Adaptive and Individualized AAC
Phase: NA
Conditions: Communication Disorders
Sponsor: Altec Inc.

 
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Study Protocol and Statistical Analysis Plan 
 
 
Protocol Title 
Adaptive and Individualized AAC 
 
Sponsor 
Altec Inc., Natick, MA 01760 
 
ClinicalTrials.gov Identifier 
NCT04247828 
 
Principal Investigator 
Paola Contessa 
 
Version Date 
September 29, 2021 
 
Note: The text below was extracted from the IRB protocols for this study, which were first 
approved on 12/16/2019 for testing at Madonna Rehabilitation Hospital (Nebraska) and on 
08/20/2019 with an amendment approved on 04/26/2021 for testing at Altec, Inc. 
 
 
 

 
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Study Protocol 
 
Background  
More than 1.3% of Americans, including over 150,000 children, suffer from severe physical 
impairments (SPI) that impede their ability to communicate. Over 500,000 of these individuals 
are adults and children with SPI who require augmentative and alternative communication 
(AAC) technology to be able to express themselves. These include a wide range of technologies 
and methods ranging from sign language and gestures to hi-tech speech-generating devices. 
However, many individuals with SPI lack the manual dexterity required to operate these assistive 
technologies and, as a result, require an alternative means of computer access such as head-or 
eye-tracking. Even then, these alternative access methods are often too tedious for individuals 
with SPI, as they require frequent recalibrations and readjustments to accommodate changes in 
disease progression, body position, and/or environment. It is therefore not uncommon that 
prospective users invest weeks or months of training time into using these devices, only to 
achieve inconsistent or inaccurate performance that impedes effective and intuitive 
communication. There is an urgent need to develop turnkey AAC devices that are able to 
automatically accommodate the unique physical access needs of individuals with SPI. 
 
Goal of the Overall Study 
Our team of experts in wearable sensor systems, algorithms, and human machine interfaces 
at Altec, Inc., in collaboration with a team of speech researchers and clinicians from Boston 
University (Stepp Lab) and Madonna Rehabilitation Hospital’s Institute for Rehabilitation 
Science & Engineer (Communication Center Lab), aims to develop a more reliable, portable, and 
intuitive AAC device for individuals with SPI. This device will leverage direct recordings of head 
movement and facial muscle contractions from a combined surface electromyographic (sEMG) 
and inertial measurement unit (IMU) sensor to provide a means for controlling cursor movements 
and selection on an individualized keyboard interface that allows to adapt the device to the 
unique residual motor function of each user for improved communication capabilities. Through 
this innovation, we aim to provide individualized AAC solutions to all individuals – including 
those with the most complex needs – to preserve the fundamental human right of communication. 
This work is a continuation of pilot studies by our team over the past 4 years, which have 
focused on the development of sensor-based access methods and adaptive interfaces that shift 
the burden of learning from the patients to the device. Since sEMG and IMU signals directly 
measure muscle control and body kinematics, such as occurs to produce head movement, they 
provide a reliable, portable, and intuitive means to adapt the device to the unique residual motor 
function of each user. 
 
Study Sites 
Data collection will take place in the research laboratories of Altec, Inc. (Natick, MA) under 
the supervision of the project PI, Dr. Paola Contessa, and the study coordinator, Dr. Serge Roy; 
the Communication Center of Excellence laboratory at Madonna Rehabilitation Hospital Institute 
for Rehabilitation Science and Engineering (Lincoln, NE) under the supervision of Susan Fager, 
Ph.D., CCC-SLP, Director of the Communication Center of Excellence - one of four Centers of 
Excellence within the Institute for Rehabilitation Science and Engineering at Madonna; or the 
Boston University Stepp Lab at Boston University (Boston, MA) under the supervision of Cara 
Stepp, Ph.D., another key collaborator on the project and speech expert, founder and Director of 
the STEPP LAB for Sensorimotor Rehabilitation Engineering at Boston University. When 

 
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necessary, we will exercise the option of conducting the data collection procedure in an offsite 
location that is convenient to the prospective subject. 
 
Specific Aims 
A series of experiments will be performed where control subjects and participants with SPI 
will be asked to perform head movements and eyeblinks to control the movement of a cursor and 
the selection of targets on a computer or tablet screen while IMU and sEMG signals are recorded 
from a sensor placed on the participants’ forehead. These experiments will demonstrate that a 
novel sEMG/IMU-based access method is uniquely capable of characterizing subject-specific 
variations in movement capabilities in a heterogeneous sample of individuals with SPI to inform 
the adaptation of an AAC keyboard interface that accommodates residual motor function unique 
to each user. Specifically, sEMG and IMU signals during head movement and eyeblinks will be 
translated into repeatable cursor control and target selection that replicate subject-specific 
movement capabilities. This information will be used to adapt the configuration, orientation, and 
layout of an AAC orthographic keyboard interface to accommodate the head movement 
characteristics unique to each subject. The newly developed sEMG/IMU-based models and 
personalized keyboard interface will be tested to demonstrate that this new access method 
improves AAC performance when compared to communicating on a generic cursor-to-text AAC 
interface that uses the same configuration but is not optimized for the individual. 
 
Protocol 
The experiments require the subjects to utilize head motion to move a cursor on a computer 
or tablet screen interface. These interfaces will be of two general kinds: an interface that affords 
us the opportunity to assess generic cursor sensor control for targets located at different 
orientations and distances; and an orthographic interface where letters are arranged in either a 
standard (QWERTY) keyboard configuration or an optimized configuration specific to their 
individual control capabilities. During all experiments, participants will be seated in front of a 
monitor or tablet and asked to move a cursor appearing on the screen based on data extracted 
from a wireless Trigno Avanti (Delsys, Inc.) sensor worn on their forehead. When the cursor 
reaches the target, the subject must select the target by contracting their facial muscle (i.e.: via 
sEMG signals from either eye blinking or raising their eyebrows). 
In some tasks, letters will be highlighted in the appropriate sequence to spell words presented 
to the subject. The selection and capture of the targets by the subject will be achieved by blinking 
or raising their eyebrow while the cursor is hovering at or near the target. In other tasks, 
participants will be asked to spell a series of words presented to them on the computer interface 
by moving the cursor with the aid of the head mounted IMU and select the target with the aid of 
the measured sEMG activity. The number of sentences will be arranged in consultation with our 
clinical collaborators so that the procedures can be completed within a reasonable timeframe. 
Additional data acquisition during these experiments may include standard video recordings 
to assist in post-processing interpretation of results; and user-rated report of fatigue, effort, 
perceived benefit, ease of use or satisfaction through a brief Likert-type questionnaire.  
Each session should require 1-3 hours over 1-2 sessions (depending on subject stamina) with 
rest periods provided at least every 10 minutes to avoid fatigue or lack of attentiveness. 
 
Involvement of Human Subjects 
Children and adults (male/female; ≥8 y.o.), including healthy controls and individuals with 
SPI, will be recruited. 

 
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Sex considerations: Even though some SPI have a sex preference – as for example the prevalence 
of people who sustain spinal cord injuries is greater in males than females – we plan to recruit 
equal numbers of males and females to assess possible differences between men and women with 
regards to the expected outcomes of this work. 
 
Age considerations: SPI affect both children and adult populations who may develop verbal 
communication impairments and require the need for AAC devices. We will therefore include 
children ≥8 yo. who are able to spell, follow 2-3 step directions, have functional vision sufficient 
to read point text, and have a motor impairment that requires the use of AAC technology. 
 
Racial/Ethnic origin considerations: We plan to recruit a subject population that includes equal 
participation of minorities and is representative of the racial and ethnic diversity of the greater 
Boston and Lincoln areas. 
 
Other considerations: Subjects must speak English so that we can accurately develop an AAC 
keyboard interface and speech model based on English-language and must be literate in English 
so that they can read speech task prompts from a computer monitor. 
 
Recording apparatus: All sensors used in this study will be non-invasive and electrically 
isolated for subject safety. A Trigno Avanti https://www.delsys.com/trigno/research/ wireless 
data acquisition system (Delsys Inc., Natick, MA) designed for detecting both sEMG and IMU 
signals from the same sensor will be located on the subject’s forehead for these experiments. The 
sensor wirelessly communicates with either a Trigno Base station or a Tablet. Signals from the 
sensors will be sampled at 2000 samples/sec using EMGWorks software (Delsys Inc., Natick, MA), 
and interfaced over USB to a PC workstation for post processing. The sensor will be secured to 
the skin using a disposable medical-grade double-sided interface. 
 
Sensor locations: The skin area of each sensor location will be prepared using alcohol wipes to 
cleanse the skin surface and repeated tape peels to remove possible superficial contaminants (oil; 
dead skin) so as to improve signal quality. Facial hair may be shaved with the subjects’ permission 
using a disposable safety razor in the immediate area of the sensor recording sites. We anticipate 
placement of no more than 1 sensor at any one time, with the IMU body placed on the 
participant’s forehead and the sEMG mini-head placed adjacent to the eye to record muscle 
activations from either blinking or raising the eyebrow. 
 
Inclusion/Exclusion Criteria 
 
INDIVIDUALS WITH SPI 
 
Inclusion criteria: 
- Adults or Children; age> 8 y.o. 
- Male or Female. 
- All participants will be: (a) able to spell, (b) able to follow 2-3 step directions, (c) have 
functional vision sufficient to read 40 point text, and (d) have a motor impairment that requires 
the use of an alternative access strategy to communicate and/or use technology. 
- Current or prospective AAC user with complex communication needs representing a broad 
spectrum of developmental and acquired SPI disabilities resulting from high spinal cord injury, 

 
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chronic Guillain-Barré syndrome, brain stem stroke, cerebral palsy, locked-in syndrome, among 
others 
- Sufficient head control and voluntary facial muscle activation (on the basis of clinical 
evaluation by Dr. Susan Fager and her team) to use the proposed wearable EMG/IMU sensor for 
the purposes of this study. 
- Evidence of at least partial voluntary head movement in at least 2 degrees of freedom 
(Individual differences in providing controlled movements of the head in various degrees of 
freedom due to their disease or trauma is not only acceptable but desirable). 
- Sufficient stamina and developmental maturity (on the basis of clinical evaluation by Dr. 
Susan Fager) to attend to the approximately 1-hour protocol outlined in Aims 1 and 3 without 
excess fatigue or distraction. 
- Availability for at least 3-4 testing sessions over the study period. 
- No medical or safety restrictions of active head and neck movement (as determined by Dr. 
Susan Fager in consultation with her clinical team). 
- Clinical evidence of preserved cognition by a score of 0 or 1 on NIHSS Consciousness and 
Communication item. 
- Ability to voluntarily blink eyes or raise eyebrows on command. 
 
Exclusion criteria: 
- Non-English speaker. 
- Inability to follow simple instructions in English. 
- Medical history of musculoskeletal conditions (arthritis, spondylosis, etc.) that severely limit 
head movement or causes pain on head movement. 
- Restricted active or passive rotation of head and neck resulting from unstable vertebral, 
spinal cord, or nerve roots that places the subject at risk. 
- Medical history of cardiac or respiratory complications, or similar disorders that would 
severely reduce stamina and/or place the subject at risk for conducting the different motor 
activities. 
- Skin disorders that result in open lesions or hyper-sensitive/fragile skin on the forehead, 
preventing the use of medical-grade adhesive tapes to secure the sensors to the skin. 
- 
Unable to provide informed consent in English. 
 
CONTROLS 
 
Inclusion Criteria: 
- Adults and Children; >8 y.o. 
- Male or Female. 
- All participants will be: (a) able to spell, (b) able to follow 2-3 step directions, (c) have 
functional vision sufficient to read 40 point text. 
- No history of communication disorders. 
- No history of neurological disorders affecting speech or head movement. 
 
Exclusion Criteria:  
- Non-English speaker. 
- Inability to follow simple instructions in English. 
- Restricted ROM of the head or neck. 
- Pain with head movement. 

 
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- Medical history of cardiac or respiratory complications, or disorders that would place the 
subject at risk for conducting the different motor activities. 
- Skin disorders that result in open lesions or hyper-sensitive/fragile skin on the forehead, 
preventing the use of medical-grade adhesive tapes to secure the sensors to the skin. 
- Unable to provide informed consent in English. 
 
Recruitment Process   
Participants with SPI meeting the Inclusion/Exclusion criteria will be recruited primarily 
through referrals from Dr. Susan Fager and Dr. Cara Stepp who provide a primary point of 
contact for AAC evaluation and intervention for children and adults with SPI. Control subjects 
meeting the Inclusion/Exclusion criteria will be recruited primarily through posting and flyers in 
the Boston University region in Boston, MA (Downtown and Mid-town Campuses in Boston) and 
in the immediate area around Altec, Inc. at local cafes, shopping malls, and fitness centers. 
 
Informed Consent 
All subjects will be properly informed of the purpose of the study by the research team. The 
prospective subjects will have the opportunity to read an IRB-approved informed consent form 
outlining the experimental procedures, risks, and rights as a human subject and see the actual 
equipment demonstrated to them. Written consent will be obtained from adults, written parental 
consent and assent will be obtained from pediatric participants. A signed and dated copy of the 
consent form will be provided to each subject/parent. All researchers involved in the 
experimental procedures and analysis of human subject data as outlined in this proposal have 
training certification on file and are familiar with the appropriate Federal guidelines regarding 
the use of human subjects for research. 
 
Potential Risk and Protection against Risk 
The identifiable risks, which fall into the category of less than minimal physical risks, are 
described below. 
 
1. The primary medical risk includes possible irritation to the skin caused by securing and 
removing the sensors from the skin. The risk is comparable to having a Band-Aid on the skin and 
peeling it off. To mitigate this risk, the skin will be inspected before and following removal of the 
sensors and wiped using an alcohol swab. An over-the-counter skin moisturizing cream will be 
available should the subject feel any irritation or dryness at the sensor locations. 
 
2. Some temporary tiredness and muscle fatigue may result in the participants with SPI from 
performing the head movement activities. This risk is similar to a light exercise session and is a 
natural consequence of using one’s muscles in daily life, or using a head mounted control for 
AAC, and will be minimized by offering frequent rest periods. 
 
3. Risks of injury or discomfort to the cervical spine caused by active movement of the head 
and neck for persons with SPI from head or neck injuries such as traumatic high-level spinal cord 
injury will warrant special consideration. SPIs in the acute phase of recovery following a spinal 
cord injury will be excluded as well as those who are immobilized using an orthotic or traction 
to minimize head movement will also be excluded. All prospective subjects with spinal cord 
injury regardless of stage of recovery will be careful screened by Dr. Susan Fager and her medical 

 
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team so that all prospective subjects are medically cleared to perform active head and neck 
movements of the kind described in this study. 
 
4. The risk of electric shock is highly unlikely and greatly minimized because the sensors 
used in this study are wireless and designed to completely isolate the subject from sources of 
electrical current. These circuits ensure subject safety in compliance with United States and 
European EN60601 safety standards for medical instrumentation. They are in compliance with 
CE and FDA Medical Device Standards for allowable leakage currents. 
 
5. Although unlikely, a breach in the secure network at our facilities could cause video or 
research data to become publicly available. All data will be kept on secure servers and will be 
shared with collaborators only through secured connections. All data will be coded for safety. 
 
Vulnerable Subjects 
Children and subjects with SPI can be considered as vulnerable populations and we will abide 
by the federal regulations in effect for inclusion of such research participants as overseen by IRB 
review and approval. 
 
Confidentiality 
The file linking subjects’ name to codes will be in paper form and will be stored in a locked 
file cabinet along with signed consent forms. All sensor data will be password protected on lab 
servers. Access will only be available to those working on the project. For cases where data are 
shared between clinical collaborators and Altec, Inc. only de-identified, raw data will be shared. 
This removes risk that a patient's privacy may be compromised. In case the subject gives explicit 
permission to take photo and video recordings during the experiment these will be stored in the 
password protected project folder on the lab servers. All digital data will be identified only by 
subject codes. To help us protect privacy, this project also has a certificate of Confidentiality from 
the Federal Government.  
 
Potential Benefits to the Subjects 
There are no anticipated benefits for subjects in this study aside from the potential benefits to 
the population of individuals with SPI in need of AAC devices for communication if our results 
lead to a more adaptable and optimized AAC system. 
 
Alternatives to Participation 
This study does not involve medical diagnostics or treatments for which alternatives should 
be offered. 
 
 

 
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Data & Statistical Analysis Plan 
 
A series of signal acquisition and processing software will be developed to collect and analyze 
sEMG and IMU signals from wearable sensors to develop algorithms for person-centric AAC 
cursor control, which will then serve to train machine learning algorithms to achieve an 
individualized AAC keyboard interface. We will validate these developments to show that an 
individualized keyboard interface can provide improved communication performance compared 
to a generic (QWERTY) keyboard interface.  
The analyses of sEMG and IMU data will be guided by our knowledge of sensor and signal 
processing solutions for human machine interfaces for preliminary prototype studies and early 
development of concepts rather than to prove efficacy. We purposely want to collect data from a 
diverse group to be able to capture a range of movement limitations so that we have a variety of 
potential “adaptations” the interface can make. A single-subject design approach will therefore 
be adopted to evaluate these different, personalized adaptations. For this reason, data analysis 
will be conducted across participants to compare individualized AAC device performance to 
generic (QWERTY) AAC device performance.  
Data analysis will follow the U.S. Department of Education standards for single-subject 
statistical designs as each participant engages in a series of transcription (scripted) tasks to 
examine user-specific communication performance between our individualized AAC device and 
a generic (QWERTY) AAC device. Participant communication performance will collected within 
a single session for each device; the QWERTY keyboard will be analyzed in the second session 
(Day 2) to serve as a reference for communication performance (i.e., due to widespread familiarity 
in using the QWERTY keyboard for mobile device communication) once participants are familiar 
with the sEMG/IMU access method. 
The change in level (mean) and variability (standard deviation) of communication 
performance will be evaluated via metrics of information transfer rate (bits/min), movement time 
(sec), target selection accuracy (%), movement variability (unitless), and perceived usability for 
each participant across the two conditions. Average level and variability metrics will be reported 
for each metric to understand the effects of using an individualized keyboard interface compared 
to a generic one. 
The output of these tasks will be a novel body-worn sensor-based access method, an access 
assessment test protocol and individualized keyboard interfaces that provide more accurate and 
accessible AAC over generic interfaces for individuals with SPI.