Safety and pain in electrodiagnostic studies

Use of machine learning methods in diagnosis of carpal tunnel syndrome

Carpal tunnel syndrome (CTS) is a common condition diagnosed using physical exams and electromyography (EMG) data. This study aimed to classify CTS severity using machine learning techniques. EMG data from 154 patients, including measurements of motor and sensory latency, velocity, and amplitude, were used to form a six-dimensional feature space. Classifiers such as DT, LDA, NB, SVM, k-NN, and ANN were applied, and the feature space was reduced using ANOVA, MRMR, Relieff, and PCA. The DT classifier with ANOVA feature selection showed the best performance for both full and reduced feature spaces.

Development and validation of a clinical model for predicting the severity of carpal tunnel syndrome

OBJECTIVES

To develop a clinical instrument to assess carpal tunnel syndrome (CTS) severity before electrodiagnostic testing.

METHODS

Data from 1037 patients with CTS (39.1% male) were included. The mean (SD) age was 58.0 (10.8) years. The severity of CTS was based on electrodiagnostic findings.

RESULTS

We devised a composite index incorporating a pain numeric rating scale (NRS) rated from 0 (no pain at all) to 10 (the worst pain ever possible), thenar muscle weakness or atrophy (TW), cross-sectional area (CSA) of the median nerve (mm2), and nocturnal pain (NP). The index was calculated as [scale(NRS)+scale(CSA)+NP+TW]/4, where NP and TW are binary features (0 or 1). The accuracy and area under the curve of the index were 0.85 and 0.71, respectively (Cohen's Kappa = 0.51, McNemar's test P = 0.249). The index increased pretest probabilities by 1.6, 1.8, and 3.3 times with positive likelihood ratios of 3.3, 2.5, and 13.5, and false-positive rates of 26.6, 17.6, and 4.8% for mild, moderate, and severe CTS, respectively. The index thresholds for mild, moderate, and severe CTS were <0.8, ≥0.8 to <1.1, and ≥1.1, respectively.

CONCLUSION

Using a composite index, patients with CTS can be categorized for the severity of the syndrome.

Oral and topical analgesia in pediatric electrodiagnostic studies

INTRODUCTION/AIMS

Electrodiagnostic examinations, such as nerve conduction studies (NCS) and needle electromyography (EMG), are perceived as painful by children and their parents/guardians. Methods to reduce peri-procedural pain improve compliance and have neurocognitive and neuropsychiatric benefits. This study aimed to assess the efficacy of combined oral and topical analgesics (COTA), oral analgesics (OA), and placebo in reducing pain during NCS/EMG in children.

METHODS

We performed a double-blind, randomized, placebo-controlled trial on children presenting to our neurophysiology lab. Patients were stratified into two age groups (6M-6Y and 7Y-18Y) and randomized into three arms: COTA, OA, and placebo. Pain scores post-NCS/EMG were assessed using the Modified Behavioral Pain Scale (MBPS) and Faces Pain Scale-Revised (FPS-R).

RESULTS

One hundred thirteen participants were enrolled. A comparison of participants from both age groups combined revealed no significant differences in guardian FPS-R scores across all arms for NCS and EMG. A significant difference in the distribution of post-NCS FPS-R score severities in children aged 7Y-18Y was noted between OA and placebo (p = .007). EMG was more painful than NCS across all arms (p < .05). In children aged 6M-6Y undergoing at least 10 muscle samplings during EMG, those receiving COTA had significantly lower pain scores (p = .014).

DISCUSSION

This study reveals the complexity of pediatric pain perception during NCS/EMG and highlights that other methods to reduce experienced pain are required. Our findings suggest that procedural characteristics, such as number of muscles sampled, may influence the effectiveness of analgesia and serve as a foundation for future research aimed at optimizing pain management strategies.

Application of radiomics model based on ultrasound image features in the prediction of carpal tunnel syndrome severity

OBJECTIVE

The aim of our study is to develop and validate a radiomics model based on ultrasound image features for predicting carpal tunnel syndrome (CTS) severity.

METHODS

This retrospective study included 237 CTS hands (106 for mild symptom, 68 for moderate symptom and 63 for severe symptom). There were no statistically significant differences among the three groups in terms of age, gender, race, etc. The data set was randomly divided into a training set and a test set in a ratio of 7:3. Firstly, a senior musculoskeletal ultrasound expert measures the cross-sectional area of median nerve (MN) at the scaphoid-pisiform level. Subsequently, a recursive feature elimination (RFE) method was used to identify the most discriminative radiomic features of each MN at the entrance of the carpal tunnel. Eventually, a random forest model was employed to classify the selected features for prediction. To evaluate the performance of the model, the confusion matrix, receiver operating characteristic (ROC) curves, and F1 values were calculated and plotted correspondingly.

RESULTS

The prediction capability of the radiomics model was significantly better than that of ultrasound measurements when 10 robust features were selected. The training set performed perfect classification with 100% accuracy for all participants, while the testing set performed accurate classification of severity for 76.39% of participants with F1 values of 80.00, 63.40, and 84.80 for predicting mild, moderate, and severe CTS, respectively. Comparably, the F1 values for mild, moderate, and severe CTS predicted based on the MN cross-sectional area were 76.46, 57.78, and 64.00, respectively..

CONCLUSION

This radiomics model based on ultrasound images has certain value in distinguishing the severity of CTS, and was slightly superior to using only MN cross-sectional area for judgment. Although its diagnostic efficacy was still inferior to that of neuroelectrophysiology. However, this method was non-invasive and did not require additional costs, and could provide additional information for clinical physicians to develop diagnosis and treatment plans.

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.

Differential impact on motor unit characteristics across severities of adult spinal muscular atrophy

OBJECTIVE

To test the hypotheses that decomposition electromyography (dEMG) motor unit action potential (MUAP) amplitude and firing rate are altered in SMA; dEMG parameters are associated with strength and function; dEMG parameters are correlated with traditional electrophysiological assessments.

METHODS

Ambulatory and non-ambulatory adults with SMA on nusinersen and healthy controls were enrolled. MUAPs were decomposed from multielectrode surface recordings during 30-s maximum contraction of the abductor digiti minimi (ADM). Isometric strength, upper limb function, patient-reported function, and standard electrophysiologic measures of the ADM (compound muscle action potential [CMAP], single motor unit potential [SMUP], motor unit number estimation [MUNE]) were collected.

RESULTS

dEMG MUAP amplitudes were higher in ambulatory versus control and non-ambulatory groups and were higher in controls versus non-ambulatory SMA. In contrast, dEMG firing rates were higher in ambulatory versus non-ambulatory and control groups but similar between non-ambulatory and control. dEMG parameters showed moderate to strong positive correlation with strength and function whereas CMAP and MUNE better correlated with function than strength. SMUP did not correlate with strength, function, or dEMG MUAP amplitude. dEMG parameters show overall good test-retest reliability.

INTERPRETATION

dEMG provided reliable, noninvasive measure of MUAP amplitude size and firing rate and revealed divergent patterns across disease severity in adults with SMA. Firing rate enhancement, as seen in milder SMA, may provide a therapeutic avenue for improving function in more severe SMA, where firing rates appear preserved. MUAP amplitude size and firing rate, quantified with dEMG, may be promising monitoring biomarker candidates for noninvasive assessment of SMA.

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.

Surgeons' Recommendations for Neurodiagnostic Testing With High Pretest Probability of Idiopathic Median Neuropathy at the Carpal Tunnel

PURPOSE

The utility of electrodiagnostic tests (EDx) for patients with a high pretest probability of idiopathic median neuropathy at the carpal tunnel (IMNCT) based on characteristic symptoms and signs is debated. Decision-making and care strategies could be informed by a better understanding of factors associated with surgeon recommendations for electrodiagnostic testing.

METHODS

Ninety-one upper-extremity surgeons participated in an online, survey-based experiment. Participants viewed 7 vignettes of patients with carpal tunnel syndrome, with the following factors randomized in each vignette: patient age, gender, magnitude of incapability, symptom intensity and the presence of nocturnal symptoms, palmar abduction weakness, and positive provocative tests results. We sought patient and surgeon factors associated with ordering EDx and surgeon-rated comfort with performing carpal tunnel release (CTR) without EDx.

RESULTS

Surgeons recommended EDx for over half of the patient vignettes, with notable variation (median, 57%; interquartile range, 14-100), and felt relatively neutral, on average, offering CTR without EDx. Twenty-six (29%) out of 91 surgeons ordered EDx for all patient scenarios, and 18 surgeons (20%) did not order testing for any scenario. A lower likelihood of EDx was associated with older age and positive provocative tests results. Greater surgeon comfort offering CTR without EDx was associated with older patients, the presence of nocturnal symptoms, palmar abduction weakness, and positive provocative tests results.

CONCLUSIONS

Upper-extremity surgeons are neutral regarding diagnosing IMNCT based on electrodiagnostic evidence of pathology and are relatively more comfortable offering surgery without EDx in older patients that present with key aspects of carpal tunnel syndrome. There is notable variation in care, with half of all surgeons always or never ordering EDx.

CLINICAL RELEVANCE

Future studies can investigate whether a treatment strategy offering surgery to patients with a high pretest probability of IMNCT and only using EDx in intermediate probability scenarios can limit use of testing without affecting patient health.

Machine learning-based approach for disease severity classification of carpal tunnel syndrome

Identifying the severity of carpal tunnel syndrome (CTS) is essential to providing appropriate therapeutic interventions. We developed and validated machine-learning (ML) models for classifying CTS severity. Here, 1037 CTS hands with 11 variables each were retrospectively analyzed. CTS was confirmed using electrodiagnosis, and its severity was classified into three grades: mild, moderate, and severe. The dataset was randomly split into a training (70%) and test (30%) set. A total of 507 mild, 276 moderate, and 254 severe CTS hands were included. Extreme gradient boosting (XGB) showed the highest external validation accuracy in the multi-class classification at 76.6% (95% confidence interval [CI] 71.2–81.5). XGB also had an optimal model training accuracy of 76.1%. Random forest (RF) and k-nearest neighbors had the second-highest external validation accuracy of 75.6% (95% CI 70.0–80.5). For the RF and XGB models, the numeric rating scale of pain was the most important variable, and body mass index was the second most important. The one-versus-rest classification yielded improved external validation accuracies for each severity grade compared with the multi-class classification (mild, 83.6%; moderate, 78.8%; severe, 90.9%). The CTS severity classification based on the ML model was validated and is readily applicable to aiding clinical evaluations.

Myo-Neurografie 1990–2020 entlang der „Wissenspunkte für die EMG-Prüfung“ der DGKN

Die „Wissenspunkte für die EMG-Prüfung“ der DGKN (https://dgkn.de/images/richtlinien/RL18_EMG_Wissenpunkte.pdf) sind zuletzt vor 10 Jahren bearbeitet worden. Diese letzte Aktualisierung hatte nur zu geringen Änderungen geführt. Fast alle dieser Punkte sind so im Wesentlichen unverändert aufgelistet, seit der Autor dieser Zeilen EMG betreibt, also seit mehr als 30 Jahren. Hier soll der Versuch unternommen werden, anhand dieser Punkte aufzuzeigen, was sich in dieser Zeit verändert hat, was neu ist, aber auch, was weggefallen ist – oder wegfallen sollte.

Needle EMG induced muscle bleeding complication after guideline approved discontinuation of anticoagulation

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After needle EMG an intramuscular hematoma, requiring surgical evacuation, occurred.

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Anticoagulation was paused according to guidelines; one patient had an undetected genetic disorder of platelet function.

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Substituting apixaban for enoxaparin may have contributed to the complications.

Introduction

Needle electromyography (EMG) is an essential part of electrodiagnosis (EDX) in neuromuscular disorders. As in all invasive procedures there is a risk of bleeding complications, but which is rare according to the current literature. Controlled, prospective studies that include patients under anticoagulation or antiplatelet therapy are lacking and would be difficult to conduct.

Case reports

We describe two patients with no history of coagulopathy who developed an intramuscular hematoma after needle EMG. They had been under therapeutic anticoagulation but this had been discontinued, and their standard coagulation parameters had returned to normal prior to the EMG. One patient was found to have a rare genetic defect in thromboxane synthesis with associated markedly impaired platelet aggregation, while no obvious cause of the bleeding was found in the second patient. However, it could have been due to an unexpectedly strong anticoagulatory response to the oral anticoagulant apixaban.

Conclusion

One must be aware of the increased risk of bleeding events in patients with therapeutic anticoagulation. These can occur even when the recommendations regarding discontinuation of anticoagulant drugs for the procedure have been followed. The patient must be actively questioned for ongoing use of NSAIDs, and if pain therapy is required alternatives with no antiplatelet activity should be given. A larger data pool of adverse EMG events would aid in risk assessment and decision making.

Hematoma Risk After Needle Electromyography in Patients Using Newer Oral Anticoagulants

PURPOSE

To assess the safety of needle electromyography in patients on non-vitamin K oral anticoagulants (NOACs) compared with warfarin.

METHODS

A retrospective chart review was done in patients who underwent needle electromyography studies while they were using warfarin and NOACs. After the needle electromyography, all the patients were monitored for 2 hours and ultrasound of high-risk muscle groups was done. The complications were classified based on the International Society on Thrombosis and Hemostasis definitions.

RESULTS

Fifty-eight patients were included: 29 were using NOACs and the other 29 were on warfarin. The mean age was 59.33 ± 16 years. Hemorrhagic complications from needle electromyography were noted in 9 patients: 7 (77.7%) NOACs and 2 (22.3%) warfarin. Among them, 6 patients (66.6%) met the diagnostic criteria for Clinically Relevant Non-Major Bleeding criteria proposed by International Society on Thrombosis and Hemostasis and 3 patients (33.4%) had an asymptomatic hematoma on ultrasound evaluation. A total of 267 muscles were tested and only 9 (3.3%) muscles had hemorrhagic complications. One patient (rivaroxaban) had acute bleeding requiring pressure bandage, five patients (two apixaban, two rivaroxaban, and one warfarin) had clinical hematoma that required ice packs, and three patients (two rivaroxaban and one warfarin) had a hematoma on ultrasound of deep muscles.

CONCLUSIONS

Patients on NOACs had minimal risk of clinically relevant hemorrhagic complications, and the risk is not significantly different from those on warfarin.

Ultrasound analysis of cervical paraspinal muscles for needle EMG examination

BACKGROUND

Ultrasound was used to determine optimal needle insertion parameters and assess the vasculature of paraspinal muscles at C5-T1 spinal levels across patients with different body mass indices (BMIs).

METHODS

Thirty patients underwent ultrasound examination of the cervical paraspinal muscles at the C5-T1 levels. Images were analyzed to determine the optimal distance and angle of needle insertion to reach the base of the right lamina. Color and spectral Doppler analysis were used to identify and map paraspinal blood vessels.

RESULTS

Mean distances and angles varied from 35.1 mm and 17.27 degrees for the low BMI group at C5 to 65.1 mm and 9.85 degrees for the high BMI group at T1. Paraspinal blood vessel mapping revealed a random distribution of vasculature.

CONCLUSIONS

Longer distances and steeper angles of needle insertion are required for patients with higher BMIs. Cervical paraspinal arteries vary in distribution and can be visualized with ultrasound.

Standards of instrumentation of EMG

Standardization of Electromyography (EMG) instrumentation is of particular importance to ensure high quality recordings. This consensus report on "Standards of Instrumentation of EMG" is an update and extension of the earlier IFCN Guidelines published in 1999. First, a panel of experts in different fields from different geographical distributions was invited to submit a section on their particular interest and expertise. Then, the merged document was circulated for comments and edits until a consensus emerged. The first sections in this document cover technical aspects such as instrumentation, EMG hardware and software including amplifiers and filters, digital signal analysis and instrumentation settings. Other sections cover the topics such as temporary storage, trigger and delay line, averaging, electrode types, stimulation techniques for optimal and standardised EMG examinations, and the artefacts electromyographers may face and safety rules they should follow. Finally, storage of data and databases, report generators and external communication are summarized.

Diffusion tensor imaging of diabetic amyotrophy

OBJECTIVE

To qualitatively and quantitatively characterize the nerves of patients with diabetic amyotrophy (DA) using magnetic resonance neurography (MRN) with diffusion tensor imaging (DTI).

MATERIALS AND METHODS

Forty controls and 13 DA cases were analyzed. 1.5-Tesla and 3.0-Tesla MRN with DTI was used. Qualitative data from 13 patient records were recorded. Region of interest (ROI) measurements were taken of bilateral L3 through S2 lumbosacral nerve roots, femoral nerves, and sciatic nerves. An ANOVA and multiple linear regression analysis were performed. An intraclass correlation coefficient (ICC) was calculated between two readers.

RESULTS

In DA cases, abnormalities of the lumbosacral nerve roots (n = 11 patients), sciatic (n = 10), femoral (n = 13), and obturator nerves (n = 4) were seen; denervation changes of the abdominopelvic muscles were also identified. Quantitatively, minimum and mean nerve signals on B600 were significantly less than controls (p < 0.001). Minimum and mean ADC values were significantly greater in cases than in controls (p < 0.001 and p = 0.002 respectively). Mean fractional anisotropy (FA) values were significantly lower in cases than in controls (p = 0.041). There were no significant differences in the minimum FA values between cases and controls. Minimum and mean ADCs correlated positively with highest recorded hemoglobin A1 (HbA1c) while controlling for sex, age, and BMI (β = 0.518, p < 0.001 and β = 0.302, p = 0.020 respectively). ICCs were 0.892 (B600), 0.717 (ADC), and 0.730 (FA).

CONCLUSION

Neuromuscular lesions secondary to DA are qualitatively and quantitatively identified on MRN with DTI, and a positive correlation of ADC levels with serum HbA1c levels exists. Thus, MRN with DTI can be employed as a non-invasive diagnostic tool, if DA is suspected.

Needle EMG muscle identification: A systematic approach to needle EMG examination

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The article discusses standard EMG examination techniques.

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Special clinical and safety concerns, (e.g. bleeding diatheses) are addressed.

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The complementary role of ultrasound is reviewed.

The proper performance of needle electromyography (EMG) requires that the examiner obtain a brief but comprehensive history, perform a directed examination and generate a short differential diagnosis as part of the initial patient encounter. Equally as important is to set reasonable expectations for this study’s performance as electronic media do not necessarily portray all of the nuances of an electrodiagnostic study. In addition to these preliminary steps, this minimonograph discusses equipment used in EMG evaluations, EMG examination techniques, muscles commonly sampled, pain reduction techniques, and special considerations that may require study modification such as anticoagulation, lymphedema, obesity and supervening infection. Clinicians performing these studies will maximize useful data collection while minimizing patient discomfort if all of these recommendations are followed.

Complications Associated With Electromyography: A Systematic Review

OBJECTIVES

The aims of the study were to systematically review the available literature concerning complications due to electromyography and to review those associated with nerve conduction studies.

DESIGN

A systematic review was undertaken of Medline and Cochrane Central Register of Controlled Trials. Any complication related to clinical electromyography written in English was included, and all bibliographies were scanned for missed articles.

RESULTS

A total of 27 articles fit the inclusion criteria, with two observational studies, and the rest case series or case studies; 42 patients were reported. Of these, 28 patients required hospitalization and 22 required surgery or a procedure, with zero deaths reported. Needle-related complications were the most prevalent (18 patients reported), with 17 related to pneumothoraces. Disorders of hemostasis were identified in 13 patients (many were asymptomatic) and cutaneous disorders were identified in 11 patients. Only one complication was identified in the narrative review related to nerve conduction studies.

CONCLUSIONS

This systematic review identified a variety of complications related to electromyography. Although the incidence of these occurrences cannot be elucidated from the case series and case study-predominant literature, adverse events seem to be rare but can cause significant morbidity. Electromyographers should be aware of all reported complications; this review outlines all reported occurrences that fit the inclusion criteria.

Quantitative assessment of diabetic amyotrophy using magnetic resonance neurography-a case-control analysis

OBJECTIVES

To quantitatively characterize diabetic amyotrophy (DA), or diabetic lumbosacral radiculoplexopathy, and compare with controls using magnetic resonance neurography (MRN).

METHODS

Forty controls and 23 DA cases were analyzed qualitatively and quantitatively. Cross-sectional areas (CSAs) of bilateral L3 through S2 lumbosacral nerve roots, femoral nerves, and sciatic nerves (proximal and distal measurements) were measured. A linear model was used to assess the nerve location and case/control effect on angle-corrected CSAs. Intra- and inter-reader analysis was performed using intraclass correlation (ICC).

RESULTS

In DA cases, abnormalities of the lumbosacral nerve roots, sciatic, femoral, and obturator nerves were seen in 21/23, 16/23, 21/23, and 9/23, respectively. Denervation abnormalities of multiple abdominopelvic muscles were seen. Quantitatively, the CSA of all measured LS plexus nerve roots and bilateral femoral nerves were significantly larger in DA cases vs. controls by 45% (95% CI, (30%, 49%); p < 0.001). The ICC was moderate for inter-rater analysis = 0.547 (95% CI, 0.456-0.626) and excellent for intra-rater analysis = 0.90 (95% CI, 0.89-92).

CONCLUSIONS

Multifocal neuromuscular lesions related to diabetic amyotrophy were qualitatively and quantitatively detected on MRN. Qualitative abnormalities distinguished cases from controls, and nerve CSAs of cases were significantly larger than those of controls. Therefore, MRN may be employed as a non-invasive diagnostic tool for the evaluation of diabetic amyotrophy.

KEY POINTS

• Qualitative abnormalities of lumbosacral nerve roots, their peripheral branches, and muscles are seen in DA. • The lumbosacral nerve roots and their peripheral branches in diabetic amyotrophy cases are significantly larger in cross-sectional area than non-diabetic subjects by 45% (95 CI, 30%, 49%; p < 0.001). • The ICC was moderate for inter-rater analysis = 0.547 (95% CI, 0.456-0.626) and excellent for intra-rater analysis = 0.90 (95% CI, 0.89-92).

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.

The provision of written information and its effect on levels of pain and anxiety during electrodiagnostic studies: A randomised controlled trial

Objective

The provision of written information is a low-cost and readily available intervention that has been found to reduce pain and anxiety in a variety of clinical settings. The current study was undertaken to determine if information provision may improve patients’ experience during conventional electrodiagnostic studies.

Methods

128 participants were recruited from a tertiary teaching hospital who were referred for electrodiagnostic studies. They were randomized into 2 groups where the intervention group was provided with written information about the electrodiagnostic testing. Patients were invited to complete a questionnaire that included pain and anxiety using a visual analogue scale (VAS) following the testing. All participants underwent nerve conduction studies (NCS) whilst a subset also underwent subsequent needle electromyography (EMG).

Results

Those who received information had a statistically significant lower perception of anxiety during NCS, whilst only females who received information had a statistically significant lower perception of pain to both NCS and EMG.

Conclusions

The provision of written information can reduce the degree of pain and anxiety experienced during electrodiagnostic testing.

Significance

Improving patient comfort and tolerability during electrodiagnostic testing may have practical implications towards more reliable and accurate results obtained from such investigations that may in turn improve patient diagnosis and management.