Background: Chronic pain often includes unrecognized neuropathic and autonomic components that are not fully captured by routine clinical examination, potentially delaying accurate diagnosis and prolonging opioid therapy—particularly concerning in high-risk populations identified by elevated Narcotic Risk Index (NARX) scores.

Methods: This retrospective observational study evaluated 1,200 nerve conduction–electromyography (NCS/EMG) studies (2012–2020), 150 sympathetic skin response (SSR) tests, and 923 heart rate variability (HRV) assessments (2017–2025) performed in adults (n=847 total unique patients) with chronic pain at a tertiary pain clinic in Ohio. High-risk status was defined by NARX scores ≥100 and validated risk-assessment instruments including Pain Assessment and Documentation Tool (PADT), Opioid Risk Tool (ORT), and Screener and Opioid Assessment for Patients with Pain (SOAPP-R), per Ohio state and federal guidelines. Prevalence of neurophysiologic and autonomic abnormalities was quantified and related to functional outcomes and opioid use following implementation of test-guided, predominantly non-opioid treatment pathways.

Results: Among high-risk patients (NARX ≥100, n=652), peripheral neuropathy meeting standard electrodiagnostic criteria was present in 74% (n=482), with frequent sensory and motor nerve abnormalities. Autonomic dysfunction was common, with 64% of high-risk patients (n=417) demonstrating abnormal SSR (prolonged latency ≥0.5 ms and/or reduced amplitude <0.5 µV) and 68% (n=443) showing reduced HRV indices (RMSSD <30 ms at rest). Patients whose management was adjusted based on abnormal test findings (neuropathic medications, interventional procedures, neuromodulation, rehabilitation, and HRV-guided interventions) achieved higher rates of functional improvement (pain reduction ≥30%, improved activities of daily living) and an approximate 40–45% relative reduction in opioid doses compared with patients without test-guided treatment modifications.

Conclusion: Routine integration of SSR, NCS/EMG, and HRV testing, when guided by NARX risk stratification and state/federal assessment standards, enables earlier and more precise diagnosis of neuropathic and autonomic mechanisms in chronic pain, supports timely use of evidence-based non-opioid therapies, and is associated with meaningful reductions in opioid utilization in complex rehabilitation populations at high risk for adverse outcomes.

Chronic pain, Electromyography, Nerve conduction studies, Sympathetic skin response, Heart rate variability, Autonomic dysfunction, Neuropathy, Cost-effectiveness, Opioid stewardship, Pain management, NARX, High-risk, Risk stratification