Robotically Augmented Mental Practice for Neuromotor Facilitation
Phase: NA
Conditions: Stroke
Sponsor: Georgia Institute of Technology

Study Title: Robotically Augmented Mental Practice for Neuromotor Facilitation 
Document Title: Study Protocol and Statistical Analysis Plan 
NCT: NCT04962698 
Document Date: 08/25/2023 

Protocol 
 
This study consists of experiments on two non-consecutive days in the Human Neuromuscular 
Physiology Laboratory located in the Biological Sciences/Applied Physiology Building of Georgia 
Tech. If subjects qualify and agree to take part in this study, subjects will be asked to read and 
sign the consent form. The whole procedure will last about 3 hours per day, including 
preparation. Subjects will come to the lab on two separate days on the same tasks. The first day 
will serve as familiarization with the same tasks as the second day. Subjects will perform the 
following experiment.   
 
Individuals will sit upright and relax their hands and shoulders. The right shoulder will be fixed 
with pads to the upper arm to prevent shoulder flexion/extension movement. The right hand and 
forearm will be rested on a plate hidden below a table. The robotic prosthesis will be placed on 
the table as one would normally place own arm on the table. There will be no physical 
connection between the hand and the robotic prosthesis.  
 
Subjects will activate a pair of the front portion of the shoulder muscles and the upper part of the 
chest muscles for making a grasping movement of the robotic prosthesis. For making a 
releasing movement of the prosthesis, subjects will activate a pair of the back portion of the 
shoulder muscles and the back muscles. Muscle activity will be recorded with two small sensors 
on each muscle. Subjects will practice activation of each muscle pair while watching the signal 
on a monitor. In each pair, a clearer signal will be used for controlling the robotic digits. 
 
Healthy subjects (N = 18): 
Healthy subjects will perform the following tasks A-F. [A: Rest] Subjects will relax their muscles 
without physical or cognitive effort while gazing at the turned-off monitor. [B: Robotic action 
observation] Subjects will relax their muscles and focus on observing the computer-controlled 
grasp and release actions (2 s in each movement) of the robotic hand. [C: Visual MI] Subjects 
will relax their muscles and perform conventional visual mental imagery (MI). With the guidance 
of audio instruction, the subjects will imagine the grasp and release motions with the right arm 
for 2 s in each motion in their mind. There will be no proximal muscle contraction. [D: 
Kinesthetic MI] The same MI procedure as Task C will be performed, except that the subjects 
will focus on the kinesthetic sensation that they would feel with the imagined motions. [E: 
Robotic-Hand Interaction (see below detailed description)] Subjects will perform robotic-hand 
interaction for grasp and release motions with the activation control of the proximal muscles. 
During this task, subjects will also imagine the kinesthetic sensation that they would feel with the 
corresponding motions with the right arm. [F: Virtual-Hand Interaction] Subjects will perform 
Task E with visual feedback of virtual robot actions in 2D on a monitor. [G: Robotic-Hand 
Interaction without MI] Subjects will perform Task E without MI. As a reaction task, subjects will 
flex the index finger as soon as they hear an auditory cue. 
 

Post-stroke subjects (N = 4): 
Tasks C [Visual MI], E [Robotic-Hand Interaction], and A [Rest] above will be performed by post-
stroke subjects with right-side hemiparesis who can volitionally activate fingers and proximal 
muscles. As a reaction task, subjects will flex the index finger as soon as they hear an auditory 
cue. The data on post-stroke subjects will be obtained to test the feasibility of the Robotic-Hand 
Interaction and observe potential trends. The data will not be used for statistical analysis. 
 
Robot-Hand Interaction with and without MI (Task E and F above): 
An individual will use proximal muscle contractions to flex and extend the robotic prosthesis 
digits for performing a grasp-release task. 1) Grasp. The individual will activate the proximal 
muscles as if for a retrieving motion (the back portion of the shoulder muscles and the back 
muscles) for 2 s. This muscle activation controls the prosthesis to flex the digits to grasp a 
cylinder-shaped object. 2) Release. The individual will relax the above-activated proximal 
muscles and activate the proximal muscles as if for a reaching motion (the front portion of the 
shoulder muscles and the top portion of the chest muscles) for 2 s. This muscle activation 
controls the prosthesis to extend the digits to release the object. After releasing the object, the 
individual will relax their proximal muscles. The individual will repeat this sequence while 
observing and hearing the actions of the prosthesis. The acceleration signal will be used to 
determine the slight displacement of the upper arm. EMG of the forearm and hand muscles will 
be monitored to ensure that those muscles are relaxed during proximal muscle activation. 
 
TMS test 
During the above-mentioned tasks, brain stimulation (called TMS) will be applied over the motor 
cortex in the left hemisphere. The TMS procedure will follow the one used in our previous 
studies. A TMS coil will be placed over a precise point on the scalp where we will stimulate the 
brain to make the muscle move. We will tell the subject when the stimulation portion of the 
procedure is about to begin. The first part of the procedure will be to find the area of the brain 
that controls muscles. We will position the TMS coil on the head and will give the subject a 
series of stimulations (called magnetic pulses). Once we find the spot that controls the muscles, 
we will find the least amount of stimulation needed to activate the resting muscles. The second 
part of the procedure will be to evoke muscle contraction with TMS at rest and during the tasks 
described above. We will apply single-pulse and paired-pulse TMS with 5-second intervals or 
more. Peak-to-peak amplitude of the motor evoked potential (MEP) will be determined. 
 
Reaction time test 
Subjects will be asked to exert finger flexion force with their index finger as soon as they hear 
an auditory cue for the reaction task. In this test, the focus was on immediacy, and there will be 
no instruction on the amount of force to produce. The audio cue timing will be randomly varied 
during the middle 60% during the flexion and extension phases of the artificial or imaginary 
finger. Reaction time, maximal rate of force development, peak EMG, and peak force will be 
determined. 

 
Statistical Analysis 
Statistical analysis will be peformed on data from 18 healthy subjects. The independent variable 
will be the task. The dependent variables will include MEP amplitude,  reaction time, maximal 
rate for force development, peak EMG, and peak force. If the assumption of sphericity is not 
violated, the variable will be tested with one-way analysis of variance (ANOVA) with repeated 
measures on task, followed by a posthoc Bonferroni-corrected pair-wise comparison, when 
appropriate. If the assumption of sphericity is violated, the variables will be with the Friedman 
test, followed by the Wilcoxon signed-rank test when appropriate. The alpha value of 0.05 will 
be used to determine the significance. The alpha value will be corrected for repeated 
comparisons.