The Impact of Function Location on Typing and Pointing Tasks With an Intraoral Tongue–Computer Interface

Abstract

Intraoral target (typing) and on-screen target (pointing/tracking) selection tasks were performed by 10 participants during 3 consecutive day sessions. Tasks were performed using 2 different intraoral sensor layouts. Reduction of undesired sensor activations while speaking as well as the influence of intraoral temperature variation on the signals of the intraoral interface was investigated. Results showed that intraoral target selection tasks were performed better when the respective sensor was located in the anterior area of the palate, reaching 78 and 16 activations per minute for repetitive and “unordered” sequences, respectively. Virtual target pointing and tracking tasks, of circles of 50, 70, and 100 pixels diameter, showed no significant difference in performance, reaching average pointing throughputs of 0.62 to 0.72 bits per second and relative time on target of 34% to 60%. Speaking tasks caused an average of 10 to 31 involuntary activations per minute in the anterior part of the palate. Intraoral temperature variation between 11.87 °C and 51.37 °C affected the sensor signal baseline in a range from –25.34% to 48.31%. Results from this study provide key design considerations to further increase the efficiency of tongue–computer interfaces for individuals with upper-limb mobility impairments.

ACKNOWLEDGEMENTS

We acknowledge the technical support provided by Henrik Vie Christensen, Ph.D. in the production of the tongue interface. Special thanks to Eileen Deaner for her comments and proofreading, and to all the study participants for their time and willingness to participate in the study.

FUNDING

We are grateful for the economic support provided by TKS A/S and the Danish Ministry of Science and Innovation.

Additional information

Notes on contributors

Héctor A. Caltenco

Héctor A. Caltenco is a research engineer with interest in human–computer interaction, computer interfaces, robotics, rehabilitation technologies and intelligent control systems. He holds a Ph.D. in biomedical engineering from the Center for Sensory-Motor Interaction, Aalborg University, Denmark, and is currently a Researcher at Certec, Lund University, Sweden.

Eugen R. Lontis

Eugen R. Lontis is a research engineer with interests in methods for the design of inductive sensors for assistive devices and interfaces. He holds a Ph.D. in biomedical engineering and is currently an associate professor at the Center for Sensory-Motor Interaction, Department of Health Science and Technology at Aalborg University, Denmark.

Bo Bentsen

Bo Bentsen graduated in odontology and holds a Ph.D. in oral pain and distraction from Århus University, Denmark. He is an associate professor at the Center for Sensory Motor Interaction, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Denmark, and owns a private dental clinic in Aalborg, Denmark.

Lotte N. S. Andreasen Struijk

Lotte N. S. Andreasen Struijk is the Tongue Control project manager with an interest in rehabilitation technology, functional electric stimulation, and neural prostheses. She holds a Ph.D. in engineering and is an associate professor at the Center for Sensory-Motor Interaction, Department of Health Science and Technology at Aalborg University, Denmark.