Non-invasive BCI-controlled Assistive Devices

Healthy Clinical Trial

Official title:

Non-invasive Brain-computer Interfaces for Control of Assistive Devices

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT05183152
• Other study ID #: 2020030073
• Status: Recruiting
• Phase: N/A
• Start date: June 16, 2021
• Est. completion date: December 30, 2025

Study information

• Verified date: June 2024
• Source: University of Texas at Austin
• Contact: Jose del R. Millan, PhD
• Phone: 512-232-8111
• Email: jose.millan[@]austin.utexas.edu
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Injuries affecting the central nervous system may disrupt the cortical pathways to muscles causing loss of motor control. Nevertheless, the brain still exhibits sensorimotor rhythms (SMRs) during movement intents or motor imagery (MI), which is the mental rehearsal of the kinesthetics of a movement without actually performing it. Brain-computer interfaces (BCIs) can decode SMRs to control assistive devices and promote functional recovery. Despite rapid advancements in non-invasive BCI systems based on EEG, two persistent challenges remain: First, the instability of SMR patterns due to the non-stationarity of neural signals, which may significantly degrade BCI performance over days and hamper the effectiveness of BCI-based rehabilitation. Second, differentiating MI patterns corresponding to fine hand movements of the same limb is still difficult due to the low spatial resolution of EEG. To address the first challenge, subjects usually learn to elicit reliable SMR and improve BCI control through longitudinal training, so a fundamental question is how to accelerate subject training building upon the SMR neurophysiology. In this study, the investigators hypothesize that conditioning the brain with transcutaneous electrical spinal stimulation, which reportedly induces cortical inhibition, would constrain the neural dynamics and promote focal and strong SMR modulations in subsequent MI-based BCI training sessions - leading to accelerated BCI training. To address the second challenge, the investigators hypothesize that neuromuscular electrical stimulation (NMES) applied contingent to the voluntary activation of the primary motor cortex through MI can help differentiate patterns of activity associated with different hand movements of the same limb by consistently recruiting the separate neural pathways associated with each of the movements within a closed-loop BCI setup. The investigators study the neuroplastic changes associated with training with the two stimulation modalities.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 100
• Est. completion date: December 30, 2025
• Est. primary completion date: December 30, 2025
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 80 Years

Eligibility

Inclusion Criteria:

1. Able-bodied participants:

• good general health

• normal or corrected vision

• no history of neurological/psychiatric disease

• ability to read and understand English (Research Personnel do not speak Spanish)

2. Subjects with motor disabilities

• motor deficits due to: unilateral and bilateral stroke / spinal cord injury / motor neuron diseases (i.e. amyotrophic lateral sclerosis, spino-cerebellar ataxia, multiple sclerosis) / muscular diseases (i.e. myopathy) / traumatic or neurological pain / movement disorders (i.e. cerebral palsy) / orthopedic / traumatic brain injury / brain tumors

• normal or corrected vision

• ability to read and understand English

• ability to provide informed consent

Exclusion Criteria:

1. Subjects with motor disabilities

• short attentional spans or cognitive deficits that prevent the subject from concentrating during the whole experimental session

• heavy medication affecting the central nervous system (including vigilance)

• concomitant serious illness (e.g., metabolic disorders)

2. All participants

• factors hindering EEG/EMG acquisition and the delivery of non-invasive electrical stimulation (e.g., skin infection, wounds, dermatitis, metal implants under electrodes)

• criteria identified in safety guidelines for MRI and TMS, in particular metallic implants

Related Conditions & MeSH terms

• Amyotrophic Lateral Sclerosis
• Brain Injuries
• Brain Injuries, Traumatic
• Healthy
• Motor Disorders
• Motor Neuron Disease
• Movement Disorders
• Multiple Sclerosis
• Muscular Diseases
• Spinal Cord Injuries
• Stroke
• Traumatic Brain Injury
• Wounds and Injuries

Intervention

Device:
• NMES Feedback
Electroencephalography (EEG) signals will be recorded from subjects as they perform cued tasks for flexing/extending their non-dominant hand. The signals will be processed and classified in real-time using machine learning algorithms to trigger electrical stimulation on the flexors/extensors of the targeted arm contingent to the detection of a subject-specific flexion/extension EEG patterns.
• Visual Feedback
Electroencephalography (EEG) - recorded from subjects as they perform cued motor imagery (MI) tasks - are classified in real-time using a subject-specific BCI decoder,. The output classification probability of the decoder is accumulated using exponential smoothing and translated into continuous visual feedback by means of a bar - on a computer screen - that moves to the right or left in response to classification of one or the other MI task.
• TESS
Transcutaneous Electrical Spinal Stimulation (TESS) is applied over the C5-C6 spinal segment for 20 minutes at 30Hz with 5kHz carrier frequency.

Locations

Country	Name	City	State
United States	The University of Texas at Austin	Austin	Texas

Sponsors (1)

Lead Sponsor	Collaborator
University of Texas at Austin

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in the BCI command delivery performance	The command delivery accuracy reflects the level of control of the subject when using the BCI. It measures the percentage of trials in which the subject-specific classifier that is used to differentiate the different imagined movements could accumulate enough evidence to support the presence of EEG patterns specifically associated with the imagined movement in those trials.; The score is 0-100, and the higher the value, the better the outcome.	immediately after each intervention session and up to one week after all sessions
Primary	Change in the focality and Strength of SMR Modulation	The focality of sensorimotor rhythm modulation is assessed from EEG using event-related desynchorinzation (ERD) and synchronization (ERS) over the motor area.; Continuous measure, the higher the better	immediately after each intervention session and up to one week after all sessions
Secondary	Stability of Motor Imagery features	The features corresponding to different motor imagery tasks become more stable at the end of the intervention.	immediately after each intervention session and one-day after all sessions
Secondary	Separability of Motor Imagery features	The features corresponding to different motor imagery tasks become more separable after the intervention.	immediately after each intervention session and one-day after all sessions
Secondary	Changes in motor-evoked potential amplitude	Continuous measure, the higher the better	immediately after each intervention session and one-day after all sessions
Secondary	Changes in electroencephalography functional connectivity	Continuous measure, the more significant changes the better	immediately after each intervention session and one-day after all sessions
Secondary	Change in focality of fMRI activation for different imagined movements	The clusters of significant activation during MI of different movements would be more focal in the associated region of the motor area Continuous measure, the more the better.	immediately after each intervention session and one-day after all sessions
Secondary	More discriminable fMRI activations for different imagined movements	The activation associated with different MI tasks would be more discriminable from BOLD signals.; Continuous measure, the more the better.	immediately after each intervention session and one-day after all sessions