Effects of additional workload on hand and tongue performance.

Tongue Drive System (TDS) is an unobtrusive, wireless, and wearable device that allows for real time tracking of the tongue motion in the oral space for communication, control, and navigation applications. Utilizing the TDS, we were able to assess the use of tongue motion as a voluntary motor modality and its effect on the human performance in a realistic environment. Preliminary human trials were conducted on 13 able-bodied subjects to assess the speed and accuracy of rapid repetitive goal-directed movements during independent or concurrent use of hand (index finger) and the tongue. The accuracy of hand and tongue movements was decreased with the concurrent hand and tongue task compared with the independent movement task. The speed of hand movement was also decreased with the concurrent hand and tongue movements, but not with the concurrent hand and cognitive task (arithmetic and memory). In contrast, the speed of tongue movement was maintained with the concurrent hand and tongue movements. Instead, the tongue speed was decreased with the concurrent tongue and cognitive task. It was suggested that control via tongue movement with TDS would have the advantage of maintaining comparable speeds between independent and concurrent use over the hand movement control during the tasks that require rapid repetitive goal-directed movements.