Nerve Conduction Study Findings Research Articles

Nerve conduction studies of sensory nerves with proven vasculitic neuropathy often show an absent electrical response.

In vasculitic neuropathy (VN), it is not known whether nerve conduction studies (NCSs) showing low amplitude sensory nerve action potentials (SNAPs) or those with absent responses have a higher yield in detecting appropriate nerves for pathological confirmation. Our goal was to describe NCS findings of nerves prior to biopsy in patients with VN. We performed a retrospective study between January 2000 and April 2021 in patients with VN who either met pathological definite criteria for VN or criteria for clinically probable VN and had NCS of the sural or superficial radial sensory nerves prior to biopsy of the same nerve. We included 61 patients with VN. The pathological findings showed 37 (60.7%) definite, 14 (23%) probable, and 2 (3.3%) possible VN; eight (13%) samples did not meet Peripheral Nerve Society pathological criteria. Most patients who met definite (20 out of 37, 54%) and probable (9 out of 14, 64%) VN pathological criteria had absent SNAPs. Only three out of eight (37.5%) patients without VN pathological findings had absent SNAPs. There was no statistically significant correlation between pathological diagnosis and SNAP amplitude (χ2 = 1.98, p = .58). Additionally, no association was found between VN pathological criteria and use of immunomodulatory treatment (p = .67) or corticosteroids (p = .52). Most nerves with pathological VN findings showed no response on NCS. In patients with suspected VN, sural or superficial radial sensory nerves with absent responses on NCS are adequate biopsy targets as compared to nerves in which SNAPs can be recorded.

Game-Based Assessment of Peripheral Neuropathy Combining Sensor-Equipped Insoles, Video Games, and AI: Proof-of-Concept Study.

Detecting peripheral neuropathy (PNP) is crucial in preventing complications such as foot ulceration. Clinical examinations for PNP are infrequently provided to patients at high risk due to restrictions on facilities, care providers, or time. A gamified health assessment approach combining wearable sensors holds the potential to address these challenges and provide individuals with instantaneous feedback on their health status. We aimed to develop and evaluate an application that assesses PNP through video games controlled by pressure sensor-equipped insoles. In the proof-of-concept exploratory cohort study, a complete game-based framework that allowed the study participant to play 4 video games solely by modulating plantar pressure values was established in an outpatient clinic setting. Foot plantar pressures were measured by the sensor-equipped insole and transferred via Bluetooth to an Android tablet for game control in real time. Game results and sensor data were delivered to the study server for visualization and analysis. Each session lasted about 15 minutes. In total, 299 patients with diabetes mellitus and 30 with metabolic syndrome were tested using the game application. Patients' game performance was initially assessed by hypothesis-driven key capabilities that consisted of reaction time, sensation, skillfulness, balance, endurance, and muscle strength. Subsequently, specific game features were extracted from gaming data sets and compared with nerve conduction study findings, neuropathy symptoms, or disability scores. Multiple machine learning algorithms were applied to 70% (n=122) of acquired data to train predictive models for PNP, while the remaining data were held out for final model evaluation. Overall, clinically evident PNP was present in 247 of 329 (75.1%) participants, with 88 (26.7%) individuals showing asymmetric nerve deficits. In a subcohort (n=37) undergoing nerve conduction study as the gold standard, sensory and motor nerve conduction velocities and nerve amplitudes in lower extremities significantly correlated with 79 game features (|R|>0.4, highest R value +0.65; P<.001; adjusted R2=0.36). Within another subcohort (n=173) with normal cognition and matched covariates (age, sex, BMI, etc), hypothesis-driven key capabilities and specific game features were significantly correlated with the presence of PNP. Predictive models using selected game features achieved 76.1% (left) and 81.7% (right foot) accuracy for PNP detection. Multiclass models yielded an area under the receiver operating characteristic curve of 0.76 (left foot) and 0.72 (right foot) for assessing nerve damage patterns (small, large, or mixed nerve fiber damage). The game-based application presents a promising avenue for PNP screening and classification. Evaluation in expanded cohorts may iteratively optimize artificial intelligence model efficacy. The integration of engaging motivational elements and automated data interpretation will support acceptance as a telemedical application.

Median nerve conduction study findings in various arm positions.

To investigate the effects of various arm positions on median nerve conduction studies (NCSs). This prospective cohort study, conducted at Adana City Training and Research Hospital between January and July 2023, included 20 healthy participants. Median NCSs were performed on the participants in three different standing positions with the elbow as the stimulation point: 1) with the arm adducted (P1), 2) with the arm anteflexed (P2), and 3) with the arm raised upwards (P3). We obtained median nerve compound muscle action potential (CMAP) latency, duration, peak-to-peak (PP) amplitude, onset-to-negative peak (OP) amplitude, negative area/duration. Three CMAPs were obtained in each position, and the mean and minimum/maximum values at each position were analyzed. The mean age (minimum-maximum) of the participants (11 male, 9 female) was 28.5±6.5 (20-42) years. Median nerve CMAP means (median) of latency/negative duration in the P1, P2, and P3 positions were 6.82±0.59 (6.83)/5.50±0.76 (5.39) ms, 6.99±0.56 (7.02)/5.72±0.73 (5.73) ms, and 7.03±0.58 (7.12)/5.79±0.80 (5.83) ms. Median nerve CMAP mean/minimum latency and negative duration were lowest in the P1 position (p<0.05). The mean median nerve CMAP OP amplitude was highest in P3 than P1 or P2 (p=0.042 and p=0.048). Median NCS results differed based on the position of the arm.

Trigeminal neuralgia, demyelinating polyneuropathy, and central nervous system involvement in a patient with an SH3TC2 mutation

Abstract Background Charcot-Marie-Tooth type 4C (CMT4C) is a slowly progressive, autosomal recessive, sensorimotor polyneuropathy characterized by demyelination and distinct clinical features, including cranial nerve involvement. CMT4C is associated with pathogenic mutations in the SH3TC2 gene. Methods A patient presenting with gait instability due to demyelinating polyneuropathy and refractory trigeminal neuralgia underwent comprehensive evaluation. Nerve conduction studies, magnetic resonance imaging (MRI) of the brain, cervical spine, and thoracic spine, lumbar puncture, and genetic test through next generation sequencing were performed. Results The genetic test found an Arg1109Stop mutation in the SH3TC2 gene, associated with demyelinating polyneuropathy and cranial neuropathy. Interestingly, brain MRI showed multiple, nonenhancing white matter hyperintensities. This is the first case of CMT4C associated with white matter lesions. Conclusion Any patient with slowly progressive peripheral nervous system symptoms and disproportionally abnormal nerve conduction study findings should be tested for an inherited polyneuropathy and brain imaging for screening of possible central nervous system involvement should be performed. Further investigation is needed to elucidate the pathogenetic basis of CMT4C and a possible association with white matter lesions.

Dorsal ulnar cutaneous nerve conduction study based on nerve ultrasound

This study investigates the impact of the anatomical separation point of the dorsal ulnar cutaneous nerve (DUCN) on nerve conduction studies (NCS). Involving 25 subjects with DUCN NCS findings, it utilizes ultrasound to mark the DUCN's divergence from the ulnar nerve. NCS was performed at four points relative to the separation point. The findings indicate the maximal amplitudes occurred 2 cm distal to the separation point. The study suggests it is ideal when the stimulation is performed between the seperation point and 2 cm distal to it.

Age-stratified mosaic of neuropathies: a comprehensive analysis of the prevalence and patterns in different age groups

Background and Objective: Neuropathies pose significant challenges in diagnosis and management due to their heterogeneous etiologies, varied clinical presentations, and differential prevalence across age groups. The objective of this study was to analyze the distribution of neuropathies among patients in various age brackets, highlighting prevalent neuropathic types and their clinical implications. Methods: From September 18, 2018 to September 17, 2019, 405 patients from Neurology Ward of Chandka Medical College Hospital in Larkana were included in this retrospective cross-sectional comprehensive analysis. Nerve conduction studies (NCS) of these patients were conducted in the electrophysiology department. The study cohort was stratified into age groups, allowing us to compare the frequency and NCS findings of various neuropathies. Statistical analysis using SPSS 23 was performed to ascertain the prevalence and distribution of specific neuropathies across different age brackets. Results: In the younger age group below 20 years, a prominent prevalence of neuropathies linked to hereditary factors was notable. Contrastingly, within the 20-40 age stratum, distinctive distribution patterns were observed, showcasing prevalent occurrences of Acute Inflammatory Demyelinating Polyneuropathy (AIDP) and those induced by trauma. Similarly, in the 40-60 and above 60 age cohorts, unique prevalence profiles emerged, spotlighting Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and neuropathies associated with diabetes and malignancies as most common. Conclusion: The findings of this study shed light on the age-related distribution of neuropathies and the corresponding NCS profiles. Such insights can aid in improving the diagnosis and management of neuropathies based on age, ensuring more tailored and effective healthcare strategies.

Traumatic Brain Injury and Guillain-Barré Syndrome: Tale of an Illicit Affair—Case Report and Brief Review of Literature

AbstractGuillain-Barré syndrome (GBS) is a common entity in neurology clinics. A variety of etiologies have been implicated in the presentation of GBS. Although rarely reported, traumatic brain injury (TBI) has also been reported to cause GBS. In this article, we report a similar case of GBS that occurred following TBI and the patient presented with acute flaccid paraparesis with intact strength in upper limbs. Paraparesis progressed to quadriparesis simulating a case of spinal injury, without any correlating imaging findings. Nerve conduction study findings, cerebrospinal fluid studies, and clinical examination led to the diagnosis of post-TBI GBS. A review of similar cases reported in literature is also attached. High index of suspicion should be maintained for GBS in all cases of imaging-negative post-TBI limb weakness which may simulate acute spinal injury.

Changes in the Cutaneous Nerve Fiber Staining and Distribution of PGP9.5 in Clinically Uninvolved Skin in Leprosy Patients after Completion of Multidrug Therapy and Assessing PGP9.5 as a Marker of Treatment Response.

Subclinical involvement of nerves may sometimes be present much before the overt clinical manifestations become apparent. Protein gene product (PGP) 9.5, a ubiquitin-C-terminal hydrolase, has been widely used as a marker to study the involvement of peripheral nerve fibers in many diseases. To evaluate the change in cutaneous nerve fiber staining and distribution from pre-treatment and post completion of multidrug therapy through the expression of PGP9.5 and to assess PGP9.5 as a marker of treatment response. In this prospective single-center observational study, skin biopsy was taken in patients with leprosy, having areas of nerve function impairment (NFI), based on findings of nerve conduction studies (NCSs), but not having lesions or impaired tactile or thermal impairment clinically. The thin nerve fiber density in the clinically normal skin in areas supplied by nerve showing changes of sensory neuropathy was evaluated to study the density of the fibers. A second biopsy was taken at the end of treatment from a site near the previous site to assess the changes in intra-epidermal nerve fiber staining and distribution. Thirty-three patients were recruited in the present study (24 males and 9 females). Pre-treatment, 27 patients had abnormal NCSs, while six patients did not have any evidence of neuropathy on NCSs. Staining for nerve fibers using PGP9.5; in the epidermis was positive in five patients pre-treatment and 11 patients post treatment (P = 0.181). Staining in the dermis revealed positivity in 14 pre-treatment, which increased to 18 post treatment (P = 0.342). Adnexae showed positivity in five patients pre-treatment and increased to 17 post treatment (P = 0.005). A reduced PGP9.5 staining in the epidermal, dermal, and adnexal regions was seen in leprosy patients, which improved post treatment. Thus, PGP9.5 may serve as a marker of NFI and treatment response.

Comparing FGFR-3 and TS-HDS Seropositive Small Fiber Neuropathy: Unique Patient Features, Symptoms, Laboratory, and Nerve Conduction Study Findings.

Small fiber neuropathy presents a significant diagnostic and therapeutic challenge. To solve this challenge, efforts have been made to identify autoantibodies associated with this condition. Previous literature has often considered tri-sulfated heparin disaccharide (TS-HDS) and fibroblast growth factor receptor 3 (FGFR3) as a singular seropositive group and/or focused primarily on symptomatic associations. One hundred seventy-two small fiber neuropathy patients with a Washington University Sensory Neuropathy panel were selected for TS-HDS seropositivity, FGFR-3 seropositivity, and seronegative controls. Data were collected to on the demographic, symptomatic, and laboratory profiles of each subgroup. Percent female (P = 0.0043), frequency of neuropathic pain symptoms (P = 0.0074), and erythrocyte sedimentation rate (P = 0.0293), vitamin D (P < 0.0001), and vitamin B12 (P = 0.0033) differed between the groups. Skin biopsy was more frequently normal within both the FGFR-3 and the TS-HDS cohort (P = 0.0253). TS-HDS and FGFR-3 display a distinct phenotype from both controls and one another. Immunoglobulin M (IgM) against FGFR-3 and IgM against TS-HDS may be individually valuable markers for the development of distinct clinical phenotypes.

Establishing the diagnosis of radial tunnel syndrome: a systematic review of published clinical series.

Radial tunnel syndrome (RTS) is a controversial diagnosis due to non-specific exam findings and frequent absence of positive electromyography (EMG) and nerve conduction study (NCS) findings. The purpose of this study was to identify the methods used to diagnose RTS in the literature. We queried PubMed, Embase, Web of Science, and Cochrane databases per PRISMA guidelines. Extracted data included article and patient characteristics, diagnostic assessments utilized and their respective findings, and treatments. Objective data were summarized descriptively. The relationship between reported diagnostic findings (i.e., physical exam and diagnostic tests) and treatments was assessed via a descriptive synthesis. Our review included 13 studies and 391 upper extremities. All studies utilized physical exam in diagnosing RTS; most commonly, patients had tenderness over the radial tunnel (381/391, 97%). Preoperative EMG/NCS was reported by 11/13 studies, with abnormal findings in 8.9% (29/327) of upper extremities. Steroid and/or lidocaine injection for presumed lateral epicondylitis was reported by 9/13 studies (46/295 upper extremities, 16%), with RTS being diagnosed after patients received little to no relief. It was also common to inject the radial tunnel to make the diagnosis (218/295, 74%). The most common reported intraoperative finding was narrowing of the PIN (38/137, 28%). The intraoperative compressive site most commonly reported was the arcade of Frohse (142/306, 46%). There is substantial heterogeneity in modalities used to diagnose RTS and the reported definition of RTS. This, in conjunction with many patients having concomitant lateral epicondylitis, makes it difficult to compare treatment outcomes for RTS. Level III. Systematic review of retrospective and prospective cohort studies.

Evaluation of smartphone-assisted infrared thermal imaging efficiency in carpal tunnel syndrome

BackgroundThermography is an industrial method for surface temperature measurements, and although it is medically safe and non-invasive, its place in daily practice has been limited. With the development of technology, thermal cameras have become more accessible and practical via adaptation to mobile phones. Among patients evaluated with bilateral nerve conduction studies (NCS) for suspected carpal tunnel syndrome (CTS), those with electrophysiological findings consistent with mild-to-moderate unilateral CTS were accepted for this prospective study. The hands with positive NCS findings were the study group, and the unaffected hands were the control group. The images were evaluated with the thermal analysis software (FLIR Tools ver. 6.4, Windows 10) and compared with NCS for statistical significance. In addition, thermal images were examined by three orthopaedic surgeons, and interobserver correlation was analyzed. Our study aims to evaluate the mobile phone-assisted thermal camera (FLIR One Pro, FLIR Systems, Wilsonville, OR, USA) as a suitable tool to diagnose CTS.Results48 patients, 35 women and 13 men were included in the study. Bilaterally, a total of 96 hands were evaluated. 18 patients had mild, and 30 patients had moderate NCS stages unilaterally. The mean temperature difference at the region of interest in the palm, first and third fingers were statistically significant between the study and control groups (p < 0.05). NCS values and stages were correlated with the temperature difference in the third finger (p = 0.002). The inter-observer reliability was high (ICC = 0.858) while detecting temperature differences.ConclusionsSince smartphone-assisted thermal cameras are easy and convenient to use, we think they are helpful in the daily practice of diagnosing mild-to-moderate carpal tunnel syndrome.

Novel ABCD1 variant causes phenotype of adrenomyeloneuropathy with cerebral involvement in Ukrainian siblings: first adult hematopoietic stem cell transplantation for ALD in Ukraine: a case report

BackgroundThis article presents a case study of two white male siblings of 24 and 31 years of age of self-reported Ukrainian ethnicity diagnosed with adrenomyeloneuropathy (AMN) associated with a novel splice site mutation in the ABCD1 gene. AMN represents a form of X-linked adrenoleukodystrophy (X-ALD) characterized by demyelination of the spinal cord and peripheral nerves. The case also presents the first adult haematopoietic stem cell transplant (HSCT) for adrenomyeloneuropathy in Ukraine. The rarity of this mutation and its cerebral involvement and the treatment make this case noteworthy and underscore the significance of reporting it to contribute to the existing medical knowledge.Case presentationThe patients of 24 and 31 years initially exhibited progressive gait disturbance, lower extremity pain, and urinary incontinence, with the older sibling experiencing more advanced symptoms of speech, hearing, and vision disturbances. A comprehensive genetic analysis identified an unreported splice site mutation in exon 3 of the ABCD1 gene, leading to the manifestation of AMN. The inheritance pattern was consistent with X-linked recessive transmission. The article also outlines the clinical features, magnetic resonance imaging (MRI), and nerve conduction study (NCS) findings. Moreover, it discusses the genetic profile of the affected individuals and female carriers within the family. The younger sibling underwent HSCT, which was complicated by mediastinal lymph node and lung tuberculosis, adding to the complexity of managing adult ALD patients.ConclusionsThis report emphasizes the importance of genetic testing in diagnosing and comprehending the underlying mechanisms of rare genetic disorders, such as AMN with cerebral involvement. The identification of a novel splice site mutation expands our understanding of the genetic landscape of this condition. Additionally, the challenges and complications encountered during the hematopoietic stem cell transplant procedure underscore the need for cautious consideration and personalized approaches in adult ALD patients.

Therapeutic Outcomes and Electrophysiological Biomarkers in Anti-Myelin-Associated Glycoprotein Neuropathy: A Multicenter Cohort Study in South Korea.

Unlike other immune-mediated neuropathies, anti-myelin-associated glycoprotein (MAG) neuropathy is often refractory to immunotherapy. It is necessary to compare the relative efficacies of various immunotherapies and develop objective biomarkers in order to optimize its clinical management. This study recruited 91 patients with high anti-MAG antibody titers from 7 tertiary hospitals in South Korea. We analyzed the baseline characteristics, therapeutic outcomes, and nerve conduction study (NCS) findings of 68 patients and excluded 23 false positive cases. The rate of positive responses to treatment was highest using zanubrutinib (50%) and rituximab (36.4%), followed by corticosteroids (16.7%), immunosuppressants (9.5%), intravenous immunoglobulin (5%), and plasma exchange (0%). Disability and weakness were significantly associated with multiple NCS parameters at the time of diagnosis, especially distal compound muscle action potential (CMAP) amplitudes. Moreover, the longitudinal trajectory of the average CMAP amplitudes paralleled the clinical courses, with a 16.2 percentile decrease as an optimal cutoff for predicting a clinical exacerbation (area under the receiver operating characteristic curve=0.792). Our study supports the use of NCS as an objective marker for estimating disease burden and tracking clinical changes in patients with anti-MAG neuropathy. We have described the beneficial effects of rituximab and a new drug, zanubrutinib, compared with conventional immunotherapies.

Chapter 3 - The role of electrodiagnosis in focal neuropathies

Electrodiagnostic (EDX) testing plays an important role in confirming a mononeuropathy, localizing the site of nerve injury, defining the pathophysiology, and assessing the severity and prognosis. The combination of nerve conduction studies (NCS) and needle electromyography findings provides the necessary information to fully assess a nerve. The pattern of NCS abnormalities reflects the underlying pathophysiology, with focal slowing or conduction block in neuropraxic injuries and reduced amplitudes in axonotmetic injuries. Needle electromyography findings, including spontaneous activity and voluntary motor unit potential changes, complement the NCS findings and further characterize chronicity and degree of axon loss and reinnervation. EDX is used as an objective marker to follow the progression of a mononeuropathy over time.

Nerve conduction study findings in females with systemic lupus erythematosus

Aim of the workTo investigate the frequency, characteristics, and associated factors of systemic lupus erythematosus-related peripheral neuropathy (SLE-PN) using nerve conduction study (NCS). Patients and methodsA retrospective chart review was conducted at the Rheumatology clinics of King Abdulaziz University Hospital, Jeddah, Saudi Arabia from 2016 to 2020. Eligibility included systemic lupus erythematosus (SLE) diagnosed patients with at least one NCS result in their clinical records. Demographic, clinical, and biological characteristics were collected. ResultsAmong 101 female SLE patients, abnormal NCS findings were observed in 11 (10.9%) patients. Of those with abnormal NCS, 27.3% showed mixed axonal and demyelinated motor neuropathy, 18.2% had sensory-motor axonal neuropathy, another 18.2% presented with axonal left common peroneal neuropathy, and the same percentage was observed for axonal sensory neuropathy. Comparisons between abnormal and normal NCS groups in a study population revealed that the abnormal NCS group had significantly higher proportions of non-Saudi nationality, lupus nephritis, seizures, and high SLICC DI. Furthermore, this group was associated with higher ANA titers and exhibited a non-significant trend towards increased positive anti-DNA frequency. Multivariate analysis identified non-Saudi nationality and the presence of end-organ damage as two significant predictors of SLE-related PN. ConclusionPeripheral neuropathy in SLE patients in Saudi Arabia is not uncommon, specifically those with heightened disease activity, organ damage, or disadvantaged socioeconomic backgrounds. Predominantly, the condition presents as axonopathy impacting sensory nerves, with possible motor involvement. The critical role of electrophysiological studies in early detection and improved patient management is high lightened.

Changes in electrophysiological findings of spinal muscular atrophy type I after the administration of nusinersen and onasemnogene abeparvovec: two case reports

BackgroundRecently, there have been significant advances in the treatment of spinal muscular atrophy (SMA). Although clinical improvement in patients with SMA after the treatment has been reported, changes in electrophysiological findings, especially needle electromyography (EMG), have rarely been reported. Herein, we report the posttreatment changes in EMG and nerve conduction study findings over time in two patients with SMA type I.Case presentationPatient 1: A 2.5-year-old girl was diagnosed with SMA type I at 1 month of age. She received nusinersen four times and onasemnogene abeparvovec (OA) was administered at 6 months of age. The compound muscle action potential (CMAP) amplitudes of the median and tibial nerves increased over time. The needle EMG after the treatment showed high-amplitude motor unit potentials (MUPs) suggestive of reinnervation during voluntary contraction, which were not seen before the treatment. However, fibrillation potentials at rest were still seen after the treatment. Patient 2: A 2-year-old girl was diagnosed with SMA type I at 6 months of age. She had received nusinersen two times and OA was administered at 7 months of age. The CMAP amplitudes and the MUPs presented similar changes as presented in Case 1.ConclusionThis is the first report on the changes in needle EMG findings after treatment in patients with SMA type I. These findings suggested that peripheral nerve reinnervation occurred after the treatment, although active denervation was still present. The accumulation of these findings will be important for evaluating the effectiveness of treatment for SMA in the future.

Recurrent Guillain-Barré Syndrome Associated with the Second Episode of Campylobacter jejuni Infection.

Guillain-Barré syndrome (GBS) cases are generally monophasic, and recurrence is rare. However, the pathogenesis and pathophysiology of recurrent GBS remain to be fully elucidated. There are few detailed reports of patients who have been infected twice with Campylobacter jejuni and have developed GBS twice. We herein report a case of recurrent GBS in a 21-year-old man with a history of GBS caused by C. jejuni infection at 19 years old. Although our patient was reinfected with C. jejuni, several different anti-ganglioside antibodies were identified, and the clinical manifestations were more severe than those in the first GBS episode. We compared the anti-ganglioside antibodies and nerve conduction studies findings between the two GBS episodes. This case suggested that different antibodies are involved and produce different symptoms even when C. jejuni infection is the trigger in recurrent episodes.

Homozygous Mutations in GDAP1 and MFN2 Genes Resulted in Autosomal Recessive Forms of Charcot-Marie-Tooth Disease in Consanguineous Pakistani Families.

Charcot-Marie-Tooth disease (CMT) is a heritable neurodegenerative disease of peripheral nervous system diseases in which more than 100 genes and their mutations are associated. Two consanguineous families Dera Ghazi Khan (PAK-CMT1-DG KHAN) and Layyah (PAK-CMT2-LAYYAH) with multiple CMT-affected subjects were enrolled from Punjab province in Pakistan. Basic epidemiological data were collected for the subjects. Nerve conduction study (NCS) and electromyography (EMG) were performed for the patients. Whole-exome sequencing (WES) followed by Sanger sequencing was applied to report the genetic basic of CMT. The NCS findings revealed that sensory and motor nerve conduction velocities for both families were <38 m/s. EMG presented denervation, neuropathic motor unit potential, and reduced interference pattern of peripheral nerves. WES identified that a novel nonsense mutation (c. 226 G>T) in GADP1 gene and a previously known missense mutation in MFN2 gene (c. 334 G>A) cause CMT4A (Charcot-Marie-Tooth disease type 4A) in the PAK-CMT1-DG KHAN family and CMT2A (Charcot-Marie-Tooth disease type 2A) in the PAK-CMT2-LAYYAH family, respectively. Mutations followed Mendelian pattern with autosomal recessive mode of inheritance. Multiple sequence alignment by Clustal Omega indicated that mutation-containing domain in both genes is highly conserved, and in situ analysis revealed that both mutations are likely to be pathogenic. We reported that a novel nonsense mutation and a previously known missense mutation in GAPD1 gene and MFN2 gene, respectively, cause CMT in consanguineous Pakistani families.

Afterdischarges in myotonic dystrophy type 1.

Electrodiagnostic testing is an important screening test for myotonic dystrophy type 1 (DM1). Although myotonic discharges are observed on electromyography in cases of DM1, it is difficult to distinguish DM1 from other myotonic disorders clinically. In the present study, afterdischarges, another type of pathological potential revealed by electrodiagnostic testing, were analyzed, and their role in distinguishing DM1 from other myotonic disorders was explored. Data from 33 patients with myotonic discharges on electromyography were analyzed retrospectively. According to gene testing, the patients were divided into DM1 (n = 20) and non-DM1 myotonia (n = 13) groups. Afterdischarges were investigated by retrospectively evaluating the electrodiagnostic findings of motor nerve conduction studies, F-waves, and repetitive nerve stimulations. Afterdischarges were observed in 17 of the 20 patients with DM1, with an occurrence rate of approximately 85%. However, afterdischarges were absent in all patients with non-DM1 myotonia. There were significant differences in the occurrence rate between the two groups (P < 0.01). Afterdischarges may serve as a suggestive role in clinical diagnosis of DM1. The discovery that DM1 can present with afterdischarges may pave a new way to study the pathogenesis of DM1.

Surgical Outcomes of Common Peroneal Nerve Entrapment Neuropathy Associated with L5 Radiculopathy.

Impingement of the common peroneal nerve, a branch of the L5 nerve root, causes common peroneal nerve entrapment neuropathy (CPNE). Although there are cases of CPNE associated with L5 radiculopathy, surgical intervention's effectiveness remains to be elucidated. This retrospective case-control study aimed to evaluate the efficacy of surgery in patients with CPNE associated with L5 radiculopathy. Twenty-two patients (25 limbs) with surgically treated CPNE between 2015 and 2022 were retrospectively reviewed. The limbs were classified into two groups: group R (limbs of CPNE associated with L5 radiculopathy) and group O (limbs of CPNE without L5 radiculopathy). The durations from onset to surgery, the nerve conduction studies (NCSs), and postoperative improvement rates for motor weakness, pain, and dysesthesia were compared between the groups. Group R included 15 limbs (13 patients), and group O included 10 limbs (9 patients). There were no significant differences in the duration from onset to surgery or abnormal findings of NCS between the two groups. The postoperative improvement rates were 88% and 100% (p = 0.62) for muscle weakness, 87% and 80% (p = 0.53) for pain, and 71% and 56% (p = 0.37) for dysesthesia in group R and group O, respectively, without significant differences between groups. CPNE associated with L5 radiculopathy is common, and the results of the present study showed that the surgical outcomes in such cases were satisfactory and comparable to those in CPNE without L5 radiculopathy.