Altering Electromyography Studies: Importance of the Electromyographer's Perception of Patient Pain

Tolerability of electrodiagnostic studies in patients: a prospective study

Introduction

Nerve conduction study (NCS) and electromyography (EMG) are electrodiagnostic studies that are highly tolerated by patients despite their nature of causing pain and discomfort. However, few studies have focused on the true tolerability of these procedures in patients. This study aimed to determine the true tolerance rate of NCS and EMG in patient populations and the factors that might be associated with them.

Methods

Participants scheduled for electrodiagnostic studies were prospectively recruited between March 2023 and September 2023. After completion of the study, the physicians completed a questionnaire on each patient's tolerance of the studies.

Results

Of the 103 patients enrolled in the study, 98 were able to tolerate both tests, and 5 patients were intolerant to 1 or both tests. The overall tolerance rate of NCS and EMG was 95.1% (0.951, 95% CI 0.897 to 0.981). Age, sex, ethnicity, the type of NCS performed and the type of EMG performed were not associated with NCS or EMG intolerance.

Conclusion

Most patients tolerated the NCS and EMG; however, a small percentage of patients were intolerant. Clinicians should recognise the intolerance of certain patients when introducing and performing electrodiagnostic tests.

Pain perception during electrodiagnostic studies and the impact of learners

INTRODUCTION/AIMS

Electrodiagnostic testing (EDX) may be perceived as painful, which may influence patient expectations and test completion. Our aim was to characterize which component of the EDX was more painful, and to determine if any factors, particularly performance by a learner, influenced this perception.

METHODS

Participants were prospectively recruited and completed a brief questionnaire to rate their perception of pain before and after each component of the EDX. Demographic information and information about the test itself was collected.

RESULTS

A total of 251 participants were recruited, 55.3% female, with a mean age of 52.9 years. Most participants rated pain after nerve conduction studies (NCS) and needle electromyography (EMG) as mild to moderate with a similar number rating each component as more painful than the other. There was no effect of sex on overall ratings, although females felt that the test was more painful than anticipated more often than males. If a learner performed the EMG, it was more likely that the test would be rated as moderately to severely painful, and more likely for the EMG to be rated as more painful than the NCS (p<0.05).

DISCUSSION

The finding that NCS and EMG perceived pain were similar may help accurately inform patients of test expectations, guide test planning and help reduce the likelihood of incomplete or canceled testing. More effort might be required to help mitigate EMG pain when learners are involved.

A simple test to assist with the diagnosis of common fibular nerve entrapment and predict outcomes of surgical decompression

BACKGROUND

Common fibular (peroneal) nerve (CFN) entrapment is the most frequent nerve entrapment in the lower extremity. It can cause pain, sensory abnormalities, and reduced ability to dorsiflex the foot or a drop foot. A simple test to assist with diagnosis of CFN entrapment is described as an adjunctive clinical tool for the diagnosis of CFN entrapment and also as a predictor of successful surgical decompression of a CFN entrapment.

METHODS

The test, a lidocaine injection into the peroneus longus muscle at the site of a common fibular nerve entrapment, was studied retrospectively in 21 patients who presented with a clinical suspicion of CFN entrapment. Patients ages ranged from 17 to 71 (mean 48.5).

RESULTS

The lidocaine injection test (LIT) was positive in 19 patients, and of these, 17 underwent surgical decompression and subsequently experienced improved ability to dorsiflex their foot and reduced sensory abnormalities.

CONCLUSION

The LIT is a simple, safe adjunctive test to help diagnose and also predict a successful outcome of surgical decompression of a CFN entrapment. The proposed mechanism of action of the LIT could lead to new, non-surgical treatments for CFN entrapment.

Motor amplitudes may predict electromyography-confirmed radiculopathy in patients referred for radiating limb pain

INTRODUCTION

Radiculopathy is diagnosed by needle electromyography, with nerve conduction studies excluding alternative diagnoses.

METHODS

In patients referred for electrodiagnostic evaluation of radiating limb pain, we compared ulnar motor amplitudes between those with and without electromyographically confirmed C8 radiculopathy, as well as fibular motor amplitudes between those with and without electromyographically confirmed L5 radiculopathy.

RESULTS

Patients with electromyographically confirmed C8 or L5 radiculopathy demonstrated decreased ulnar or fibular motor amplitudes, respectively, as compared to patients without radiculopathy. Receiver operating characteristic curves demonstrated good diagnostic accuracy, with areas under the curve of 0.85 and 0.82, respectively. Optimal cut-offs for electromyographically confirmed C8 and L5 radiculopathies were 10.2 mV and 3.6 mV, respectively, with associated sensitivities/specificities of 0.86/0.74 and 0.92/0.60.

DISCUSSION

Ulnar and fibular motor amplitudes may have clinical utility in assessing the likelihood of patients demonstrating electromyographically confirmed C8 and L5 radiculopathies with active denervation. The findings may be particularly useful in patients intolerant of needle electromyography. Muscle Nerve 59:561-561, 2019.