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- PublicationShort Bouts of Gait Data and Body-Worn Inertial Sensors Can Provide Reliable Measures of Spatiotemporal Gait Parameters from Bilateral Gait Data for Persons with Multiple SclerosisBackground: Wearable devices equipped with inertial sensors enable objective gait assessment for persons with multiple sclerosis (MS), with potential use in ambulatory care or home and community-based assessments. However, gaitdata collected in non-controlled settings is often fragmented and may not provide enough information forreliable measures. We evaluate a novel approach, extracting pre-defined numbers of gait cycles from the fulllength of a walking task, and their effects on the reliability of spatiotemporal gait parameters. Methods: The present study evaluates intra-session reliability of spatiotemporal gait parameters for short bouts of gaitdata extracted from the full length of the walking tasks to 1) determine the effects of the length of the walkingtask on the reliability of calculated measures and 2) identify spatiotemporal gait parameters that can providereliable measures for gait assessments and reference data in different settings. Thirty-seven participants (37) diagnosed with relapsing-remitting MS (EDSS rage 0 to 4.5) executed two trials,walking 20m each, with inertial sensors attached to their right and left shanks. Previously published algorithms were applied to identify gait events from the medio-lateral angular velocity. Short bouts of gait data wereextracted from each trial, with lengths varying from 3 to 9 gait cycles. Twenty-one measures of spatiotemporalgait parameters were calculated. Intraclass correlation coefficients (ICCs) were calculated to evaluate how the degree of agreement between the two trials of each participant varied with the number of gait cycles included inthe analysis. Results: Spatiotemporal gait parameters calculated as the mean across included gait cycles reach excellent reliabilityfrom three gait cycles. Stride time variability and asymmetry, as well as stride velocity variability and asymmetry, reach good reliability from six gait cycles and should be further explored for persons with MS, whilestride time asymmetry and step time asymmetry do not seem to provide reliable measures and should bereported carefully. Conclusion: Short bouts of gait data, including at least six gait cycles of bilateral data, can provide reliable gait measurements for persons with MS, opening new perspectives for gait assessment using wearable devices in non-controlled environments, to support monitoring of symptoms of persons with neurological diseases.
- PublicationPremorbid cognitive functioning influences differences between self-reported cognitive difficulties and cognitive assessment in multiple sclerosisCognitive difficulties are reported in up to 60% of people with MS (pwMS). There is often a discrepancy between self-reported cognitive difficulties and performance on cognitive assessments. Some of this discrepancy can be explained by depression and fatigue. Pre-MS cognitive abilities may be another important variable in explaining differences between self-reported and assessed cognitive abilities. PwMS with high estimated premorbid cognitive functioning (ePCF) may notice cognitive difficulties in daily life whilst performing within the average range on cognitive assessments. We hypothesised that, taking into account depression and fatigue, ePCF would predict (1) differences between self-reported and assessed cognitive abilities and (2) performance on cognitive assessments. We explored whether ePCF predicted (3) self-reported cognitive difficulties. Eighty-seven pwMS completed the Test of Premorbid Functioning (TOPF), the Brief International Cognitive Assessment for MS (BICAMS), self-report measures of cognitive difficulty (MS Neuropsychological Questionnaire; MSNQ), fatigue (MS Fatigue Impact Scale; MFIS) and depression (Hospital Anxiety and Depression Scale; HADS). Results revealed that, taking into account covariates, ePCF predicted (1) differences between self-reported and assessed cognitive abilities, p < .001 (model explained 29.35% of variance), and (2) performance on cognitive assessments, p < .001 (model explained 46.00% of variance), but not (3) self-reported cognitive difficulties, p = .545 (model explained 35.10% of variance). These results provide new and unique insights into predictors of the frequently observed discrepancy between self-reported and assessed cognitive abilities for pwMS. These findings have important implications for clinical practice, including the importance of exploring premorbid factors in self-reported experience of cognitive difficulties.
- PublicationVisualisation of the medial longitudinal fasciculus using fibre tractography in multiple sclerosis patients with internuclear ophthalmoplegiaBackground: This study investigates the use of fibre tractography to facilitate visualisation of the medial longitudinal fasciculus (MLF) and the impact of internuclear ophthalmoplegia (INO) causing lesions on these reconstructions of the tract. Improved visualisation of such tracts may improve knowledge, understanding and confidence related to neurological conditions. Aims: To explore the use of fibre tractography for the visualisation of the MLF in patients with INO. Methods: Twelve MS subjects with clinical evidence of INO and 12 matched controls underwent magnetic resonance imaging (MRI), including diffusion tensor imaging (DTI), of the brain. Fibre tractography reconstructions were then evaluated and validated by an experienced neuroanatomist. Results: The evaluating neuroanatomist confirmed that the MLF had been reproduced in all of the reconstructed cases (fibre tractography was unsuccessful in five cases). The sensitivity of fibre tractography to MLF pathology was 58.3 % while the specificity was much higher at 85.7 % with a positive predictive value of 87.5 % and a negative predictive value of 54.6 %, with excellent intra-reader reliability. Conclusion: This study demonstrates that fibre tractography of the MLF can potentially be performed with a view to facilitating improved visualisation of the tract and associated pathology in cases of INO. This may help explain the association between lesion type and location with clinical symptomatology and may assist in monitoring disease progression. These reconstructions may provide a valuable addition to the teaching and understanding of clinical signs related to subtle pathology.
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