Effect of NMES on Spasticity: A Single-Subject Experimental Study

May 25, 2026 updated by: ilker şengül, Izmir Katip Celebi University

The Effect of Neuromuscular Electrical Stimulation on Spasticity: A Single-Subject Experimental Study

The goal of this clinical trial is to learn if neuromuscular electrical stimulation (NMES) works to treat spasticity in adult patients with spasticity related to stroke. The main question it aims to answer is:

• Does NMES reduces the severity of spasticity? Researchers will compare NMES treatment to baseline and non-stimulation periods to see if NMES works to treat spasticity.

Participants will:

• first undergo an initial assessment at 10-minute intervals for one hour, followed by 20 minutes of NMES exposure, and subsequent post-treatment assessments at 10-minute intervals for two hours. This daily procedure will be repeated over four days for one patient, and performed only once for the remaining three patients.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Spasticity is a sensory-motor control disorder arising from upper motor neuron lesions, affecting approximately 97% of chronic stroke patients presenting with moderate-to-severe motor impairment. This pathology is driven by stretch reflex hyperexcitability, stemming from secondary alterations in the supraspinal, spinal interneuronal, and striated muscle systems; it manifests as an exaggerated reflex response to peripheral stimuli and concomitant excessive muscle activity. While several definitions exist in the literature, the operational conceptualization of spasticity as 'the enhancement of velocity-dependent stretch reflexes, measured at rest' establishes it as a highly quantifiable and robust target variable for clinical evaluation and scientific investigation.

Spasticity management encompasses diverse therapeutic modalities, ranging from pharmacological to non-pharmacological approaches. Among these, neuromuscular electrical stimulation (NMES) has emerged as a prominent intervention. Although documented as a beneficial adjunctive therapy, the clinical translation of NMES from randomized controlled trials to bedside practice is frequently hindered by marked study heterogeneity and a scarcity of high-quality evidence. Moreover, despite its clinical adoption, NMES application parameters remain largely unstandardized, and substantial inter-individual variability precludes the direct extrapolation of group-level averages to individual patients. Therefore, rigorous experimental frameworks capable of generating robust, individual-level scientific evidence are required to guide real-world practice and optimize personalized therapeutic decisions. Within this paradigm, single-subject experimental designs represent a highly promising methodological approach.

Consequently, this study investigates the therapeutic efficacy of NMES on spasticity among chronic stroke patients with spastic paresis lasting longer than one year, utilizing single-subject experimental methodologies-specifically withdrawal/reversal and multiple-baseline designs. To achieve this, this research addresses four primary objectives: evaluating whether standalone NMES reduces spasticity severity; determining the longevity of any observed therapeutic effect; quantifying the precise magnitude of this intervention; and examining the generalizability of the outcomes. Framed within the context of the experimental design-analysis paradigm, we hypothesize that isolated NMES application will significantly reduce spasticity. This hypothesis will be systematically tested across three distinct stages. The initial pilot stage will delineate the presence, magnitude, and duration of NMES efficacy using predefined stimulation parameters. Subsequently, the second stage will implement a withdrawal/reversal design with built-in wash-out periods to provide robust causal evidence regarding NMES outcomes. Finally, the third stage will deploy a multiple-baseline design across participants to establish the generalizability of the intervention parameters.

In the first stage, a basic phase-change (A-B) design will be applied to a single participant, where Phase A represents the untreated baseline period, and Phase B denotes the NMES application followed immediately by post-treatment assessments. Specifically, the participant will undergo a baseline assessment at 10-minute intervals for one hour, followed by a 20-minute NMES application, and subsequent post-treatment assessments at 10-minute intervals for two hours. This initial stage serves as a pilot phase designed to evaluate potential NMES-related effects, and progression to Stage 2 will occur independently of the treatment's efficacy status during this pilot.

In the second stage, this daily procedure is planned to be repeated over four consecutive days separated by washout intervals for the same participant, yielding a full A-B-A-B-A-B-A sequence. However, the study incorporates a strict ethical stopping rule: if visual analysis reveals no positive clinical response by the end of the second day (concluding the initial A-B-A-B phases), the protocol will be discontinued immediately due to futility, and the study will not proceed to the final stage. Conversely, if a positive response is verified visually, the full four-day sequence will be completed, and a non-concurrent multiple baseline design across participants (the final stage) will subsequently be implemented.

In the final stage, the single-day (A-B) procedure will be applied only once to three additional participants. To ensure methodological rigor, the baseline lengths for these three participants will consist of 5, 7, and 9 assessments, respectively, assigned in a randomized order.

Study Type

Interventional

Enrollment (Estimated)

4

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Turkey (Türkiye)
    • Karabağlar
      • Izmir, Karabağlar, Turkey (Türkiye), 35150
        • İzmir Katip Çelebi University
        • Principal Investigator:
          • İlker Şengül, M.D.
        • Contact:
        • Contact:
        • Sub-Investigator:
          • Aleyna Uğurlu, M.D.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age between 18 and 70 years
  • Post-stroke wrist flexor spasticity scored as Grade 2 or 3 on the Australian Spasticity Assessment Scale (ASAS), specifically selecting patients whose passive stretch resistance (post-catch response) can be easily overcome to ensure accurate and unconfounded electrophysiological evaluation.
  • Provision of voluntary, written informed consent prior to study enrollment.

Exclusion Criteria:

  • Age <18 or >70 year
  • Contraindications to neuromuscular electrical stimulation (e.g., active electronic implants, history of epilepsy, or localized skin lesions preventing electrode placement)
  • Concomitant wrist contracture or pain sufficient to impede clinical evaluation
  • Structural abnormalities of the elbow joint obstructing median nerve stimulation
  • Median nerve neuropathy or injury in the ipsilateral upper extremity.
  • Non-stable dosage of antispastic medications within the 2 weeks prior to baseline
  • Initiation of medications affecting nerve conduction (e.g., antidepressants, anticonvulsants, anesthetics) within the past month; patients on a stable dose for >1 month remain eligible
  • Botulinum toxin infiltration in the target spastic muscles within the preceding 3 months
  • History of neurolytic procedures targeting spasticity in the affected limb.
  • History of orthopedic or neurological surgery targeting spasticity in the affected limb
  • Cognitive impairment severe enough to compromise adherence to study protocols
  • Inability to maintain the required testing positions for the upper extremity joints (shoulder, elbow, forearm, and wrist)
  • Pregnancy

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Neuromuscular electrical stimulation (NMES)
Neuromuscular electrical stimulation (NMES) (a symmetric, biphasic, rectangular waveform) will be administered to the antagonist wrist extensors (extensor carpi radialis longus/brevis and extensor carpi ulnaris) of the spastic wrist flexors in the B (intervention) phase. The configuration consists of an application duration of 20 minutes, a stimulation frequency of 35 Hz, and a pulse duration of 300 μs. The duty cycle will feature a 20-second ON time and 20-second OFF time (1:1 ratio), with ramp-up and ramp-down durations set at 5 seconds. During Phase A, no intervention will be carried out
Device: Neuromuscular electrical stimulation (NMES)
Neuromuscular electrical stimulation (NMES) (a symmetric, biphasic, rectangular waveform) will be administered to the antagonist wrist extensors (extensor carpi radialis longus/brevis and extensor carpi ulnaris) of the spastic wrist flexors in the B phase. The configuration consists of an application duration of 20 minutes, a stimulation frequency of 35 Hz, and a pulse duration of 300 μs. The duty cycle will feature a 20-second ON time and 20-second OFF time (1:1 ratio), with ramp-up and ramp-down durations set at 5 seconds.
Device: Neuromuscular electrical stimulation (NMES)
Neuromuscular electrical stimulation (NMES) is a therapeutic modality used in neurorehabilitation. By delivering transcutaneous electrical currents, NMES elicits repetitive, patterned muscle contractions to augment or restore motor functions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Angle of Muscle Reaction
Time Frame: From enrollment up to 1 day (Stages 1 and 3) or 2 to 4 days (Stage 2), depending on the assigned stage.
The Angle of Muscle Reaction is the specific joint angle at which a catch response is elicited in the target muscles (flexor carpi radialis and flexor carpi ulnaris) during a passive stretch delivered at the highest possible velocity.
From enrollment up to 1 day (Stages 1 and 3) or 2 to 4 days (Stage 2), depending on the assigned stage.
Hmax / Mmax ratio
Time Frame: From enrollment to the completion of treatment, varying by stage: 1 day for Stages 1 and 3, and 2 to 4 days for Stage 2.
The Hmax / Mmax ratio serves as an objective electrophysiological index of spinal motor neuron pool excitability. Although it does not directly measure velocity-dependent mechanical resistance, this neurophysiological marker quantifies spinal hyperexcitability, thereby providing a critical adjunct to subjective clinical scales.
From enrollment to the completion of treatment, varying by stage: 1 day for Stages 1 and 3, and 2 to 4 days for Stage 2.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Izmir Katip Celebi University

Investigators

  • Principal Investigator: İlker Şengül, M.D., İzmir Katip Çelebi University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 15, 2026

Primary Completion (Estimated)

March 16, 2028

Study Completion (Estimated)

March 16, 2028

Study Registration Dates

First Submitted

May 25, 2026

First Submitted That Met QC Criteria

May 25, 2026

First Posted (Actual)

June 1, 2026

Study Record Updates

Last Update Posted (Actual)

June 1, 2026

Last Update Submitted That Met QC Criteria

May 25, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • 2026-KAE-0011

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Since all necessary demographic, clinical, and outcome data will be reported and published in a manuscript as per the study methodology, IPD sharing is currently not deemed required.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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