EDX Findings Research Articles

F31. Longitudinal neurophysiological study of dominant intermediate Charcot-Marie-Tooth type C neuropathy

Dominant intermediate Charcot-Marie-Tooth neuropathy subtype C (DI-CMTC) is associated with mutations in the YARS gene, encoding tyrosyl-tRNA synthetase (TyrRS). In a prospectively designed study we were the first to report the phenotype and genotype of DI-CMTC from a U.S. and a Bulgarian family using electrodiagnostic (EDX) and morphological studies. Here we present longitudinal data for the U.S. family 16 years after the initial evaluation. After re-consenting, 13 of 21 original DI-CMTC participants underwent EDX and physical examinations. Data of 2000 and 2016 were compared for specific nerves using paired t-tests. General linear model univariate analysis was used to relate findings to patient age. Data are presented as mean ± SD. Four women and 9 men were examined at ages 8–77 years in 2000 and 24–93 years in 2016. During this time median nerve compound muscle action potential (CMAP) amplitudes decreased from 9.3 ± 2.9 mV to 6.0 ± 2.9 mV (p = 0.002), while distal motor latencies (DML) increased from 4.2 ± 0.6 ms to 4.5 ± 0.6 ms (p = 0.04); mean motor nerve conduction velocity (MNCV) remained largely unchanged at 37 m/s. Over the same period ulnar nerve CMAP amplitudes decreased from 9.2 ± 2.1 mV to 6.1 ± 1.8 mV (p = 0.004); mean MNCV remained the same at 39 m/s. In 2000 and 2016 all adult participants had absent peroneal motor responses, as well as absent tibial responses (except for 2 patients with CMAP amplitudes <1 mV and MNCV 32–35 m/s in 2000 and 28–32 m/s in 2016). In the interval sural sensory nerve action potential (SNAP) amplitudes changed from 2.0 ± 2.5 mV to 1.0 ± 2.4 mV (p = 0.10), and sensory nerve conduction velocities (SNCV) from 39.3 ± 1.0 to 35.5 ± 2.1 m/s (p = 0.13); this did not reach statistical significance. Median nerve sensory peak latencies increased from 3.4 ± 0.4 to 3.9 ± 0.4 ms (p = 0.01), SNAP amplitudes changed from 7.2 ± 5.3 to 6.5 ± 5.1 mV (p = 0.055), and SNCV from 46 ± 1.7 to 41.3 ± 7.6 m/s (p = 0.328). There was an age-dependent decrease of CMAP amplitudes of median (p = 0.044), peroneal and tibial (p < 0.001), and SNAP amplitudes of median(p = 0.008), radial (p = 0.013) and sural (p = 0.028). EMG revealed distal dominant acute and chronic denervation and reinnervation in lower limb muscles and some hand muscles. In this study MNCV remained stable over 16 years, but motor and sensory amplitudes decreased. DI-CMT C appears to produce a progressive age- and nerve length-dependent axonal degenerative process. Longitudinal EDX findings are consistent with our previous cross-sectional morphological study of sural nerves, which also revealed an age-dependent loss of large and small myelinated axons.

Femoral nerve and lumbar plexus injury after minimally invasive lateral retroperitoneal transpsoas approach: electrodiagnostic prognostic indicators and a roadmap to recovery.

Injury to the lumbosacral (LS) plexus is a well-described complication after lateral retroperitoneal transpsoas approaches to the spine. The prognosis for functional recovery after lumbosacral plexopathy or femoral/obturator neuropathy is unclear. We designed a retrospective case-control study with patients undergoing one-level lateral retroperitoneal transpsoas lumbar interbody fusion (LLIF) between January 2011 and June 2016 to correlate electrodiagnostic assessments (EDX) to physiologic concepts of nerve injury and reinnervation, and attempt to build a timeline for patient evaluation and recovery. Cases with post-operative obturator or femoral neuropathy were identified. Post-operative MRI, nerve conduction studies (NCS), electromyography (EMG), and physical examinations were performed at intervals to assess clinical and electrophysiologic recovery of function. Two hundred thirty patients underwent LLIF. Six patients (2.6%) suffered severe femoral or femoral/obturator neuropathy. Five patients (2.2%) had immediate post-operative weakness. One of the six patients developed delayed weakness due to a retroperitoneal hematoma. Five out of six patients (83%) demonstrated EDX findings at 6weeks consistent with axonotmesis. All patients improved to at least MRC 4/5 within 12months of injury. In conclusion, neurapraxia is the most common LS plexus injury, and complete recovery is expected after 3months. Most severe nerve injuries are a combination of neurapraxia and variable degrees of axonotmesis. EDX performed at 6weeks and 3, 6, and 9months provides prognostic information for recovery. In severe injuries of proximal femoral and obturator nerves, observation of proximal to distal progression of small-amplitude, short-duration (SASD) motor unit potentials may be the most significant prognostic indicator.

Do Electrodiagnostic Variables Correlate with Functional Outcomes in Carpal Tunnel Syndrome?

Background: The most common entrapment neuropathy seen in electrodiagnostic (EDX) laboratories is carpal tunnel syndrome (CTS). The diagnostic value of EDX with regard to CTS is well-established, but EDX’s predictive value is unclear. To date, only one study has attempted to establish a relationship between EDX findings and a patient’s clinical status pre- and post-treatment, and there was no significant relationship found. Objective: To establish a relationship between EDX variables and clinical severity assessment with Disabilities of the Arm, Shoulder, and Hand (DASH) scores at a single point in time and over a period of time. Methods: The study was a prospective single group cohort. 41 patients referred to an EDX clinic with suspected diagnoses of CTS were enrolled. Patients underwent EDX studies and completed DASH questionnaires at initial and follow-up visits at 8-month to 12-month intervals. Data collected included median sensory, mixed, and motor latencies, amplitudes, conduction velocities, and needle electromyography (EMG). Correlation coefficients were determined between EDX data variables and severity assessment (independent variables) and patients’ DASH questionnaire measures (dependent variables) at initial and follow-up assessments. Results: Change in DASH score over time positively correlated with left distal median motor latency (DMML) decrement and right transcarpal median sensory conduction block and negatively correlated with left median sensory nerve action potential (SNAP) amplitude decrement percentage, right needle EMG motor unit morphology abnormality, and right median forearm motor conduction velocity increment. The correlations observed are of unclear significance since the DASH scores themselves did not change significantly over time. Conclusions: Objective EDX data coupled with patient-reported outcome (PRO) measures such as the DASH score may be more meaningful in directing clinical care than either of them alone.

G.P.33 - Clinical and pathological features in SMA patients, confirmed by genetic analysis

Spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by degeneration of the anterior horn cells of the spinal cord, resulting in symmetrical limb muscle atrophy and weakness. It is difficult to diagnose SMA patients in some cases, because of its clinical presentations mimicking muscular dystrophies. We aimed to describe clinical and pathologic characteristics of SMA patients, confirmed by genetic test. We reviewed clinical and pathological features of 14 patients, who were completely done with electrodiagnostic study (EDX) and muscle biopsy, and diagnosed as SMA with genetic study from November 1, 2005 to December 31, 2013. Among 14 patients, 8 patients (57.1%) were male. The mean age of symptom onset was 35 months old. Mean age at final genetic diagnosis was 21.1 years old and mean duration between clinical and genetic diagnosis was 7.3 years. All patients showed proximal dominant weakness and their most common first symptoms were both leg weakness. With clinical, EDX and muscle biopsy findings, 10 patients (71.4%) were diagnosed as SMA, but other 4 patients (28.6%) were diagnosed as myopathy. Those 4 patients showed proximal dominant weakness and their first symptoms were both leg weakness, meaning their CK levels were 395 U/L, higher than clinical and pathologically SMA group (45 U/L). Among them (9 patients), EDX showed chronic neurogenic process of 3 patients and myopathic change in 1 patient. Muscle biopsy presented myopathic change with 3 patients, no pathologic diagnosis with 1 patient and neurogenic change in 1 patient. Even though the results of muscle biopsy and electrodiagnostic study show ‘myopathic change’, genetic study of SMN1 gene may show ‘exon 7, 8 deletions’. It is helpful to consider the genetic test for SMN1 gene when we diagnose patients with unspecified neuromuscular disease.

Ultrasound combined with electrodiagnosis improves lesion localization and outcome in posterior interosseous neuropathy.

Posterior interosseous nerve (PIN) syndrome is a rare compression neuropathy. Electrodiagnostic studies (EDx) combined with neuromuscular ultrasound (US) enable precise lesion localization and may improve patient outcome. In 4 patients with finger extension weakness, US was used to accurately localize concentric electromyographic (EMG) needle placement in PIN muscles and to visualize the lesion site. EMG with US guidance showed decreased recruitment with abnormal configuration in PIN muscles. Active denervation was not always observed. US scanning demonstrated larger PIN diameter in the affected arm. All patients had surgical intervention to confirm EDx and US findings and had improved outcome on follow-up. These cases demonstrate the benefits of augmenting EDx with US by guiding accurate electrode localization and providing diagnostic information about lesion location.

Synthesis, characterization, and photocatalytic activity of sol–gel prepared Mg/ZnO nanoparticles

In this study, ZnO nanoparticles with different Mg contents and calcination temperatures were synthesized by the sol–gel method. The photocatalytic activity of the synthesized nanoparticles was investigated in the photocatalytic degradation of Rhodamine B. The products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX)-mapping, scanning electron microscopy (SEM), transmission electron microscopy (TEM), diffuse reflectance spectroscopy (DRS), and Brunauer–Emmett–Teller (BET) techniques. The XRD results showed that the doped nanoparticles had the same crystal structure as the pure ZnO. The EDX and mapping findings indicated the existence of Mg in the doped sample. SEM and TEM analysis showed the spherical shape and uniform-size distribution of the nanoparticles. Based on DRS spectra, the band gap energy value of 2.0 wt% Mg doped ZnO was 3.26 eV, which was larger than the ZnO nanoparticles’ band gap energy. Using BET analysis, the surface areas of ZnO and 2.0 wt% Mg/ZnO were calculated to be 14.9 and 22.5 m2 g−1, respectively. The results of the photocatalytic activity indicated that Mg/ZnO was more active than pure ZnO photocatalyst due to its higher surface area and larger band gap energy. Maximum photocatalytic activity was achieved for Mg/ZnO nanoparticles with 2.0 wt% Mg and at the calcination temperature of 400°C.

A comparison of magnetic resonance imaging with electrodiagnostic findings in the evaluation of clinical radiculopathy: a cross-sectional study

The aim of this study was to evaluate the agreement of magnetic resonance imaging and electrodiagnostic studies by comparing their findings in patients with clinically suspected radiculopathy. The agreements between these two procedures and clinical findings were also examined. In a 2-year cross-sectional study, a total of 114 patients with clinically suspected cervical or lumbosacral radiculopathy were included. The total agreements between clinical with MRI and EDX findings were 72 and 52%, respectively while their agreements were similar in group definite (89 vs. 82%). The agreement between EDX and MRI was 59.6 in total and 49% with respect to clinical findings. This study further supports that these two methods are complementary in general. It is reasonable to add EDX when there is discrepancy between MRI and clinical findings or when MRI neurologic findings are not visible.

Correlation between Ultrasonography Findings and Electrodiagnostic Severity in Carpal Tunnel Syndrome: 3D Ultrasonography.

Background and PurposeTo determine the correlation between the cross-sectional area (CSA) of the median nerve measured at the wrist using three-dimensional (3D) ultrasonography (US) and the electrophysiological severity of carpal tunnel syndrome (CTS).MethodsWe prospectively examined 102 wrists of 51 patients with clinical CTS, which were classified into 3 groups according to the electrodiagnostic (EDX) findings. Median nerve CSAs were measured using 3D US at the carpal tunnel inlet and at the level of maximal swelling.ResultsTen wrists were negative for CTS. Of the 92 CTS-positive wrists, 23, 30, and 39 were classified as having mild, moderate, and severe CTS, respectively. The median nerve CSA differed significantly between the severe- and moderate-CTS groups (p=0.0007 at the carpal tunnel inlet and p<0.0001 at the maximal swelling site). There was a correlation between median nerve CSA and EDX parameters among those wrists with severe and mild CTS (p<0.0001 at both sites).ConclusionsThe median nerve CSA as measured by 3D US could provide additional information about the severity of CTS, as indicated by the strong correlation with standard EDX findings.

Hereditary Motor and Sensory Neuropathy With Proximal Predominance (HMSN-P)

Hereditary motor and sensory neuropathy with proximal predominance (HMSN-P) is a rare disorder inherited in an autosomal dominant fashion. Patients present with slowly progressive proximal-predominant weakness, painful muscle cramps, fasciculations, large-fiber sensory loss, and areflexia. Electrodiagnostic (EDX) studies typically reveal abnormalities consistent with a sensorimotor neuronopathy. A patient with HMSN-P underwent EDX studies, revealing ongoing and chronic neurogenic denervation, motor unit instability, and neuromyotonic discharges, further defining the spectrum of EDX findings in HMSN-P. The clinical, pathological, and genetic features are also reviewed. The appearance of HMSN-P in the United States and elsewhere calls for clinicians in nonendemic regions to be familiar with this rare disorder, which has typically been geographically confined.

Nerve ultrasound in diabetic polyneuropathy: Correlation with clinical characteristics and electrodiagnostic testing

Diabetic polyneuropathy (DPN) is increasingly prevalent in the USA, but nerve ultrasound (US) findings have not been assessed systematically. Our aim was to establish the sonographic characteristics of lower extremity nerves in DPN and correlate them with electrodiagnostic (EDx) findings. Consecutive patients (n = 25) with evidence of DPN and 25 patient controls without DPN underwent blinded US imaging of the fibular and sural nerves. Nerve cross-sectional area (CSA), diameter and echogenicity were recorded. There were no differences in fibular or sural nerve CSA, diameter, or echogenicity between the 2 groups. No correlations between nerve CSA and EDx studies were found. In DPN, there were moderate inverse correlations with age (r = -0.44 sural ankle, r = -0.39 sural leg, r = -0.45 fibular ankle). US measurements of lower extremity nerves in DPN do not differ from controls or correlate with EDx findings. Novel US techniques and/or pedal nerve US may be necessary to detect differences.

Electrodiagnostic Studies, "Role in The Diagnosis And Follow-Up in Children With Pompe Disease"

Pompe disease is a neuromuscular disorder that was progressive and fatal prior to enzyme replacement therapy (ERT). The advent of treatment has made early recognition imperative. Electrodiagnostic (EDx) studies represent a valuable diagnostic tool in Pompe disease, but there has been little contemporary data. The clinical characteristics in children and adults are very similar. Needle electromyography demonstrated spontaneous activity (SA) in 80% of children and 83% of adults. Myotonic discharges were found in 53% of children and 72% of adults, often isolated to the paraspinal muscles in adults. There could be some improvements in EDX findings after enzyme replacement therapy. EDx studies remain a helpful tool in diagnosing Pompe disease, but do not appear to be sensitive for monitoring response to ERT. Paraspinal examination is necessary in adults with symptoms suggestive of Pompe disease, as abnormalities may be isolated to this region. Standard EDx studies are not sufficient to monitor early response to ERT and further research on potential biomarkers is needed. • Electrodiagnostic abnormalities are present in most patients with Pompe disease. • Myotonic discharges and other abnormalities may be seen in this type of

Chronic bilateral T1 denervation in women with macromastia

The objective of this study was to identify the pattern of neurological deficits and document electrophysiological changes in women with macromastia. Patients with macromastia and neurological complaints underwent clinical evaluation and electrodiagnostic (EDx) studies of the upper limbs. Findings include low-amplitude medial antebrachial cutaneous (MACN) sensory nerve action potentials (SNAPs) and median compound muscle action potentials (CMAPs) and chronic denervation changes in the bilateral abductor pollicis brevis (APB) muscles on needle electrode examination (NEE), indicating axonal loss in the bilateral T1 distribution. The EDx data are in keeping with lesions involving bilateral T1 anterior primary rami (APR). Potential sites of compromise of the T1 APR are discussed. Further study of the effect of treatment for macromastia on the clinical and EDx findings is proposed.

Individual Finger Sensibility in Carpal Tunnel Syndrome

Sensibility testing plays a role in the diagnosis of carpal tunnel syndrome (CTS). No single physical examination test has proven to be of critical value in the diagnosis, especially when compared with electrodiagnostic testing (EDX). The purpose of this study was to define which digits are most affected by CTS, both subjectively and with objective sensibility testing. A prospective series of 35 patients (40 hands) with EDX-positive, isolated CTS were evaluated preoperatively using 2 objective sensibility tests: static 2-point discrimination (2PD) and abbreviated Semmes-Weinstein monofilament (SWMF) testing. Detailed surveys of subjective symptoms were also collected. Patients identified the middle finger as the most symptomatic over all others (51%). Objective 2PD results of each digit mirrored the subjective data, with higher values for the middle finger (mean 6.07 mm, (p < .0001). Values for the index finger failed to show a significant difference from the ulnar-innervated small finger. The most symptomatic finger matched 2PD results in over two thirds of patients. The SWMF testing showed similar, statistically significant results (middle > thumb > index > small). Correlations failed between EDX, symptoms, and SWMF results or 2PD in the index finger. Positive but weak correlation (p = .002, r = .42) was found between EDX and 2PD only in the middle fingers. The middle finger is the most likely to show changes in 2PD in patients with positive EDX findings for CTS. Middle finger 2PD is best able to correlate with EDX when compared with 2PD of other digits. The SWMF testing also shows the middle digit testing as more sensitive, but this finding may be difficult to use clinically. Diagnostic I.

A biomimetic strategy to form calcium phosphate crystals on type I collagen substrate

Objective The aim of this study is to induce mineralization of collagen by introducing phosphate groups onto type I collagen from eggshell membrane (ESM) by treating with sodium trimetaphosphate (STMP). This strategy is based on the hypothesis that phosphate groups introduced on collagen can mimic the nucleating role of phosphorylated non-collagenous proteins bound to collagen for inducing mineralization in natural hard tissue. Method The collagen membrane was phosphorylated by treating it with a solution of STMP and saturated calcium hydroxide. The phosphorylated collagen was subsequently exposed to a mineralization solution and the pattern of mineralization on the surface of phosphorylated collagen substrate was analyzed. Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), field emission electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and microhardness test were used to characterize the collagen substrate and the pattern of minerals formed on the collagen surface. Results The FTIR and EDX results indicated that the phosphate groups were incorporated onto the collagen surface by treatment with STMP. During the mineralization process, the plate-like mineral, octacalcium phosphate (OCP), which was initially formed on the surface of ESM, was later transformed into needle-like hydroxyapatite (HAP) as indicated by the SEM, FESEM, EDX and XRD findings. The microhardness test displayed significant increase in the Knoop hardness number of the mineralized collagen. Conclusions Phosphate groups can be introduced onto type I collagen surface by treating it with STMP and such phosphorylated collagen can induce the mineralization of type I collagen.

Single-step synthesis of a highly active photocatalyst for oxidation of trichloroethylene

We have developed a single-step synthesis approach to fabricate ZnO/TiO2–SiO2 monoliths as active photocatalysts. The photocatalysts were thoroughly characterized by XRD, FTIR, SEM, TEM, EDX and XPS. The synthetic manipulation shows evidence of the feasibility to load high amounts of the ZnO into the support matrixes (i.e. up to 25%). The developed ZnO/TiO2–SiO2 materials were used as effective photocatalysts to oxidize trichloroethylene (TCE) to HCl and CO2 in the presence of UV light at λ=365nm. The TEM profiles and EDX findings indicated that ZnO particles were homogeneously dispersed into TiO2–SiO2 matrixes. On such heterogeneous photocatalytic systems, the oxidation affinity of TCE was substantially affected by the loading amount of ZnO particles onto the TiO2–SiO2 matrixes, indicating the exclusive effect of the ZnO nanoparticles on TCE photocatalytic oxidation. Our results showed that the photoactivity of ZnO/TiO2–SiO2 monoliths was decreased from 96% to 80% after 5 reuse cycles. The formation of ZnO inside TiO2–SiO2 led to strengthen the frameworks of TiO2–SiO2 matrixes. The ZnO/TiO2–SiO2 monoliths thus achieve high performance and are therefore highly applicable to environmental cleanup of toxic compounds.

A subset of fibromyalgia patients have findings suggestive of chronic inflammatory demyelinating polyneuropathy and appear to respond to IVIg

The aetiopathogenesis of the fibromyalgia syndrome (FMS) remains unknown. Recent reports, however, suggest that a subgroup of FMS subjects has an immune-mediated disease. Therefore, our primary objective was to study FMS subjects for evidence of an immune-mediated demyelinating polyneuropathy. Our secondary objective was to determine the effects of treating these FMS subjects with the immune modulator, intravenous immunoglobulin (IVIg). Fifty-eight FMS subjects, 26 rheumatic non-FMS subjects and 52 non-rheumatic non-FMS subjects were studied. Subjective measures of paraesthesias, weakness, stocking hypaesthesia, pain, fatigue and stiffness were made. Objective measures of tenderness, proximal muscle strength and electrodiagnostic (EDX) evidence of polyneuropathy and demyelination were also made. Eleven other FMS subjects underwent sural nerve biopsy. Paraesthesias, subjective weakness and stocking hypaesthesia were more common in FMS than in rheumatic non-FMS (P < or = 0.0001). Proximal muscle strength was less in FMS than in rheumatic non-FMS (P < or = 0.0001). EDX demonstrated a distal demyelinating polyneuropathy, suggestive of chronic inflammatory demyelinating polyneuropathy (CIDP), in 33% of FMS subjects. No rheumatic non-FMS subject had polyneuropathy (P = 0.005), or demyelination (P = 0.05). Fifteen FMS/CIDP subjects were subsequently treated with IVIg (400 mg/kg each day for 5 days). Pain (P = 0.01), tenderness (P = 0.001) and strength (P = 0.04) improved significantly. Fatigue and stiffness trended towards improvement. A significant subset of FMS subjects have clinical and EDX findings suggestive of CIDP. IVIg treatment shows promise in treating this subset. These observations have implications for better understanding and treating some FMS patients.

Electrodiagnostic studies of the facial nerve in peripheral facial palsy and hemifacial spasm

Electrodiagnostic (EDX) assessment is one of the most important aspects in the evaluation of the two most common disorders of the facial nerve: facial palsy and hemifacial spasm. Facial palsy is usually an acute disorder that resolves in a few weeks but, in a number of cases, leads to a postparalytic facial syndrome featuring muscle synkinesis, myokymia, and involuntary mass contractions of muscles on the affected side. Hemifacial spasm is usually a chronic disorder characterized by paroxysms of involuntary, clonic, and synchronous twitching of all facial muscles on the affected side. EDX studies provide information on lesion location and severity, pathophysiology underlying the two disorders, and differential diagnosis between syndromes presenting with abnormal facial muscle activity. This monograph is intended to describe the most relevant EDX findings in the two disorders and the most appropriate timing for the examinations in order to provide useful information for prognosis and therapeutic decision-making.

Pitfalls in the electrodiagnostic studies of sacral plexopathies

This retrospective review characterizes the electrodiagnostic (EDX) features and etiologies of sacral plexopathies (SPs) and discusses difficulties in their identification. The EDX findings of 171 clinically suspected SPs were reviewed using the following criteria: reduced/absent sensory nerve action potentials (SNAPs) of the sural or superficial peroneal nerve, denervation of plexus-innervated muscles, and the absence of paraspinal denervation. Sixty cases localized unequivocally to the sacral plexus. The majority were cancer-related, followed by traumatic, idiopathic, and iatrogenic causes. Final diagnoses in the remaining 111 cases were indeterminate. Lesions localized to either the plexus or L4-5, S1 roots in 52 cases, the plexus or sciatic nerve in 32 cases, and were equally compatible with an SP, sciatic neuropathy, or radiculopathy in 27 cases. Findings in the EDX evaluation of SPs are often complex and difficult to localize to a specific site due to multiple complicating factors. Frequently, SPs cannot be diagnosed definitively by EDX assessment alone.

Comparison of clinical and electrodiagnostic features in B12 deficiency neurological syndromes with and without antiparietal cell antibodies

Background and aims: This study was undertaken to compare the clinical and electrodiagnostic (Edx) features in autoimmune and nutritional vitamin B12 deficiency neurological syndromes. Methods: Consecutive patients with vitamin B12...

The Sensitivity and Specificity of Electrodiagnostic Testing for the Clinical Syndrome of Lumbar Spinal Stenosis

Prospective, masked, double controlled diagnostic trial. To determine the sensitivity and specificity of electrodiagnostic consultation (EDX) for the clinical syndrome of lumbar spinal stenosis. EDX has been used for more than 50 years to diagnose spinal disorders but has not met the new standards of evidence-based medicine. A total of 150 subjects (asymptomatic volunteers and patients with MRIs suggesting back pain or spinal stenosis; 55-80 years of age) underwent physiatrist history and physical examination, MRI, and review of this data by a neurosurgeon, with each clinician masked to any outside information, leading to a unanimous consensus on diagnosis in 55. After masked EDX testing, 7 subjects with undiagnosed neuromuscular disease were discovered. EDX findings were related to "clinical gold standard" diagnoses in 48 persons. Paraspinal mapping EMG score of >4 had 100% specificity and 30% sensitivity for stenosis compared with either the back pain or asymptomatic groups (each, P < 0.04). A composite limb and paraspinal fibrillation score had a sensitivity of 47.8% and specificity of 87.5% (P = 0.008), and H-wave sensitivity was 36.4, specificity 91.3 (P = 0.026) for stenosis versus all controls. This first masked study in the 60-year history of needle electromyography also introduces anatomically validated needle placement, quantified and reproducible examination of the paraspinal muscles, and dual control populations to EDX research in spinal disorders. EDX has statistically significant, clinically meaningful specificity for spinal stenosis and detects neuromuscular diseases that may masquerade as stenosis.