Reflex Conditioning for Cerebral Palsy

(SRC-CP Trial)

Overseen By Devina Kumar, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: Burke Medical Research Institute

Must not be taking: Antiseizure medicines

Disqualifiers: Pregnancy, Uncontrolled diabetes, Cardiac conditions, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 33

Duration: 8 weeks

12 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores a new method to help adults with spastic Cerebral Palsy (CP) improve muscle control. The focus is on reducing the automatic reflex response in the calf muscles to aid movement. Participants will undergo 30 sessions of a special reflex training called Soleus Stretch Reflex Operant Conditioning over approximately two months. It suits those who can walk at least 10 meters and have a stable medical condition. As an unphased trial, this study allows participants to contribute to innovative research that could enhance treatment options for CP.

Will I have to stop taking my current medications?

No, you will not have to stop taking your current medications. The trial requires that your current medication remains unchanged for 3 months.

What prior data suggests that this reflex conditioning technique is safe for adults with cerebral palsy?

Research shows that reflex training, such as the soleus stretch reflex conditioning, is generally safe. Studies have found no major side effects from this type of training. Specifically, individuals with spinal injuries have tolerated it well. Participants reported no serious side effects from the small energy pulses used to stimulate the leg nerve. This suggests that the treatment is likely safe for similar exercises in individuals with cerebral palsy. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Researchers are excited about the reflex conditioning technique for cerebral palsy because it offers a unique approach compared to traditional therapies like physical therapy and medication. This method focuses specifically on training the soleus muscle in the calf to reduce its reflex activity by using small energy pulses to the tibial nerve. This is different from existing treatments, which typically aim to manage muscle spasticity more broadly. By targeting the spinal reflexes directly, this technique could lead to more precise and effective improvements in muscle control and movement for those with cerebral palsy.

What evidence suggests that this reflex conditioning is effective for cerebral palsy?

Research has shown that training the soleus muscle reflex in the calf can effectively change its response. In this trial, participants will undergo spinal reflex conditioning to decrease their reflex in their calf muscles. Studies have found that participants can significantly reduce this reflex. This non-invasive method, which does not involve surgery or entering the body, has no known side effects. Additionally, it may offer long-term benefits, as the effects of the training could persist. This approach shows promise for reducing muscle stiffness in people with cerebral palsy. ^{1 3 4 6 7}

Who Is on the Research Team?

Kathleen Friel, PhD

Principal Investigator

Burke Neurological Institute

Are You a Good Fit for This Trial?

Adults over 18 with spastic Cerebral Palsy, able to walk at least 10 meters with or without help. They should be classified as level I-III in motor function and not planning any medication changes for three months. Participants must not be pregnant, have uncontrolled diabetes, skin disorders, heart conditions, latex allergies, recent Botox treatments or surgeries on the affected leg.

Inclusion Criteria

I have been diagnosed with spastic Cerebral Palsy.

I can walk or move with some assistance.

Stable medical background

Exclusion Criteria

I have not had a seizure since I was 2 years old.

I have a history of heart conditions.

I have weak muscle movement in my ankle and foot.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Baseline

Participants complete 6 baseline sessions to establish initial reflex measurements

2 weeks

6 visits (in-person)

Treatment

Participants undergo 24 down conditioning sessions to decrease the magnitude of the H-Reflex

8 weeks

24 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

3 months

3 visits (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Soleus Stretch Reflex Operant Conditioning

Trial Overview The trial is testing a technique called spinal reflex conditioning on adults with Cerebral Palsy to reduce the H-Reflex magnitude in their muscles. It involves baseline assessments followed by sessions thrice weekly where participants work to decrease this reflex through specific trials.

How Is the Trial Designed?

Group I: Spinal reflex conditioning Experimental Treatment 1 Intervention

The OC intervention includes 6 baseline sessions and 24 conditioning/ no conditioning sessions held 3 times/week. To elicit an H-reflex, participants will be asked to stand in a comfortable position. Small pulses of energy will be applied to a nerve in the leg called the tibial nerve. We will record when the participant maintains leg muscle activity. During the intervention, participants will be trained to decrease their reflex in their calf.

Who Is Running the Clinical Trial?

Burke Medical Research Institute

Lead Sponsor

Trials

24

Recruited

1,500+

Published Research Related to This Trial

Ambulatory individuals with cerebral palsy can modulate lower-limb reflexes, as shown by a significant reduction in soleus H-reflex excitability when performing a more complex unilateral standing task, indicating some retained neural control capabilities.

There is a strong positive correlation between refined neural control during walking and the ability to modulate reflex excitability, suggesting that deficits in motor control may impact reflex modulation in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Soleus H-reflex modulation in cerebral palsy and its relationship with neural control complexity: a pilot study. Conner, BC., Spomer, AM., Bishe, SSPA., et al.[2023]

In a study involving normal humans, down-conditioning of the soleus H-reflex led to a significant reduction of 27.2% in reflex size, but this did not translate into long-term changes in the medial and lateral gastrocnemius H-reflexes or improvements in locomotion.

The results suggest that while task-dependent adaptations occur in normal subjects, they do not lead to the beneficial long-term changes seen in individuals with incomplete spinal cord injury, highlighting a difference in reflex plasticity and its impact on movement between these populations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans. Makihara, Y., Segal, RL., Wolpaw, JR., et al.[2021]

Operant conditioning can effectively change the size of the soleus stretch reflex (M1), with participants able to significantly increase or decrease M1 size, indicating potential for rehabilitation in individuals with CNS disorders.

The study found that changes in the stretch reflex involved both immediate task-dependent adaptations and longer-term changes, suggesting that this method could be a valuable tool for enhancing motor function and rehabilitation strategies.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Acquisition of a simple motor skill: task-dependent adaptation and long-term changes in the human soleus stretch reflex. Mrachacz-Kersting, N., Kersting, UG., de Brito Silva, P., et al.[2020]

In a study involving 12 participants with chronic spastic hemiparesis after stroke, operant down-conditioning successfully reduced the soleus H-reflex size by an average of 30% in half of the participants, indicating potential for reflex modification even in cases of supraspinal injury.

Participants whose H-reflex decreased also showed improvements in walking speed, with an average increase of 0.14 m/s, suggesting that reflex down-conditioning can enhance motor function in stroke patients, although the overall success rate was lower than in individuals with incomplete spinal cord injury.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Operant down-conditioning of the soleus H-reflex in people after stroke. Thompson, AK., Gill, CR., Feng, W., et al.[2023]

A 24-session conditioning protocol significantly altered the H-reflex recruitment curves in subjects, indicating that operant conditioning can modify reflex responses across various stimulus strengths, not just at a specific threshold.

Both up-conditioning (HRup) and down-conditioning (HRdown) resulted in overall shifts in the H-reflex response, suggesting that these conditioning methods can broadly influence motor control and reflexive actions in the body.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Soleus H-reflex operant conditioning changes the H-reflex recruitment curve. Thompson, AK., Chen, XY., Wolpaw, JR.[2022]

A training program targeting the tonic stretch reflex successfully reduced spasticity by an average of 50% in eight subjects with cerebral palsy aged 6 to 19 years, while control subjects showed no significant changes.

Although the training reduced spasticity, it did not alter muscle contracture, suggesting that additional muscle-lengthening procedures may be necessary to effectively address contracture alongside reflex training.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reduction of spasticity in cerebral palsy using feedback of the tonic stretch reflex: a controlled study. O'Dwyer, N., Neilson, P., Nash, J.[2019]

In a study of 10 adults with acquired brain injury, serial casting for 5 weeks significantly improved ankle dorsiflexion, with median increases of 30 degrees (knee flexed) and 15 degrees (knee extended), indicating enhanced muscle extensibility.

The intervention also led to a notable increase in passive ankle range in response to a displacing torque, suggesting that serial casting effectively reduces spasticity and improves mobility in patients with spastic equinovarus deformity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Evaluation of extensibility, passive torque and stretch reflex responses in triceps surae muscles following serial casting to correct spastic equinovarus deformity. Singer, BJ., Singer, KP., Allison, GT.[2019]

Citations

1. clinicaltrials.gov clinicaltrials.gov/study/NCT05571033

Operant Conditioning of the Soleus Stretch Reflex in Adults ... In the study, the investigators will attempt to decrease the increased muscle tone of individuals with CP. If successful, it will not only provide evidence for ...

2. withpower.com withpower.com/trial/phase-paralysis-8-2022-0d177

Reflex Conditioning for Cerebral Palsy (SRC-CP Trial) Operant conditioning can effectively change the size of the soleus stretch reflex (M1), with participants able to significantly increase or decrease M1 size, ...

3. sciencedirect.com sciencedirect.com/science/article/pii/S1878747923010528

Clinical Translation of Spinal Reflex Operant Conditioning This paper reviews the value of spinal reflexes and the therapeutic promise of spinal reflex operant conditioning protocols.

4. centerwatch.com centerwatch.com/clinical-trials/listings/NCT05571033/operant-conditioning-of-the-soleus-stretch-reflex-in-adults-with-cerebral-palsy

Operant Conditioning of the Soleus Stretch Reflex in Adults ... Its many known benefits include easy administration, non-invasive technique, no side effects, and long-term retention. In the study, the ...

5. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9397960/

Reducing the Soleus Stretch Reflex With Conditioning Operant conditioning of the stretch reflex is a promising non-invasive paradigm with potential long-term sustained effects.

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC9397863/

Operant down-conditioning of the soleus H-reflex in people ... This study examined whether down-conditioning can decrease the soleus H-reflex in people with supraspinal injury (ie, cortical or subcortical stroke).

7. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC4137250/

Operant conditioning of the soleus H-reflex does not ... In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes.