Esclerose Multipla (TEM)", Braga, Portugal; Centre of Mathematics, Department of Mathematics and Applications, University of Minho, Braga, Portugal. Electronic address: ppereira@math.uminho.pt. 3. Association "Todos com a Esclerose Multipla (TEM)", Braga, Portugal. Electronic address: martafgparreira@gmail.com. 4. Centre of Mathematics, Department of Mathematics and Applications, University of Minho, Braga, Portugal. Electronic address: isousa@math.uminho.pt. 5. Association "Todos com a Esclerose Multipla (TEM)", Braga, Portugal. Electronic address: minsk1enator@gmail.com. 6. Neurosciences Domain; Life and Health Sciences Research Institute, School of Health Sciences and ICVS/3B's Associate Laboratory, University of Minho, Braga, Portugal; Clinical Academic Centre (CCA), Hospital de Braga, Braga, Portugal. Electronic address: jcerqueira@ecsaude.uminho.pt. 7. Vision Rehabilitation Lab.; Centre/Department of Physics and Optometry, University of Minho, Braga, Portugal; Linnaeus University, Department of Medicine and Optometry, SE 39182 Kalmar, Sweden. Electronic address: antonio.macedo@lnu.se.
Abstract
PURPOSE: Multiple Sclerosis (MS) is likely to cause dysfunction of neural circuits between brain regions increasing brain working load or a subjective overestimation of such working load leading to fatigue symptoms. The aim of this study was to investigate if saccades can reveal the effect of fatigue in patients with MS. METHODS: Patients diagnosed with MS (EDSS<=3) and age matched controls were recruited. Eye movements were monitored using an infrared eyetracker. Each participant performed 40 trials in an endogenous generated saccade paradigm (valid and invalid trials). The fatigue severity scale (FSS) was used to assess the severity of fatigue. FSS scores were used to define two subgroups, the MS fatigue group (score above normal range) and the MS non-fatigue. Differences between groups were tested using linear mixed models. RESULTS: Thirty-one MS patients and equal number of controls participated in this study. FSS scores were above the normal range in 11 patients. Differences in saccade latency were found according to group (p<0.001) and trial validity (p=0.023). Differences were 16.9ms, between MS fatigue and MS non-fatigue, 15.5ms between MS fatigue and control. The mean difference between valid and invalid trials was 7.5ms. Differences in saccade peak velocity were found according to group (p<0.001), the difference between MS fatigue and control was 22.3°/s and between MS fatigue and non-fatigue was 12.3°/s. Group was a statistically significant predictor for amplitude (p<0.001). FSS scores were correlated with peak velocity (p=0.028) and amplitude (p=0.019). CONCLUSION: Consistent with the initial hypothesis, our study revealed altered saccade latency, peak velocity and amplitude in patients with fatigue symptoms. Eye movement testing can complement the standard inventories when investigating fatigue because they do not share similar limitations. Our findings contribute to the understanding of functional changes induced by MS and might be useful for clinical trials and treatment decisions.
PURPOSE:Multiple Sclerosis (MS) is likely to cause dysfunction of neural circuits between brain regions increasing brain working load or a subjective overestimation of such working load leading to fatigue symptoms. The aim of this study was to investigate if saccades can reveal the effect of fatigue in patients with MS. METHODS:Patients diagnosed with MS (EDSS<=3) and age matched controls were recruited. Eye movements were monitored using an infrared eyetracker. Each participant performed 40 trials in an endogenous generated saccade paradigm (valid and invalid trials). The fatigue severity scale (FSS) was used to assess the severity of fatigue. FSS scores were used to define two subgroups, the MS fatigue group (score above normal range) and the MS non-fatigue. Differences between groups were tested using linear mixed models. RESULTS: Thirty-one MS patients and equal number of controls participated in this study. FSS scores were above the normal range in 11 patients. Differences in saccade latency were found according to group (p<0.001) and trial validity (p=0.023). Differences were 16.9ms, between MS fatigue and MS non-fatigue, 15.5ms between MS fatigue and control. The mean difference between valid and invalid trials was 7.5ms. Differences in saccade peak velocity were found according to group (p<0.001), the difference between MS fatigue and control was 22.3°/s and between MS fatigue and non-fatigue was 12.3°/s. Group was a statistically significant predictor for amplitude (p<0.001). FSS scores were correlated with peak velocity (p=0.028) and amplitude (p=0.019). CONCLUSION: Consistent with the initial hypothesis, our study revealed altered saccade latency, peak velocity and amplitude in patients with fatigue symptoms. Eye movement testing can complement the standard inventories when investigating fatigue because they do not share similar limitations. Our findings contribute to the understanding of functional changes induced by MS and might be useful for clinical trials and treatment decisions.
Authors: Marisa Borges Ferreira; Paulo Alexandre Pereira; Marta Parreira; Ines Sousa; José Figueiredo; João José Cerqueira; Antonio Filipe Macedo Journal: PeerJ Date: 2018-10-04 Impact factor: 2.984