Immediate Effects of Anti-Spastic Epidural Cervical Spinal Cord Stimulation on Functional Connectivity of the Central Motor System in Patients with Stroke- and Traumatic Brain Injury-Induced Spasticity: A Pilot Resting-State Functional Magnetic Resonance Imaging Study

Biomedicines, 2023 · DOI: 10.3390/biomedicines11082266 · Published: August 14, 2023

Simple Explanation

This pilot study investigated whether epidural spinal cord stimulation (SCS) at the level of the C3–C5 cervical segments, aimed at reducing spasticity, alters the patterns of functional connectivity of the brain. Eight patients with spasticity in the right limbs as a result of left cerebral hemisphere damage were assessed with fMRI immediately before and immediately after short-term (1 to 6 days) test cervical epidural SCS therapy. The control group consisted of 8 persons with right-sided paresis and spasticity due to ischemic stroke, except one patient with TBI.

Study Duration

1 to 6 days

Participants

16 patients (8 SCS therapy, 8 control) with spasticity

Evidence Level

Pilot Study

Key Findings

1
Higher functional connectivity of the brainstem to the right premotor cortex and changes in functional connectivity between cortical motor areas.
2
Increased functional connectivity between the right and left lateral nodes of the sensorimotor network.
3
A positive correlation between decreased spasticity in the right leg and increased functional connectivity within the right hemisphere sensorimotor cortex.

Research Summary

This controlled pilot study described rearrangements of brain functional connectivity in acquired spasticity after a short course of anti-spastic epidural cervical SCS therapy and the association of these changes with clinically observed reductions in spasticity. After the SCS therapy, there were three main ﬁndings: (1) higher functional connectivity of the brainstem to the right premotor cortex and changes in functional connectivity between cortical motor areas, (2) increased functional connectivity between the right and left lateral nodes of the sensorimotor network, and (3) a positive correlation between decreased spasticity in the right leg and increased functional connectivity within the right hemisphere sensorimotor cortex. We were thus able to detect intrinsic brain connectivity rearrangements that occurred during spasticity mitigation following short epidural SCS therapy.

Practical Implications

Therapeutic Effect of SCS

Epidural cervical spinal cord stimulation may have a direct therapeutic effect in patients with acquired spasticity.

Cortical Reorganization

Anti-spastic SCS treatment may lead to cortical reorganization.

Understanding Adaptive Neuroplasticity

The study contributes to understanding the mechanisms of adaptive neuroplasticity of the motor system.

Study Limitations

1
The study could not address whether the observed changes were part of spontaneous recovery or a placebo effect.
2
Limited generalizability due to small sample size.
3
No fMRI with a task was performed.

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