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Automated Point-of-Care Nerve Conduction Tests

Policy Number: MP-304

 

Latest Review Date: June 2019

Category: Medicine

Policy Grade: C

Description of Procedure or Service:

Portable devices have been developed to provide point-of-care nerve conduction studies. These devices have computational algorithms that are able to drive stimulus delivery, measure and analyze the response, and provide a report of study results. These nerve conduction tests are performed with pre-configured electrodes customized to a specific anatomic site. Automated nerve conduction could be used in various settings, including primary care, without the need for specialized training or equipment.

Electrodiagnostic Testing

Nerve conductions studies (NCS) and needle electromyography (EMG), when properly performed by a trained practitioner, are considered the criterion standard of electrodiagnostic testing for the evaluation of focal and generalized disorders of peripheral nerves. However, the need for specialized equipment and personnel may limit the availability of electrodiagnostic testing for some patients.

Carpal Tunnel Syndrome

Carpal Tunnel Syndrome is a pressure-induced entrapment neuropathy of the median nerve as it passes through the carpal tunnel, resulting in sensorimotor disturbances. This syndrome is defined by its characteristic clinical symptoms, which may include pain, subjective feelings of swelling, and nocturnal paresthesia.

Diagnosis

A variety of simple diagnostic tools are available, and a positive response to conservative management (steroid injection, splints, and modification of activity) can confirm the clinical diagnosis. Electrodiagnostic studies may also be used to confirm the presence or absence of a median neuropathy at the wrist, assess the severity of the neuropathy, and assess alternate associated diagnoses. Nerve conduction is typically assessed prior to surgical release of the carpal tunnel, but the use of electromyography in the diagnosis of CTS is controversial. One proposed use of automated nerve conduction devices is to assist in the diagnosis of carpal tunnel syndrome.

Lumbosacral Radiculopathy

Electrodiagnostic studies are useful in the evaluation of lumbosacral radiculopathy in the presence of disabling symptoms of radiculopathy or neuromuscular weakness. These tests are most commonly considered in patients with persistent disabling symptoms when neuroimaging findings are inconsistent with clinical presentation. Comparisons of automated point-of-care (POC) NCSs with EMGs and standardized NCSs have been evaluated as alternative electrodiagnostic tools.

Peripheral Neuropathy

Peripheral neuropathy is relatively common in patients with diabetes mellitus, and the diagnosis is often made clinically through the physical examination. Diabetic peripheral neuropathy can lead to important morbidity including pain, foot deformity, and foot ulceration.

Diagnosis

Clinical practice guidelines recommend using simple sensory tools such as the 10-g Semmes-Weinstein monofilament or the 128-Hz vibration tuning fork for diagnosis. These simple tests predict the presence of neuropathy defined by electrophysiological criteria with a high level of accuracy. Electrophysiological testing may be used in research studies and may be required in cases with an atypical presentation. POC nerve conduction testing has been proposed as an alternative to standard electrodiagnostic methods for the diagnosis of peripheral neuropathy and, in particular, for detecting neuropathy in patients with diabetes.

Normative Values

NeuroMetrix (2009) published reference ranges for key nerve conduction parameters in healthy subjects. Data analyzed were pooled from 5 studies, including from 92 to 848 healthy subjects with data on the median, ulnar, peroneal, tibial, and sural nerves. Subject age and height were found to affect the parameters. In addition to providing reference ranges for clinicians to use (providing that NCS techniques are consistent with those described in the article), the authors stated that clinicians could use the same method to develop their reference ranges. At this time, the proposed reference ranges have not been validated in a clinical patient population.

Due to the lack of uniform standards in nerve conduction testing in the United States, the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) identified 7 criteria that would identify high-quality NCS articles that would be appropriate for using as reference standards (2016). AANEM identified normative criteria for nerve conduction velocity tests based on a review of high-quality published studies (see Table 1). In March 2017, the American Academy of Neurology affirmed AANEM’s recommendations.

Table 1. Criteria for Evaluating Published Sources for Normative Standards

Criteria

Description

Year published

Published during or after 1990, written in or translated from other languages into English

Sample size

>100 normal subjects

Subjects

Inclusion and exclusion criteria must be methodologically sound and reflect a true “normal” group of asymptomatic individuals

Testing factors

  • Use of digital electromyographic equipment

  • Methods of temperature control stated

  • Testing techniques with electrode placement and distances between simulating and recording electrodes specified

  • Filter settings specified

  • Screen display parameters (milliseconds per division, microvolts/millivolts per division) specified

Age

Wide distribution of subject ages >18 years with adequate sampling of the elderly

Statistical analyses

  • Data distribution should be described and appropriate statistical methods used to account for non-Gaussian distributions

  • Cutoff values expressed and derived as percentiles of the distribution (the preferred method)

  • Percentage of subjects who have an absent response should be reported

Data presentation

Reference values and cutoff points for NCS parameters clearly presented in a useful format

Adapted from Dillingham et al (2016).

NCS: nerve conduction study.

Chen (2016) published reference values for upper and lower NCSs in adults, as a companion study to the Dillingham et al (2016) report (above), to address the need for greater standardization in the field of electrodiagnostic medicine. Using the consensus-based criteria developed by AANEM, a comprehensive literature search was conducted for 11 routinely performed sensory and motor NCS from 1990 to 2012. Over 7500 articles were found, but after review, a single acceptable study meeting all criteria was identified for the 11 nerves. Reviewers determined there were multifactorial reasons that so few studies met the criteria. Large-scale normative studies are time intensive, requiring significant resources and cost. Data from many studies did not address the non-Gaussian distribution of NCS parameters and often derived cutoff values using the mean and standard deviations rather than percentiles.

Policy:

Automated nerve conduction tests are considered not medically necessary and investigational.

Examples of automated nerve conduction devices include, but are not limited to, NC-Stat by NeuroMetrix®, Neurometer® and Brevio® NCS-Monitor.

For coverage criteria addressing Neuromuscular and Electrodiagnostic Testing (EDX), see: Medical Policy #228 Nerve Conduction Studies (NCS) and Electromyography (EMG) Studies.

Key Points:

The most recent literature review for this policy was performed on April 01, 2019.

Evidence reviews assess whether a medical test is clinically useful. In order to determine if a test is clinically useful, the test must provide information to make a clinical management decision that improves the net health outcome. The balance of benefits and harms is better when the test is used to manage the condition than when another test or no test is used to manage the condition.

The formulation of the clinical context and purpose of the test is the first step in assessing a medical test. The test must be technically reliable, clinically valid, and clinically useful for that purpose.

Carpal Tunnel Syndrome

Clinical Context and Test Purpose

The purpose of automated point-of-care (POC) nerve conduction testing in patients who have carpal tunnel syndrome (CTS) is to inform the diagnosis of neuropathy.

The question addressed in this evidence review is: Does use of automated POC nerve conduction testing improve health outcomes in patients who have CTS?

The following PICOTS were used to select literature to inform this review.

Patients

The relevant populations of interest are individuals with CTS.

Interventions

The test being considered is automated POC nerve conduction testing.

Comparators

The following tests are currently being used: standard clinical examination, needle electromyography (EMG), and standardized nerve conduction studies (NCS).

Outcomes

The primary outcomes of interest relate to diagnostic accuracy (i.e., test accuracy and validity) and health outcomes (i.e., symptoms, functional outcomes).

Timing

Diagnostic accuracy is a short-term outcome. Symptoms and functional outcomes would be measured over the long term after patients have been diagnosed and treated.

Setting

Patients would be tested in the primary care or specialty care setting (e.g., neurology or orthopedics).

Technically Reliable

Assessment of technical reliability focuses on specific tests and operators and requires review of unpublished and often proprietary information. Review of specific tests, operators, and unpublished data are outside the scope of this evidence review, and alternative sources exist. This evidence review focuses on the clinical validity and clinical utility.

Clinically Valid

A test must detect the presence or absence of a condition, the risk of developing a condition in the future, or treatment response (beneficial or adverse).

In an early report of NC-stat technology using DML to diagnose CTS, Leffler et al (2000) reported that in 248 symptomatic hands (apparently a combination of an initial and validation group), compared with conventional diagnosis, testing using this device had a sensitivity of 86% and specificity of 90%. In the 2004 report by Rotman et al, the NC-stat DML had a sensitivity of 89% “at the predetermined specificity of 95%” for the diagnosis of CTS for “70 hands” that met the standardized CTS case definition. However, in a 2006 POC study evaluating industrial workers for possible CTS using DML, many patients who were identified with prolonged DML by NC-stat fell within the normal range (using a 95% cutoff point) as defined by this study population.

A report by Armstrong et al (2008) report assessed the diagnostic performance of NC-stat against the criterion standard NCS in patients who had been referred for electrodiagnostic testing at one of the several academic medical centers. Of 47 patients invited to participate in the study, 12 declined to participate, and records from 1 patient were missing, resulting in data analysis of 33 patients. The goal of the study was to compare the diagnostic performance of both testing methods as they would be used in standard practice; thus, patients were not excluded by the particular diagnosis for which they were referred. The diagnosis being tested was CTS in 25 (76%) patients, with the remaining 8 patients having other potential diagnoses. NC-stat testing was independently performed by assistants (medical students, physical therapy assistants, occupational therapy assistants) who were trained to operate the device following the manufacturer’s recommendations. NC-stat results could not be obtained for 2 patients for median nerve motor studies and 3 (15%) patients for median nerve sensory studies. Based on the manufacturer’s suggested cutoff for abnormal nerve conduction, sensitivity was 100% for both the motor and sensory median-ulnar difference; specificity was 62% to 69% for the motor median-ulnar difference and 41% to 47% for the sensory median-ulnar difference. Pearson correlation coefficients ranged from 0.40 for the ulnar nerve to 0.91 for the median dorsal motor nerve. The ICCs had generally lower values than the Pearson coefficients, reflecting systematic bias due to methodologic differences in the 2 methods of NCS. The authors concluded that the recommended cutoff values for NC-stat might need to be adjusted, although specific study results were limited by the small sample size. Also, the authors noted that the study did not evaluate how well physicians can assign clinical relevance to the results and that, while the device may be suited for research studies or screening of symptomatic patients, “in many clinical situations referral to a specialist for a more comprehensive evaluation would be prudent.”

Section Summary: Clinically Valid

There are no randomized controlled trials. Several uncontrolled nonrandomized studies have reported on the diagnostic accuracy of NC-stat to evaluate symptoms suggestive of CTS. There were no clinical comparators. There was high sensitivity but low specificity using manufacturer reference standards. Specificity results were also inconsistent across the trials. No reference ranges were validated, and normative values were not defined in these studies. No validation of testing by trained medical assistants vs trained specialist was reported in the studies.

Clinically Useful

A test is clinically useful if the use of the results informs management decisions that improve the net health outcome of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy, or avoid unnecessary testing.

Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. Because these are intervention studies, the preferred evidence would be from randomized controlled trials.

In 2011, Bourke et al reported a non-randomized comparison of clinic-based NC-stat versus referral to standard electrodiagnostic testing that evaluated efficiency of workup and costs. The study included 142 patients being considered for decompression surgery for CTS at a hand clinic. Seventy-one patients who accepted nerve conduction studies (NCSs) in a nurse-led clinic were compared with 71 historical controls that had been sent for NCSs at the regional neurophysiological unit. Patients with known or suspected complex neurological conditions were excluded from the study. Outcome measures were time from presentation to carpal tunnel decompression, and the practicalities of using the device in the clinic. In the NC-stat group, 43 patients (61%) had a diagnosis of CTS confirmed by NC-stat and underwent decompression surgery, and 28 patients (39%) had normal or inconclusive tests. Of the 28, 12 were referred for electrodiagnostic testing, and 2 of the 12 were recommended for decompression surgery (3% false negative). In the referred group, 44 patients (62%) had confirmation of CTS and underwent decompression surgery. Use of NC-stat in the clinic reduced the time from presentation to surgery from 198 days to 102 days. Health outcomes for the two approaches were not assessed.

The NeuroMetrix data registry was analyzed by Megerian et al (2007) for all NC-stat studies performed over a period of ten days that were coded for CTS and performed by a primary care provider. The initial data set consisted of studies on 1,190 patients performed by 613 different physician practices; studies that met CTS testing guidelines (82% met strict guidelines and 93% met less restrictive guidelines) were further analyzed. Thus, in nearly one of five patients (18.4%), the studies did not meet strict CTS testing guidelines. From the limited set, 31% were identified as normal, 53% exhibited CTS, 5% demonstrated an ulnar neuropathy, and 11% showed a nonspecific neuropathy. No comparison was made with standard nerve conduction testing nor was an assessment made of the impact of this testing on relevant clinical outcomes.

Chain of Evidence

Indirect evidence on clinical utility rests on clinical validity. If the evidence is insufficient to demonstrate test performance, no inferences can be made about clinical utility.

Because the evidence is insufficient to demonstrate clinical validity for automated POC nerve conduction testing, no inferences can be made about clinical utility.

Section Summary: Clinical Utility

One nonrandomized study has reported on the clinical outcomes of NC-stat vs referral to standard electrodiagnostic testing. Health outcomes assessing patient symptoms or changes in functional status outcomes were not assessed. A data set from a NeuroMetrix registry on NC-stat did not report on relevant clinical or health outcomes.

Lumbosacral Radiculopathy

Clinical Context and Test Purpose

The purpose of automated POC nerve conduction testing in patients who have lumbosacral radiculopathy is to inform the diagnosis of neuropathy.

The question addressed in this evidence review is: Does use of automated POC nerve conduction testing improve health outcomes in patients who have lumbosacral radiculopathy?

The following PICOTS were used to select literature to inform this review.

Patients

The relevant populations of interest are individuals with lumbosacral radiculopathy.

Interventions

The relevant intervention of interest is automated POC nerve conduction testing.

Comparators

The comparators of interest are a standard clinical evaluation, and electrophysiologic NCS combined with needle EMG.

Outcomes

The primary outcomes of interest relate to diagnostic accuracy (i.e., test accuracy and validity) and health outcomes (i.e., symptoms, functional outcomes).

Timing

Diagnostic accuracy is a short-term outcome. Symptoms and functional outcomes would be measured over the long term after patients have been diagnosed and treated.

Setting

Patients would be tested in the primary care or specialty care setting (e.g., neurology or orthopedics).

Technically Reliable

Assessment of technical reliability focuses on specific tests and operators and requires review of unpublished and often proprietary information. Review of specific tests, operators, and unpublished data are outside the scope of this evidence review, and alternative sources exist. This evidence review focuses on the clinical validity and clinical utility.

Clinically Valid

A test must detect the presence or absence of a condition, the risk of developing a condition in the future, or treatment response (beneficial or adverse).

Fisher et al (2008) explored the relation between NC-stat and routine NCS/needle EMG in 34 consecutive patients with a clinical history and/or examination consistent with lumbosacral radiculopathy. Inclusion in the study was based on a chart review of symptoms from clinical history and/or examination (including low back pain or buttock pain, numbness, and/or paresthesia of one or both lower extremities) and having undergone testing with both NC-stat and routine electrodiagnostic studies. All testing was conducted by the principal investigator, and the reason for and timing of NC-stat testing was not specified. Of 34 patients included in the study, 28 had magnetic resonance imaging of the lumbosacral spine within 6 months of electrodiagnosis, 2 had a postmyelogram computed tomography scan, and 3 had lumbosacral spine radiographs. A neuroradiologist who was blinded to the clinical evaluation and electrodiagnostic results determined from magnetic resonance imaging or computed tomography that lumbosacral root injury was likely at the L4-5 and/or L5-S1 levels in 18 (60%) patients. The study found some correlation between the electrodiagnostic testing and NC-stat. However, 6 of 10 patients who had unremarkable routine electrodiagnostic results had abnormal F-wave and compound muscle action potential amplitude abnormalities with NC-stat testing. The clinical implications of this finding are uncertain.

A 2011 report by Schmidt et al assessed the accuracy of NC-stat diagnosis of lumbosacral radiculopathy in 50 patients and 25 controls with no history of lumbosacral radiculopathy. The patient cohort included patients referred to a tertiary referral EMG laboratory for testing of predominantly unilateral leg symptoms (pain, numbness, weakness). Control subjects were recruited from clinic employees and from patients referred to the EMG laboratory for upper-limb symptoms. All patients underwent a focused history and physical examination and both standard and automated electrodiagnostic testing. Automated testing was performed by experienced technicians who were unaware of the electrodiagnostic test results. Data were transmitted to the manufacturer and compared with a large database of previously recorded data, which were adjusted for the age and height of the patient, and subsequently determined to be normal or abnormal. In the patient cohort, the sensitivity of NC-stat was found to be 0% for L4 radiculopathy, 69% for L5 radiculopathy, and 64% for S1 radiculopathy compared with standard electrodiagnostic testing. By standard electrodiagnostic evaluation, 22 (44%) of the 50 symptomatic patients had findings consistent with L4, L5, or S1 radiculopathy, and 28 (56%) patients were found to be normal or to have a diagnosis other than lumbosacral radiculopathy; NC-stat identified only 4 of these 28 cases (specificity, 14%). Standard electrodiagnostic testing also identified other important diagnoses in 9 (18%) patients not identified by the automated test, while NC-stat reported 6 other diagnoses in patients found to be normal by standard electrodiagnostic testing. All standard electrodiagnostic tests in the control group were normal, but the automated test found that 18 of these subjects were abnormal (specificity, 32%). The study found that raw nerve conduction data were comparable for both techniques; however, computer-generated interpretations by the automated device showed low specificity (numerous false positives) in both symptomatic patients and normal control subjects. An accompanying editorial by England and Franklin (2011) stated that the use of automated nerve conduction devices is controversial and that the use of NC-stat for lumbosacral radiculopathy would likely lead to a high misdiagnosis rate and potentially inappropriate treatment, including surgery. England and Franklin also concluded that an overly sensitive but not very specific test for CTS, or other mono- or polyneuropathies, cannot replace expert use and interpretation of conventional electrodiagnostic testing.

 

Section Summary: Clinically Valid

One nonrandomized study comparing results of NCT-stat with results of standard EMG plus NCSs to evaluate the potential diagnosis of lumbosacral radiculopathy found a poor correlation. A second nonrandomized study using an asymptomatic control group reported an unacceptably high false-positive rate in both the patient and control groups when definitive electrodiagnostic testing was performed. Reference ranges were not validated, and normative values were not defined in these studies.

Clinically Useful

A test is clinically useful if the use of the results informs management decisions that improve the net health outcome of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy, or avoid unnecessary testing.

Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. Because these are intervention studies, the preferred evidence would be from randomized controlled trials.

No clinical outcome studies were identified to inform this review.

Chain of Evidence

Indirect evidence on clinical utility rests on clinical validity. If the evidence is insufficient to demonstrate test performance, no inferences can be made about clinical utility.

Because the evidence is insufficient to demonstrate clinical validity for automated POC nerve conduction testing, no inferences can be made about clinical utility.

Diabetic Peripheral Neuropathy

Clinical Context and Test Purpose

The purpose of automated POC nerve conduction testing in patients who have diabetic peripheral neuropathy (DPN) is to inform the diagnosis of neuropathy.

The question addressed in this evidence review is: Does use of automated POC nerve conduction testing improve health outcomes in patients who have DPN?

The following PICOTS were used to select literature to inform this review.

Patients

The relevant populations of interest are individuals with suspected diabetic peripheral neuropathy (DPN).

Interventions

The relevant intervention of interest is automated POC nerve conduction testing.

Comparators

The following tests are currently being used: standard clinical examination, needle EMG, and standardized NCS.

Outcomes

The primary outcomes of interest relate to diagnostic accuracy (i.e., test accuracy and validity) and health outcomes (i.e., symptoms, functional outcomes).

Timing

Diagnostic accuracy is a short-term outcome. Symptoms and functional outcomes would be measured over the long term after patients have been diagnosed and treated.

Setting

Patients would be tested in the primary care or specialty care setting (e.g., neurology or endocrinology).

Technically Reliable

Assessment of technical reliability focuses on specific tests and operators and requires review of unpublished and often proprietary information. Review of specific tests, operators, and unpublished data are outside the scope of this evidence review, and alternative sources exist. This evidence review focuses on the clinical validity and clinical utility.

Clinically Valid

A test must detect the presence or absence of a condition, the risk of developing a condition in the future, or treatment response (beneficial or adverse).

A nonrandomized study assessed the validity of NC-stat to diagnose diabetic peripheral neuropathy through sural nerve testing in patients from diabetes and diabetic neuropathy outpatient practices. Seventy-two consecutive patients (64 with Type 2 diabetes) who completed a clinical evaluation, a conventional nerve conduction study, and a point-of-care NC-stat assessment were enrolled. The point-of-care assessment was independently conducted by non-technologist research staff following a single one-hour lesson in the NC-stat protocol. The amplitude potential of the sural nerve was tested as an early indicator of diabetic neuropathy. Using a threshold of 6μV, the authors report that the sensitivity and specificity of NC-stat for diagnosis of diabetic sensorimotor polyneuropathy, as defined by clinical and conventional electrophysiological evaluation, was 92% and 82%, respectively. The Spearman correlation coefficient (compared with the reference standard) was 0.95. Further study is needed in a broad spectrum of patients, including those who present with atypical neuropathy in a clinical setting.

In 2015, Sharma et al assessed the technical accuracy of NC-stat DPN-Check in 162 patients with diabetes and 80 healthy controls. Based on the 10-point Neuropathy Disability Score, diabetic peripheral neuropathy was categorized as none, mild, moderate, or severe. Measurements with the POC device were conducted by blinded assessors. Receiver operating characteristic (ROC) curves showed high overall accuracy in participants with either no neuropathy or severe neuropathy. However, for patients with mild neuropathy who would benefit most from early diagnosis, accuracy was substantially lower.

In 2016, Chatzikosma et al reported on the diagnostic accuracy of NC-stat DPN-Check by comparing sural nerve conduction in the diagnosis of peripheral neuropathy in 114 patients with type 2 diabetes (58 men, 56 women) with an age- and sex-matched group of 46 healthy controls (24 men, 22 women). Diagnosis of DPN was based on the standardized NDS developed by Young et al (1993). An NDS of 3 or more was considered diagnostic of DPN. DPN was diagnosed in 42 (36.84%) patients using the NDS. Examination with NC-stat DPN-Check exhibited 90.48% sensitivity, 86.11% specificity, 79.17% positive predictive value, and 93.94% negative predictive value. The positive likelihood ratio was 6.51, and the negative likelihood ratio was 0.11. In the control group, the NDS was normal in all subjects, while automated NCS was abnormal in 2 subjects. The investigators concluded that the NC-stat DPNCheck “exhibited a very good diagnostic performance” to rule in DPN and was “especially reliable as a screening tool to rule out DPN.” Limitations of this study were identified as the inclusion of patients from a tertiary care setting and not the general diabetic population, exclusion of patients with type I diabetes, and no confirmation of the diagnosis of DPN by classical NCS.

Section Summary: Clinically Valid

Three nonrandomized studies reported on the diagnostic accuracy of POC automated nerve conduction testing to evaluate a diagnosis of suspected DPN. Two studies used the NC-stat DPNCheck. The 2015 study using NC-Stat DPNCheck used laser Doppler technology as a comparator. The 2016 study using NC-Stat DPNCheck used standardized clinical examination as its comparator. High sensitivity indicated there may be potential diagnostic value to detect DPN in symptomatic patients. However, specificity was low and inconsistent across the trials. No reference ranges were validated, and normative values were not defined in 2 of the 3 studies. No validation of testing by trained medical assistants vs trained specialist was reported in the studies.

Clinically Useful

A test is clinically useful if the use of the results informs management decisions that improve the net health outcome of care. The net health outcome can be improved if patients receive correct therapy, or more effective therapy, or avoid unnecessary therapy, or avoid unnecessary testing.

Direct Evidence

Direct evidence of clinical utility is provided by studies that have compared health outcomes for patients managed with and without the test. Because these are intervention studies, the preferred evidence would be from randomized controlled trials.

No clinical outcome studies were identified to inform this review.

Chain of Evidence

Indirect evidence on clinical utility rests on clinical validity. If the evidence is insufficient to demonstrate test performance, no inferences can be made about clinical utility.

Because the evidence is insufficient to demonstrate clinical validity for automated POC nerve conduction testing, no inferences can be made about clinical utility.

Summary of Evidence

For individuals who have entrapment carpal tunnel syndrome who received automated POC NCSs, the evidence includes studies on the diagnostic accuracy, and clinical outcomes from industry-sponsored trials, nonrandomized trials, and registry data. Relevant outcomes are test accuracy and validity, symptoms, and functional outcomes. Four RCTs have reported on the diagnostic accuracy of automated POC nerve conduction testing to diagnose carpal tunnel syndrome. Sensitivity testing has suggested there could be diagnostic value in detecting carpal tunnel syndrome; specificity testing was inconsistent across trials. No reference ranges were validated, and normative values were not defined in these studies. No validation testing by trained medical assistants vs trained specialist was reported in the studies. The evidence on clinical outcomes was limited to a single nonrandomized clinical trial and NeuroMetrix registry data. Neither reported health outcomes assessing patient symptoms or changes in functional status. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals with lumbosacral radiculopathy who received automated POC NCSs, the evidence includes industry-sponsored trials and a nonrandomized study of diagnostic accuracy. Relevant outcomes are test accuracy and validity, symptoms, and functional outcomes. The evidence on the diagnostic accuracy of POC NCS in this population has shown variable test results across reported trials. No normative values were defined. Weaknesses of the studies included lack of applicable or valid reference ranges for testing, and variable test results validating or confirming pathology. The results of the 2 studies on diagnostic performance were inconclusive, with high false-positive results in a single trial. No trials on health outcomes assessing patient symptoms or changes in functional status were identified. The evidence is insufficient to determine the effects of the technology on health outcomes.

For individuals with diabetic peripheral neuropathy who received automated POC NCSs, the evidence includes industry-sponsored observational trials and nonrandomized studies on the diagnostic accuracy. Relevant outcomes are test accuracy and validity, symptoms, and functional outcomes. Of 3 studies reporting evidence on diagnostic accuracy, two used NC-stat DPN-Check. Sensitivity testing has suggested there could be diagnostic value in detecting diabetic peripheral neuropathy in symptomatic patients; the evidence to detect patients who are suspected of disease but who have mild symptoms was inconsistent. No reference ranges were validated, and normative values were not defined in 2 of the 3 studies. No validation testing by trained medical assistants vs trained specialist was reported in the studies. No trials on health outcomes assessing patient symptoms or changes in functional status were identified. The evidence is insufficient to determine the effects of the technology on health outcomes.

Practice Guidelines and Position Statements

American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM)

In 2006, the American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) issued a position statement that illustrates how standardized nerve conduction studies performed independent of needle EMG studies may miss data essential for an accurate diagnosis and how nerve disorders are far more likely to be misdiagnosed or missed completely if a practitioner without the proper skill and training is interpreting the data, making a diagnosis, and establishing a treatment plan. The organization states that, “the standard of care in clinical practice dictates that using a predetermined or standardized battery of NCSs for all patients is inappropriate,” and concludes that, “It is the position of the AANEM that, except in unique situations, NCSs and needle EMG should be performed together in a study design determined by a trained neuromuscular physician.” This position statement was reviewed and updated by the Professional Practice Committee and approved by the AANEM Board in June 2014. No changes were made to the earlier statement on NCSs.

American Academy of Orthopaedic Surgeons

The American Academy of Orthopaedic Surgeons (2016) released guidelines on the management of carpal tunnel syndrome. The guidelines were endorsed by other specialty societies including the American College of Radiology and American College of Surgeons. The guidelines found “limited evidence” for a “hand-held nerve conduction study.”

U.S. Preventive Services Task Force Recommendations

Not applicable.

Key Words:

Nerve conduction tests, automated nerve conduction tests, NC-stat, NeuroMetrix, Brevio® nerve conduction monitoring system, NeuroMetrix ADVANCE™, ADVANCE™, Axon-II™, XL Tek Neuropath, Cadwell Sierra® Summit, Cadwell Sierra® Ascent

Approved by Governing Bodies:

Multiple devices have been cleared for POC neural conduction testing. For example, in 1986, Neurometer® CPT/C (Neurotron®) was cleared for marketing by the U.S. Food and Drug Administration (FDA) through the 510(k) process (K853608). The device evaluates and documents sensory nerve impairments at cutaneous or mucosal sites. The evaluation detects and quantifies hyperesthesia in early stages of progressive neuropathy and hypoesthesia in more advanced conditions.

In 1998 NC-stat® (NeuroMetrix) was cleared by FDA through the 510(k) process (K982359). NC-stat® is intended “to measure neuromuscular signals that are useful in diagnosing and evaluating systemic and entrapment neuropathies.” This version is no longer commercially available. It is the predicate device for the NC-stat DPNCheck® (K041320), cleared in 2004, and the NeuroMetrix Advance (K070109), cleared in 2008. The NC‐stat DPNCheck device measures the sural nerve conduction velocity and sensory nerve action potential amplitude. It is a handheld device with an infrared thermometer, noninvasive electrical stimulation probes, and a single-use biosensor for each test. NC-stat DPNCheck is designed specifically for NCS of the sural nerve in the assessment of diabetic peripheral neuropathy. The NeuroMetrix ADVANCE is a POC test that can be used to perform needle EMG in addition to surface electrodes for the performance of NCSs. If the needle EMG module is used, then the device is also intended to measure signals useful in evaluating disorders of muscles.

On January 23, 2017, Cadwell Sierra Summit, Cadwell Sierra Ascent (Cadwell Industries) was cleared for marketing by FDA through the 510K process (K162383). There is a portable laptop version and a desktop application with a handheld device. The system is used for acquisition, display, storage, transmission, analysis, and reporting of electrophysiologic and environmental data including EMG, NCS, evoked potentials, and autonomic responses (RR interval variability). The Cadwell Sierra Summit is used to detect the physiologic function of the nervous system, and to support the diagnosis of neuromuscular diseases or conditions.

Other examples of devices cleared for marketing by FDA through the 510(k) process are noted in Table 1.

Table 2. Select FDA Cleared Devices for Neural Conduction Testing

Device

Manufacturer

Date Cleared

510 (k)

Indications

Axon-II™

PainDX

1998

K980866

Part of a routine neurologic exam or screening procedure for detection of peripheral neuropathy, which may be caused by various pathologic conditions or exposures to toxic substances

Brevio®

Neurotron Medical

2001

K012069

To measure nerve response latency and amplitude in the diagnosis and monitoring of peripheral neuropathies

NC-stat®

NC-stat DPN-Check

NeuroMetrix

2004

K041320

To stimulate and measure neuromuscular signals in diagnosing and evaluating systemic and entrapment neuropathies. Added the sural biosensor for use in diagnosing neuropathies affecting the sural nerve.

NC-stat®

NeuroMetrix

2006

K060584

Addition of the modified median motor-sensory biosensor to stimulate and measure neuromuscular signals useful in diagnosing and evaluating systemic and entrapment neuropathies

XLTEK NEUROPATH

Excel Tech

2006

K053058

To stimulate and measure neuromuscular signals useful in diagnosing and evaluating systemic and entrapment neuropathies

NeuroMetrix Advance™

NeuroMetrix

2008

K070109

To measure neuromuscular signals useful as an aid in diagnosing and evaluating patients suspected of having focal or systemic neuropathies. If the elective needle EMG module is used, then the device is also intended to measure signals useful as an aid in evaluating disorders of muscles.

Benefit Application:

Coverage is subject to member’s specific benefits. Group specific policy will supersede this policy when applicable.

ITS: Home Policy provisions apply

FEP contracts: FEP does not consider investigational if FDA approved and will be reviewed for medical necessity.

Current Coding:

CPT codes:

95905 Motor and/or sensory nerve conduction, using preconfigured electrode array(s), amplitude and latency/velocity study, each limb, includes F-Wave study wen performed, with interpretation and report
95999 Unlisted neurological or neuromuscular diagnostic procedure

 

 

 

 

HCPCS Codes: G0255 Current perception threshold/sensory nerve conduction test (SNCT), per limb

CPT codes 95900, 95903, 95904 should not be used to bill for automated point-of-care- nerve conduction tests.

References:

  1. American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM). AANEM Proper Performance and Interpretation of Electrodiagnostic Studies. 2014 www.aanem.org/getmedia/bd1642ce-ec01-4271-8097-81e6e5752042/Position-Statement_Proper-Performance-of-EDX_-2014.pdf.aspx. Accessed May 18, 2018.

  2. American Academy of Orthopaedic Surgeons. Management of Carpal Tunnel Syndrome Evidence-Based Clinical Practice Guideline. 2016; https://www.aaos.org/uploadedFiles/PreProduction/Quality/Guidelines_and_Reviews/guidelines/CTS%20CPG_2.29.16.pdf. Accessed May 25, 2018

  3. American Association of Neuromuscular and Electrodiagnostic Medicine. Recommended Policy for Electrodiagnostic Medicine, www.aanem.org.

  4. American Association of Neuromuscular and Electrodiagnostic Medicine. AANEM position statement: Proper performance and interpretation of electrodiagnostic studies. Muscle and Nerve 2006; 33(3):436-439.

  5. American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM). Proper Performance and Interpretation of Electrodiagnostic Studies. 2014 https://www.aanem.org/getmedia/bd1642ce-ec01-4271-8097- 81e6e5752042/Position-Statement_Proper-Performance-of-EDX_-2014.pdf.aspx. Accessed May 18, 2018.

  6. American Academy of Neurology (AAN). Practice Guidelines: Endorsed or Affirmed Guidelines. n.d.; www.aan.com/Guidelines/Home/ByStatusOrType?status=affirmed. Accessed May 18, 2018.

  7. Armstrong TN, Dale AM, Al-Lozi MT et al. Median and ulnar nerve conduction studies at the wrist: criterion validity of the NC-stat automated device. J Occup Environ Med 2008:50(7):758-64.

  8. Boulton Andrew JM, Vinik Arthur I, et al. Diabetic neuropathies: A statement by the American Diabetes Association. Diabetes Care, April 2005, Vol. 28, No. 4.956-962.

  9. Bourke HE, Read J, Kampa R et al. Clinic-based nerve conduction studies reduce time to surgery and are cost effective: a comparison with formal electrophysiological testing. Ann R Coll Surg Engl 2011; 93(3):236-40.

  10. Chatzikosma G, Pafili K, Demetriou M, et al. Evaluation of sural nerve automated nerve conduction study in the diagnosis of peripheral neuropathy in patients with type 2 diabetes mellitus. Arch Med Sci. Apr 01 2016; 12(2):390-393.

  11. Chen S, Andary M, Buschbacher R, et al. Electrodiagnostic reference values for upper and lower limb nerve conduction studies in adult populations. Muscle Nerve. Sep 2016; 54(3):371-377.

  12. Dillingham T, Chen S, Andary M, et al. Establishing high-quality reference values for nerve conduction studies: A report from the normative data task force of the American Association of Neuromuscular & Electrodiagnostic Medicine. Muscle Nerve. Sep 2016; 54(3):366-370.

  13. Elkowitz SJ, Dubin NH, Richards BE, and Wilgis EF. Clinical utility of portable versus traditional electrodiagnostic testing for diagnosing, evaluating, and treating carpal tunnel syndrome. Am J Orthop, August 2005; 34(8): 362-364.

  14. England JD, Franklin GM. Automated hand-held nerve conduction devices: raw data, raw interpretations. Muscle Nerv 2011; 43(1):6-8.

  15. Fisher MA. Comparison of automated and manual F-wave latency measurements. Clinical Neurophysiology, February 2005; 116(2): 264-269.

  16. Fisher MA, Bajwa R, Somashekar KN. Routine electrodiagnosis and a multiparameter technique in lumbosacral radiculopathies. Acta Neurol Scand 2008; 118(2):99-105.

  17. Hardy T, Sachson R, Shen S, et al. Does treatment with duloxetine for neuropathic pain impact glycemic control? Diabetes Care, January 2007, Vol. 30, No. 1, pp. 21-26.

  18. Jablecki CK, Andary MT, Floeter MK et al. American Association of Electrodiagnostic Medicine; American Academy of Neurology; American Academy of Physical medicine and Rehabilitation. Practice parameter: Electrodiagnostic studies in carpal tunnel syndrome. Report of the American Association of Electrodiagnostic Medicine, American Academy of Neurology, and the American Academy of Physical Medicaine and Rehabilitation. Neurology 2002; 58(11):1589-92.

  19. Jabre Joe F, Salzsieder Byron T, and Gnemi Kenneth E. Criterion validity of the NC-stat automated nerve conduction measurement instrument. Physiol Meas, January 2007; 28: 95-104.

  20. Katz RT. NC-stat as a screening tool for carpal tunnel syndrome in industrial workers. J Occup Environ Med, April 2006; 48(4): 414-418.

  21. Kong X, Gozani SN, Hayes MT and Weinberg DH. NC-stat sensory nerve conduction studies in the median and ulnar nerves of symptomatic patients. Clin Neurophysiol, February 2006; 117(2): 405-413.

  22. Kong X, Lesser Eugene A, Megerian J Thomas and Gozani Shai N. Repeatability of nerve conduction measurements using automation. Journal of Clinical Monitoring and Computing 2006; 20: 405-410.

  23. Kong X, Lesser EA and Gozani SN. Repeatability of nerve conduction measurements derived entirely by computer methods. BioMedical Engineering Online 2009; 8:33.

  24. Kong X, Schoenfeld DA, Lesser EA and Gozani SN. Implementation and evaluation of a statistical framework for nerve conduction study reference range calculation. Comput Methods Programs Biomed, January 2010; 97(1): 1-10.

  25. Leffler CT, Gozani SN and Cros D. Median neuropathy at the wrist: Diagnostic utility of clinical findings and an automated electrodiagnostic device. Journal of Occupational and Environmental Medicine 2000; 42(4): 398-409.

  26. MacDermid JC and Doherty T. Clinical and electrodiagnostic testing of carpal tunnel syndrome: A narrative review. J Orthop Sports Phys Ther, October 2004; 34(10): 565-588.

  27. Megerian J Thomas, Kong Xuan, Lesser Eugene and Gozani Shai N. NC-stat as a screening tool for carpal tunnel syndrome. Journal of Occupational and Environmental Medicine, August 2006, Vol. 48, No. 8.

  28. Megerian J Thomas, Kong Xuan and Gozani Shai N. Utility of nerve conduction studies for carpal tunnel syndrome by family medicine, primary care and internal medicine physicians. J Am Board Fam Med 2007; 20(1):60-4.

  29. Perkins Bruce A, Grewal Jaspreet, et al. Validation of a novel point-of-care nerve conduction device for the detection of diabetic sensorimotor polyneuropathy. Diabetes Care 2006; 29: 2023-2027.

  30. Rotman MB, Enkvetchakul BV, et al. Time course and predictors of median nerve conduction after carpal tunnel release. J Hand Surg, May 2004; 29(3): 367-372.

  31. Schmidt K, Chinea NM, Sorenson EJ et al. Accuracy of diagnoses delivered by an automated hand-held nerve conduction device in comparison to standard electrophysiological testing in patients with unilateral leg symptoms. Muscle Nerve 2011; 43(1):9-13.

  32. Sharma S, Vas PR, Rayman G. Assessment of diabetic neuropathy using a point-of-care nerve conduction device shows significant associations with the LDIFLARE method and clinical neuropathy scoring. J Diabetes Sci Technol. Jan 2015; 9(1):123-131.

  33. U.S. Food and Drug Administration (FDA) 510(k) Summary Brevio. www.fda.gov/cdrh/pdf6/K061828.pdf.

  34. Vinik Aaron I, Emley Mark S, Megerian J Thomas and Gozani Shai N. Median and ulnar nerve conduction measurements in patients with symptoms of diabetic peripheral neuropathy using the NC-stat® system. Diabetes Technology and Therapeutics, December 2004, Vol. 6, No. 6, pp. 816-824.

  35. Vinik AI, et al. Diabetic nerve conduction abnormalities in the primary care setting. Diabetes Technology Therapeutics, December 2006; 8(6): 654-662.

  36. www.viasyshealthcare.com/prod_serv/downloads/202_TECA_Synergy_Brochure.pdf.

  37. Young MJ, Boulton AJ, MacLeod AF, et al. A multicentre study of the prevalence of diabetic peripheral neuropathy in the United Kingdom hospital clinic population. Diabetologia. Feb 1993; 36(2):150-154.

Policy History:

Medical Policy Group, February 2007 (1)

Medical Policy Administration Committee, March 2007

Available for comment April 6-May 21, 2007

Medical Policy Group, November 2007

Medical Policy Group, April 2008 (2)

Medical Policy Administration Committee, April 2008

Available for comment April 4-May 18, 2008

Medical Policy Group, April 2008 (2)

Medical Policy Administration Committee May 2008

Available for comment May 3-June 16, 2008

Medical Policy Group, June 2008 (2)

Medical Policy Administration Committee, July 2008

Available for comment June 17-July 31, 2008

Medical Policy Panel June, 2009

Medical Policy Group, June 2009 (2)

Medical Policy Administration Committee, July 2009

Medical Policy Group, June 2010 (1): Policy update, no changes in coverage statement

Medical Policy Group, March 2011 (3)

Medical Policy Panel, June 2012

Medical Policy Group, July 2012 (2): Updated Key Points, Key Words, Approved by Governing Bodies, and References. No change in coverage statement. Description updated to include the Axon-II™ (PainDx)

Medical Policy Panel, June 2013

  1. Policy Group, September 2013 (2): Policy Statement unchanged. New codes added. Policy Panel, June 2014

Medical Policy Group, June 2014 (5): Policy Statement unchanged.

Medical Policy Panel, June 2015

Medical Policy Group, June 2015 (6): Updates to Description, Key Points, Approved by Governing Bodies, Coding and References; no change to policy statement.

Medical Policy Panel, August 2017

Medical Policy Group, September 2017 (6): Updates to Description, Key Points, Governing Bodies, removed old deleted coding and References. No change to policy statement.

Medical Policy Panel, June 1018

Medical Policy Group, July 2018 (6): Updates to Description, Key Points, Governing Bodies and References.

Medical Policy Panel, June 2019

Medical Policy Group, June 2019 (3):2019 Updates to Key Points, References and Key Words: added: Cadwell Sierra® Summit, Cadwell Sierra® Ascent. No changes to policy statement or intent.

This medical policy is not an authorization, certification, explanation of benefits, or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All medical policies are based on (i) research of current medical literature and (ii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.

This policy is intended to be used for adjudication of claims (including pre-admission certification, pre-determinations, and pre-procedure review) in Blue Cross and Blue Shield’s administration of plan contracts.

The plan does not approve or deny procedures, services, testing, or equipment for our members. Our decisions concern coverage only. The decision of whether or not to have a certain test, treatment or procedure is one made between the physician and his/her patient. The plan administers benefits based on the member’s contract and corporate medical policies. Physicians should always exercise their best medical judgment in providing the care they feel is most appropriate for their patients. Needed care should not be delayed or refused because of a coverage determination.

As a general rule, benefits are payable under health plans only in cases of medical necessity and only if services or supplies are not investigational, provided the customer group contracts have such coverage.

The following Association Technology Evaluation Criteria must be met for a service/supply to be considered for coverage:

1. The technology must have final approval from the appropriate government regulatory bodies;

2. The scientific evidence must permit conclusions concerning the effect of the technology on health outcomes;

3. The technology must improve the net health outcome;

4. The technology must be as beneficial as any established alternatives;

5. The improvement must be attainable outside the investigational setting.

Medical Necessity means that health care services (e.g., procedures, treatments, supplies, devices, equipment, facilities or drugs) that a physician, exercising prudent clinical judgment, would provide to a patient for the purpose of preventing, evaluating, diagnosing or treating an illness, injury or disease or its symptoms, and that are:

1. In accordance with generally accepted standards of medical practice; and

2. Clinically appropriate in terms of type, frequency, extent, site and duration and considered effective for the patient’s illness, injury or disease; and

3. Not primarily for the convenience of the patient, physician or other health care provider; and

4. Not more costly than an alternative service or sequence of services at least as likely to produce equivalent therapeutic or diagnostic results as to the diagnosis or treatment of that patient’s illness, injury or disease.