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Smartphone sensors are used increasingly in the assessment of ataxias. To date, there is no specific consensus guidance regarding a priority set of smartphone sensor measurements, or standard assessment criteria that are appropriate for clinical trials. As part of the Ataxia Global Initiative Digital-Motor Biomarkers Working Group (AGI WG4), aimed at evaluating key ataxia clinical domains (gait/posture, upper limb, speech and oculomotor assessments), we provide consensus guidance for use of internal smartphone sensors to assess key domains. Guidance was developed by means of a literature review and a two stage Delphi study conducted by an Expert panel, which surveyed members of AGI WG4, representing clinical, research, industry and patient-led experts, and consensus meetings by the Expert panel to agree on standard criteria and map current literature to these criteria. Seven publications were identified that investigated ataxias using internal smartphone sensors. The Delphi 1 survey ascertained current practice, and systems in use or under development. Wide variations in smartphones sensor use for assessing ataxia were identified. The Delphi 2 survey identified seven measures that were strongly endorsed as priorities in assessing 3/4 domains, namely gait/posture, upper limb, and speech performance. The Expert panel recommended 15 standard criteria to be fulfilled in studies. Evaluation of current literature revealed that none of the studies met all criteria, with most being early-phase validation studies. Our guidance highlights the importance of consensus, identifies priority measures and standard criteria, and will encourage further research into the use of internal smartphone sensors to measure ataxia digital-motor biomarkers.
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With disease-modifying drugs on the horizon for degenerative ataxias, ecologically valid, finely granulated, digital health measures are highly warranted to augment clinical and patient-reported outcome measures. Gait and balance disturbances most often present as the first signs of degenerative cerebellar ataxia and are the most reported disabling features in disease progression. Thus, digital gait and balance measures constitute promising and relevant performance outcomes for clinical trials.This narrative review with embedded consensus will describe evidence for the sensitivity of digital gait and balance measures for evaluating ataxia severity and progression, propose a consensus protocol for establishing gait and balance metrics in natural history studies and clinical trials, and discuss relevant issues for their use as performance outcomes.
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There are currently no standard methods for evaluating gait and balance performance at home. Smartphones include acceleration sensors and may represent a promising and easily accessible tool for this purpose. We performed an interventional feasibility study and compared a smartphone-based approach with two standard gait analysis systems (force plate and motion capturing systems). Healthy adults (n = 25, 44.1 ± 18.4 years) completed two laboratory evaluations before and after a three-week gait and balance training at home. There was an excellent agreement between all systems for stride time and cadence during normal, tandem and backward gait, whereas correlations for gait velocity were lower. Balance variables of both standard systems were moderately intercorrelated across all stance tasks, but only few correlated with the corresponding smartphone measures. Significant differences over time were found for several force plate and mocap system-obtained gait variables of normal, backward and tandem gait. Changes in balance variables over time were more heterogeneous and not significant for any system. The smartphone seems to be a suitable method to measure cadence and stride time of different gait, but not balance, tasks in healthy adults. Additional optimizations in data evaluation and processing may further improve the agreement between the analysis systems.
Assuntos
Marcha , Smartphone , Adulto , Humanos , Fenômenos Mecânicos , Equilíbrio PosturalRESUMO
PURPOSE: Stroboscopic training is suggested to improve visuomotor abilities in sports. However, previous research has primarily focused on untrained participants and only considered behavioral data. Because visuomotor performance is substantially determined by neural visual processes, this study aimed to examine the effects of stroboscopic training on visuomotor performance and neural visual function of athletes. METHODS: A total of 10 German top-level badminton players (intervention: n = 5 and control: n = 5) participated in this study. Over a 4-week training period, athletes performed badminton-specific visuomotor tasks either wearing shutter glasses (intervention) or under normal visual conditions (control). Prior to and after the training period, behavioral smash-defense tests and neurophysiologic investigations of the N2 motion onset visual evoked potential were used to identify modulations in the athletes' visuomotor performance and visual perception speed, respectively. RESULTS: Badminton training improved visuomotor performance in both groups; however, stroboscopic training resulted in superior posttraining performance compared with normal visual conditions (P = .007). Training-induced modulations in N2 latency did not reach significance, although a strong relationship was observed between changes in N2 latency and changes in visuomotor performance (r = -.55), indicating that higher performance gains following training were associated with a stronger reduction in N2 latency. CONCLUSIONS: The results indicate that stroboscopic training may be more effective than conventional visuomotor training for improving visuomotor abilities even in athletes performing at high skill levels. Furthermore, visuomotor performance gains could potentially be mediated by neural adaptations in the visual motion system. These findings should be confirmed for athletes from different disciplines.
