The purpose of this study is to investigate the immediate effects of a mental practice technique, called Physical, Environment, Task, Timing, Learning, Emotion, Perspective (PETTLEP)-based Action Observation and Motor Imagery (AOMI), on arm movement in stroke survivors. Stroke often causes difficulty in moving the arm smoothly, leading patients to compensate by using their back or shoulder. In this study, participants will either receive a single session of the AOMI training (watching and mentally practicing a reach-to-grasp movement) or a control relaxation task. The researchers will use a smartphone-based motion capture system (OpenCap) to measure if the mental practice immediately improves the smoothness of the arm movement and reduces compensatory body movements.
This study employs a single-blind, pretest-posttest, prospective randomized controlled trial design to evaluate the acute effects of a single session of Physical, Environment, Task, Timing, Learning, Emotion, Perspective (PETTLEP)-based Action Observation and Motor Imagery (AOMI) in stroke patients. Following a stroke, patients often develop pathological movement patterns and maladaptive compensatory strategies, such as trunk displacement or shoulder girdle elevation, due to impaired motor commands. Traditional task practice requires voluntary motor output that many severely impaired patients lack. Motor imagery combined with action observation offers a cognitive simulation alternative that activates neural motor planning circuits. A total of 28 eligible stroke survivors will be randomized in a 1:1 ratio into an experimental (AOMI) group or a control (cognitive and somatic) group. Baseline kinematics of a standardized Reach-to-Grasp task will be recorded using OpenCap, a markerless 3D motion capture system utilizing smartphone cameras. The intervention consists of three blocks lasting approximately 25 minutes in total. The experimental group will engage in a scaffolded AOMI protocol using a 1:3 physical-to-mental practice ratio. This includes sensory priming (holding the target object), action observation (watching a 1st-person video of the task), and selective motor imagery with specific constraints targeting movement smoothness and the inhibition of compensatory trunk and shoulder movements. The control group will perform matched-duration non-motor tasks, including body scanning and visuospatial navigation. Immediately following the intervention, the reach-to-grasp task will be re-assessed using the OpenCap system to quantify short-term changes in movement smoothness (Number of Velocity Peaks), trunk displacement, and shoulder girdle elevation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
28
A mental practice protocol involving sensory priming, action observation, and motor imagery of a reach-to-grasp task with selective functional constraints (Smoothness, Dissociation/Glued Back, and Relaxed Shoulder).
Structured operations including somatic attention (body scanning) and visuospatial control (spatial navigation) timed and paired to exhaust attention without motor system participation.
Change in Movement Smoothness (Number of Velocity Peaks)
Movement smoothness of the affected upper limb will be evaluated using the OpenCap system (a markerless 3D motion capture system). It is calculated by the Number of Velocity Peaks (NVP) derived from the hand marker (3rd Metacarpal head) velocity profile during a standardized reach-to-grasp task. A reduction in NVP indicates increased movement smoothness and better motor control.
Time frame: Immediately before the intervention (baseline) and immediately after the single 25-minute intervention session.
Shoulder Girdle Elevation (Compensatory Strategy)
Calculated by measuring the relative vertical (Y axis) displacement of the Shoulder marker with respect to the Neck marker during movement using the OpenCap system.
Time frame: Immediately before and immediately after the 25-minute intervention session.
Trunk Displacement (Compensatory Strategy)
Calculated by measuring the change in the Lumbar Extension angle in the sagittal plane during the reaching phase, obtained from the OpenSim kinematic model.
Time frame: Immediately before and immediately after the 25-minute intervention session.
Gross Manual Dexterity - Box and Block Test (BBT)
Participants are asked to move as many blocks as they can from one side of a wooden box to the other in 60 seconds using their affected hand. The score is the number of blocks moved successfully.
Time frame: Immediately before and immediately after the 25-minute intervention session.
Pain - Visual Analog Scale (VAS)
Participants indicate their pain intensity by placing a mark on a 10-cm horizontal line. The left side is labeled "no pain" (0) and the right side is labeled "worst pain imaginable".
Time frame: Immediately before and immediately after the 25-minute intervention session.
Movement Imagery Ability - Movement Imagery Questionnaire-3 (MIQ-3)
Evaluates the participant's capacity for movement imagery within three subscales: Kinesthetic, Internal Visual and External Visual. Participants evaluate the vividness of imagery on a Likert scale (higher scores signify greater vividness).
Time frame: Immediately before and immediately after the 25-minute intervention session.
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