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Pain & Sensory Evaluation System

PATHWAY CHEPS has been replaced by the new generation of QST devices. Medoc’s new TSA2 provides a platform for different applications and thermode types. The TSA2 CHEPS thermode enables contact heat evoked potentials, as well as cold evoked potentials to very low temperatures. For users interested in high speeds for paradigms such as Temporal Summation, Virtual Reality, or for use in the fMRI; the TSA2 CHEPS and TSA2 CHEPS fMRI thermode would serve you well.

Advancing toward an objective assessment of pain


PATHWAY CHEPS (Contact Heat-Evoked Potential Stimulator) is an advanced thermal stimulator for pain evoked-potential equipped with functional MRI (fMRI) capabilities.

 Used together with EEG recording systems, CHEPS documents objective response to pain perception by investigating human thermal and nociceptive pathways that mediate sensory and pain perception. This is achieved via selective stimulation and identification of A-Delta & C-fibers through EEG signal waveform recording.


CHEPS is considered the most advanced and sophisticated device for pain assessment available today and is opening exciting opportunities in pain research.

Documenting and measuring objective response to evoked-pain is important in clinical and research applications, such as assessing pain associated with medications and treatments.

In addition to the ability of evoked-potential generation, through rapid and precise thermal stimulation oscillation control, PATHWAY model CHEPS enables the evaluation of temporal summation/Windup, providing unique information regarding central pain processing mechanisms related to central sensitization.

Technological breakthrough


PATHWAY CHEPS deploys an extremely rapid heating rate of 70°C/sec and cooling rate of 40°C/sec, to deliver pain stimuli within a temperature range of 30°C to 55°C in less than 300 milliseconds.

This rapid heating is possible due to Medoc’s new 27mm diameter thermode and thermal stimulator which enable testing large skin areas to reach greater receptor fields.

The CHEPS system is equipped with heat-foil technology, combined with a solid-state thermoelectric cooler (Peltier elements), as well as powerful temperature-controlled algorithms.


PATHWAY CHEPS is also available in an fMRI conditional configuration. CHEPS Thermode can be used to deliver thermal stimuli inside fMRI scanners. By using a special fMRI filter, the PATHWAY system ensures accurate stimulation and reduced imaging artifacts.

CHEPS Features

  • Specially developed software enabling test signals to be delivered online, recorded (via EEG), saved and exported for further data analysis

  • Built with sophisticated hardware and software for better temperature control, ease of use and powerful performance

  • Specific fast oscillation protocols for windup

  • Unique protocols for selective stimulation of A-Delta & C fibers

  • fMRI-conditional (optional)

  • Cold Evoked Potentials (CEPs) – Recording of reliable Cold Evoked Potentials (CEPs) is available using extended software capabilities allowing to reach the destination temp. as low as 20˚C. CEPs are used as an objective, non-invasive and painless tool for the assessment of A-delta fiber integrity. For more information on CEPs recording procedure and diagnostic value click here

  • Full synchronization at stimuli start, end and /or peak temperature, with EEG or MRI (via TTL output)

  • Flexible control of protocol parameters (baseline, peak temp, peak-to-peak intervals, warning signal) Versatile WINDOWS™ based software with a flexible selection range of test paradigms for clinical, research and drug trial requirements. The software meets hospital requirements for maximum data security and remote access for online service

  • Quick setup and system initialization

  • Modular design for easy upgrade

  • Mobile


Useful in monitoring, treating and testing in:

  • Objective pain response to medications and treatments

  • fMRI applications with long and strong sensation evoked to increase activation of brain regions responsible for A-Delta or C-Fibers

  • Potential new “surrogate marker” to prioritize new and existing compounds to reduce time-to-market in pharmaceutical development

  • Various phases of clinical trials for new drug development – from basic level ‘proof of concept’ to full Phase III studies

Download the PATHWAY brochure

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