Combined Psychophysical and Neurophysiological Responses to Intra-epidermal Electrical Stimulation: Clinical Explorations in Patients with Chronic Pain

Diagnosing and treating patients with chronic pain is challenging because the underlying mechanisms responsible for persistent pain often cannot be identified through clinical evaluation. For example, those with peripheral diabetic neuropathy and persistent spinal pain syndrome type 2 are expected to have altered peripheral and central nociceptive function. There is a need for clinical measures that can assess nociceptive dysfunction to enable early diagnosis and personalized treatment of chronic pain syndromes.
Recently, our research group introduced the novel NDT-EP method that combines intra-epidermal electric pulse sequences with neurophysiological measurements of evoked potentials (EPs). This method estimates nociceptive detection thresholds (NDTs) and evaluates neurophysiological responses. However, the main question is whether and how NDT-EP measures can provide insights into the altered nociceptive function of patients.
The thesis has two main objectives: 1) to evaluate the feasibility of the NDT-EP method in patients with chronic pain and 2) to explore NDT-EP phenomena that describe the nociceptive function and analyze potential factors that affect NDT-EP outcomes.
Our findings demonstrate that the NDT-EP method is feasible to use in diabetic patients with and without painful neuropathy and patients with PSPS-T2. Altered NDT-EP outcomes were observed in patients compared to healthy subjects, although the underlying reasons for these differences remain unclear. For example, age and sex seemed to contribute to these variations. Our results from diabetic patients with painful neuropathy compared to age- and sex-matched controls suggest that NDT-EP measures may quantify aspects of altered task execution or peripheral nociceptive function.
These results provide the first insights into NDT-EP measures in chronic pain syndromes. Future research should refine the technological procedure and clinically validate the findings to identify early-stage dysfunctions and improve future prevention and treatment strategies for patients with chronic pain.