Mapping the Cortical Representation of Paraspinal Muscles Using Transcranial Magnetic Stimulation Optimized in People...

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Pain Management

Background:

• Chronic low back pain (CLBP) is a global health issue with unknown causes, potentially linked to motor cortex reorganization.
• Conventional transcranial magnetic stimulation (TMS) for mapping motor cortex function is often impractical for CLBP patients due to reduced corticospinal excitability.

Purpose of the Study:

• To enhance the practicality and tolerability of TMS brain mapping for individuals with CLBP.
• To adapt TMS techniques to overcome reduced corticospinal excitability in CLBP patients.

Main Methods:

• Employed a biphasic paired-pulse TMS paradigm in conjunction with anticipatory postural adjustment (APA) and maximal voluntary activation (MVC) of paraspinal muscles.
• The study included 18 participants (8 men, 10 women) with CLBP lasting over three months.

Main Results:

• TMS mapping was successfully achieved in all CLBP participants at TMS intensities below 50% of maximum stimulator output (MSO).
• Observed reorganization in cortical maps of paraspinal muscles, characterized by an anterior and lateral shift in the center of gravity (COG).
• A reduced number of discrete peaks in cortical maps was noted in 33% of participants.

Conclusions:

• Facilitating corticospinal excitability (CSE) to paraspinal muscles improves TMS mapping practicality and tolerability in CLBP.
• This adapted TMS approach lowers the risk of adverse effects like seizures and discomfort associated with high-intensity pulses.