The usability of a wireless vocal fold vibration switch for individuals with complex communication needs: a caregiver-inclusive iterative home-based evaluation.

Purpose: A vocal fold vibration switch is a type of access technology that detects voluntary vibrations of the vocal cords. In two sequential usability studies, we evaluated successive prototypes of a novel wireless vocal fold vibration switch.

Methods: Each usability study enroled 7 dyads consisting of individuals with complex communication needs and their caregivers. Each study entailed a 2-week period of independent home use flanked by initial and final usability tests. Each usability test comprised nine tasks including donning and configuration of the switch, connecting it to other devices, and actual activation of the switch. Perceived task difficulty was measured via nine 21-point scales, while caregiver impressions were captured through open-ended questions, both encapsulated within a usability questionnaire. Caregivers described their experience in an open-ended interview in the second usability study.

Results: Perceived task difficulty was uniformly low with both prototypes. The vast majority of tasks could be completed either independently or with hints. A small number of contraindications for use were identified with the second prototype, which included episodes of dystonia and heavy breathing, and some aspects of the physical design and robustness were flagged as needing further improvement.

Conclusions: The overall qualitative feedback was overwhelmingly positive with caregivers generally desiring to keep and eager to recommend the device to others. Additionally, caregivers expressed that the vocal fold vibration switch expanded the switch user's capabilities, and they foresaw applications beyond the study setting. Overall, our findings suggest that the wireless vocal fold vibration switch is useable in the home setting.