Upper-limb exoskeletons (ULEs) have the potential to restore functional independence in individuals with severe motor impairments; however, the clinical relevance of wrist degrees of freedom (DoF), particularly abduction-adduction (Ab-Ad), remains insufficiently evaluated. This study investigates the functional and user-perceived impact of wrist Ab-Ad assistance during two activities of daily living (ADLs). Wrist Ab-Ad assistance in a tongue-controlled 6-DoF ULE, EXOTIC2, was evaluated in a within-subject study involving one individual with amyotrophic lateral sclerosis and five individuals with spinal cord injury. Participants performed drinking and scratch stick leveling tasks with EXOTIC2 under two conditions: with and without wrist Ab-Ad assistance. Outcome measure included task success, task completion time, kinematic measures, and a usability questionnaire capturing comfort, functional perception, and acceptance. Enabling wrist Ab-Ad improved task success rates across both ADLs, with consistent reductions in spillage (from 77.8% spillages to 22.2%) and failed placements (from 66.7% to 16.7%). Participants utilized task-specific subsets of the available wrist range of motion, indicating that effective control within functional ranges was more critical than maximal joint excursion. Questionnaire responses indicated no increase in discomfort with the additional DoF and reflected perceived improvements in task performance. In conclusion, wrist Ab-Ad assistance enhances functional task performance in assistive exoskeleton use without compromising user comfort. However, its effectiveness depends on task context, control usability, and individual user strategies. This study provides clinically relevant, user-centered evidence supporting the inclusion of wrist Ab-Ad in ULEs, emphasizing the importance of balancing functional capability with usability in assistive device design.

翻译：上肢外骨骼（ULEs）具有恢复严重运动功能障碍患者功能独立性的潜力，然而手腕自由度（DoF）——特别是外展-内收（Ab-Ad）——的临床相关性尚未得到充分评估。本研究探讨了在两项日常生活活动（ADLs）中，手腕Ab-Ad辅助功能对功能和用户感知的影响。在一项包含一名肌萎缩侧索硬化症患者和五名脊髓损伤患者的被试内研究中，评估了舌控6自由度ULE（EXOTIC2）中的手腕Ab-Ad辅助功能。参与者在启用与关闭手腕Ab-Ad辅助两种条件下，使用EXOTIC2执行饮水与刮棒调平任务。结果指标包括任务成功率、任务完成时间、运动学参数以及涵盖舒适度、功能感知和接受度的可用性问卷。启用手腕Ab-Ad辅助可提升两项ADLs的任务成功率，并一致性地减少液体泼溅（从77.8%降至22.2%）和放置失败（从66.7%降至16.7%）情况。参与者利用可用手腕活动范围的任务特定子集，表明在功能范围内实现有效控制比最大关节活动度更为关键。问卷反馈显示，增加该自由度未引起不适感加剧，并反映了用户感知的任务表现改善。综上所述，手腕Ab-Ad辅助功能可在不损害用户舒适度的前提下增强辅助外骨骼的功能性任务表现。然而，其有效性取决于任务情境、控制可用性及个体用户策略。本研究提供了支持将手腕Ab-Ad纳入ULE的临床相关、用户中心证据，强调了辅助设备设计中功能能力与可用性平衡的重要性。