Evaluation of a Tongue Operated Assistive Technology for Individuals With Severe Paralysis

This study was intended to evaluate a new assistive neuro-technology, known as the Tongue Drive System (TDS), by its potential end-users, i.e. individuals with severe disabilities, who are the best experts for indicating the benefits and possible shortcomings of any new ANT. Our goal is to assess the acceptability and usability of the TDS for various tasks that are important in daily lives of these individuals, such as computer access, wheeled mobility, and environmental control.

A new assistive neuro-technology (ANT), called the Tongue Drive System (TDS), enables individuals with severe disability access their environment with nothing but their tongue motion. The human tongue is inherently capable of sophisticated control and manipulation tasks with many degrees of freedom. It can move rapidly and accurately within the mouth such that the tip can touch every single tooth. The direct connection between the brain and the tongue generally allows it to escape damage even in severe spinal cord injuries (SCI). Unlike the brain, the tongue is accessible, and its location inside the mouth affords a degree of privacy.

TDS consists of a magnetic tracer, the size of a lentil, attached to the tongue by gluing, implantation, or piercing. The tracer generates a magnetic field inside and around the mouth that is detected by an array of magnetic sensors mounted on a wireless headset. Tongue-movement-induced changes in the magnetic field are sent wirelessly to an ultra-mobile computer or smartphone, carried by the user, which processes and translates every tongue motion to a particular user-defined function.

Once an individual with disability is "enabled" to access a computing device, he/she can nearly do everything that an able-bodied individual can do with that device. This includes communicating, education, training, entertainment, and controlling other devices such as powered wheelchairs (PWC), assistive robotic manipulators, and other home/office appliances on a local area network (LAN). Even the individual's own natural or prosthetic limbs can be manipulated to move by functional electrical stimulation (FES).

This study was intended to evaluate the TDS by the ultimate intended users, individuals with severe disabilities, who are the best experts for indicating the benefits and possible shortcomings of any new ANT. Our goal is to assess the acceptability and usability of the TDS for various tasks that are important in daily life such as computer access, wheeled mobility, and environmental control.

Three groups of subjects were recruited:

Group-A: Able-bodied subjects who already have tongue piercing

Group-B: Able-bodied subjects who wanted to receive tongue piercing as part of this trial

Group-C: Subjects with high-level disability, who wanted to receive tongue piercing as part of this trial

Each group of subjects participated in a battery of tasks that quantitatively measures their performance in accessing computers and driving wheelchairs using the TDS.

We also devised acceptable procedures for receiving a magnetic tongue piercing (required in order to use the TDS), and assess its potential safety issues.

Eligibility Criteria:
Inclusion Criteria:

Inclusion group-A:

* Age 18-65
* Able-bodied with a tongue piercing Must have had the tongue piercing for at least 3 months and still be using it
* Piercing is located in the midline of the tongue between the tip and the frenulum, almost in the center of the mouth
* Can understand and speak English
* Have some experience in using computers

Inclusion group-B:

* Age 18-65
* No overt sign of disability or neurological disease
* Do not have a tongue piercing, but are willing to receive one in the midline between the tip and lingual frenulum, almost in the center of the mouth
* Can understand and speak English
* Have some experience in using computers

Inclusion group-C:

* Age 18-65
* Have mobility limitations requiring a power wheel chair and also have inadequate upper limb strength to manage a hand or arm control i.e. have severe motor disabilities and need alternative control
* Either using or suitable for an alternative control
* Able to follow simple commands
* Sitting tolerance of at least 4 hours (each experiment session will be no more than 4 hours and the researcher follows the standard pressure relief schedule)
* Have some experience in using computers
* Be able to move the tongue
* Be able to speak or respond to questions by themselves or through an augmentative and alternative communication (AAC) device
* Be able to give consent
* Be able to have a caregiver, who can respond immediately in the event of an emergency, available during the period of the study.
* Can understand and speak English
* Have or are willing to receive a tongue piercing in the midline between the tip and the lingual frenulum, almost in the center of the mouth

Exclusion Criteria:

Exclusion Group-A:

* Original tongue piercing and the insertion site is too wide.
* Ongoing difficulties with current tongue jewelry
* Tongue piercing not located in the correct position on the tongue
* No experience with computers or illiterate
* Severe hearing or visual deficiency or impairing neurological disease
* Have any ongoing systemic condition deemed to be relevant by the local investigator-clinician
* Is pregnant
* Cognitive impairment so that unable to follow simple commands
* Wounds or ulcers on the head or in the mouth or on the tongue
* Using sensitive electronic implantable medical device such as a deep brain stimulator or a pacemaker in the upper body
* Intra-oral space occupying lesion or orthodontic appliance
* Unable to come to GT or RIC on a regular basis during the study-period
* Miss more than two appointments without prior notification
* Unable to comply with any of the procedures in the protocol

Exclusion Group-B:

* Tongue too short or the tongue web too far extended, making tongue piercing difficult
* Have a torus mandibularis or palatini or other space-occupying intra-oral lesion or orthodontic appliance
* No experience with computers or illiterate
* Severe hearing or visual deficiency or impairing neurological disease
* Cardiovascular and respiratory diseases, artificial heart valve, congenital heart disease
* On an immunosuppressive medication or otherwise immunocompromised
* Diabetic or have any other ongoing systemic condition deemed to be relevant by the local investigator-clinician
* Ongoing neoplastic disease other than localized basal cell or squamous cell carcinoma of the skin
* Have known asthma, physical urticaria or angioedema
* Have any current infectious condition
* Cognitive impairment to the extent that cannot follow simple commands
* Is pregnant
* Wounds or ulcers on the head or in the mouth or on the tongue
* Using sensitive electronic implantable medical device such as a deep brain stimulator or a pacemaker in the upper body
* Space occupying orthodontic appliances
* Unable to come SCA or NU for a tongue piercing, 72 hour visit and to GTB or RIC on a regular basis during the study-period
* Miss more than two appointments without prior notification
* Unable to comply with any of the procedures in the protocol

Exclusion Group-C:

* Unable to move the tongue
* Have a large object or tube in the mouth blocking tongue motion
* Tongue or tongue frenulum short or the tongue frenulum extended far forward, making tongue piercing difficult
* Have a torus mandibularis or palatini or other space-occupying intra-oral lesion or orthodontic appliance
* Medically or mentally unstable
* Known sensitivity or allergy to an adhesive
* Using a halo brace or facial pads that would block the use of a headset or headgear
* Cognitive impairment to the extent that the subject cannot follow simple commands
* Severe hearing or visual deficiency
* Cardiovascular and respiratory diseases, artificial heart valve, congenital heart disease
* On any form of anticoagulation including but not limited to warfarin, heparin, low-molecular-weight heparin, factor Xa inhibitors, aspirin, aspirin-containing products, or nonsteroidal anti-inflammatory medications that the subject's supervising attending physician states cannot be stopped during the pre-piercing period which may include not only the appropriate medication-specific washout period before the piercing but also up to 5 days after the procedure.
* On an immunosuppressive or otherwise immunocompromised
* Have a decubitus ulcer stage III or higher or a decubitus ulcer of any stage that is worsening.
* Diabetic or have any other ongoing systemic condition, as deemed to be relevant by the local investigator-clinician
* Ongoing neoplastic disease other than localized basal cell or squamous cell carcinoma of the skin
* Have known asthma, physical urticaria or angioedema
* Have any current infectious condition
* Is pregnant
* No experience with computers or illiterate
* Using a sensitive electronic implantable medical device such as a deep brain stimulator or a pacemaker in the upper body
* Unable to sit for 4 hours with pressure relief
* Wounds or ulcers on the head or in the mouth or on the tongue
* No continuous access to a caregiver
* Unable to come to the SCA or NMH for a three day stay for tongue piercing and to SCA or RIC on a regular basis during the study-period
* Miss more than three appointments without prior notification
* Unable to comply with any of the procedures in the protocol