A custom designed system to measure corticospinal tract jitter

Area of Science:

• Neuroscience
• Biomedical Engineering
• Clinical Electrophysiology

Background:

• Cortical stimulation latency in limb muscles typically ranges from 10-50 ms.
• Accurate measurement of latency variability (jitter) requires high temporal resolution, at least 20 microseconds.
• Standard electromyography (EMG) equipment lacks the necessary precision for such detailed jitter studies.

Purpose of the Study:

• To develop custom solutions for upgrading commercially available EMG equipment.
• To enable high-resolution latency and jitter analysis following magnetic or electric cortical stimulation.
• To facilitate advanced studies in clinical neurophysiology.

Main Methods:

• Designed a hardware unit for adjustable data acquisition delay post-stimulus.
• Implemented a system to divert amplified biological signals and EMG triggers to an external computer with an analog-to-digital converter (ADC) module.
• Developed custom software to enable high-speed ADC during the entire data acquisition period.

Main Results:

• Two distinct custom-designed solutions were successfully implemented.
• These solutions were integrated with a Vickers Medical Mystro electromyograph.
• The upgraded system has been in successful clinical use for two years at the Institute of Clinical Neurophysiology in Ljubljana.

Conclusions:

• Custom hardware and software upgrades can significantly enhance EMG equipment capabilities.
• Achieving microsecond resolution is feasible for precise latency variability studies.
• These advancements support more accurate diagnostic and research applications in clinical neurophysiology.