Evaluation of a Head-Tongue Controller for Power Wheelchair Driving by People With Quadriplegia

The head-tongue controller (HTC) is a multimodal alternative controller designed for people with quadriplegia to access complex control capabilities by combining tongue and head tracking to offer both discrete and proportional controls in a single controller. In this human study, 17 patients with quadriplegia and current users of alternative controllers were asked to perform four trials of either simple driving tasks or advanced maneuvers in a custom-designed course. Completion time and accuracy were compared between their personal alternative controller (PAC) and various combinations of driving modalities with the HTC. Out of 8 subjects assigned to simple driving, the best HTC trial of 3 subjects was completed faster than their PAC for the tasks of rolling forward and turning around cones, and 5 subjects in rolling backward. Across all these subjects, the average completion time of their best HTC modality is 23 s for rolling forward, 15 s for rolling backward, and 70 s for turning around cones as compared to 19 s, 17 s, and 45 s with their PAC. For advanced driving, the course was completed faster with the HTC by 1 out of 9 subjects, while the best HTC trials of all subjects are less than 1.3 times of their best PAC completion time with an average of 170 s for the HTC and 140 s for their PAC. The qualitative feedback provided by all subjects to a post-study questionnaire scored to an average of 7.5 out of 10 which shows their interests in the HTC and acknowledgement of its usefulness for this population.