EEG Monitoring Is Feasible and Reliable during Simultaneous Transcutaneous Electrical Spinal Cord Stimulation

Sensors, 2021 · DOI: 10.3390/s21196593 · Published: October 2, 2021

Simple Explanation

This study investigates whether it's possible to get useful EEG readings while using tSCS, a method that stimulates the spinal cord through the skin. The main concern is that the electrical stimulation creates strong artifacts in the EEG signal, making it hard to see the brain's activity. Researchers recorded EEG from healthy volunteers while applying tSCS to their necks. They looked at how the stimulation affected the EEG signal and tried different techniques to remove the artifacts. They wanted to see if they could still accurately monitor brain activity during stimulation. The study found that tSCS does create noticeable artifacts in EEG, but certain filtering methods can reduce these artifacts enough to allow for meaningful analysis of brain activity. This suggests that EEG can be used to study how the brain responds to tSCS, potentially leading to better therapies for spinal cord injuries.

Study Duration

Not specified

Participants

21 healthy volunteers (7 females, 14 males; 28 ± 5 years old)

Evidence Level

Not specified

Key Findings

1
tSCS manifested as narrow, high-amplitude peaks in the time domain at a rate equal to the stimulation frequency, making the EEG nearly an order of magnitude more powerful than normal EEG.
2
The degree of EEG contamination was highly dependent on stimulation intensity and electrode position relative to the stimulation site.
3
A superposition of moving averages (SMA) filter resulted in descriptive statistics most resembling that of normal EEG and notch filtering was effective at reducing spectral power contribution.

Research Summary

This study investigates the feasibility of EEG monitoring during transcutaneous electrical spinal cord stimulation (tSCS) by characterizing artifacts and evaluating artifact-suppression techniques. The researchers recorded EEG from healthy volunteers during tSCS and analyzed the data in time and frequency domains, finding that tSCS introduces narrow, high-amplitude peaks at the stimulation frequency. They demonstrated that superposition of moving averages (SMA) and notch filtering techniques can effectively suppress these artifacts, making EEG monitoring feasible during tSCS and opening avenues for future research on sensorimotor cortex activity during tSCS-based rehabilitation.

Practical Implications

Improved understanding of tSCS mechanisms

EEG monitoring during tSCS can provide insights into the neural mechanisms underlying motor and sensory recovery in spinal cord injury patients.

Advancements in BCI technology

The study paves the way for brain-computer interfaces that can operate effectively in the presence of spinal stimulation, enhancing neurorehabilitation strategies.

Optimization of artifact removal techniques

The findings highlight the effectiveness of SMA and notch filtering techniques for suppressing tSCS artifacts in EEG, which can be further refined for better signal quality.

Study Limitations

1
The average stimulation intensity applied to the healthy volunteers (10–60 mA) was likely lower than what would be delivered in clinical practice.
2
The results from this study therefore may not be representative of what is feasible in practice.
3
Due to the variation in stimulation parameters used across tSCS studies conclusions can only be inferred with regards to the parameters that we have used here.

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