Task-Based Spinal fMRI using a Median Nerve Stimulation Reveals Functional Alterations in Degenerative Cervical...

Area of Science:

• Neuroscience
• Radiology
• Biomedical Engineering

Background:

• Degenerative cervical myelopathy (DCM) causes spinal cord compression, leading to sensorimotor deficits.
• Standard functional MRI (fMRI) is challenging in DCM due to motor impairments.
• Novel fMRI paradigms are needed to assess spinal cord function in DCM.

Purpose of the Study:

• To implement and validate a task-based spinal cord fMRI paradigm using median nerve stimulation.
• To evaluate sensorimotor pathway activation in DCM patients and healthy controls (HC).
• To identify functional biomarkers for DCM using fMRI.

Main Methods:

• 23 DCM patients and 23 age-matched HCs underwent fMRI with median nerve stimulation.
• Stimulation included motor thresholds (visible twitch) and sub-motor thresholds (no visible twitch).
• BOLD signals were analyzed across cervical spinal cord segments (C5-C8).

Main Results:

• HCs showed greater activation with motor vs. sub-motor stimulation (+7.1%).
• DCM patients exhibited reduced activation with higher stimulation (-2.2%) and altered spatial patterns.
• DCM responses showed reduced gray matter localization, were more ipsilateral, and displayed abnormal recruitment across segments.

Conclusions:

• Median nerve stimulation is a feasible and effective fMRI paradigm for assessing spinal cord function in DCM.
• Distinct spatial and quantitative activation patterns differentiate DCM patients from HCs.
• This approach serves as a functional biomarker for disease-specific alterations in spinal cord compression.