To Hear or Not to Hear: Sound Availability Modulates Sensory-Motor Integration

Walking With Ears: Altered Auditory Feedback Impacts Gait Step Length in Older Adults

Auditory feedback may provide the nervous system with valuable temporal (e. g., footstep sounds) and spatial (e.g., external reference sounds) information that can assist in the control of upright walking. As such, hearing loss may directly contribute to declines in mobility among older adults. Our purpose was to examine the impact of auditory feedback on the control of walking in older adults. Twenty older adults (65-86 years) with no diagnosed hearing loss walked on a treadmill for three sound conditions: Baseline, Ear Plugs, and White Noise. We hypothesized that in response to reduced temporal auditory feedback during the Ear Plugs and White Noise conditions, participants would adapt shorter and faster steps that are traditionally believed to increase mechanical stability. This hypothesis was not supported. Interestingly, we observed increases in step length (p = 0.047) and step time (p = 0.026) during the Ear Plugs condition vs. Baseline. Taking longer steps during the Ear Plugs condition may have increased ground reaction forces, thus allowing participants to sense footsteps via an occlusion effect. As a follow-up, we performed a Pearson's correlation relating the step length increase during the Ear Plugs condition to participants' scores on a clinical walking balance test, the Functional Gait Assessment. We found a moderate negative relationship (rho = -0.44, p = 0.055), indicating that participants with worse balance made the greatest increases in step length during the Ear Plugs condition. This trend suggests that participants may have actively sought auditory feedback with longer steps, sacrificing a more mechanically stable stepping pattern. We also hypothesized that reduced spatial localization feedback during the Ear Plugs and White Noise conditions would decrease control of center of mass (COM) dynamics, resulting in an increase in lateral COM excursion, lateral margin of stability, and maximum Lyapunov exponent. However, we found no main effects of auditory feedback on these metrics (p = 0.580, p = 0.896, and p = 0.056, respectively). Overall, these results suggest that during a steady-state walking task, healthy older adults can maintain walking control without auditory feedback. However, increases in step length observed during the Ear Plugs condition suggest that temporal auditory cues provide locomotor feedback that becomes increasingly valuable as balance deteriorates with age.

Sound matters: The impact of auditory deprivation on movement precision in rowing

Purpose of the study was to quantify the importance of auditory feedback for movement precision in elevated rowing task difficulty with elite athletes under normal and masked hearing conditions. It was hypothesized that rowing with masked hearing would reduce the precision of movement, particularly at the non-usual/less-preferred stroke frequencies (SF). Self-reported questionnaires helped to understand the difficulty of the task. Twenty rowers completed 2 × 1000 m-distance-blocks, each separated into 4 × 250 m, with increasing SF 18, 20, 22 24 strokes/minute once with normal and once with masked hearing. Precision was determined as the deviation between the SF target and the SF actually performed (DSF). Athletes' subjective perception was requested before and after the experiment. A 2 (hearing condition) × 4 (SF 18, 20, 22, 24) repeated measures ANOVA showed systematically larger DSF during masked hearing for all SFs compared to the DSF in the normal hearing condition (p < .01). Further, the highest DSFs were found for SF 18 and 24 in both hearing conditions (no interaction effect). The athletes' perception of the relevance of natural movement sounds for their rowing performance changed when evaluated before and after the experiment. Rowing without hearing was evaluated as mentally more demanding than physically. The results confirmed our initial assumptions and showed the relevance of natural auditory information for movement precision in rowing practice, even at a high level of expertise.

Bodily Expression Support for Creative Dance Education by Grasping-Type Musical Interface with Embedded Motion and Grasp Sensors

Dance has been made mandatory as one of the physical education courses in Japan because it can cultivate capacities for expression and communication. Among several types of dance education, creative dance especially contributes to the cultivation of these capacities. However, creative dance requires some level of particular skills, as well as creativity, and it is difficult to presuppose these pre-requisites in beginner-level dancers without experience. We propose a novel supporting device for dance beginners to encourage creative dance performance by continuously generating musical sounds in real-time in accordance with their bodily movements. It has embedded sensors developed for this purpose. Experiments to evaluate the effectiveness of the device were conducted with ten beginner-level dancers. Using the proposed device, the subjects demonstrated enhanced creative dance movements with greater variety, evaluated in terms of Laban dance movement description. Also, using the device, they performed with better accuracy and repeatability in a task where they produced an imagined circular trajectory by hand. The proposed interface is effective in terms of creative dance activity and accuracy of motion generation for beginner-level dancers.