Nerve Compound Muscle Action Potential Research Articles

Reference values for nerve conduction studies of the peroneal, tibial, and sural nerve derived from a large population-based cohort: Associations with demographic and anthropometric characteristics-The Maastricht study.

Nerve conduction studies (NCSs) are widely used to support the clinical diagnosis of neuromuscular disorders. The aims of this study were to obtain reference values for peroneal, tibial, and sural NCSs and to examine the associations with demographic and anthropometric factors. In 5099 participants (aged 40-79 years) without type 2 diabetes of The Maastricht Study, NCSs of peroneal, tibial, and sural nerves were performed. Values for compound muscle action potential (CMAP) and sensory nerve action potential amplitude, nerve conduction velocity (NCV), and distal latency were acquired. The association of age, sex, body mass index (BMI), and height with NCS values was determined using uni- and multivariate linear regression analyses. Detailed reference values are reported per decade for men and women. Significantly lower NCVs and longer distal latencies were observed in all nerves in older and taller individuals as well as in men. In these groups, amplitudes of the tibial and sural nerves were significantly lower, whereas a lower peroneal nerve CMAP was only significantly associated with age. BMI showed a multidirectional association. After correction for anthropometric factors in the multivariate analysis, the association between sex and NCS values was less straightforward. These values from a population-based dataset could be used as a reference for generating normative values. Our findings show the association of NCS values with anthropometric factors. In clinical practice, these factors can be considered when interpreting NCS values.

Relationship between Gravidity, Parity, and Neurophysiological Features in Carpal Tunnel Syndrome (CTS) Patients with a History of Pregnancy.

It is not yet clear if gravidity and parity have any relationships with the electrodiagnostic parameters of carpal tunnel syndrome (CTS). To determine whether there is a relationship between electrodiagnostic findings, gravidity, and parity number in CTS. Female patients over 18 years of age with CTS were included in this retrospective cohort study. The gravidity/parity number, median nerve compound muscle action potential (CMAP), and compound nerve action potential (CNAP) of the patients were analyzed. The two subgroups of the Boston carpal tunnel syndrome questionnaire (BCTSQ): The Symptom Severity Scale (SSS) and Functional Severity Scale (FSS) were applied to the patients. CTS patients were divided into two groups aged at first pregnancy ≤20 years and >20 years. One hundred and eight CTS extremities (seven right-sided CTS, three left-sided CTS, 49 bilateral CTS) of 59 patients were included. The median (interquartile range: 25%-75%) number of gravidity, parity, and abortion were 3 (2-5), 3 (2-4), and 0 (0-0), respectively. Right-sided CTS patients at the age of first pregnancy ≤20 years had higher BCTSQ-SSS/FSS scores and median nerve CMAP latency compared to patients at the age of first pregnancy >20 years (P = 0.029 for SSS; P = 0.042 for FSS; and P = 0.041 for CMAP latency). A negative correlation was found between the gravidity/parity numbers and median nerve CNAP/CMAP amplitudes (P = 0.028/0.031, r = -0.293/-0.289 for CNAP amplitude; and P = 0.006/0.035, r = -0.363/-0.283 for CMAP amplitude). Neurophysiological findings worsen as the number of gravidity and parity increase. Electrodiagnostic and clinical features of CTS may be worsening in females below 20 years at first pregnancy.

Pathologic classification of a late-onset peripheral neuropathy in a spontaneous Labrador retriever dog model.

Late-onset peripheral neuropathy (LPN) is a heritable canine neuropathy commonly found in Labrador retrievers and is characterized by laryngeal paralysis and pelvic limb paresis. Our objective was to establish canine LPN as a model for human hereditary peripheral neuropathy by classifying it as either an axonopathy or myelinopathy and evaluating length-dependent degeneration. We conducted a motor nerve conduction study of the sciatic and ulnar nerves, electromyography (EMG) of appendicular and epaxial musculature, and histologic analysis of sciatic and recurrent laryngeal nerves in LPN-affected and control dogs. LPN-affected dogs exhibited significant decreases in compound muscle action potential (CMAP) amplitude, CMAP area, and pelvic limb latencies. However, no differences were found in motor nerve conduction velocity, residual latencies, or CMAP duration. Distal limb musculature showed greater EMG changes in LPN-affected dogs. Histologically, LPN-affected dogs exhibited a reduction in the number of large-diameter axons, especially in distal nerve regions. In conclusion, LPN in Labrador retrievers is a common, spontaneous, length-dependent peripheral axonopathy that is a novel animal model of age-related peripheral neuropathy that could be used for fundamental research and clinical trials.

Decreased phrenic nerve compound muscle action potential, inspiratory muscle strength, and exercise capacity after COVID-19.

Respiratory muscle weakness with higher ventilatory demands were reported even in patients recovering from only mild COVID-19 symptoms. Aim of this study was to assess the function of phrenic nerve and inspiratory respiratory muscle as well as cardiopulmonary exercise capacity in patients with prolonged exertional dyspnea after COVID-19 infection. In this observational exploratory study, electrophysiological examination of the phrenic nerve, inspiratory muscle capacity as well as lung function test, 6-min walk distance (6MWD) and cardiopulmonary exercise test, have been performed in 22 patients post COVID-19 diagnosis (post-CoV). Exercise capacity (peak workload, Wpeak % predicted and peak oxygen uptake, VO2peak % predicted) were significantly affected in the post-CoV patients (61.8 ± 23.3 Wpeak % and 70.9 ± 22.3 VO2peak %). Maximum inspiratory pressure (MIP) was reduced (60.1 ± 25.5 mbar). In 6 of the 22 patients the electrophysiological response of the phrenic nerve was pathologically decreased (reduced compound muscle action potential, CMAP), while nerve conduction velocity (NCV) was normal, which corresponds to reduced muscle fiber contraction capacity. Positive relationships were demonstrated between 6MWD and MIP (rs = 0.88) as well as quality of life questionnaire (CRQ) and MIP (rs = 0.71) only in patients with reduced CMAP. Respiratory muscle weakness and exercise capacity is associated with reduced phrenic nerve CMAP without signs of neuropathy. This indicates that muscle fiber pathology of the diaphragm may be one pathophysiological factor for the prolonged respiratory symptoms after COVID-19 infections.

Nerve Transfer After Cervical Spinal Cord Injury: Who Has a “Time Sensitive” Injury Based on Electrodiagnostic Findings?

ObjectiveTo use the ulnar compound muscle action potential (CMAP) to abductor digiti minimi (ADM) to identify the proportion of individuals with cervical spinal cord injury (SCI) who have lower motor neuron (LMN) abnormalities involving the C8-T1 spinal nerve roots, within 3-6 months, and thus may influence the response to nerve transfer surgery. DesignRetrospective analysis of prospectively collected data. Data were analyzed from European Multicenter Study About SCI database. SettingMulti-center, academic hospitals. ParticipantsWe included 79 subjects (age=41.4±17.7, range:16-75; 59 men; N=79), who were classified as cervical level injuries 2 weeks after injury and who had manual muscle strength examinations that would warrant consideration for nerve transfer (C5≥4, C8<3). InterventionsNone. Main Outcome MeasuresThe ulnar nerve CMAP amplitude to ADM was used as a proxy measure for C8-T1 spinal segment health. CMAP amplitude was stratified into very abnormal (<1.0 mV), sub-normal (1.0-5.9 mV), and normal (>6.0 mV). Analysis took place at 3 (n=148 limbs) and 6 months (n=145 limbs). ResultsAt 3- and 6-month post-injury, 33.1% and 28.3% of limbs had very abnormal CMAP amplitudes, respectively, while in 54.1% and 51.7%, CMAPs were sub-normal. Median change in amplitude from 3 to 6 months was 0.0 mV for very abnormal and 1.0 mV for subnormal groups. A 3-month ulnar CMAP <1 mV had a positive predictive value of 0.73 (95% CI 0.69-0.76) and 0.78 (95% CI 0.75-0.80) for C8 and T1 muscle strength of 0 vs 1 or 2. ConclusionA high proportion of individuals have ulnar CMAPs below the lower limit of normal 3- and 6-month post cervical SCI and may also have intercurrent LMN injury. Failure to identify individuals with LMN denervation could result in a lost opportunity to improve hand function through timely nerve transfer surgeries.

Evaluation of risdiplam efficacy in 5q spinal muscular atrophy: A systematic comparison of electrophysiologic with clinical outcome measures.

To assess compound muscle action potential (CMAP) amplitudes as electrophysiologic markers in relation to clinical outcome in adult patients with 5q-linked spinal muscular atrophy (SMA) before and during treatment with risdiplam. In this monocentric longitudinal cohort study, CMAP of 18 adult patients with SMA type 2 or 3 were assessed at baseline (T0 ) and after 10 months (T10 ) of risdiplam treatment. CMAP amplitudes of the median, ulnar, peroneal, and tibial nerves were compared with established clinical outcome scores, and with the course of disease before start of treatment. During a pharmacotherapy-naive pre-treatment period of 328 ± 46 days, Revised Upper Limb Module (RULM) score and peroneal nerve CMAP amplitudes decreased, while CMAP of tibial and upper limb nerves remained unchanged. CMAP amplitudes positively correlated with clinical scores (Hammersmith Functional Motor Scale-Expanded [HFMSE], RULM) at T0 . During risdiplam treatment, HFMSE and Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) scores increased, paralleled by marked increase of CMAP amplitudes in both median nerves (T10 -T0 ; right: Δ = 1.4 ± 1.4 mV, p = 0.0003; left: Δ = 1.3 ± 1.4 mV, p = 0.0007), but not in ulnar, peroneal, or tibial nerves. A robust increase of median nerve CMAP amplitudes correlated well with an increase in the HFMSE score (T10 -T0 ). Median nerve CMAP amplitudes at T0 were associated with subsequent risdiplam-related improvement of HFMSE and CHOP INTEND scores at T10 . Median nerve CMAP amplitudes increase with risdiplam treatment in adult SMA patients, and should be further evaluated as potential easy-to-use electrophysiologic markers in assessing and monitoring clinical response to therapy.

Facial nerve neurographies in intensive care unit-acquired weakness

BackgroundPatients with an intensive care unit-acquired weakness (ICU-AW) often present clinically with severe paresis of the limb and trunk muscles while facial muscles appear less affected. To investigate whether the facial nerves are partially spared from this condition, we performed both peripheral and cranial nerve conduction studies in critically ill patients.MethodsIn patients requiring prolonged ICU therapy, the motor and sensory nerve conduction velocities of the peroneal, ulnar and facial nerves and the muscle action potentials of the associated muscles, as well as the orbicularis oculi reflexes were assessed shortly after admission, and on ICU days 7 and 14.ResultsEighteen patients were included in the final data analysis (average age 54.2 ± 16.8 years, 8 females). The amplitudes of the peroneal nerve compound muscle action potentials (CMAPs) were reduced in all patients at ICU days 7 and 14 (F(1.39; 23.63) = 13.85; p < 0.001). There was no similar decrease in the CMAP amplitudes of the ulnar or facial nerve. Other parameters of nerve function (latencies, sensory and motor nerve conduction velocities, sensory nerve action potentials) remained unchanged. The reproducibility of the orbicularis oculi reflex was reduced during the disease course, while its latencies did not change significantly during the disease course.ConclusionsThere is a relative preservation of CMAPs in facial and hand as opposed to foot muscles. This is compatible with the clinical observation that the facial muscles in patients with ICU-AW are less severely affected. This may be primarily a function of the nerve length, and consequently more robust trophic factors in shorter nerves.Trial registration This study was prospectively registered in the German Clinical Trial Register on April 20th 2020 (DRKS00021467).

Polydeoxyribonucleotide and Shock Wave Therapy Sequence Efficacy in Regenerating Immobilized Rabbit Calf Muscles.

This study primarily aimed to investigate the combined effects of polydeoxyribonucleotide (PDRN) and extracorporeal shock wave therapy (ESWT) sequences on the regenerative processes in atrophied animal muscles. Thirty male New Zealand rabbits, aged 12 weeks, were divided into five groups: normal saline (Group 1), PDRN (Group 2), ESWT (Group 3), PDRN injection before ESWT (Group 4), and PDRN injection after ESWT (Group 5). After 2 weeks of cast immobilization, the respective treatments were administered to the atrophied calf muscles. Radial ESWT was performed twice weekly. Calf circumference, tibial nerve compound muscle action potential (CMAP), and gastrocnemius (GCM) muscle thickness after 2 weeks of treatment were evaluated. Histological and immunohistochemical staining, as well as Western blot analysis, were conducted 2 weeks post-treatment. Staining intensity and extent were assessed using semi-quantitative scores. Groups 4 and 5 demonstrated significantly greater calf muscle circumference, GCM muscle thickness, tibial nerve CMAP, and GCM muscle fiber cross-sectional area (type I, type II, and total) than the remaining three groups (p < 0.05), while they did not differ significantly in these parameters. Groups 2 and 3 showed higher values for all the mentioned parameters than Group 1 (p < 0.05). Group 4 had the greatest ratio of vascular endothelial growth factor (VEGF) to platelet endothelial cell adhesion molecule-1 (PECAM-1) in the GCM muscle fibers compared to the other four groups (p < 0.05). Western blot analysis revealed significantly higher expression of angiogenesis cytokines in Groups 4 and 5 than in the other groups (p < 0.05). The combination of ESWT and PDRN injection demonstrated superior regenerative efficacy for atrophied calf muscle tissue in rabbit models compared to these techniques alone or saline. In particular, administering ESWT after PDRN injection yielded the most favorable outcomes in specific parameters.

New Neuromuscular Training for Peripheral Nerve Disorders Using an Ankle Joint Hybrid Assistive Limb: A Case Series.

Peripheral nerve disorder of the lower extremities causes drop foot and disturbs the daily living activities of patients. The ankle joint hybrid assistive limb (HAL) provides voluntary ankle joint training using surface bioelectrical signals from the muscles of the lower extremities. We investigated the neurological effects of ankle joint HAL training in three patients. Sensory nerve action potentials (SNAPs) and compound muscle action potentials (CMAPs) were analyzed for the peroneal and tibial nerves prior to the first ankle joint HAL training session. Integrated surface electromyography EMG signals were recorded before and after the HAL training sessions to evaluate the effects of training for neuromuscular disorders. The patients were hospitalized to receive rehabilitation with HAL training for 2 weeks. The HAL training was performed daily with two 60 min sessions. All cases demonstrated severe neuromuscular impairment according to the result of the CMAP. All integrated EMG measurements of antagonistic muscle activities decreased after the ankle joint HAL training. The manual muscle testing (MMT) scores of each muscle were slightly increased after the HAL intervention for Case 2(tibialis anterior, from 2 to 2+; gastrocnemius muscles, from 2- to 2; extensor digitorum longus, and extensor hallucis longus, from 1 to 3). The MMT scores were also slightly increased except for gastrocnemius muscle for Case 3 (tibialis anterior, extensor digitorum longus, and extensor hallucis longus, from 2- to 2). These two patients demonstrated voluntary muscle contractions and nerve signals in the CMAP before the HAL training. Even though the amplitude of CMAPs was low, the HAL training may provide voluntary ankle joint movements by reducing the antagonistic muscle contraction via computer processing. The HAL training may enhance muscle movement and coordination through motor learning feedback.

Diagnostic accuracy of nerve excitability and compound muscle action potential scan derived biomarkers in amyotrophic lateral sclerosis.

The lack of reliable early biomarkers still causes substantial diagnostic delays in amyotrophic lateral sclerosis (ALS). The aim was to assess the diagnostic accuracy of a novel electrophysiological protocol in patients with suspected motor neuron disease (MND). Consecutive patients with suspected MND were prospectively recruited at our tertiary referral centre for MND in Utrecht, The Netherlands. Procedures were performed in accordance with the Standards for Reporting of Diagnostic Accuracy. In addition to the standard diagnostic workup, an electrophysiological protocol of compound muscle action potential (CMAP) scans and nerve excitability tests was performed on patients' thenar muscles. The combined diagnostic yield of nerve excitability and CMAP scan based motor unit number estimation was compared to the Awaji and Gold Coast criteria and their added value was determined. In all, 153 ALS or progressive muscular atrophy patients, 63 disease controls and 43 healthy controls were included. Our electrophysiological protocol had high diagnostic accuracy (area under the curve [AUC] 0.85, 95% confidence interval [95% CI] 0.80-0.90), even in muscles with undetectable axon loss (AUC 0.78, 95% CI 0.70-0.85) and in bulbar-onset patients (AUC 0.85, 95% CI 0.73-0.95). Twenty-four of 33 (73%) ALS patients who could not be diagnosed during the same visit were correctly identified, as well as 8/13 (62%) ALS patients not meeting the Gold Coast criteria and 49/59 (83%) ALS patients not meeting the Awaji criteria during this first visit. Our practical and non-invasive electrophysiological protocol may improve early diagnosis in clinically challenging patients with suspected ALS. Routine incorporation may boost early diagnosis, enhance patient selection and generate baseline measures for clinical trials.

The relationship between neuron-specific enolase, high sensitivity C reactive protein, and diabetic peripheral neuropathy in Chinese patients with type 2 diabetes: A prospective nested case–control analysis

BackgroundDiabetic peripheral neuropathy (DPN) involves a very complex pathogenesis, and there is no neuro-specific marker for risk prediction. Neuron-specific enolase (NSE), a key enzyme in glycolysis, has a broad spectrum neurotrophic and neuroprotective effect on neurons, and also cause injury and inflammatory response of peripheral nerves. The relationship between neuron-specific enolase, highly sensitive c-reactive protein (hsCRP), and diabetic peripheral neuropathy remains unclear. We aimed to investigate whether elevated serum NSE and hsCRP levels increased the risk of DPN in patients with type 2 diabetes.Materials and methodsIn this prospective nested case–control study, a total of 1072 eligible subjects with type 2 diabetes constituted the follow-up cohort. Demographic data and parameters including serum NSE and hsCRP were collected at baseline. Two neuropathy screening scales (MNSI and MDNS) were used to assess DPN during follow-up period. Nerve conduction studies were performed at the end of follow-up. Conditional logistic regression was used to inspect the risk factors of the incidence of DPN.ResultsDuring an average follow-up period of 5.1 years, 176 subjects developed DPN. Serum NSE and hsCRP levels at baseline were significantly higher in DPN group than in matched non-DPN groups (p < 0.001). NSE was positively correlated with age and hsCRP (p < 0.001). The amplitude of sensory nerve action potential and compound muscle action potential of the lower extremity nerves were significantly decreased in the high tertile of NSE. After adjustment for matching and confusing factor, conditional logistic regression showed the risk of DPN in the high tertile of NSE level was still 3.176 times higher than that in the low tertile of NSE level (p < 0.001).ConclusionElevated serum NSE levels predicted the high incidence of DPN in Chinese patients with type 2 diabetes for an average of 5.1 years, which may be associated with increased neuroinflammatory response caused by high NSE levels, but further studies are needed.

Large-gap peripheral nerve repair using xenogeneic transplants in rhesus macaques.

Surgical intervention is required to successfully treat severe, large-gap (≥4cm) peripheral nerve injuries. However, all existing treatments have shortcomings and an alternative to the use of autologous nerves is needed. Human and porcine nerves are physiologically similar, with comparable dimensions and architecture, presence and distribution of Schwann cells, and conserved features of the extracellular matrix (ECM). We report the repair of fully transected radial nerves in 10 Rhesus Macaques using viable, whole sciatic nerve from genetically engineered (GalT-KO), designated pathogen free (DPF) porcine donors. This resulted in the regeneration of the transected nerve, and importantly, recovery of wrist extension function, distal muscle reinnervation, and recovery of nerve conduction velocities and compound muscle action potentials similar to autologous controls. We also demonstrate the absence of immune rejection, systemic porcine cell migration, and detectable residual porcine material. Our preliminary findings support the safety and efficacy of viable porcine nerve transplants, suggest the interchangeable therapeutic use of cross-species cells, and highlight the broader clinical potential of xenotransplantation.

Promising application of a new ulnar nerve compound muscle action potential measurement montage in amyotrophic lateral sclerosis: a prospective cross-sectional study.

Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional "belly-tendon" montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles. A new method of ulnar nerve compound muscle action potential measurement was developed in 2020, which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal wrist. This new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action potential. In this prospective cross-sectional study, we included 64 patients with amyotrophic lateral sclerosis and 64 age- and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third Hospital. The compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional montage. In the controls, no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage recordings. In amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy, the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2 (P < 0.01). Using the new method, damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method, in particular for patients in early stage amyotrophic lateral sclerosis. In addition, the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale scores. These findings suggest that the new ulnar nerve compound muscle action potential measurement montage reduces the effects of the reference electrode through altering the E2 electrode position, and that this method is more suitable for monitoring disease progression than the traditional montage. This method may be useful as a biomarker for longitudinal follow-up and clinical trials in amyotrophic lateral sclerosis.

The relationship between fatigue, neuropathic pain, and neurophysiological features in carpal tunnel syndrome

Introduction: Carpal tunnel syndrome (CTS) is the most common entrapment mononeuropathy and can affect patients' daily living activities. In this study, it was aimed to find out whether there is a relationship between fatigue, neuropathic pain and neurophysiological features in CTS.&#x0D; Material and Method: Patients with clinical features compatible with CTS were included in this retrospective study. Median nerve compound muscle action potential (CMAP) and compound nerve action potential (CNAP) of the patients were analyzed. The Turkish version of the Fatigue Severity Scale (FSS) was administered to all patients. Patients with a mean FSS score of ≥4 were considered to have fatigue. In addition, Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) was applied to some patients. If the LANSS score was 12 or higher, these patients were considered to have neuropathic pain.&#x0D; Results: Thirty-two female and eight male CTS patients were included in the study. Thirty-two patients had clinically bilateral CTS and eight patients had right-sided CTS. FSS and LANSS were administered to 40 and 18 patients, respectively. There were 29 CTS patients (72.5%) with an FSS score ≥ 4. CNAP/CMAP amplitudes and sensory/motor nerve conduction velocities of patients with fatigue were lower than those without fatigue (p

Combination Therapy of Polydeoxyribonucleotide and Microcurrent in Muscle Regeneration on Cast-Induced Muscle Atrophy in Rabbit.

The aim of this study was to evaluate how polydeoxyribonucleotide (PDRN) and microcurrent therapy (MT) functioned synergistically in a cast-immobilized rabbit model with an atrophied calf muscle. At the age of 12 weeks, 32 male New Zealand rabbits were enrolled in four groups. After 2 weeks of cast-immobilization, 4 procedures were performed on atrophied calf muscle [weekly two injections normal saline 0.2 ml injection group 1 (G1-NS), weekly two injections 0.2 ml PDRN injection group 2 (G2-PDRN), MT group 3 (G3-MT), and 0.2 ml PDRN injection with MT group 4 (G4-PDRN+MT)]. For 2 weeks, MT was used for 60 minutes each day. The calf circumference (CC), the thickness of gastrocnemius muscle (TGCM), and the tibial nerve compound muscle action potential (CMAP) were evaluated using ultrasound before and after 2 weeks of treatment. Proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor, and platelet endothelial cell adhesion molecule-1 (PECAM-1) of GCM fibers (type I, type II, and total) were measured. Statistical analyses were performed using ANOVA. The mean atrophic alterations of right CC, CMAP, and TGCM (medial/lateral) were substantially lower in G4-PDRN+MT than in the G1-NS, G2-PDRN, and G3-MT, respectively (p < 0.05). Furthermore, mean CSAs (type I, type II, and total) of medial and lateral GCM muscle fibers in G4-PDRN+MT were significantly higher when compared to other three groups (p < 0.05). In terms of the PCNA-, VEGF-, and PECAM-1-positive cell ratio of medial and lateral GCM muscle fibers, G4-PDRN+MT was considerably higher than G1-NS, G2-PDRN, and G3-MT (p < 0.05). On the atrophied calf muscle of the rabbit model, PDRN injection combined with MT was more effective than PDRN injection alone, MT alone, and normal saline injection separately.

Patterns of facial and blink reflex abnormalities in type 2 diabetes mellitus patients with short disease duration: a clue to subclinical cranial neuropathy

Abstract Background Cranial neuropathies occur in 3 to 14% of diabetic patients. Motor conduction study of the facial nerve and blink reflex study are electrophysiologic techniques used to assess the facio-trigeminal pathway in diabetic patients. The patterns of facial and blink reflex abnormalities are inconsistent among studies. This study aimed to assess the subclinical facial nerve and blink reflex abnormalities patterns in short-duration type 2 diabetes mellitus patients. This cross-sectional study included 30 type 2 diabetic patients with disease duration ≤ 5 years. We included only patients with the Toronto clinical neuropathy score ≤ 5. We enrolled 30 age- and sex-matched healthy subjects as a control group. We performed facial nerve motor conduction and blink reflex studies. Patients with prior history of cranial nerve lesions, stroke, or any other disease-causing polyneuropathy or drug-induced neuropathy were excluded from the study. Results Thirty diabetic patients were included, 20 females (66.7%) and ten males (33.3%). Their mean age was 52.63 ± 8.94 years. None of the patients had clinical evidence of neuropathy. There were significant differences between patients and controls in the distal latencies and amplitudes of facial nerve compound muscle action potentials and contralateral R2 late response latencies of the blink reflex. We detected subclinical cranial abnormalities in 6 diabetic patients (20%). One of them (3.3%) had facial nerve conduction abnormalities, four of them (13.4%) had blink reflex abnormalities, and one of them (3.3%) had both facial nerve and blink reflex abnormalities. Conclusion Subclinical cranial neuropathy can occur in short-duration type 2 diabetes mellitus patients. We detected different blink reflex patterns and facial conduction study abnormalities. We recommend blink reflex and facial nerve conduction studies as simple tests for the early evaluation of neurological subclinical affection in patients with short disease duration of T2DM as they may appear in the absence of peripheral neuropathy.

Prediction of lower extremity strength by nerve conduction study in cauda equina syndrome.

An electrodiagnostic test is more useful than the lower extremity isometric strength test for objectively determining the degree of nerve damage and prognosis in cauda equina syndromes (CES). This study evaluated the correlation between nerve conduction study (NCS) parameters and the lower extremity isometric strength and manual muscle test (MMT) grades.The isometric strengths of knee extension (KE), ankle dorsiflexion (ADF), and ankle plantarflexion (APF) were measured. NCS parameters, MMT, and isometric strength of femoral, peroneal, and tibial nerves were evaluated, including their correlations with each other. A regression equation between the isometric strength and compound muscle action potential (CMAP) amplitudes was derived and cutoff values were used to confirm boundary values of strength and amplitude between the MMT grades.KE isometric strength and femoral nerve CMAP amplitude were significantly correlated (r = 0.738, P < .001). ADF isometric strength and peroneal nerve CMAP amplitude were significantly correlated (tibialis anterior, r = 0.707, P < .001). KE (r = 0.713, P < .001), ADF (r = 0.744, P < .001), and APF (r = 0.698, P < .001) isometric strengths were correlated with the MMT grades. For the regression curve, the second-order curve was more reasonable than the first-order curve. Cutoff femoral nerve CMAP amplitude and isometric strength cutoff values were ≥2.05 mV and 17.3, respectively, for MMT grades 2 to 3 and 2.78 ± 1.08 and 20.8 ± 9.33, respectively, for grade 3.The isometric strengths of the KE, ADF, and APF and the CMAP amplitude of the electrophysiologic parameters were correlated in CES patients and a significant correlation with MMT grade was also identified. Accordingly, it is possible to identify the precise neurological condition, objectively evaluate the degree of paralysis and disability, and determine the quantitative muscle strength from MMT in order to establish an appropriate rehabilitation treatment plan.

The Armadillo as a Model for Leprosy Nerve Function Impairment: Preventative and Therapeutic Interventions.

Mycobacterium leprae infection of peripheral nerves and the subsequent nerve function impairment (NFI), especially in response to reactional episodes, are hallmarks of leprosy. Improved treatments for M. leprae-induced nerve injury are needed, as most if not all of the disability and stigma associated with leprosy arises from the direct or indirect effects of NFI. Nine-banded armadillos (Dasypus novemcinctus), like humans, exhibit the full clinical spectrum of leprosy and extensive involvement of the peripheral nerves. In this study, state-of-the-art technology was used to compare nerve function between uninfected and M. leprae-infected armadillos. Motor nerve conduction velocity (MNCV) and compound muscle action potential (cMAP), which measure changes in the rate of impulse conduction velocity and amplitude, revealed a progression of impairment that was directly correlated with the duration of M. leprae infection and enabled development of an objective nerve impairment scoring system. Ultrasonography accompanied by color Doppler imaging detected enlargement of the M. leprae-infected nerves and increased vascularity, possibly due to inflammation. Assessment of epidermal nerve fiber density (ENFD), which shows a length-dependent innervation in armadillos that is similar to humans, identified small fiber degeneration early after M. leprae infection. Staining for neuromuscular junction (NMJ) integrity, which is an indicator of signal transduction efficiency into skeletal muscle, discerned a markedly lower number and structural integrity of NMJ in M. leprae-infected armadillo footpads. These tools for assessing nerve injury were used to monitor the effects of intervention therapy. Two potential neuro-protective drugs, ethoxyquin (EQ) and 4-aminopyridine (4-AP), were tested for their ability to ameliorate peripheral nerve injury in M. leprae-infected armadillos. 4-AP treatment improved MNCV, cMAP, and EFND compared to untreated animals, while EQ had less effect. These results support the armadillo as a model for M. leprae-induced peripheral nerve injury that can provide insights toward the understanding of NFI progression and contribute to the preclinical investigation of the safety and efficacy of neuro-preventive and neuro-therapeutic interventions for leprosy.

Long-Term Outcome of Electrodiagnostic Values and Symptom Improvement After Carpal Tunnel Release: A Retrospective Cohort Study

The aim of this study was to evaluate electrodiagnostic studies and clinical outcomes after carpal tunnel release surgery in moderate and severe cases of carpal tunnel syndrome (CTS). Seventy-two patients with moderate or severe CTS who underwent carpal tunnel release surgery (46 unilateral; 26 bilateral; total, 98 surgeries) between 2009 and 2014 were included in the study. The cases were divided into 2 groups according to electrodiagnostic results: those with moderate CTS and those with severe CTS. Michigan Hand Outcomes Questionnaire scores and electrodiagnostic data (sensory nerve action potentials and compound muscle action potentials) were recorded before surgery and in postoperative follow-up studies obtained at 3 months, 1 year, and 5 years. There were 56 surgeries in the moderate CTS group and 42 surgeries in the severe CTS group. Sensory nerve action potentials and compound muscle action potentials were significantly lower in the severe CTS group when compared to the moderate CTS group at all follow-up times. There was a significant difference in Michigan Hand Outcomes Questionnaire scores between the groups before surgery, but no significant differences at the final follow-up. It was found that the values of all parameters (sensory nerve action potentials, compound muscle action potentials, and Michigan Hand Outcomes Questionnaire score) demonstrated significant improvements with time in both the severe and the moderate CTS groups. Carpal tunnel release surgery improves symptoms, regardless of the preoperative severity. Postoperative electrodiagnostic study results of patients with moderate CTS improve to a greater degree than those of patients with severe CTS, but all remain abnormal. Prognosis IIb.

Changes in phrenic nerve compound muscle action potential in streptozotocin-induced diabetic rats

PurposeTo evaluate the phrenic nerve compound muscle action potential (CMAP) in rats after diabetes mellitus (DM) induction. MethodsTwenty DM animals (intravenous streptozotocin, 45 mg.kg−1) and 25 controls underwent CMAP analysis before and 30, 60 and 90 days after DM induction. ResultsAmplitude (mV) progressively declined in DM group after 30 (Mean difference (MD): –0.915, 95 % Confidence interval (CI) –1.580 to –0.250, p < 0.01), 60 (MD: –1.122, 95 % CI –1.664 to –0.581, p < 0.001) and 90 days (MD: –2.226, 95 % CI –3.059 to –1.393, p < 0.001); as well as the area (mV.ms) after 30 (MD: –3.19, 95 % CI –5.94 to –0.44, p < 0.05), 60 (MD: –3.94, 95 % CI –6.24 to –1.64, p < 0.001) and 90 days (MD: –8.64, 95 % CI –12.08 to –5.21, p < 0.001). Transient differences were observed in latency and duration at 60 days. ConclusionsThe progressive changes in phrenic nerve CMAP observed during DM suggest a decrement in axonal function rather than substantial demyelination.