Electrodiagnostic evaluation in diabetes mellitus: A study based on case series in 72 diabetic patients.

Diabetic peripheral neuropathy (DPN) is one of the most common complications of diabetes; so, a nerve conduction study (NCS) is conducted to detect the type of neuropathy that is present. To discuss the NCS findings in diabetic patients. An observational study was conducted in the Physiology Department of AIIMS, Bhopal, in collaboration with the Medicine Department of the Institute. Seventy-two diagnosed type 2 diabetes mellitus (T2DM) patients were examined using NCS (Nihon Kohden Neuropack XI Machine). Microsoft Excel was utilized for data compilation and result analysis. Based on NCS, 94% of patients were abnormal, and 6% were normal. Of abnormal patients, 89% had asymmetrical involvement, and 5% had symmetrical involvement. About 74% had mixed neuropathy, 11% had motor neuropathy, and 10% had sensory neuropathy. Mixed involvement was seen in 60% of patients and axonal involvement in 35% of patients, and 5% were normal. Lower limb involvement was seen predominately. The most common bilaterally involved motor nerve was the peroneal nerve, seen in 49% of cases, whereas the most common bilaterally involved sensory nerve was the sural nerve involved in 59% of cases. The left tibial nerve was the most common unilaterally involved motor nerve seen in 32% of cases, and the left sural nerve was the most common sensory nerve involved in 54% of cases. Asymmetric sensorimotor involvement with mixed involvement (axonal + demyelinating) was seen in diabetic patients. Peroneal and sural nerves were the most common bilaterally involved motor and sensory nerves, respectively. Similarly, the left tibial and left sural nerves were the most common unilaterally affected motor and sensory nerves, respectively.

Cochlear Implant Insertion Routes and Intra-operative Electrophysiological Measurements: A Retrospective Analysis at a Tertiary Care Centre.

BACKGROUND: Cochlear implant surgeries are performed by different surgical routes, Round window (RW), Extended round window (Ext RW) and Cochleostomy (C). Optimum intracochlear electrode placement is important to achieve a successful outcome. Intra-operative electrophysiological testing (Impedance and ECAP) is crucial to assess the device function and appropriate electrode placement. The variability of portal of electrode insertion might affect the neural response and its characteristics. OBJECTIVE: To compare the intraoperative electrophysiological measurements (Impedance and ECAP) for possible differences on auditory nerve stimulation across the three electrode insertion routes. MATERIALS AND METHODS: This is a retrospective data analysis of 47 cochlear implant recipients at a tertiary care centre in Central India over a period of 4 years. They were broadly divided into two groups depending on the electrode design as full banded and half banded. Intraoperative impedances were recorded for different modes of stimulation and ECAP measured at E5, E10, E15, E20 electrodes in both the groups across the three insertion routes. RESULTS: In the half-banded group, the impedance values in different modes CG, MP1, MP2, MP1 + 2 did not differ significantly among the surgical routes at all four electrodes. While in the full banded group, for CG mode impedance values at E5 differ significantly. Rest for other modes in full banded group, there was no statistically significant difference across the three routes. CONCLUSION: The present study supports that there is no statistically significant difference in the intraoperative impedance and ECAP measurements in both, the full-banded and half- banded electrodes across the three surgical routes implying that, all the three surgical approaches provide equal stimulation of the auditory nerve. The CI surgeon can select the electrode insertion portal based on the surgical anatomy, the implant type and individual preferences.

Value of Periprocedural Electrophysiology Testing During Transcatheter Aortic Valve Replacement for Risk Stratification of Patients With New-Onset Left Bundle-Branch Block.

Background Despite being the most frequent complication following transcatheter aortic valve replacement (TAVR), optimal management of left bundle-branch block (LBBB) remains unknown. Electrophysiology study has been proposed for risk stratification. However, the optimal timing of electrophysiology study remains unknown. We aimed to investigate the temporal dynamics of atrioventricular conduction in patients with new-onset LBBB after TAVR by performing serial electrophysiology study and to deduce a treatment strategy. Methods and Results We assessed consecutive patients undergoing TAVR via His-ventricular interval measurement prevalve and postvalve deployment and the day after TAVR. Infranodal conduction delay was defined as a His-ventricular interval >55 milliseconds. Among 107 patients undergoing TAVR, 53 patients (50%) experienced new-onset LBBB postvalve deployment and infranodal conduction delay was noted in 24 of 53 patients intraprocedurally (45%). LBBB resolved the day after TAVR in 35 patients (66%). In patients with new-onset LBBB postvalve deployment and no infrahisian conduction delay intraprocedurally, the His-ventricular interval did not prolong in any patient to >55 milliseconds the following day. Overall, 4 patients (7.5%) with new-onset LBBB after TAVR were found to have persistent infrahisian conduction delay 24 hours after TAVR. During 30-day follow-up, 1 patient (1.1%) with new LBBB and a normal His-ventricular interval after TAVR developed new high-grade atrioventricular block. Conclusions Among patients with new-onset LBBB postvalve deployment, infrahisian conduction delay can safely be excluded intraprocedurally, suggesting that early intracardiac intraprocedural conduction studies may be of value in these patients.

Electrophysiological Screening for Children With Suspected Auditory Processing Disorder: A Systematic Review.

Objective: This research aimed to provide evidence for the early identification and intervention of children at risk for auditory processing disorder (APD). Electrophysiological studies on children with suspected APDs were systematically reviewed to understand the different electrophysiological characteristics of children with suspected APDs. Methods: Computerized databases such as PubMed, Cochrane, MEDLINE, Web of Science, and EMBASE were searched for retrieval of articles since the establishment of the database through May 18, 2020. Cohort, case-control, and cross-sectional studies that evaluated the literature for the electrophysiological assessment of children with suspected APD were independently reviewed by two researchers for literature screening, literature quality assessment, and data extraction. The Newcastle-Ottawa Scale and 11 entries recommended by the Agency for Healthcare Research and Quality were used to evaluate the quality of the literature. Results: In accordance with the inclusion criteria, 14 articles were included. These articles involved 7 electrophysiological testing techniques: click-evoked auditory brainstem responses, frequency-following responses, the binaural interaction component of the auditory brainstem responses, the middle-latency response, cortical auditory evoked potential, mismatch negativity, and P300. The literature quality was considered moderate. Conclusions: Auditory electrophysiological testing can be used for the characteristic identification of children with suspected APD; however, the value of various electrophysiological testing methods for screening children with suspected APD requires further study.

Identification of a Novel de Novo Variant in the SYT2 Gene Causing a Rare Type of Distal Hereditary Motor Neuropathy.

OBJECTIVE: To report the first de novo missense mutation in the SYT2 gene causing distal hereditary motor neuropathy. METHODS: Genetic testing was carried out, including clinical exome sequencing for the proband and Sanger sequencing for the proband and his parents. We described the clinical and electrophysiological features found in the patient. RESULTS: We reported a proband with a new de novo missense mutation, c.917C>T (p.Ser306Leu), in the C2B domain of SYT2. The clinical presentation was similar to that of phenotypes described in previous studies. A notable feature in our study was normal electrophysiological testing results of the patient. CONCLUSIONS: In this study we reinforced the association between SYT2 mutations and distal hereditary motor neuropathy. We also described the clinical presentation of the patient carrying this pathogenic variant and provided unusual results of electrophysiological testing. The results showed that a diagnosis of SYT2-associated neuropathy should be based on the similarity of clinical manifestations, rather than the results of electrophysiological testing.

Vibration-induced depression in spinal loop excitability revisited.

KEY POINTS: While it has been well described that prolonged vibration locally applied to a muscle or its tendon (up to 1 h) decreases spinal loop excitability between homonymous Ia afferents and motoneurons, the involved mechanisms are not fully understood. By combining electrophysiological methods, this study aimed to provide new insights into the mechanisms involved in soleus decreased spinal excitability after prolonged local vibration. We report that prolonged vibration induces a decrease in motoneuron excitability rather than an increase in presynaptic mechanisms (as commonly hypothesized in the current literature). The present results may help to design appropriate clinical intervention and could reinforce the interest in vibration as a treatment for spastic patients who are characterized by spinal hyper-excitability responsible for spasms and long-lasting reflexes. ABSTRACT: The mechanisms that can explain the decreased spinal loop excitability in response to prolonged local vibration (LV), as assessed by the H-reflex, remain to be precisely determined. This study provides new insights into how prolonged Achilles' tendon LV (30 min, 100 Hz) acutely interacts with the spinal circuitry. The roles of presynaptic inhibition exerted on Ia afferents (Experiment A, n = 15), neurotransmitter release at the synapse level (Experiment B, n = 11) and motoneuron excitability (Experiment C, n = 11) were investigated in soleus. Modulation of presynaptic inhibition was assessed by conditioning the soleus H-reflex (tibial nerve electrical stimulation) with fibular nerve (D1 inhibition) and femoral nerve (heteronymous facilitation, HF) electrical stimulations. Potential vibration-induced changes in neurotransmitter depletion at the Ia afferent terminals was assessed through paired stimulations applied over the tibial nerve (HD). Intrinsic motoneuron excitability was assessed with thoracic motor evoked potentials (TMEPs) in response to electrical stimulation over the thoracic spine. Non-conditioned H-reflex was depressed by ∼60% after LV (P < 0.001), while D1 and HF H-reflexes increased by ∼75% after LV (P = 0.03 and 0.06, respectively). In Experiment B, HD remained unchanged after LV (P = 0.80). In Experiment C, TMEPs were reduced by ∼13% after LV (P = 0.01). Overall, presynaptic mechanisms do not seem to be involved in the depression of spinal excitability after LV. It rather seems to rely, at least in part, on a decrease in intrinsic motoneuron excitability. These results may have implications in reducing spinal hyper-excitability in spastic patients.

The Role of Electrophysiological Severity Scales for Decision-making with Regard to Surgery in Idiopathic Carpal Tunnel Syndrome.

The distribution of electrophysiological severity of carpal tunnel syndrome (CTS) in an outpatient setting and whether electrophysiological severity could be an objective tool for decision-making regarding choice of surgery were investigated. During conservative treatment, 1079 outpatients with idiopathic CTS were classified according to the electrophysiological severity scale (Stage 1-5). The results were provided to the patients and explained, but they were not indicated a treatment protocol intentionally. We recommended surgery to those outpatients who presented with difficulty in pinching due to severe thenar atrophy and/ or showing poor response to conservative treatment. However, the decision-making of surgical or nonsurgical treatment remained with patients. In the distribution of severity stages, Stage 4 was the most common (34%). Two hands were not classifiable. Surgery was chosen in 443 of 1077 hands (41.1%): The operation selection rate increased with severity of the stage and the patients with Stage 5 showed the greatest preference among Stage 1-5 (p<0.0001). This was shown in both female and male groups in gender analysis, and in both ≤ 69 y.o. and ≥70 y.o. groups in the age analysis. There was no significant difference between female and male hands, and ≤ 69 y.o. and ≥70 y.o. hands. Among varied reasons for the decision-making process for surgical treatment in CTS, electrophysiological severity scale plays an important role as an objective tool without being influenced by subjective elements; gender and age.

Turning Electromyography Reports Upside Down: A Pilot Study Surveying Referring Providers.

Providers are expressing a desire for more efficient ways to retrieve relevant clinical data from the Electronic Health Record. In an effort to improve our Electromyography and Nerve Conduction Study reports, we surveyed referring providers on the effects of having the IMPRESSION at the start of the report. Our survey respondents felt that using this format for an Electromyography and Nerve Conduction Study report significantly improved the quality of the report while saving them time and/or mouse clicks when interpreting the report. Electro diagnosticians might consider using this format for their Electromyography and Nerve Conduction Study reports to improve referring provider satisfaction.

Clinical, electrophysiological, and biochemical markers of peripheral and central nervous system disease in canine globoid cell leukodystrophy (Krabbe's disease).

Globoid cell leukodystrophy (GLD), or Krabbe's disease, is a debilitating and always fatal pediatric neurodegenerative disease caused by a mutation in the gene encoding the hydrolytic enzyme galactosylceramidase (GALC). In the absence of GALC, progressive loss of myelin and accumulation of a neurotoxic substrate lead to incapacitating loss of motor and cognitive function and death, typically by 2 years of age. Currently, there is no cure. Recent convincing evidence of the therapeutic potential of combining gene and cell therapies in the murine model of GLD has accelerated the requirement for validated markers of disease to evaluate therapeutic efficacy. Here we demonstrate clinically relevant and quantifiable measures of central (CNS) and peripheral (PNS) nervous system disease progression in the naturally occurring canine model of GLD. As measured by brainstem auditory-evoked response testing, GLD dogs demonstrated a significant increase in I-V interpeak latency and hearing threshold at all time points. Motor nerve conduction velocities (NCVs) in GLD dogs were significantly lower than normal by 12-16 weeks of age, and sensory NCV was significantly lower than normal by 8-12 weeks of age, serving as a sensitive indicator of peripheral nerve dysfunction. Post-mortem histological evaluations confirmed neuroimaging and electrodiagnostic assessments and detailed loss of myelin and accumulation of storage product in the CNS and the PNS. Additionally, cerebrospinal fluid psychosine concentrations were significantly elevated in GLD dogs, demonstrating potential as a biochemical marker of disease. These data demonstrate that CNS and PNS disease progression can be quantified over time in the canine model of GLD with tools identical to those used to assess human patients. © 2016 Wiley Periodicals, Inc.

Carpal tunnel syndrome in breast cancer survivors with upper extremity lymphedema.

INTRODUCTION: Lymphedema has long been considered a risk factor for median nerve compression at the wrist and carpal tunnel syndrome (CTS). This association is based on limited and poor quality data. We analyzed the association between lymphedema and CTS. METHODS: Breast cancer survivors with upper extremity lymphedema and electrophysiologically confirmed CTS were assessed retrospectively. The severity of lymphedema was graded using the National Institutes of Health Common Terminology Criteria for Adverse Events (CTCAE) v4.03. The severity of CTS was graded in accordance with accepted criteria. RESULTS: Nineteen patients (38 sides) met the criteria for analysis. There was no association between presence of lymphedema and CTS (P = 0.66) or between lymphedema severity and CTS severity (P = 0.79). There were no cases of infection or worsening lymphedema as a result of needle EMG. CONCLUSIONS: These findings do not support lymphedema as an etiologic factor in the pathogenesis of CTS.

Peri-articular suprascapular neuropathy.

Suprascapular nerve entrapment was first described in 1959 by Kopell and Thompson. Although rare, this condition is among the causes of poorly explained shoulder pain in patients with manifestations suggesting a rotator-cuff tear but normal tendons by imaging studies. Suprascapular nerve entrapment may cause 2% of all cases of chronic shoulder pain. Among the many reported causes of suprascapular nerve entrapment, the most common are para-labral cysts, usually in the spinoglenoid notch, and microtrauma in elite athletes. The potential relevance of concomitant rotator-cuff tears remains debated. Less common causes include tumours, scapular fractures, and direct trauma involving traction. Early diagnosis and treatment are crucial to avoid the development of irreversible muscle wasting. Endoscopic surgery to treat the various causes of suprascapular nerve compression has superseded open nerve release.

Median and ulnar neuropathies in US Army dental personnel at Fort Sam Houston, Texas.

BACKGROUND: Dental personnel have an increased prevalence of upper-extremity (UE) musculoskeletal (MSK) disorders, including carpal tunnel syndrome (CTS). Military dental personnel report more UE MSK complaints than their civilian counterparts. Literature using nerve conduction studies (NCS) to diagnose UE neuropathy in dental personnel is lacking. PURPOSE: The purpose of this descriptive study was to determine the presence of electrodiagnostic abnormalities of the median and ulnar nerves in active duty military dental personnel assigned to Fort Sam Houston, TX. SUBJECTS: Twenty (14 male, 6 female) active duty, US Army dentists (n=9), preventive dental specialists (n=4), dental assistants (n=3), dental lab technicians (n=3), and dental logistics technician (n=1) assigned to the Dental Command at Fort Sam Houston, TX, volunteered to participate in the study. The mean age of the dental personnel was 38±9.8 years (range: 26 to 56 years). The mean time in dental practice was 13.3±7.96 years (range: 2 to 29 years). The mean length of time in the US Army dental services was 11.8±7.7 years (range: one to 26 years). METHODS AND MATERIALS: Subjects completed a history form, were interviewed, and underwent a physical examination of the cervical spine and bilateral upper extremities. Nerve conduction studies of the bilateral median and ulnar nerves were performed. Electrophysiological variables served as the reference standard for median and ulnar neuropathy and included distal sensory latencies, distal motor latencies, amplitudes, conduction velocities, and comparison study latencies. Descriptive statistics for subject demographics and nerve conduction study variables were also calculated. RESULTS: Seven of the 20 subjects (35%) presented with abnormal electrophysiologic values suggestive of an upper extremity mononeuropathy. Five of the subjects had abnormal electrophysiologic values of the median nerve at or distal to the wrist (3 bilateral, 2 unilateral). Two subjects had abnormal ulnar nerve findings at or distal to the wrist (1 bilateral, 1 unilateral). Three of the 7 subjects with electrodiagnostic evidence of median and ulnar neuropathies had positive findings on physical examination. However, there was no significant correlation between the NCS and history/physical examination findings. CONCLUSIONS AND CLINICAL SIGNIFICANCE: The prevalence of mononeuropathies in this sample of US Army dental personnel is similar to previous research involving dental assistants and preventive dental specialists and far exceeds that reported in the general population. This is the first dental study to report electrodiagnostic findings of ulnar mononeuropathy at or distal to the wrist. The NCS findings did not correlate with subjective or physical exam findings. Prospective research investigating screening, examination items, and injury prevention measures in dental personnel appears to be warranted.