Gabriel Grace A, Harris Laurence R, Henriques Denise Y P, Pandi Maryam, Campos Jennifer L
KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, Canada.
Department of Psychology, University of Toronto, Toronto, ON, Canada.
Front Aging Neurosci. 2022 Aug 25;14:816512. doi: 10.3389/fnagi.2022.816512. eCollection 2022.
Self-motion perception (e.g., when walking/driving) relies on the integration of multiple sensory cues including visual, vestibular, and proprioceptive signals. Changes in the efficacy of multisensory integration have been observed in older adults (OA), which can sometimes lead to errors in perceptual judgments and have been associated with functional declines such as increased falls risk. The objectives of this study were to determine whether passive, visual-vestibular self-motion heading perception could be improved by providing feedback during multisensory training, and whether training-related effects might be more apparent in OAs vs. younger adults (YA). We also investigated the extent to which training might transfer to improved standing-balance. OAs and YAs were passively translated and asked to judge their direction of heading relative to straight-ahead (left/right). Each participant completed three conditions: (1) vestibular-only (passive physical motion in the dark), (2) visual-only (cloud-of-dots display), and (3) bimodal (congruent vestibular and visual stimulation). Measures of heading precision and bias were obtained for each condition. Over the course of 3 days, participants were asked to make bimodal heading judgments and were provided with feedback ("correct"/"incorrect") on 900 training trials. Post-training, participants' biases, and precision in all three sensory conditions (vestibular, visual, bimodal), and their standing-balance performance, were assessed. Results demonstrated improved overall precision (i.e., reduced JNDs) in heading perception after training. Pre- vs. post-training difference scores showed that improvements in JNDs were only found in the visual-only condition. Particularly notable is that 27% of OAs initially could not discriminate their heading at all in the visual-only condition pre-training, but subsequently obtained thresholds in the visual-only condition post-training that were similar to those of the other participants. While OAs seemed to show optimal integration pre- and post-training (i.e., did not show significant differences between predicted and observed JNDs), YAs only showed optimal integration post-training. There were no significant effects of training for bimodal or vestibular-only heading estimates, nor standing-balance performance. These results indicate that it may be possible to improve unimodal (visual) heading perception using a multisensory (visual-vestibular) training paradigm. The results may also help to inform interventions targeting tasks for which effective self-motion perception is important.
自我运动感知（例如，行走/驾驶时）依赖于多种感官线索的整合，包括视觉、前庭和本体感觉信号。在老年人（OA）中已观察到多感官整合效能的变化，这有时会导致感知判断错误，并与功能衰退相关，如跌倒风险增加。本研究的目的是确定在多感官训练期间提供反馈是否可以改善被动的视觉 - 前庭自我运动航向感知，以及训练相关效果在老年人与年轻人（YA）中是否可能更明显。我们还研究了训练在多大程度上可能转化为改善的站立平衡。让老年人和年轻人进行被动平移，并要求他们判断相对于正前方（左/右）的航向。每个参与者完成三种情况：（1）仅前庭（在黑暗中被动身体运动），（2）仅视觉（点云显示），以及（3）双峰（一致的前庭和视觉刺激）。针对每种情况获得航向精度和偏差的测量值。在3天的过程中，要求参与者进行双峰航向判断，并在900次训练试验中提供反馈（“正确”/“错误”）。训练后，评估参与者在所有三种感官条件（前庭、视觉、双峰）下的偏差和精度，以及他们的站立平衡表现。结果表明训练后航向感知的总体精度有所提高（即，减小了最小可觉差）。训练前与训练后的差异分数表明，仅在仅视觉条件下最小可觉差有所改善。特别值得注意的是，27%的老年人在训练前仅视觉条件下最初根本无法辨别其航向，但在训练后仅视觉条件下获得了与其他参与者相似的阈值。虽然老年人在训练前和训练后似乎都表现出最佳整合（即，预测和观察到的最小可觉差之间没有显著差异），但年轻人仅在训练后表现出最佳整合。训练对双峰或仅前庭航向估计以及站立平衡表现没有显著影响。这些结果表明，使用多感官（视觉 - 前庭）训练范式可能改善单峰（视觉）航向感知。这些结果也可能有助于为针对有效自我运动感知很重要的任务的干预措施提供信息。
