Nerve Action Potential Amplitude Research Articles

Glycemic variability is associated with sural nerve conduction velocity in outpatients with type2diabetes: Usefulness of a new point-of-care device for nerve conduction studies.

Although several studies have shown the association between continuous glucose monitoring (CGM)-derived glycemic variability (GV) and diabetic peripheral neuropathy, no studies have focused on outpatients or used NC-stat®/DPNCheck™, a new point-of-care device for nerve conduction study (NCS). We investigated the association between CGM-derived GV and NCS using DPNCheck™ in outpatients with type 2 diabetes, and further analyzed the difference in results between patients with and without well-controlled HbA1c levels. All outpatients with type 2 diabetes using the CGM device (FreeStyle Libre Pro®) between 2017 and 2022 were investigated. Sural nerve conduction was evaluated by sensory nerve action potential (SNAP) amplitude and sensory conduction velocity (SCV) using DPNCheck™. Associations of CGM-derived GV metrics with SNAP amplitude and SCV were investigated. In total, 304 outpatients with type 2 diabetes were included. In a linear regression model, most CGM-derived GV metrics except for the mean amplitude of glucose excursion and low blood glucose index were significantly associated with SCV, but not with SNAP amplitude. The significant associations of most CGM-derived GV metrics with SCV remained after adjustment for possible confounding factors, but not after adjustment for glycated hemoglobin (HbA1c). Most CGM-derived GV metrics were significantly associated with SCV after adjustment for HbA1c in patients with a HbA1c ≤ 6.9%, but not in those with a HbA1c ≥ 7.0%. In outpatients with type 2 diabetes, multiple CGM-derived GV metrics were significantly associated with SCV obtained by DPNCheck™. GVmay have independent impacts on peripheral nerve function, particularly in patients with well-controlled HbA1c levels.

Evaluation of hand-arm vibration syndrome owing to nerve conduction study and cumulative exposure index -A 2.5-year cohort study.

This study aims to clarify the relationship between peripheral neuropathy in hand-arm vibration syndrome and cumulative exposure index. 68 participants without symptoms were surveyed. The participants were divided into three groups based on past and current vibration exposure (VE). Comparison among groups according to past VE showed that the median and ulnar sensory nerve conduction velocities and median sensory nerve action potential (SNAP) amplitude were significantly lower in past high and low exposure groups than in the past non-exposure group. Comparison among groups according to current VE showed that the median and ulnar SNAP amplitudes were significantly lower in the current high exposure group than in the current low or non-exposure group. Vibration tool handlers have potential peripheral nerve lesions at a certain stage without subjective symptoms of the finger.

Conduction slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies: Electrophysiology meets pathology.

Nerve conduction studies are usually the first diagnostic step in peripheral nerve disorders and their results are the basis for planning further investigations. However, there are some commonplaces in the interpretation of electrodiagnostic findings in peripheral neuropathies that, although useful in the everyday practice, may be misleading: (1) conduction block and abnormal temporal dispersion are distinctive features of acquired demyelinating disorders; (2) hereditary neuropathies are characterized by uniform slowing of conduction velocity; (3) axonal neuropathies are simply diagnosed by reduced amplitude of motor and sensory nerve action potentials with normal or slightly slow conduction velocity. In this review, we reappraise the occurrence of uniform and non-uniform conduction velocity slowing, conduction block and temporal dispersion in demyelinating, dysmyelinating and axonal neuropathies attempting, with a translational approach, a correlation between electrophysiological and pathological features as derived from sensory nerve biopsy in patients and animal models. Additionally, we provide some hints to navigate in this complex field.

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.

Comparative multimodal sensory testing in multifocal motor neuropathy and multifocal variant of chronic inflammatory demyelinating polyradiculoneuropathy

Comparative multimodal sensory testing in multifocal motor neuropathy and multifocal variant of chronic inflammatory demyelinating polyradiculoneuropathy

Simplified electrophysiological approach combining a point-of-care nerve conduction device and an electrocardiogram produces an accurate diagnosis of diabetic polyneuropathy.

This study aimed to investigate the diagnostic potential of two simplified tests, a point-of-care nerve conduction device (DPNCheck™) and a coefficient of variation of R-R intervals (CVR-R ), as an alternative to traditional nerve conduction studies for the diagnosis of diabetic polyneuropathy (DPN) in patients with diabetes. Inpatients with type 1 or type 2 diabetes (n = 167) were enrolled. The study population consisted of 101 men, with a mean age of 60.8 ± 14.8 years. DPN severity was assessed using traditional nerve conduction studies, and differentiated based on Baba's classification (BC). To examine the explanatory potential of variables in DPNCheck™ and CVR-R regarding the severity of DPN according to BC, a multiple regression analysis was carried out, followed by a receiver operating characteristic analysis. Based on BC, 61 participants (36.5% of the total) were categorized as having DPN severity of stage 2 or more. The multiple regression analysis yielded a predictive formula with high predictive power for DPN diagnosis (estimated severity of DPN in BC = 2.258 - 0.026 × nerve conduction velocity [m/s] - 0.594 × ln[sensory nerve action potential amplitude (μV)] + 0.528In[age(years)] - 0.178 × ln[CVR-R ], r = 0.657). The area under the curve in receiver operating characteristic analysis was 0.880. Using the optimal cutoff value for DPN with severer than stage 2, the predictive formula showed good diagnostic efficacy: sensitivity of 83.6%, specificity of 79.2%, positive predictive value of 51.7% and negative predictive value of 76.1%. These findings suggest that DPN diagnosis using DPNCheck™ and CVR-R could improve diagnostic efficiency and accessibility for DPN assessment in patients with diabetes.

Electrophysiological variations of Guillain-Barre syndrome in Bangladesh- Hospital based study

Introduction: Guillain-Barre syndrome (GBS) is an immune mediated disorder of peripheral nerves which usually presents by rapidly evolving ascending weakness & mild sensory loss and hypo- or areflexia. Electrodiagnostic study (EDS) is the basis for classification of different subtypes of the disease. EDS also has a crucial role in diagnosis, ruling out of some differential diagnosis like myopathic and motor neuron disorders and confirming the neuropathic nature of GBS. The benefit of immunotherapy is greatest when introduced early. In addition, electrophysiological characteristic can predict the prognosis of patients with GBS. This study was conducted to determine the predominant subtype and electrophysiological pattern of GBS in the context of Bangladesh. Objectives: Objective of this study was to compare the electrophysiological variations among different electrophysiological subtypes of GBS. Methods: It is an observational cross sectional study conducted in Department of Medicine and Neurology, Sir Salimullah Medical College & Mitford Hospital and National Institute of Neuroscience (NINS), Dhaka, over a period of one year & four months. Total 30 patients were selected by purposive sampling technique. Demographic data were collected from the patients and recorded in structured case report form. Clinical examination and relevant investigations were done meticulously. Collected questionnaire were checked to identify any error in data. Data was analyzed with SPSS version 21 software. Result: In this study, maximum numbers of patients 53% were between 21-30 years of age group with mean value 27.47±8.1 years. Male to female ratio was 1.7:1. Frequency of Guillain-Barre syndrome is predominance at middle age group. Commonest presentation was limb weakness (parapledgia or quadripledgia) in 60% patients, paresthesias & numbness (40%), pain (100%) and deviation of mouth (63%) of GBS patients. Cerebrospinal fluid shows a mild pleocytosis (5 to 50 cells/µl) in majority of cases was found in 76% of patients. Whereas elevated CSF Protein (>45 mg/dl) was seen in all GBS patient. Increased distal motor latency (DML) was found in 93% patients, whereas 7% patients had normal DML. In the case of the lower limbs, increased distal motor latency was predominant. Decreased amplitude of sensory nerve action potential (SNAP) was seen in 83% patients while 16% patients had normal. Slowing of motor conduction velocities, decreased amplitude as well as increase in distal motor latencies were observed, being more pronounced in the lower limbs. F-wave was completely absent in 20.0% patients while 20% patients showed decreased conduction velocity with prolonged latency. Sensory nerve action potential revealed that decreased sensory conduction velocity (SCV) was seen in 26%, absent SCV in 10% and normal SCV in 63% patients. Present study demonstrated that Acute inflammatory demyelinating polyneuropathy (AIDP) was the commonest type of Guillain-Barré syndrome, present in 56% of patient. Around 30% of the patients belonged to acute motor axonal polyneuropathy (AMAN) and 13% were acute motor sensory axonal polyneuropathy (AMSAN). Conclusion: In this study AIDP was the most frequent subtype. The characteristic findings supportive of AIDP include prolonged distal motor latencies, reduced conduction velocities, conduction blocks at non-entrapment sites, temporal dispersion and prolonged F wave latencies. J MEDICINE 2024; 25: 11-16

Effect of age on metabolomic changes in a model of paclitaxel-induced peripheral neurotoxicity.

Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most common dose-limiting side effects of paclitaxel (PTX) treatment. Many age-related changes have been hypothesized to underlie susceptibility to damage or impaired regeneration/repair after nerve injury. The results of these studies, however, are inconclusive and other potential biomarkers of nerve impairment need to be investigated. Twenty-four young (2 months) and 24 adult (9 months) Wistar male rats were randomized to either PTX treatment (10 mg/kg i.v. once/week for 4 weeks) or vehicle administration. Neurophysiological and behavioral tests were performed at baseline, after 4 weeks of treatment and 2-week follow-up. Skin biopsies and nerve specimens collected from sacrificed animals were examined for intraepidermal nerve fiber (IENF) density assessment and nerve morphology/morphometry. Blood and liver samples were collected for targeted metabolomics analysis. At the end of treatment, the neurophysiological studies revealed a reduction in sensory nerve action potential amplitude (p < .05) in the caudal nerve of young PTX-animals, and in both the digital and caudal nerve of adult PTX-animals (p < .05). A significant decrease in the mechanical threshold was observed only in young PTX-animals (p < .001), but not in adult PTX-ones. Nevertheless, both young and adult PTX-rats had reduced IENF density (p < .0001), which persisted at the end of follow-up period. Targeted metabolomics analysis showed significant differences in the plasma metabolite profiles between PTX-animals developing peripheral neuropathy and age-matched controls, with triglycerides, diglycerides, acylcarnitines, carnosine, long chain ceramides, sphingolipids, and bile acids playing a major role in the response to PTX administration. Our study identifies for the first time multiple related metabolic axes involved in PTX-induced peripheral neurotoxicity, and suggests age-related differences in CIPN manifestations and in the metabolic profile.

Sensory nerve conduction studies in infants, children and teenagers – An update

ObjectiveNerve conduction studies (NCS) in children remain technically challenging and depend on the cooperation of the child. Motor NCS are not compromised by analgosedation but data for sensory NCS are lacking. Here, we ask whether sensory NCS is influenced by analgosedation. We also compare the present data with NCS studies from the 1990s regarding anthropometric acceleration of the contemporary paediatric population. MethodsSensory NCS of the median nerve and sural nerve were performed in 182 healthy subjects aged 1 to 18 years during general anaesthesia and in 47 of them without analgosedation. ResultsSensory NCS was not influenced by midazolam or propofol. The sensory nerve action potential (SNAP) amplitude and the nerve conduction velocity (NCV) of the sural nerve as well as the SNAP of the median nerve show no significant age dependence in age range 1–18 years. The sensory NCV of the median nerve increased age-dependent. ConclusionsIn clinical practice, analgosedation can be used for diagnostic NCS. Sensory NCS data show no relevant secular trend over the last 30 years. Differences due to technical inconsistency predominate. SignificanceAnalgosedation can improve diagnostic quality of sensory NCS in children. Additionally, we provide sensory NCS values from a large pediatric cohort.

Effect of metformin nanoemulsion through AMP-activated protein kinase (AMPK)-mediated autophagy on diabetic neuropathy

Metformin (MET) is the preferred first-line treatment for patients with type 2 diabetes. However, the mechanism of diabetic peripheral neuropathy (DPN) is still unclear. To improve the oral utilization of metformin, a metformin nanoemulsion (MET-NE) was prepared to investigate its effects on DPN and its underlying mechanism. In this study, a DPN model was established in Wistar rats induced by streptozotocin (STZ). The diabetic rats were randomly divided into four groups: the diabetic model group (DM group), the metformin tablet-treated group (MET group), the metformin nanoemulsion-treated group (MET-NE group), and a normal control group consisting of five normal Wistar rats. All groups were administered the treatment orally for a period of 10 weeks. The findings of the study demonstrated that both MET and MET-NE significantly reduced blood glucose levels, glycated serum protein levels, food intake, and water intake in DM rats. It was also observed that MET-NE was more effective than MET in reducing blood glucose levels. Additionally, both MET and MET-NE treatments significantly increased the motor nerve conduction velocity (MNCV), sensory nerve conduction velocity (SNCV), and sensory nerve action potential (SNAP) amplitude in DM rats. Furthermore, these treatments improved mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL), resulting in a reduced sensitivity to pain stimuli. Moreover, both MET and MET-NE treatments promoted the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) proteins, as well as increased the activity of autophagic proteins in the sciatic nerve. However, no significant differences were observed between MET and MET-NE treatments in terms of these effects. In conclusion, the MET-NE demonstrated a rapid decrease in blood glucose levels and improved glucose tolerance and metabolism, which was found to be superior to MET. Furthermore, MET-NE significantly improved the neurophysiological function and sciatic nerve pain threshold in DPN rats. These beneficial effects may be attributed to the regulation of AMPK-mediated autophagy by MET-NE.

Alterations of the nervous system in patients with vibration disease

Introduction. An important aspect of prevention is the dynamic monitoring of workers exposed to the vibration in the workplace, which not only forms the basis for the diagnosis of occupational intoxication, but also ensures timely resolution of issues of examination of working capacity.&#x0D; Materials and methods. Twenty one male patient with an established diagnosis of vibration disease (VD) associated with exposure to local vibration. A dynamic survey was conducted, 3 observation periods were studied.&#x0D; Results. Over the 3rd period of the examination, the latency of N10 and N30 increased when compared with the 1st period. In periods 2 and 3, the duration of N13–N18 increased compared to period 1. The rate of pulse conduction (RPC) along the ulnar nerve decreased during period 2 when compared with period 1. Over the period 3, a decrease in RPC along the tibial nerve was revealed when compared with periods 1 and 2. During periods 2 and 3, the amplitude of the ulnar nerve action potential decreased when compared with period 1, along the afferent axons of the ulnar nerve the RPC decreased during period 2 when compared with 1. In period 3, the RPC along the median nerve decreased when compared with period 1.&#x0D; Limitations. The limitation of this study is that the dynamics of changes depending on the degree of vibration disease has not been analyzed. This task was not implemented due to the small number of observations in the sample. &#x0D; Conclusion. The progression of vibration disease syndromes and the degree of severity of vibration disease in dynamics were noted. The time of activation of neurons of the somatosensory zone of the cerebral cortex and the time of passage of the pulse from neurons of the cervical thickening to the thalamic structures in dynamics was found to slow down. There were increased disturbances in the conduction of the pulse along the axons at the level of the brachial plexus and from the brachial plexus to the lower parts of the brain stem. Demyelinating changes in the motor component of the peripheral nerves of the upper and lower extremities were aggravated in patients.

Sensory nerve action potential in patients with functional neurological disorders with sensory manifestations.

Functional neurological disorder (FND) has various clinical manifestations. Even though diagnostic criteria for FND have been proposed, FND characteristics with sensory manifestations have not been elucidated. Therefore, we aimed to investigate the association between sensory nerve action potential (SNAP) amplitudes and FND with sensory manifestations. We included 76 outpatients with FND with sensory manifestations whose nerve conduction studies were performed retrospectively. Additionally, we defined 121 patients with other neurological diseases who did not have peripheral neuropathy as disease controls. The SNAP amplitudes were compared between the two groups. We also explored the relationship between SNAP amplitudes and FND-specific clinical symptoms in patients with FND. No differences were observed in SNAP amplitudes adjusted for age between patients with FND who had sensory manifestations and disease control patients. Additionally, no differences were observed between patients with FND who had and did not have FND-specific clinical symptoms. The SNAP amplitude in patients with FND who had sensory manifestations was equivalent to that in controls.

Association of Sensory Nerve Action Potential Amplitude and Velocity With Type 2 Diabetic Peripheral Neuropathy

Association of Sensory Nerve Action Potential Amplitude and Velocity With Type 2 Diabetic Peripheral Neuropathy

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

Amyloid-β Effects on Peripheral Nerve: A New Model System.

Although there are many biochemical methods to measure amyloid-β (Aβ)42 concentration, one of the critical issues in the study of the effects of Aβ42 on the nervous system is a simple physiological measurement. The in vitro rat sciatic nerve model is employed and the nerve action potential (NAP) is quantified with different stimuli while exposed to different concentrations of Aβ42. Aβ42 predominantly reduces the NAP amplitude with minimal effects on other parameters except at low stimulus currents and short inter-stimulus intervals. The effects of Aβ42 are significantly concentration-dependent, with a maximum reduction in NAP amplitude at a concentration of 70 nM and smaller effects on the NAP amplitude at higher and lower concentrations. However, even physiologic concentrations in the range of 70 pM did reduce the NAP amplitude. The effects of Aβ42 became maximal 5-8 h after exposure and did not reverse during a 30 min washout period. The in vitro rat sciatic nerve model is sensitive to the effects of physiologic concentrations of Aβ42. These experiments suggest that the effect of Aβ42 is a very complex function of concentration that may be the result of amyloid-related changes in membrane properties or sodium channels.

Age-Related Changes in Neurologic Examination and Sensory Nerve Amplitude in the General Population: Aging of the Peripheral Nervous System.

Chronic axonal polyneuropathy is a common disease of the peripheral nervous system with increasing prevalence with age. Typical neurologic signs are present in patients with polyneuropathy but may also occur in individuals without disease. Owing to limited knowledge on normal aging of the peripheral nervous system, it can be difficult to distinguish peripheral nerve dysfunction due to disease from variations in normal aging. Therefore, we described the changes in neurologic examination and nerve conduction studies that accompany aging in the general population. In this cross-sectional population-based study, we screened participants for chronic polyneuropathy in a controlled environment using standardized methods including a symptom questionnaire, neurologic examination, and nerve conduction studies (NCS). Inclusion criteria were 40 years or older and living in a suburb of Rotterdam, the Netherlands. Participants not diagnosed with chronic polyneuropathy, based on the discussion of findings in the screening by an expert team, were included to determine the effect of age (range 41-96 years) on features of neurologic examination and NCS using frequency calculations and quantile regression analysis. In total, 4,179 participants (mean age 64.5 ± 12.7 years, 54.9% female) were included of whom 3,780 (90.5%) did not fulfil the criteria for polyneuropathy. In the population without polyneuropathy, the frequency of normal features at neurologic examination declined with age, most pronounced for vibration sense at the hallux (from 6.6 [SD ± 1.5] in 40-49 years to 3.6 [SD ± 3.1] in 80 years or older) and Achilles tendon reflexes (absent in 9% in 40-49 years up to 33% in 80 years or older). Superficial pain sensation and patellar tendon reflexes remained stable over time. Sural sensory nerve action potential (SNAP) amplitude declined with age from 11.2 μV in 40-49 years to 3.3 μV in 80 years or older. Nonrecordable SNAP amplitudes were found in 25.1% of the participants older than 80 years, more often in men (30.3%) than in women (21.0%). This study showed the effect of age on features of neurologic examination and sural nerve amplitude in the general population. These findings are helpful to distinguish features suggesting polyneuropathy from variations of normal aging of the peripheral nervous system.

Nerve conduction studies through landmark based recording and effects of hand length

As per existing guidelines, the distance between stimulator and recording electrodes in nerve conduction studies (NCS) should be the same (fixed) in all the subjects, i.e., it should not be based on anatomical landmarks. However, there are no studies comparing fixed distance recordings with landmark based NCS. We postulated that hand length can influence the NCS parameters in fixed distance recordings and this can be nullified using landmark based recordings. To test this theory, we performed NCS in 48 normal subjects as per standard guidelines (standard protocol) and then compared it to NCS with ulnar styloid as the landmark (modified protocol). NCS were performed on median and ulnar nerves of the right upper limb. Three motor NCS parameters including distal latency, compound muscle action potential (CMAP) amplitudes and nerve conduction velocities were measured. Sensory nerve action potential (SNAP) amplitudes and conduction velocities were the two sensory parameters measured. On analysis, ulnar motor conduction velocity was the only parameter affected by hand length in both standard and modified protocols. Modified protocol did not have any additional advantage to the standard protocol advised by NDTF. We conclude that the NDTF guidelines are therefore reasonable when considering the effects of hand length. Possible reasons for this result including anatomical and anthropometric explanations are discussed.

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.

ANXIETY AND DEPRESSION IN TYPE 2 DIABETES MELLITUS: A STUDY INCLUDING NERVE CONDUCTION STUDY AND NEUROPATHIC PAIN

Objective: It is known that neuropathy, neuropathic pain and psychiatric disorders are associated with diabetes mellitus (DM). It was aimed to find out whether there is a relationship between nerve conduction study findings, neuropathic pain, depression and anxiety.&#x0D; &#x0D; Material and Methods: Type 2 DM patients that applied to our clinical neurophysiology laboratory between September 2021 and January 2022 were included in this study. Median, ulnar, sural, peroneal and posterior tibial nerve conduction studies were performed on the patients. Douleur Neuropathique 4 Questions (DN4) was applied to the patients to evaluate neuropathic pain. Hospital Anxiety and Depression Scale (HADS) was applied to the patients. Anxiety (HADS-A) and depression (HADS-S) scores, which are the two subsections of HADS, were included in the analysis.&#x0D; &#x0D; Results: Forty DM patients (27 males, 13 females) were included in the study. The mean age of the patients was 57.9±12.7 (min-max 23-83) years. The number of patients with neuropathic pain, polyneuropathy according to neurophysiological findings, abnormal HADS-A and HADS-D scores were 32 (80%), 23 (58%), 17 (43%), and 24 (60%), respectively. Neuropathic pain was present in 22 (96%) and 10 (59%) of the patients with and without polyneuropathy, respectively. Neuropathic pain was found in 22 (92%) patients with depression and 16 (63%) patients without depression (p=0.046). Among patients with neuropathic pain, compound nerve action potential amplitudes of median, ulnar and sural nerves were lower than those without neuropathic pain (p=0.011, p=0.027, p

MRI negative Varicella zoster virus (VZV) plexopathy in a young man with history of malignancy (P2-4.001)

<h3>Objective:</h3> To emphasize the importance of including VZV plexopathy in differential diagnosis in young individuals and to prevent the delay in diagnosis and treatment <h3>Background:</h3> VZV-associated plexopathy in mainly patients over 60 years old. Post herpetic neuralgia is a well-known complication of Herpes Zoster (HZ), however segmental zoster paresis secondary to HZ was reported in 1–20% of the cases in literature. MRI findings may be positive in up to 70% of the patients. <h3>Design/Methods:</h3> N/A <h3>Results:</h3> 43 years-old man with history of grade 2 left frontal oligodendroglioma which was treated with 2 partial resections, radiation and adjuvant procarbazine/lomustine presented with left upper extremity pain and developed a blistering rash in dermatomal pattern in left proximal upper extremity 2 weeks after the initial symptoms. He was diagnosed with shingles and treated with steroids and acyclovir with minimal improvement. 6 weeks after presentation, physical exam revealed left deltoid, supraspinatus and infraspinatus weakness with normal muscle stretch reflexes and decreased sensation on C5 dermatome. EMG revealed absent left lateral antebrachial cutaneous sensory nerve action potentials (SNAP) amplitude, and a small left radial SNAP amplitude compared to the right side. Evidence of ongoing denervation with reinnervation was seen in the left upper trunk supplied muscles. MRI of the brachial plexus was negative for any abnormalities. Patient was diagnosed with VZV-associated plexopathy, improved with pregabalin and physical therapy. <h3>Conclusions:</h3> Our patient was significantly younger than expected in HZ group. MRI usually shows T2 hyperintensities and thickening of the nerve roots in patients with VZV-associated plexopathy. However, the presentation, onset of symptoms, characteristics of the rash and clinical course was diagnostic of HZ, and the weakness pattern, supported by the EMG findings were diagnostic for VZV-associated plexopathy. <b>Disclosure:</b> Dr. Gul has nothing to disclose. Ms. Ahmed has nothing to disclose. Dr. McGraw has nothing to disclose. Dr. Alshiekh Nasany has nothing to disclose.