Minimizing Sensory Habituation in Nerve Stimulation Through Strategic Temporal Stimulation Patterns

Transcutaneous nerve stimulation (TNS) has the potential to restore sensory feedback in upper-limb prosthetic users. However, its effectiveness is limited by habituation, which is a reduction in the perceived stimulation intensity with prolonged use. This study investigated TNS parameter optimization to maintain consistent sensation, focusing on median and ulnar nerve stimulation through a high-density 2 × 5 electrode grid positioned on the upper arm. Through a systematic evaluation of six experimental conditions varying in block duration, rest intervals, and stimulation patterns, we identified optimal stimulation parameters that significantly reduced habituation while maintaining robust sensory feedback. The most effective protocol demonstrated 37.87% higher sensitivity than the standard protocol while maintaining a low decay rate (0.09 $\pm$ 0.02). During the main protocol, force output stabilized after the initial adaptation and remained significantly above baseline (p $< $ 0.0001). Notably, we observed nerve-specific responses to stimulation parameters, with the median nerve showing significantly heightened sensitivity to parameter variations compared with the ulnar nerve (p = 0.0267). These findings offer a promising approach for maintaining stable sensory feedback in neuroprosthetic applications, with the potential to improve user experience and device adoption. The identified stimulation condition, which features 1-minute blocks and strategic rest intervals, lays the groundwork for more effective TNS-based sensory feedback systems in clinical applications.