Simultaneous Multimodal Access to Wheelchair and Computer for People with Tetraplegia.

Existing assistive technologies often capture and utilize a single remaining ability to assist people with tetraplegia which is unable to do complex interaction efficiently. In this work, we developed a multimodal assistive system (MAS) to utilize multiple remaining abilities (speech, tongue, and head motion) sequentially or simultaneously to facilitate complex computer interactions such as scrolling, drag and drop, and typing long sentences. Inputs of MAS can be used to drive a wheelchair using only tongue motion, mouse functionalities (e.g., clicks, navigation) by combining the tongue and head motions. To enhance seamless interface, MAS processes both head and tongue motions in the headset with an average accuracy of 88.5%. In a pilot study, a modified center-out tapping task was performed by four able-bodied participants to navigate cursor, using head tracking, click using tongue command, and text entry through speech recognition, respectively. The average throughput in the final round was 1.28 bits/s and a cursor navigation path efficiency of 68.62%.