Assessment of the tongue-drive system using a computer, a smartphone, and a powered-wheelchair by people with tetraplegia

Tongue-Drive System (TDS) is a wireless and wearable assistive technology that enables people with severe disabilities to control their computers, wheelchairs, and smartphones using voluntary tongue motion. To evaluate the efficacy of the TDS, several experiments were conducted, in which the performance of nine able-bodied (AB) participants using a mouse, a keypad, and the TDS, as well as a cohort of 11 participants with tetraplegia (TP) using the TDS, were observed and compared. Experiments included the Fitts' law tapping, wheelchair driving, phone-dialing, and weight-shifting tasks over five to six consecutive sessions. All participants received a tongue piercing, wore a magnetic tongue stud, and completed the trials as evaluable participants. Although AB participants were already familiar with the keypad, throughputs of their tapping tasks using the keypad were only 1.4 times better than those using the TDS. The completion times of wheelchair driving task using the TDS for AB and TP participants were between 157 s and 180 s with three different control strategies. Participants with TP completed phone-dialing and weight-shifting tasks in 81.9 s and 71.5 s, respectively, using tongue motions. Results showed statistically significant improvement or trending to improvement in performance status over the sessions. Most of the learning occurred between the first and second sessions, but trends did suggest that more practice would lead to increased improvement in performance using the TDS.