Compound Muscle Action Potential Latency Research Articles

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.

Transcranial Magnetic Stimulation in the Diagnosis of Compressive Myelopathy at the Thoracolumbar Junction.

The disc level in the thoracolumbar junction at which measurement of the central motor conduction time in the lower limbs (CMCT-LL) is useful for a diagnosis remains unclear. Therefore, this study investigated the spinal vertebral level at which compressive myelopathy due to ossification of the ligamentum flavum in the thoracolumbar junction is detectable using CMCT-LL. We preoperatively measured CMCT-LL in 57 patients (42 men, 15 women; aged 35-85 years) with a single ossification of the ligamentum flavum from the T10-11 to T12-L1 disc levels and in 53 healthy controls. Motor evoked potentials after transcranial magnetic stimulation, compound muscle action potentials, and F waves were recorded from the abductor hallucis. Central motor conduction time in the lower limbs was calculated as follows: Motor evoked potential latency - (compound muscle action potential latency + F latency - 1)/2 (ms). Central motor conduction time in the lower limbs was compared between patients and controls. Compressive lesions were located at the T10 to 11 level in 27 patients, the T11 to 12 level in 28, and the T12-L1 level in 2. Central motor conduction time values in the lower limbs at the T10 to 11 level (19.9 ± 4.7 ms) and T11 to 12 level (18.1 ± 3.4 ms) were significantly longer than control values (11.8 ± 1.1 ms; P < 0.01). Central motor conduction time in the lower limbs was not calculated at the T12-L1 level because motor evoked potentials were not recorded in any patient. We confirmed that CMCT-LL was significantly longer in patients with ossification of the ligamentum flavum at the T10 to 11 and T11 to 12 levels because the S2 segment of the spinal cord is caudal at the T12 vertebral body level. Therefore, CMCT-LL is useful for diagnosing thoracolumbar junction disorders proximal to the T12 vertebral body level.

Electrophysiologic pattern of carpal tunnel syndrome among patients with and without diabetes mellitus

Background: Carpal tunnel syndrome (CTS) is the most common compression neuropathy in the upper limb in general population. Female gender, obesity, increase of age, diabetes mellitus (DM), hypothyroidism, pregnancy, rheumatoid arthritis, osteoarthritis and occupational factors like repetitive work are the main risk factors for CTS. The objective of this study was to determine whether the nerve conduction study measurement of the median nerve (MN) at the wrist differ between diabetic and non-diabetic CTS patients. Methods: This cross-sectional study was conducted at Electrodiagnostic Lab of BIRDEM General Hospital and Popular Medical College Hospital, Dhaka during the period of October 2017 to August 2019. Five hundred and seventeen hands from 377 patients were sampled according to inclusion criteria. Participants were assigned to two groups: Group 1 (CTS with DM) and Group 2 (CTS without DM). NCS study were performed using Nihon Kohden electrodiagnostic machine. Measurements at the MN was taken under consideration for study. Severity of CTS was graded according to Canterbury electrophysiologic grading scale and parameters were compared among diabetic and non-diabetic participants. Data were analyzed using Statistical Package for the Social Sciences SPSS version 23 (SPSS Inc., Chicago, IL, USA). Results: The 377 participants comprised 144 and 233 in Group 1 and Group 2, respectively. Out of 377 patients, 334 (88.59%) were females and there was no statistically significant difference between two groups. The average age was 50.66±10.2 years in diabetic participants and 43.34±10.7 years in non- diabetic participants. In the study population moderate CTS (Grade 3) was the most frequent (46.4%) followed by very severe (Grade 5) CTS. There was no statistically significant difference in incidence between diabetic and non-diabetic patients. Analysis of electrophysologic parameters of MN showed statistically significant difference in mean MN sensory nerve action potential (SNAP) amplitude (P 0.003), compound muscle action potential (CMAP) amplitude (p 0.05, right) and CMAP latency (p 0.02, right and 0.05, left) between diabetic and non –diabetic patients. Inter-group comparison revealed that impaired glycaemic status and duration of diabetes in diabetic population had a minimal influence in the electrophysiological severity of CTS in either hands. Conclusion: Some nerve conduction study parameters of the MN differ significantly between diabetic and non-diabetic patients with CTS and may provide both diagnostic and predictive results across the entire spectrum of CTS. BIRDEM Med J 2023; 13(3): 136-142

Recurrent laryngeal motor nerve conduction studies in a rat model: Establishing an objective measure for investigating laryngeal innervation.

Disease or injury can cause neuromuscular changes to the larynx that can affect voice, breathing, and swallowing. Motor nerve conduction studies have had limited use in the study of laryngeal neurophysiology, despite their importance in other anatomic sites. The aim of this study was to explore the feasibility of performing recurrent laryngeal motor nerve conduction studies (rlMNCS) in a rat model. rlMNCS were performed in 15 rats under anesthesia. A bipolar stimulating electrode was placed on the recurrent laryngeal nerve (RLN) 5 mm below the cricoid cartilage. Via direct laryngoscopy, a recording electrode was placed transorally into the thyroarytenoid muscle. The RLN was maximally stimulated to determine the compound muscle action potential (CMAP). Three consecutive trials were averaged. The mean stimulating threshold to the RLN to achieve a CMAP from the thyroarytenoid was 1.7 ± 0.6 mA. RLN stimulation caused a visible adductor twitch of the vocal fold in all animals. The mean negative amplitude was 2.0 ± 0.8 mV, and the total area was 1.0 ± 0.4 mV ms. The CMAP latency and negative duration were 1.0 ± 0.1 ms and 0.9 ± 0.2 ms, respectively. rlMNCS are feasible and may be useful in understanding laryngeal neurophysiology with disease or injury. This work could provide a tractable animal model for studying and monitoring treatment of neuromuscular conditions affecting voice, breathing, and swallowing.

Sensitivity and specificity of phrenic nerve electrophysiology to predict mechanical ventilation in the Guillain-Barré syndrome.

In Guillain-Barré syndrome (GBS), the sensitivity and specificity of phrenic compound muscle action potential (CMAP) measurements to predict endotracheal mechanical ventilation are unknown. Hence, we sought to estimate sensitivity and specificity. We performed a 10-year retrospective analysis of adult GBS patients from our single-center laboratory database (2009 to 2019). The phrenic nerve amplitudes and latencies before ventilation were recorded along with other clinical and demographic features. Receiver operating curve (ROC) analysis with area under the curve (AUC) was used to determine the sensitivity and specificity with 95% confidence interval (CI) for phrenic amplitudes and latencies in predicting the need for mechanical ventilation. Two hundred five phrenic nerves were analyzed in 105 patients. The mean age was 46.1 ± 16.2 years, with 60% of them being male. Fourteen patients (13.3%) required mechanical ventilation. The average phrenic amplitudes were lower in the ventilated group (P = .003), but average latencies did not differ (P = .133). ROC analysis confirmed that phrenic amplitudes could predict respiratory failure (AUC = 0.76; 95% CI, 0.61 to 0.91; P < .002), but phrenic latencies could not (AUC = 0.60; 95% CI, 0.46 to 0.73; P = .256). The best threshold for amplitude was ≥0.6 mV, with sensitivity, specificity, and positive and negative predictive values of 85.7%, 58.2%, 24.0%, and 96.4%, respectively. Our study suggests that phrenic CMAP amplitudes can predict the need for mechanical ventilation in GBS. In contrast, phrenic CMAP latencies are not reliable. The high negative predictive value of phrenic CMAP amplitudes ≥0.6 mV can preclude mechanical ventilation, making these a useful adjunct to clinical decision-making.

Correlation between Elbow Flexor Muscle Strength and Needle Electromyography Parameters after Musculocutaneous Nerve Injury.

To explore the changes of elbow flexor muscle strength after musculocutaneous nerve injury and its correlation with needle electromyography (nEMG) parameters. Thirty cases of elbow flexor weakness caused by unilateral brachial plexus injury (involving musculocutaneous nerve) were collected. The elbow flexor muscle strength was evaluated by manual muscle test (MMT) based on Lovett Scale. All subjects were divided into Group A (grade 1 and grade 2, 16 cases) and Group B (grade 3 and grade 4, 14 cases) according to their elbow flexor muscle strength of injured side. The biceps brachii of the injured side and the healthy side were examined by nEMG. The latency and amplitude of the compound muscle action potential (CMAP) were recorded. The type of recruitment response, the mean number of turns and the mean amplitude of recruitment potential were recorded when the subjects performed maximal voluntary contraction. The quantitative elbow flexor muscle strength was measured by portable microFET 2 Manual Muscle Tester. The percentage of residual elbow flexor muscle strength (the ratio of quantitative muscle strength of the injured side to the healthy side) was calculated. The differences of nEMG parameters, quantitative muscle strength and residual elbow flexor muscle strength between the two groups and between the injured side and the healthy side were compared. The correlation between elbow flexor manual muscle strength classification, quantitative muscle strength and nEMG parameters was analyzed. After musculocutaneous nerve injury, the percentage of residual elbow flexor muscle strength in Group B was 23.43% and that in Group A was 4.13%. Elbow flexor manual muscle strength classification was significantly correlated with the type of recruitment response, and the correlation coefficient was 0.886 (P<0.05). The quantitative elbow flexor muscle strength was correlated with the latency and amplitude of CMAP, the mean number of turns and the mean amplitude of recruitment potential, and the correlation coefficients were -0.528, 0.588, 0.465 and 0.426 (P<0.05), respectively. The percentage of residual elbow flexor muscle strength can be used as the basis of muscle strength classification, and the comprehensive application of nEMG parameters can be used to infer quantitative elbow flexor muscle strength.

VEGFA-modified DPSCs combined with LC-YE-PLGA NGCs promote facial nerve injury repair in rats

ObjectiveThe aim of this research was to investigate the effect of vascular endothelial growth factor A (VEGFA)-overexpressing rat dental pulp stem cells (rDPSCs) combined with laminin-coated and yarn-encapsulated poly(l-lactide-co-glycolide) (PLGA) nerve guidance conduit (LC-YE-PLGA NGC) in repairing 10 mm facial nerve injury in rats. Study DesignrDPSCs isolated from rat mandibular central incisor were cultured and identified in vitro and further transfected with the lentiviral vectors (Lv-VEGFA). To investigate the role and mechanisms of VEGFA in neurogenic differentiation in vitro, semaxanib (SU5416), Cell Counting Kit-8 (CCK-8), real-time quantitative polymerase chain reaction (qPCR) and Western blotting were performed. Ten-millimeter facial nerve defect models in rats were established and bridged by LC-YE-PLGA NGCs. The repair effects were detected by transmission electron microscopy (TEM), compound muscle action potential (CMAP), immunohistochemistry and immunofluorescence. ResultsExtracted cells exhibited spindle-shaped morphology, presented typical markers (CD44+CD90+CD34−CD45−), and presented multidirectional differentiation potential. The DPSCs with VEGFA overexpression were constructed successfully. VEGFA enhanced the proliferation and neural differentiation ability of rDPSCs, and the expression of neuron-specific enolase (NSE) and βIII-tubulin was increased. However, these trends were reversed with the addition of SU5416. This suggests that VEGFA mediates the above effects mainly through vascular endothelial growth factor receptor 2 (VEGFR2) binding. The LC-YE-NGC basically meet the requirements of facial nerve repair. For the in vivo experiment, the CMAP latency period was shorter in DPSCS-VEGFA-NGC group in comparison with other experimental groups, while the amplitude was increased. Such functional recovery correlated well with an increase in histological improvement. Further study suggested that VEGFA-modified DPSCs could increase the myelin number, thickness and axon diameter of facial nerve. NSE, βIII-tubulin and S100 fluorescence intensity and immunohistochemical staining intensity were significantly enhanced. ConclusionVEGFA-modified rDPSCs combined with LC-YE-PLGA NGCs have certain advantages in the growth and functional recovery of facial nerves in rats.

Effects of Ketamine/Xylazine and Urethane Anesthesia on Compound Muscle Action Potential Latency of Gastrocnemius Muscle in Rats

ABSTRACT Objective: Anesthetic agents, which are used in appropriate doses for the application of the experimental procedure in animals, relieve pain when applied in sufficient amounts as well as muscle relaxation. However, many anesthetics can alter the dynamics of neuromuscular systems. We aimed to compare the effects of two frequently used anesthetic agents on electromyographic parameters in rats. Materials and Methods: This study was performed on male Wistar albino rats aged 22–24 months. The animals were divided into two groups: urethane (1.5 gkg−1, i.p; n = 6) and ketamine+xylazine (K+X) (80 mg/kg, i.p; n = 6). Under general anesthesia, rats were electrically stimulated with bipolar hook electrodes from both legs, and compound muscle action potential (CMAP) was recorded from the needle electrode of the gastrocnemius muscle. Motor nerve action potential latency (MNAPL) was measured from the sciatic nerve of the rats. Results: The results of electrodiagnostic findings related to two different anesthetics in the animals were compared, and CMAP parameters were found to differ between the groups. MNAPL in both the right and left legs was significantly reduced in the urethane group compared to the K+X group (P &lt; 0.05). Conclusion: Urethane anesthesia may be a better choice than K+X anesthesia to evaluate nerve and muscle functions in animal electromyography studies.

Electrophysiological Changes in Patients with Carpal Tunnel Syndrome after Open Carpal Tunnel Release

Objective: Carpal tunnel syndrome (CTS) is the most common peripheral neuropathy affecting the upper limbs. Various treatment methods exist for this disease, but only a few reports have compared the effects of various treatments using objective indicators. This study analyzed the changes in electrophysiological parameters after carpal tunnel release.Methods: In patients planning to undergo surgical treatment for CTS, electrophysiological studies, including nerve conduction studies and electromyography (EMG), of both upper extremities were performed before and 6 to 8 weeks after mini-open transverse carpal ligament release and median nerve neurolysis.Results: After surgical intervention, the onset latency and amplitude of the sensory nerve action potential (SNAP) and the onset latency of the compound muscle action potential (CMAP) of the median nerve improved. Additionally, the grade of abnormal spontaneous activity in needle EMG of the abductor pollicis brevis (APB) and the severity of the electrodiagnostic study results significantly decreased after the intervention compared to the initial evaluation.Conclusion: This study shows that the onset latency of SNAP and CMAP, the amplitude of SNAP of the median nerve, and EMG findings in the APB can be useful electrodiagnostic parameters for postoperative monitoring in CTS patients.

Clinical Relevance of Ultrasonographic and Electrophysiological Findings of the Median Nerve in Unilateral Carpal Tunnel Syndrome Patients.

Few studies have compared the unaffected and affected sides in the same carpal tunnel syndrome (CTS) patients using ultrasonography and electrophysiological tests. We focused on unilateral idiopathic CTS patients to investigate whether clinical test results differ between the unaffected and affected sides. The bilateral wrist joints of 61 unilateral idiopathic CTS patients were evaluated. The median nerve cross-sectional area of ultrasound image, and latencies of the compound muscle action potential (CMAP) and sensory nerve action potential (SNAP) were measured. The values obtained were compared between the affected and unaffected sides. The diagnostic accuracies of each parameter were assessed, and cut-off values were defined. Significant differences were observed in all parameters between the affected and unaffected sides (p &lt; 0.01). Area under the curve (AUC) values were 0.74, 0.88, and 0.73 for the cross-sectional area, CMAP distal latency, and SNAP distal latency, respectively. Cut-off values were 11.9 mm2, 5.1 ms, and 3.1 ms for the cross-sectional area, CMAP distal latency, and SNAP distal latency, respectively. The most reliable parameter that reflected clinical symptoms was the distal latency of CMAP. Cut-off values for each parameter are considered to be an index for the onset of the clinical symptoms of CTS.

Ameliorative Potential of Hot Compress on Sciatic Nerve Pain in Chronic Constriction Injury-Induced Rat Model.

Hot compress modalities are used to ameliorate pain despite prevalent confusion about which modality should be used and when. Most recommendations for hot compresses are based on empirical experience, with limited evidence to support its efficacy. To obtain insight into the nerve transmission mechanism of hot compresses and to identify the nerve injury marker proteins specifically associated with sciatic nerve pain, we established a rat model of chronic constriction injury (CCI) and performed mechanical allodynia, electrophysiology, and histopathological analysis. All CCI rats exhibited geometric representation of the affected hind paw, which indicated a hyper-impact on both mechanical gait and asymmetry of gait on day 28. The CCI model after 28 days of surgery significantly reduced compound muscle action potential (CMAP) amplitude, but also significantly reduced latency. Administration of hot compress for 3 weeks (heated at 40–42°C, cycle of 40 min, and rest for 20 min, three cycles each time, three times per week) significantly increased the paw withdrawal thresholds in response to stimulation by Von Frey fibers and reversed the CCI-induced reduced sciatic functional index (SFI) scores. Hot compress treatment in the CCI model improved CMAP amplitude and latency. The S100 protein expression level in the CCI+Hot compression group was 1.5-fold higher than in the CCI group; it dramatically reduced inflammation, such as tumor necrosis factor alpha and CD68 expression in nerve injury sites. Synaptophysin (Syn) expression in the CCI+Hot compression group was less than threefold in the CCI group at both nerve injury sites and brain (somatosensory cortex and hippocampus). This finding indicates that local nerve damage and inflammation cause significant alterations in the sensorimotor strip, and hot compress treatment could significantly ameliorate sciatic nerve pain by attenuating Syn and inflammatory factors from local pathological nerves to the brain. This study determines the potential efficacy and safety of hot compress, and may have important implications for its widespread use in sciatic nerve pain treatment.

The Amplitude of Diaphragm Compound Muscle Action Potential Correlates With Diaphragmatic Excursion on Ultrasound and Pulmonary Function After Supraclavicular Brachial Plexus Block.

ObjectiveThis prospective, double-blind, randomized study assessed (1) the associations between diaphragm compound muscle action potential (CMAP), hemidiaphragmatic excursion, and pulmonary function after supraclavicular brachial plexus block (SCBPB) and (2) diagnostic efficacy of pulmonary function for hemidiaphragmatic paralysis evidenced by diaphragm CMAP as an assessment of diaphragm strength was evaluated.MethodsEighty-six patients were scheduled for the removal of hardware after healing of a right upper limb fracture distal to the shoulder who were randomly assigned in a 1:1 ratio to two groups: Group A (diaphragmatic excursion), or Group B (pulmonary function). Phrenic nerve conduction studies (PNCSs), M-mode ultrasonography of the diaphragm, and pulmonary function tests (PFTs) were performed before and 30 min after SCBPB. PNCSs were used to determine the latency and amplitude of diaphragm CMAP. Ultrasonography of the diaphragm was performed with patients in a supine position using a low-frequency probe over the subcostal space at the midclavicular line. The diaphragmatic excursion was measured during quiet breathing and deep breathing. Pulmonary function, i.e., forced vital capacity (FVC), predicted value of FVC, and forced expiratory flow in the first second (FEV1), was measured with spirometry. Receiver Operating Characteristic (ROC) curve analysis was used to assess the diagnostic efficacy of pulmonary function for hemidiaphragmatic paralysis evidenced by diaphragm CMAP as an assessment of diaphragm strength.ResultsThere were significant associations between the reduction in amplitude of diaphragm CMAP and reductions in diaphragmatic excursion during quiet breathing (r = 0.70, p < 0.01) and deep breathing (r = 0.63, p < 0.01) when expressed as a percentage of baseline values. There were significant associations between the reduction in amplitude of diaphragm CMAP and reductions in FVC (r = 0.67, p < 0.01), FVC% (r = 0.67, p < 0.01), and FEV1 (r = 0.62, p < 0.01), when expressed as percentage of baseline values. The area under the ROC curve for FVC was 0.86. A decrease of >8.4% in FVC compared to pre-block predicted hemidiaphragmatic paralysis (determined by diaphragm CMAP) with sensitivity and specificity of 79.2 and 100%, respectively.ConclusionsThe relative reduction in diaphragm CMAP amplitude after SCBPB was correlated with relative reductions in diaphragmatic excursion and pulmonary function. FVC has potential as a useful diagnostic indicator of hemidiaphragmatic paralysis, evidenced by diaphragm CMAP, after SCBPB. These data establish diaphragm CMAP as a direct and objective index of diaphragmatic paralysis after SCBPB.

The Investigation of Ameliorating Effect of Methylene Blue on Cisplatin-Induced Neurotoxicity in Female Rats

Objective: Cisplatin is indispensable in many solid tumors, and peripheral neurotoxicity is an essential dose-limiting side effect. The study aims to investigate the ameliorating effect of methylene blue, which has anti-oxidant properties, in rats with neurotoxicity due to cisplatin treatment. Materials and methods: Twenty-four adult female rats were included in the study and divided into 3 groups. The first group (n=8), the control group, did not receive any treatment. The second (n=8) and the third (n=8) group received 2.5 mg/kg/day of cisplatin and 1 ml/kg/day of 0.9% NaCl (saline) twice a week for 4 weeks. Also, the third group received 20 mg/kg/day of methylene blue every day for 4 weeks. Blood samples were collected from rats for malondialdehyde (MDA), glutathione (GSH), tumor necrosis factor- α (TNF-α), and interleukin-6 (IL-6) levels, and electromyography (EMG) and motor function were evaluated. Results: In non-treated cisplatin injected rats, a significant increase in the lipid peroxidation product MDA and pro-inflammatory cytokines compared to the control group (p<0.001). Electromyography measurements also resulted in a significant decrease in cisplatin injected rats’ compound muscle action potential (CMAP) amplitude and prolongation in CMAP latency compared to the control group (p<0.05). A statistically significant decrease in MDA, TNF-α, and IL-6 levels and a statistically significant increase in GSH levels and CMAP amplitude was observed in the methylene blue-treated group compared to the group injected with cisplatin alone. Conclusions: We concluded that methylene blue has ameliorating effects against cisplatin-induced neurotoxicity (CIN) by enhancing anti-oxidative capacity, energy metabolism and suppressing inflammatory parameters and oxidative stress.

Demonstration of the protective effect of propofol in rat model of cisplatin-induced neuropathy.

Cisplatin is commonly used in the treatment of lung, genitourinary, and gastrointestinal cancers. Peripheral neuropathy is the most important side effect, leading to a decrease in the dose of cisplatin or its complete cessation in the early period. 16 rats were given cisplatin at a dose of 2.5 mg/ kg/day twice a week for 4 weeks to induce neuropathy model. The rats taking Cisplatin were divided into 2 groups. Group 1 rats (n = 8) were given 1 ml/kg/day 0.9 % NaCl intraperitoneally, and Group 2 rats were given 10 mg/kg/day Propofol intraperitoneally daily for 4 weeks. The remaining 8 rats served as the control group. At the end of the study, all animals were tested for motor functions. Blood samples were collected for the measurement of plasma lipid peroxidation (malondialdehyde; MDA), tumor necrosis factor (TNF-α), glutathione (GSH), IL-6 and HSP-70 levels. Electromyography findings revealed that compound muscle action potential (CMAP) amplitude was significantly higher in the cisplatin-Propofol group than in the cisplatin-saline group. Also, cisplatin-Propofol treated group showed significantly lower TNF-α, MDA and IL-6 levels and higher GSH and HSP-70 levels than cispalatin-Saline group (p < 0.01, p < 0.001). In addition, while the CMAP latency was decreased in the propofol group, the CMAP amplitude was increased, and a significant improvement was observed in the Inclined test scores. Besides, histological examinations showed an increase in axon diameter and NGF expression with Propofol treatment. This study demonstrated that Propofol exerts protective activity against cisplatin-induced neurotoxicity by increasing endogenous antioxidants and reducing lipid peroxidation and inflammation (Tab. 3, Fig. 4, Ref. 30). Text in PDF www.elis.sk Keywords: cisplatin, neuropathy, propofol, oxidative damage, ınflammation.

Radial motor nerve conduction studies recorded from triceps brachii and extensor carpi radialis longus: Techniques and reference values.

Optimal timing of nerve transfer surgery in cervical spinal cord injury (SCI) depends upon the integrity of lower motor neurons (LMNs) in recipient nerves, which is best predicted by compound muscle action potential (CMAP) amplitude. There are no established techniques for obtaining the CMAP in two recipient muscles: triceps brachii and extensor carpi radialis longus (ECRL). This study aimed to develop recording techniques for radial motor studies to triceps and ECRL, and to determine reference values for CMAP amplitudes in healthy volunteers. This was a prospective observational study of healthy adults aged 18 years and older. Motor nerve conduction studies were performed, stimulating the radial nerve in the axilla, over the axillary pulse at the pectoralis major insertion. Recording was from triceps (long head) and ECRL. CMAP amplitude, area, latency, and stimulus intensity were recorded. Reference values (RV) were calculated for CMAP amplitudes using a value 2 standard deviations below the mean. Cube root or logarithmic transformations were used to correct for non-normal distributions. Twenty-five healthy subjects participated. Triceps mean CMAP amplitude was 15.5mV (SD 4.19), with an RV of 8.1mV. ECRL mean CMAP amplitude was 11.5mV (SD 3.54), with an RV of 6.2mV. CMAP amplitude at ECRL was 75% (95% confidence interval 50%-100%) of that at triceps. We describe a technique for recording radial motor NCS from triceps and ECRL. Knowledge of normal CMAP amplitudes will help identify LMN injury in patients with cervical SCI being considered for nerve transfers.

Radiological factors associated with the severity of corticospinal tract dysfunctions for cervical spondylotic myelopathy: An analysis of the central motor conduction time and kinematic CT myelography

Patients with cervical spondylotic myelopathy (CSM) often exhibit symptoms in clinical practice, particularly the elderly, whose lower extremity functions are more likely to deteriorate; however, the underlying mechanisms currently remain unclear. The present study aimed to elucidate the relationship between the neurological severity of CSM based on an electrophysiological examination and radiological findings.Eighty-six patients with CSM were examined using kinematic CT myelography. The cross-sectional area of the spinal cord and dynamic changes in the spinal cord were measured at the affected level.The central motor conduction time (CMCT) using transcranial magnetic stimulation was calculated as follows: motor evoked potential latency - (compound muscle action potential latency + F latency − 1)/2 (ms). A multiple logistic regression analysis was performed to identify the radiological parameters associated with severe lower limb dysfunction.CMCT in the upper limbs correlated with spinal cord compression during neck extension, while that in the lower limbs correlated with a larger C2-7 sagittal vertical axis, cervical lordosis, a small C2-7 range of motion (ROM), and spinal cord compression during neck flexion. In a multiple logistic regression analysis, significant risk factors specific for severe lower limb dysfunction were greater anterior spondylolisthesis during neck extension (P = 0.006, OR: 2.53, 95%CI: 1.13–2.07) and small C2-7 ROM in neutral to flexion (P = 0.035, OR: 0.67, 95%CI: 0.52–0.88).Imaging findings affect upper and lower extremity functions in specific manners. Cervical stiffness or anterior compression factors may be associated with the deterioration of lower limb function.

Value of intraoperative monitoring of the trigeminal nerve in detection of a superiorly displaced facial nerve during surgery for large vestibular schwannomas.

The aim of this study was to investigate the role of trigeminal and facial nerve monitoring in the early identification of a superiorly (anterior and superior (AS)) displaced facial nerve. This prospective study included 24 patients operated for removal of large vestibular schwannomas (VS). The latencies of the electromyographic (EMG) events recorded from the trigeminal and facial nerve innervated muscles after mapping the superior surface of the tumor were analyzed. The mean latency of the recorded compound muscle action potential (CMAP) from the masseter muscle was 3.6 ± 0.5ms and of the peripherally transmitted responses by volume conduction from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles was 4.6 ± 0.9, 4.1 ± 0.7, 3.9 ± 0.4, 4.3 ± 0.8, and 4.5 ± 0.6ms, respectively, after trigeminal nerve stimulation in 24 (100%) patients (pattern I response). In 6 (25%) patients, the mean latency of CMAP on the masseter was 3.3 ± 0.3ms, and the latencies of the CMAP from the frontalis, o. oculi, nasalis, o. oris, and mentalis muscles were 6.5 ± 1.3, 5.0 ± 1.5, 7.5 ± 1.3, 7.4 ± 0.6, and 7.0 ± 1.5ms, respectively, longer than those of the peripherally transmitted responses (p = 0.002, p = 0.001, p < 0.001, and p = 0.015, respectively) indicating simultaneous stimulation of both nerves (pattern II response). All patients with this response were later confirmed to have an AS-displaced facial nerve. Recognizing the response resulting from simultaneous stimulation of both the facial and trigeminal nerves is important to help early identification of an AS-displaced facial nerve before it is visible in the surgical field and to avoid misleading information by confusing this pattern for a pure trigeminal nerve response.

Dexpanthenol reduces fibrosis and aids repair following nerve laceration and neurorrhaphy.

The aim of the present study was to investigate the effect of dexpanthenol on nerve healing following neurorrhaphy in lacerated peripheral nerves. A total of 30 mature Sprague Dawley rats were used. Surgical sciatic nerve dissection and repair was performed on an experimental group of 20 rats. The remaining 10 rats were designated as the control group. The experimental group was divided into 2 subgroups. The surgery + saline group (SSLE; n=10) was given 1 ml/kg 0.9% sodium chloride saline intraperitoneally. The surgery + dexpanthenol group (SDPL; n=10) rats were given 500 mg/kg/day dexpanthenol intraperitoneally. Histological evaluation of the sciatic nerve tissue revealed that the fibrosis score was significantly lower in the SDPL group than in the SSLE group (P<0.001). Electrophysiological evaluation of compound muscle action potential (CMAP) indicated that the CMAP level in the SDPL group was significantly higher than that of the SSLE group (P<0.001), and the CMAP latency period was lower in the SDPL group compared with the SSLE group (P<0.001). In addition, the SDPL group malondialdehyde level was significantly lower than that of the SSLE group (P<0.001). Functional evaluation with an inclined plane test revealed a significant difference between the SSLE (39.6±5.5˚) and SDPL (79.1±6.93˚) groups (P<0.001). Dexpanthenol was observed to have a positive effect on nerve tissue repaired with neurorrhaphy in a rat sciatic model of laceration-type injuries similar to those frequently encountered in the clinic.

Impact of shoulder subluxation on peripheral nerve conduction and function of hemiplegic upper extremity in stroke patients: A retrospective, matched-pair study

ABSTRACT Purpose: To investigate the impact of shoulder subluxation (SS) on peripheral nerve conduction and function of the hemiplegic upper extremity (HUE) in poststroke patients. Methods: Thirty post-stroke patients were selected (SS group: 15 patients, non-SS group: 15 patients, respectively). Evaluation of nerve conduction in upper limbs: the compound muscle action potential (CMAP) amplitude and latency of suprascapular, axillary, musculocutaneous, radial, median, and ulnar nerves; the motor and sensory conduction velocity and the sensory nerve action potential (SNAP) amplitude of median, ulnar, and radial nerves. The Brunnstrom stage scale was used to evaluate the HUE motor function. Results: Compared with the healthy side, the CMAP and SNAP amplitudes of tested nerves on the HUE in both groups were lower, and the CMAP latency of the suprascapular, axillary and musculocutaneous nerves on the HUE in the SS group was longer (P < 0.05). Compared with the HUE in non-SS group, the CMAP amplitude of tested nerves (except ulnar) was decreased more (P < 0.05), the motor conduction velocity of the median nerve was lower (P < 0.05), and the Brunnstrom stage of the HUE was lower in SS group (P < 0.05). Conclusions: Stroke may lead to extensive abnormal nerve conduction on the HUE, and SS may aggravate the abnormality, which may disturb the recovery of upper limb function.

Radial motor nerve conduction studies in the upper arm.

The main goal of this study was to determine the contribution of the anterior forearm muscles to the compound muscle action potential (CMAP) recorded from the extensor digitorum (ED) after proximal stimulation. Twenty-one healthy volunteers and 114 patients with compressive and traumatic radial neuropathies were examined. Stimulation was carried out at six different points: distal third of the upper arm; Erb's point; axilla; medial upper arm; antecubital fossa; and ulnar groove. In the control group, Erb's CMAP area was significantly greater than the distal CMAP area. In compressive neuropathy, there was conduction block, but no change in conduction velocity. There were no differences in Erb's CMAP latencies between the control group and the neuropathies group. CMAPs recorded over the ED with stimulation at the brachial plexus represent the sum of the motor unit action potentials of the posterior and anterior forearm muscles.