University of Southampton Auditory Implant Service, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
Faculty of Engineering and Physical Sciences, University of Southampton, University Road, Southampton, SO17 1BJ, UK.
Sci Rep. 2021 Jan 11;11(1):312. doi: 10.1038/s41598-020-79150-z.
Hearing aid and cochlear implant (CI) users often struggle to locate and segregate sounds. The dominant sound-localisation cues are time and intensity differences across the ears. A recent study showed that CI users locate sounds substantially better when these cues are provided through haptic stimulation on each wrist. However, the sensitivity of the wrists to these cues and the robustness of this sensitivity to aging is unknown. The current study showed that time difference sensitivity is much poorer across the wrists than across the ears and declines with age. In contrast, high sensitivity to across-wrist intensity differences was found that was robust to aging. This high sensitivity was observed across a range of stimulation intensities for both amplitude modulated and unmodulated sinusoids and matched across-ear intensity difference sensitivity for normal-hearing individuals. Furthermore, the usable dynamic range for haptic stimulation on the wrists was found to be around four times larger than for CIs. These findings suggest that high-precision haptic sound-localisation can be achieved, which could aid many hearing-impaired listeners. Furthermore, the finding that high-fidelity across-wrist intensity information can be transferred could be exploited in human-machine interfaces to enhance virtual reality and improve remote control of military, medical, or research robots.
助听器和人工耳蜗（CI）用户常常难以定位和区分声音。主要的声音定位线索是耳朵之间的时间和强度差异。最近的一项研究表明，当这些线索通过每个手腕上的触觉刺激提供时，CI 用户可以更准确地定位声音。然而，手腕对这些线索的敏感性以及这种敏感性对年龄的影响尚不清楚。本研究表明，手腕之间的时间差敏感性比耳朵之间差得多，并且随着年龄的增长而下降。相比之下，发现了对跨腕强度差异的高度敏感性，这种敏感性对年龄具有很强的鲁棒性。这种高灵敏度适用于幅度调制和未调制正弦波的一系列刺激强度，并且与正常听力个体的耳间强度差异灵敏度相匹配。此外，发现手腕上的触觉刺激的可用动态范围大约是 CI 的四倍。这些发现表明，可以实现高精度的触觉声音定位，这可以帮助许多听力受损的听众。此外，发现可以传输高保真的跨腕强度信息，可以在人机界面中利用这一点来增强虚拟现实并改善对军事、医疗或研究机器人的远程控制。
