Jeonghee Kim

The Tongue Enables Computer and Wheelchair Control for People with Spinal Cord Injury

Individuals with severe spinal cord injury control a computer and powered wheelchair by using a wireless tongue-operated assistive technology called the Tongue Drive System. Tying the Tongue to Motor Control Voluntary tongue motion may help people with limited upper limb mobility, such as those with high-level spinal cord injury, to access computers and to drive wheelchairs. The Tongue Drive System (TDS) is a wireless and wearable assistive technology that allows individuals with severe motor impairments to access their environments using voluntary tongue motion. Kim et al. report on a new study of TDS efficacy in patients with severe spinal cord injury. Two groups of able-bodied participants and a group of patients with spinal cord injury received a magnetic tongue barbell. Participants used the TDS during five to six testing sessions. Comparisons between the TDS and the keypad for the able-bodied groups and a sip-and-puff device (a traditional assistive technology) for those with tetraplegia were based on widely accepted measures of speed and accuracy. A combination of TDS flexibility and inherent human tongue abilities enabled individuals with severe motor impairments to access computers and drive wheelchairs more quickly but just as accurately as when using traditional assistive technologies. The Tongue Drive System (TDS) is a wireless and wearable assistive technology, designed to allow individuals with severe motor impairments such as tetraplegia to access their environment using voluntary tongue motion. Previous TDS trials used a magnetic tracer temporarily attached to the top surface of the tongue with tissue adhesive. We investigated TDS efficacy for controlling a computer and driving a powered wheelchair in two groups of able-bodied subjects and a group of volunteers with spinal cord injury (SCI) at C6 or above. All participants received a magnetic tongue barbell and used the TDS for five to six consecutive sessions. The performance of the group was compared for TDS versus keypad and TDS versus a sip-and-puff device (SnP) using accepted measures of speed and accuracy. All performance measures improved over the course of the trial. The gap between keypad and TDS performance narrowed for able-bodied subjects. Despite participants with SCI already having familiarity with the SnP, their performance measures were up to three times better with the TDS than with the SnP and continued to improve. TDS flexibility and the inherent characteristics of the human tongue enabled individuals with high-level motor impairments to access computers and drive wheelchairs at speeds that were faster than traditional assistive technologies but with comparable accuracy.

Evaluation of a Smartphone Platform as a Wireless Interface Between Tongue Drive System and Electric-Powered Wheelchairs

Tongue drive system (TDS) is a new wireless assistive technology (AT) for the mobility impaired population. It provides users with the ability to drive powered wheelchairs (PWC) and access computers using their unconstrained tongue motion. Migration of the TDS processing unit and user interface platform from a bulky personal computer to a smartphone (iPhone) has significantly facilitated its usage by turning it into a true wireless and wearable AT. After implementation of the necessary interfacing hardware and software to allow the smartphone to act as a bridge between the TDS and PWC, the wheelchair navigation performance and associated learning was evaluated in nine able-bodied subjects in five sessions over a 5-week period. Subjects wore magnetic tongue studs over the duration of the study and drove the PWC in an obstacle course with their tongue using three different navigation strategies; namely unlatched, latched, and semiproportional. Qualitative aspects of using the TDS-iPhone-PWC interface were also evaluated via a five-point Likert scale questionnaire. Subjects showed more than 20% improvement in the overall completion time between the first and second sessions, and maintained a modest improvement of ~9% per session over the following three sessions.

New ergonomic headset for tongue-drive system with wireless smartphone interface

Tongue Drive System (TDS) is a wireless tongue-operated assistive technology (AT), developed for people with severe physical disabilities to control their environment using their tongue motion. We have developed a new ergonomic headset for the TDS with a user-friendly smartphone interface, through which users will be able to wirelessly control various devices, access computers, and drive wheelchairs. This headset design is expected to act as a flexible and multifunctional communication interface for the TDS and improve its usability, accessibility, aesthetics, and convenience for the end users.

Development and preliminary evaluation of an intraoral tongue drive system

Tongue Drive System (TDS) is a wireless tongue-operated assistive technology (AT), developed for people with severe physical impediments to control their environments using their tongue motion. We have developed a new intraoral TDS (iTDS) in a form of a dental retainer, which can tightly clasp onto the upper teeth, completely hidden inside the mouth, using commercial off-the-shelf components (COTS). The iTDS retainer was tested by two healthy subjects and their performance was compared with that of an external TDS (eTDS) implemented in the form of a headset. The iTDS retainer showed comparable performance with the eTDS headset. The iTDS is expected to improve the stability and robustness of the TDS, while giving users a certain degree of privacy.

Tongue-operated assistive technology with access to common smartphone applications via Bluetooth link

Tongue Drive System (TDS) is a wireless and wearable assistive technology (AT) that enables people with severe disabilities to control their computers, wheelchairs, and electronic gadgets using their tongue motion. We developed the TDS to control smartphones (iPhone/iPod Touch) built-in and downloadable apps with a customized Bluetooth mouse module by emulating finger taps on the touchscreen. The TDS-iPhone Bluetooth mouse interface was evaluated by four able-bodied subjects to complete a scenario consisting of seven tasks, which were randomly ordered by using touch on the iPhone screen with index finger, a computer mouse on iPhone, and TDS-iPhone Bluetooth mouse interface with tongue motion. Preliminary results show that the average completion times of a scenario with touch, mouse, and TDS are 165.6 ± 14.50 s, 186.1 ± 15.37 s, and 651.6 ± 113.4 s, respectively, showing that the TDS is 84.37% and 81.16% slower than touch and mouse for speed of typing with negligible errors. Overall, considering the limited number of commands and unfamiliarity of the subjects with the TDS, we achieved acceptable results for hands-free functionality.

Safety and efficacy of medically performed tongue piercing in people with tetraplegia for use with tongue-operated assistive technology

BACKGROUND Individuals with high-level spinal cord injuries need effective ways to perform activities. OBJECTIVES To develop and test a medically supervised tongue-piercing protocol and the wearing of a magnet-containing tongue barbell for use with the Tongue Drive System (TDS) in persons with tetraplegia. METHODS Volunteers with tetraplegia underwent initial screening sessions using a magnet glued on the tongue to activate and use the TDS. This was followed by tongue piercing, insertion of a standard barbell, a 4-week healing period, and an exchange of the standard barbell for a magnet-containing barbell. This was then used twice weekly for 6 to 8 weeks to perform computer tasks, drive a powered wheelchair, accomplish in-chair weight shifts, and dial a phone. Symptoms of intraoral dysfunction, change in tongue size following piercing, and subjective assessment of receiving and wearing a magnet-containing tongue barbell and its usability with the TDS were evaluated. RESULTS Twenty-one volunteers underwent initial trial sessions. Thirteen had their tongues pierced. One individuals barbell dislodged during healing resulting in tongue-tract closure. Twelve had the barbell exchanged for a magnet-containing barbell. One subject withdrew for unrelated issues. Eleven completed the TDS testing sessions and were able to complete the assigned tasks. No serious adverse events occurred related to wearing or using a tongue barbell to operate the TDS. CONCLUSIONS Using careful selection criteria and a medically supervised piercing protocol, no excess risk was associated with tongue piercing and wearing a tongue barbell in people with tetraplegia. Participants were able to operate the TDS.

An apparatus for improving upper limb function by engaging synchronous tongue motion

Studies of neuroplasticity indicate that areas of the brain not injured by stroke are able to reorganize neural pathways when actively engaged. We have combined two advanced technologies, a robotic hand therapy device and a control system driven by tongue movements, to determine the effects of the wearable Tongue Drive System paired with the Hand Mentor therapeutic robot (TDS-HM) on improving upper extremity motor functions in stroke survivors with severe hemiparesis. For this pilot study, a TDS-HM prototype was constructed and evaluated by three able-bodied subjects with a set of graphical user interfaces. The tongue movements were translated to wrist motion based on three control modes: discrete (CDC), semi-proportional (DPC), and proportional (RPC). Preliminary results showed that the TDS-HM worked reliably with all three control modes, and three healthy subjects showed average RMS deviations of 7.09 ± 1.09, 6.19 ± 1.41, and 7.06 ± 1.78 degrees from a given sinusoidal target path in these modes, respectively. They also played three flash games using the TDS-HM in the three control modes, and achieved on average, 59.4% of their scores when using keypad and mouse.

Longitudinal wearable tremor measurement system with activity recognition algorithms for upper limb tremor

Assessments of tremor characteristics by movement disorder physicians are usually done at single time points in clinic settings, so that the description of the tremor does not take into account the dependence of the tremor on specific behavioral situations. Moreover, treatment-induced changes in tremor or behavior cannot be quantitatively tracked for extended periods of time. We developed a wearable tremor measurement system with tremor and activity recognition algorithms for long-term upper limb behavior tracking, to characterize tremor characteristics and treatment effects in their daily lives. In this pilot study, we collected sensor data of arm movement from three healthy participants using a wrist device that included a 3-axis accelerometer and a 3-axis gyroscope, and classified tremor and activities within scenario tasks which resembled real life situations. Our results show that the system was able to classify the tremor and activities with 89.71% and 74.48% accuracies during the scenario tasks. From this results, we expect to expand our tremor and activity measurement in longer time period.