Passive Robots for Stroke Rehabilitation: A Feasibility Study

Passive Robots for Stroke Rehabilitation

The purpose of this study is to examine the feasibility and effectiveness of a novel, multimodal approach that combines passive devices with noninvasive neuromuscular stimulation for upper extremity rehabilitation after stroke.

Study Overview

• Status: Recruiting
• Conditions: Stroke
• Intervention / Treatment: Device: Functional Training with SepaRRo and NeuRRoFES

Detailed Description

About 800,000 individuals suffer from a stroke every year in the United States. The majority of stroke survivors often experience lingering deficits in upper extremity function. High-end robotic devices can improve outcomes and clinical productivity; however, these devices are expensive and bulky, making them not practical for many clinical or home environments. This study aims to evaluate the feasibility of low-cost non-motorized devices for stroke rehabilitation in a long-term intervention. The intervention will involve training with a table-top, semi-passive (i.e., no motors) exercise equipment called SepaRRo and commonly-used neuromuscular stimulation. The stimulation will be provided during functional activities using a custom controller (NeuRRoFES) to trigger stimulation. These instruments are designed to provide flexible, compliant assistance/resistance to improve upper extremity function and can be used in a home setting. The study will measure technical feasibility (e.g., qualitative survey, adherence, time on task, retention, ability to perform tasks) as well as clinical feasibility (i.e., changes in biomechanical, neurophysiological, and functional measures) of an intervention with these devices in stroke survivors. The findings aim to support the development of affordable, home-use rehabilitation systems for stroke patients.

• Study Type: Interventional
• Enrollment (Estimated): 4
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Chandramouli Krishnan, PT, PhD; Phone Number: 7349364031; Email: mouli@umich.edu
• Study Contact Backup: Name: Thomas E Augenstein, PhD; Phone Number: 7342320898; Email: tomaugen@umich.edu

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48108
      • Recruiting
      • University of Michigan - NeuRRo Lab
      • Contact: Thomas E. Augenstein, PhD; Phone Number: 734-936-4031; Email: tomaugen@umich.edu
      • Principal Investigator: Chandramouli Krishnan, PT PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18 to 75 years;
• Ischemic or hemorrhagic stroke confirmed by CT, MRI, or clinical criteria;
• No major deficits of sensation or proprioception;

Exclusion Criteria:

• Bilateral stroke
• Unable to think clearly and remember (Mini-Mental State Exam score < 22 and miniMOCA < 8);
• Uncontrolled Diabetes or Hypertension;
• Severe limitations of joint range of motion that will lead to inability of testing
• Severe spasticity and joint contractures that will lead to inability of testing
• Complete paresis with no possible movements
• Severe aphasia
• Any other medical condition that will significantly impact the study results
• Unable to obtain reliable motor evoked potentials
• Are pregnant or are actively trying to conceive
• Have a recent history of repeated fainting spells or syncope.
• Have a recent history of seizure (epilepsy) while on anti-seizure medication
• Have a recent history of skull fracture/head injury
• Have metal implants in the skull
• Have cardiac pacemakers

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Device Feasibility
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Robotic Intervention; Participants will receive upper extremity rehabilitation using SepaRRo and NeuRRoFES 2-5 times per week for 2-6 weeks

Device: Functional Training with SepaRRo and NeuRRoFES; Participants will perform functional movements (e.g., reach for targets) with their extremities. During movements, the devices will be used to assist or resist their motion. Participants may receive biofeedback of their movements to better engage them in training. Participants may receive assistance from the devices (including neuromuscular stimulation) and/or their less-impaired limb.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Device Survey For Feasibility	Subjective feedback regarding feasibility of the device for training	Post-intervention (immediately following last session of intervention)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retention	Measure of how many participants completed intervention	Post-intervention (immediately following last session of intervention)
Adherence	Measure of percentage of sessions completed	Post-intervention (immediately following last session of intervention)
Upper extremity Fugl-Meyer Score	Changes in upper extremity Fugl-Meyer score from before the intervention (from baseline) to after its completion using publicly available scoring sheets. The Fugl-Meyer score is a measure of functional impairment and runs from 0 to 66 points, with higher numbers reflecting better outcome.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively.
Reachable workspace	Changes in reachable workspace from before the intervention (from baseline) to after its completion). The reachable workspace area will be measured with SepaRRo obtained from optical encoders mounted in the device.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Voluntary hand opening	Changes in voluntary ability to open the hand from before the intervention (from baseline to after its completion). Voluntary hand opening will be measured with motion capture equipment.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Action Research Arm Test Score	Changes in the Action Research Arm Test Score from before the intervention (from baseline) to after its completion using publicly available scoring sheets. The Action Research Arm Test is a measure of arm functional ability and runs from 0 to 57 points, with higher numbers reflecting better outcome.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Box and Block (BBT)	Changes in functional measure of arm disability (BBT) from before the intervention (from baseline) to after its completion using publicly available scoring sheets.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Hand Strength	Changes in force produced by the hand from before the intervention (from baseline) to after its completion as measured by force production recorded with a dynamometer	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Arm strength	Changes in force produced by the arm from before the intervention (from baseline) to after its completion as measured by force production recorded with a dynamometer	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Muscle coordination	Changes in muscle coordination of the upper extremity muscles as measured using surface electromyography between before the intervention (from baseline) to after its completion.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Joint coordination	Changes in coordination of the upper extremity joints as measured motion capture between before the intervention (from baseline) to after its completion.	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively
Corticospinal excitability	Changes in corticospinal excitability of the upper extremity muscles as measured using surface electromyography and transcranial magnetic stimulation between before the intervention (from baseline) to after its completion	Baseline and post-intervention measurements will be taken on separate days, within a week of the first and last sessions of the intervention, respectively

Collaborators and Investigators

• Sponsor: University of Michigan
• Investigators: Principal Investigator: Chandramouli Krishnan, PT, PhD, University of Michigan

Study record dates

Study Major Dates

• Study Start (Actual): November 5, 2025
• Primary Completion (Estimated): October 1, 2027
• Study Completion (Estimated): October 1, 2027

Study Registration Dates

• First Submitted: October 15, 2025
• First Submitted That Met QC Criteria: October 16, 2025
• First Posted (Estimated): October 20, 2025

Study Record Updates

• Last Update Posted (Actual): November 10, 2025
• Last Update Submitted That Met QC Criteria: November 5, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: hemiparesis; robot; upper extremity; weakness; stroke survivors; synergy
• Additional Relevant MeSH Terms: Neurologic Manifestations; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Stroke; Paresis; Asthenia
• Other Study ID Numbers: HUM00087962

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No