Normal Nerve Conduction Studies Research Articles

Median Nerve Shear Wave Elastography is Associated With the Neurophysiological Severity of Carpal Tunnel Syndrome.

This study examines the associations between the median nerve (MN) shear wave elastography (SWE), the MN cross-sectional area (CSA), patient's symptoms, and the neurophysiological severity of carpal tunnel syndrome (CTS). The most appropriate site to perform SWE was also tested. This prospective study comprised 86 wrists of 47 consecutive patients who volunteered for MN ultrasound after an electrodiagnostic study. The neurophysiological severity of CTS was assessed according to the results of a nerve conduction study (NCS). The MN CSA was measured at the carpal tunnel inlet (wCSA) and the forearm (fCSA). SWE was performed on the MN in a longitudinal orientation at the wrist crease (wSWE), at the forearm (fSWE), and within the carpal tunnel (tSWE). The wCSA and wSWE correlated positively with the neurophysiological severity of CTS (r = .619, P < .001; r = .582, P < .001, respectively). The optimal cut-off values to discriminate the groups with normal NCS and with findings indicating CTS were 10.5 mm2 for the wCSA and 4.12 m/s for the wSWE. With these cut-off values, wCSA had a sensitivity of 80% and specificity of 87% and wSWE a sensitivity of 88% and specificity of 76%. Neither tSWE nor fSWE correlated with the neurophysiological severity of CTS or differed between NCS negative and positive groups (P = .429, P = .736, respectively). Shear wave velocity in the MN at the carpal tunnel inlet increases in CTS and correlates to the neurophysiological CTS severity equivalently to CSA measured at the same site.

A revised approach for electrodiagnosis-based severity classification in carpal tunnel syndrome

BACKGROUND: An electrodiagnostic evaluation is conducted to diagnose carpal tunnel syndrome (CTS) and evaluate its severity. OBJECTIVE: This study proposes a revised approach for classifying the severity of electrophysiological findings for patients with CTS. METHODS: This retrospective cross-sectional study included patients with CTS confirmed through electrodiagnostic evaluations. Based on the Stevens’ classification, the patients were divided into three groups (mild/moderate/severe). A new intermediate group was defined to identify patients with normal motor nerve conduction studies and abnormal electromyographic results. CTS pain was evaluated using a numeric rate scale. Physical examinations and sonographic evaluation were performed to detect anatomical abnormalities. RESULTS: Overall, 1,069 CTS hands of 850 CTS patients were included. The mean age was 57.9 ± 10.8 years, and 336 (39.5%) were men. There were 522 (48.8%) mild cases; 281 (26.3%) moderate cases; and 266 (24.9%) severe cases. In the severe group, 49 cases were reclassified into the intermediate group. The median cross-sectional area in the intermediate group significantly differed from that in the severe group. However, the pain score significantly differed from that of the moderate group. CONCLUSION: The intermediate CTS group showed clinical features that were intermediate to those of the moderate and severe CTS groups.

Cutaneous nerve biopsy in patients with symptoms of small fiber neuropathy: a retrospective study.

We aimed to investigate to what extent small fiber tests were abnormal in an unselected retrospective patient material with symptoms suggesting that small fiber neuropathy (SFN) could be present, and to evaluate possible gender differences. Nerve conduction studies (NCS), skin biopsy for determination of intraepidermal nerve fiber density (IENFD) and quantitative sensory testing (QST) were performed. Z-scores were calculated from reference materials to adjust for the effects of age and gender/height. Two hundred and three patients, 148 females and 55 males had normal NCS and were considered to have possible SFN. 45.3 % had reduced IENFD, 43.2 % of the females and 50.9 % of the males. Mean IENFD was 7.3±2.6 fibers/mm in females and 6.1±2.3 in males (p<0.001), but the difference was not significant when adopting Z-scores. Comparison of gender differences between those with normal and abnormal IENFD were not significant when Z-scores were applied. QST was abnormal in 50 % of the patients (48.9 % in females and 52.9 % in males). In the low IENFD group 45 cases out of 90 (50 %) were recorded with abnormal QST. In those with normal IENFD 51 of 102 (50 %) showed abnormal QST. Less than half of these patients had reduced IENFD, and 50 % had abnormal QST. There were no gender differences. A more strict selection of patients might have increased the sensitivity, but functional changes in unmyelinated nerve fibers are also known to occur with normal IENFD. Approval to collect data was given by the Norwegian data protection authority at University Hospital of North Norway (Project no. 02028).

Small fiber neuropathy in irritable bowel syndrome.

In this study, we intend to evaluate the occurrence of small fiber neuropathy in patients with irritable bowel syndrome (IBS). Small fiber neuropathy (SFN) is a sensory neuropathy that results from the degeneration of small Aδ and unmyelinated C fibers. SFN manifests positive symptoms, such as tingling, burning, prickling, and aching, and negative symptoms, including numbness, tightness, and coldness. The SFN coexistence with other comorbidities (e.g., fibromyalgia, inflammatory bowel disease, celiac disease) has been reported in previous studies. We conducted a cross-sectional study to assess the coexistence of SFN and IBS. Forty-two IBS patients and forty-three healthy individuals were asked to complete the Michigan Neuropathy Screening Instrument (MNSI) questionnaire. Results greater than three (>3) were considered positive. Participants with positive MNSI questionnaire results were examined for any neuropathy signs according to the Utah Early Neuropathy Scale (UENS) examination. The participants with positive results for the questionnaire and examination were checked for the sural and the superficial peroneal nerve conduction study (NCS). Normal NCS represented intact large fibers and the diagnosis of SFN. Ten participants, 7 (16.7 %) in the IBS group and 3 (6.9 %) in the healthy group, had positive results for the questionnaire. Four participants were positive for the examination, with normal NCS, and were classified as SFN-positive. All four SFN diagnoses were from the IBS group. No one in the healthy group was diagnosed with SFN. We could find a significant statistical difference (p<0.05) between the IBS and healthy groups regarding the prevalence of SFN diagnosis. The co-occurrence of SFN and IBS suggests the possibility of a generalized neuropathy syndrome characterized by widespread neuronal impairment. Thus, any peripheral neuropathy symptom in IBS patients (and potentially other chronic pain disorders) should be evaluated for SFN since timely diagnosis and proper treatment result in a better quality of life for the patients.

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.

Detailed clinical, physiological and pathological phenotyping can impact access to disease-modifying treatments in ATTR carriers

BackgroundHereditary transthyretin amyloidosis is a life-threatening autosomal dominant systemic disease due to pathogenic TTR variants (ATTRv), mostly affecting the peripheral nerves and heart. The disease is characterised by a combination...

Post-diphtheritic Polyneuropathy in Children with Diphtheria: A Prospective Observational Study

This study aimed to determine the proportion of diphtheria patients who develop post-diphtheritic polyneuropathy (DP) later on and also to study the clinical features and outcomes of children with post-DP. This prospective observational study was conducted at the Department of Pediatrics, King George’s Medical University, Lucknow, Uttar Pradesh, India. Children under 14 hospitalized with clinically diagnosed diphtheria and post-DP were recruited (n = 81). Detailed clinical examination with appropriate investigations was conducted, including throat swabs for staining and culture for Corynebacterium diphtheria, nerve conduction studies, electrocardiography, and echocardiography. The data were analyzed using Statistical Package for Social Sciences (SPSS) version 16.0. Seventy-four cases of diphtheria and seven cases of post-DP were enrolled, 56.8% were male, and the most prevalent age group afflicted was two to five years. Fifty-three children (65.4%) were partially immunized for diphtheria. Neck swelling, voice change, difficulty breathing, noisy breathing, respiratory involvement, and stridor were significantly more common in the unimmunized group. Voice change, heart rate irregularity, and hypotension were substantially more common in patients who developed clinical neuropathy than those who did not. Early administration of antibiotics in children with diphtheria before hospital admission was found to be significant in those children who did not develop clinical polyneuropathy, 38.5% of diphtheria survivors had abnormal nerve conduction study at six weeks of illness. Neck swelling and change in voice were significantly more common in patients with abnormal nerve conduction velocity (NCV) than in normal nerve conduction studies, 87.5% of children who had taken antibiotics before hospital admission had no clinical neuropathy, and NCV was also normal. Clinical neuropathy developed in just 20% of diphtheria patients with impaired NCV. Any child diagnosed with diphtheria should be followed for three to six months in anticipation of neurological complications. DP carries a good prognosis; hence, timely diagnosis and differentiation from other neuropathies is a prerequisite for rational management.

Normal Values of Nerve Conduction Studies in Children Aged 7 Days to 14 Years Referred to Electrodiagnosis Clinic of Iranian Children's Medical Center

Background: The normal values of nerve conduction studies (NCS) are different in children compared to adults. Moreover, racial and geographical factors can affect these values. Objectives: The present study aimed to investigate the normal NCS values in children of different ages. Methods: The present cross-sectional study included children referred to the Electrodiagnosis Clinic of the Children's Medical Center in Iran, who had normal NCS results based on the references and had no exclusion criteria. The patients were divided into 8 age groups (7 days to one month, 1 - 3 months, 3 - 6 months, 6 - 12 months, 1 - 2 years, 2 - 4 years, 4 - 6 years, and 6 - 14 years), and the NCS was performed using a Nihon Kohden electromyogram. The NCS values in the normal range were included in the analysis. Results: The normal ranges of amplitude and conduction velocity of 4 motor nerves (median, ulnar, deep peroneal, and tibial) and 2 sensory nerves (median and medial plantar), as well as the F-wave latency values of 2 nerves (ulnar and tibial), were established as the reference values for the pediatric patients. Conclusions: The NCS parameters of Iranian children were slightly different from the normal references reported by studies in other countries. Moreover, the SNAP and CMAP amplitudes and motor conduction velocity of these children usually reached the normal values of the adult population earlier.

Sympathetic skin response for early detection of type 2 diabetic peripheral neuropathy and nephropathy.

Diabetic peripheral neuropathy (DPN) and diabetic nephropathy (DN) are common complications of type 2 diabetes mellitus (T2DM). Although nerve conduction studies (NCS) and sympathetic skin response (SSR) can detect DPN, the more sensitive method for early diagnosis remains unclear. Furthermore, whether DPN can be used as a predictor for diabetic nephropathy needs clarification. We evaluated nerve conduction studies, sympathetic skin response, and the diabetic nephropathy indicator microalbuminuria (MAU) in 192 patients with type 2 diabetes mellitus and 50 healthy controls. Patients with type 2 diabetes mellitus showed a lower sensory nerve conduction velocity (SCV), sensory active nerve potential (SNAP), motor nerve conduction velocity (MCV), and compound motor action potential (CMAP) than the controls on NCS. Abnormal rates for nerve conduction studies and sympathetic skin response were 75.0% and 83.3%, respectively, in patients with type 2 diabetes mellitus. Interestingly, 54.2% of patients with normal nerve conduction studies had an abnormal sympathetic skin response. Moreover, we found a positive correlation between sympathetic skin response and microalbuminuria for the first time. The abnormal rate of microalbuminuria was 53.8%, lower than that of abnormal nerve conduction studies or sympathetic skin response patients. Sympathetic skin response is a more sensitive method than nerve conduction studies for the early diagnosis of diabetic peripheral neuropathy. Abnormal sympathetic skin response might serve as an indicator for early diabetic nephropathy. Additionally, diabetic peripheral neuropathy may occur earlier than diabetic nephropathy in the development of type 2 diabetes mellitus.

Nerve Conduction Differences in a Large Clinical Population: The Role of Age and Sex.

The normal limits of nerve conduction studies are commonly determined by testing healthy subjects. However, in comprehensive real-life nerve conduction electrodiagnostic (EDX) evaluations, multiple nerves are tested, including normal nerves, for purposes of comparison with abnormal ones. This study aims to evaluate the average values of normal nerve conduction studies in a large population and examined the influence of age and sex. EDX parameters were extracted from an electronic database of studies performed from May 2016 to February 2022. Established normal values were used to determine the classification of a nerve study as normal. We identified 10,648 EDX reports with 5077 normally interpreted nerve conduction studies (47.6%) of which 57% (n = 2890) were for females. The median age of studies with no abnormalities was 45.1 years (range < 1 to 92) overall and 42.5 years (range: 0.16 -89.5 years) for males and 47.5 years (range:<1 -91.7) for females. Correlations between age and amplitude, latency, and velocity (p < 0.001) were observed in most nerves. Amplitude correlated negatively with age in adults in all nerves with a mean of -0.44 (range: -0.24 to -0.62). However, in the pediatric population (age < 18 years), amplitude as well as velocity increased significantly with age. In the adult cohort, sex differences were noted, where females had higher mean sensory nerve action potentials in ulnar, median, and radial evaluations (p < 0.001). In older patients (aged > 70 years) with normally interpreted EDX studies (845 records of 528 patients), sural responses were present in 97%. This real-life study confirms that advanced aging is associated with decreased nerve conduction amplitudes, increased latency, and the slowing of conduction velocity. The findings also indicate higher sensory amplitudes and conduction velocities in females. Sural nerve responses were identified in most adults over age 70.

ÜST VE ALT EKSTREMİTEDE AYNI SİNİR TARAFINDAN İNERVE OLAN PROKSİMAL VE DİSTAL KASLARDAN KAYDEDİLEN F DALGASI: YENİ BİR YÖNTEM OLABİLİR Mİ?

Purpose&#x0D; The F- wave is a valuable measurement that provides information about both the proximal and distal parts of the nerve. Classical F-wave recording methods are performed from the distal muscles of the limb and so are affected from distal pathologies. Nerve conduction velocity of a nerve is affected by the diameter of the nerve. The diameter of a nerve gets thinner as it gives branches and travels distally. So it is expected that the nerve conduction velocity of a nerve is faster in proximal segment of the nerve than the distal part even they are the parts of the same nerve. The aim of this study is to compare the nerve conduction parameters of F waves recorded in proximal and distal muscles innervated by the same nerve. Which will provide additional information and may be valuable in detecting proximal pathologies accompanying background pathologies affecting the distal nerve&#x0D; Materials and Methods&#x0D; Twenty –six healthy volunteers who have normal routine nerve conduction studies are included in this study. The latencies of ulnar and peroneal F-waves of all participants were recorded from the proximal and distal muscles innervated by the same nerve.&#x0D; Results&#x0D; F-wave latencies recorded from proximal muscles were significantly later than the ones recorded from distal muscles.&#x0D; Conclusion&#x0D; Although the distances travelled by stimulation are shorter in F latencies recorded from proximal muscles , and the segment /branch of the nerve is expected to be thicker and faster however the latencies recorded from proximal muscles were longer than the ones recorded from distal muscles . This may be due to the distance of the recording electrodes effected by subcutaneous tissues in the proximal large mass muscles. One reason for this difference may be that the proximal relatively large mass muscles have higher desynchronization and temporal dispersions.

Corneal Confocal Microscopy Abnormalities in Children and Adolescents With Type 1 Diabetes

ObjectiveUtility of corneal confocal microscopy (CCM) in children and adolescents with type 1 diabetes mellitus (T1DM) without neuropathic symptoms or signs and minimal abnormality in large and small nerve fiber function tests remains largely undetermined. This study aimed to evaluate the performance of CCM in comparison to thermal detection thresholds (TDT) testing and nerve conduction studies (NCS) for detecting neuropathy in children with T1DM. MethodsA cohort of children and adolescents with T1DM (n = 51) and healthy controls (n = 50) underwent evaluation for symptoms and signs of neurological deficits, including warm detection threshold, cold detection threshold, vibration perception threshold, NCS, and CCM. ResultsChildren with T1DM had no or very minimal neuropathic symptoms and deficits based on the Toronto Clinical Neuropathy Score, yet NCS abnormalities were present in 18 (35%), small fiber dysfunction defined by an abnormal TDT was found in 13 (25.5%) and CCM abnormalities were present in 25 (49%). CCM was abnormal in a majority of T1DM children with abnormal TDT (12/13, 92%) and abnormal NCS (16/18, 88%). CCM additionally was able to detect small fiber abnormalities in 13/38 (34%) in T1DM with a normal TDT and in 9/33 (27%) with normal NCS. ConclusionCCM was able to detect corneal nerve loss in children with and without abnormalities in TDT and NCS.

CSF Findings in Relation to Clinical Characteristics, Subtype, and Disease Course in Patients With Guillain-Barré Syndrome.

To investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study. Albuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/μL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%). In 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25-0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27-0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/μL in 1,005 patients (83%), 5-49 cells/μL in 200 patients (16%), and ≥50 cells/μL in 13 patients (1%). ACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/μL, is compatible with GBS after a thorough exclusion of alternative diagnoses. This study provides Class IV evidence that CSF ACD (defined by the Brighton Collaboration) is common in patients with GBS.

Study of clinical patterns of diabetic neuropathy in patients of type 2 diabetes mellitus in a tertiary care hospital

Introduction:Diabetic neuropathy manifests with sensory, motor, and autonomic functions. The symptoms ofneuropathy are highly unpleasant, affecting the quality of life. The diagnosis of diabetic neuropathy is often delayed,so there remains a substantial need for its early diagnosis for timely management. Objective:The aim of this study was to describe patterns of diabetic neuropathy, study nerve conduction study(NCS) findings in diabetic patients with symptoms of neuropathy, and find the relationship between clinical patternsof neuropathy and worsening glycemic control. Methods:This is a hospital-based cross-sectional study of 104 known cases of diabetes mellitus patients withsymptoms of neuropathy visiting Sree Gokulam Medical College and undergoing NCS as a part of the investigation.The Fisher’s exact test was used accordingly. Results:The mean age of the study population was 63.1±6.1 years. The mean body mass index was27.1±3.2 kg/m2. Overall, 97.1% patients had HbA1c above 7%. Approximately 54.8% of patients presented withtingling sensation, 42.3% with burning sensation, 31.7% complained of pain, 16.3% presented with numbness,51% patients had abnormal NCS findings in sural and peroneal nerves, 54.8% in superficial peroneal nerve,46.2% in tibial nerve, and 31.7% patients had abnormal NCS findings in median nerve. Based on the patterns ofneuropathy, 68.2% had sensory motor polyneuropathy, 5.8% had carpal tunnel syndrome, 20.2% had small fiberneuropathy (normal NCS), 2.9% had tibial mononeuropathy, and 2.9% had ulnar mononeuropathy. No associationwas found between the clinical patterns of neuropathy and glycemic control (HbA1c). Conclusion:The most common pattern of neuropathy was sensory motor polyneuropathy. The common nervesinvolved were sural, peroneal, and superficial peroneal nerve, and the most common presenting complaintwas tingling sensation, followed by burning sensation. There was no relationship between clinical patterns ofneuropathy and worsening glycemic control.

Electrophysiological Investigations in DiabetıC Patients

Introduction: The aim of the study is to search proximal nerve involvement by using proximal root stimulation and possible autonomic neuropathy in type 2 diabetic patients with and without distal symmetric sensorimotor polyneuropathy (DSPN). Patients and Methods: Forty patients with type 2 diabetes and ten volunteers who had no history of diabetes and neuropathy were included. Diabetic patients were equally distributed into two groups according to nerve conduction studies (NCSs): First group comprised of with electrophysiologically confirmed DSPN and second group with normal NCSs. Electrophysiological tests included motor and sensory nerve conduction, needle electromyography, F-response, H-reflex, R-R interval, and sympathetic skin responses (SSRs) studies as well as lumbar root stimulation and cauda equina motor conduction time (CEMCT) calculation. Results: The patients with DSPN had significantly longer F-response latencies and had no H-reflex while H-reflex was observed in 35% of the patients in second group. In the first group, SSRs could not be obtained from both upper and lower limbs in 45% of the patients; however, in the second group, they were absent only in 10% of patients in lower limbs. R-R interval variability was significantly lower in both diabetic groups than volunteers. When compared to the volunteers, cauda equine motor conduction time was significantly prolonged in all diabetic patients, but there was no significant difference between the patient groups. Conclusions: CEMCT prolongation, absence of H-reflex, and decreased R-R interval abnormalities indicating dysautonomia were the most important findings of our study. These results show that early electrophysiological examinations using these methods are important in diabetic patients without polyneuropathy.

Young infants with PMP22 duplication can have minor nerve conduction study abnormalities

Charcot-Marie-Tooth disease type 1A (CMT1A) is related to PMP22 gene duplication. It is characterized at electrodiagnostic testing (EDX) by diffuse homogeneous signs of demyelination, such as velocity slowing and prolonged distal latencies. These abnormalities are less pronounced in infants under two years old, and the possibility of normal nerve conduction studies (NCS) in infants with CMT1A under one year of age has been questioned. We report three infants who displayed normal or almost normal NCS. EDX abnormalities in CMT1A patients may therefore appear late during development. This may affect early EDX diagnosis in infants and should be considered for upcoming clinical trials.

P.10 Compound CACNA1S heterozygosity resulting in a novel phenotype of congenital myopathy and early onset periodic paralysis: report of two probands

Skeletal muscle contraction is mediated by excitation-contraction coupling (ECC), a process involving the rapid elevation of cytosolic calcium. L-type voltage gated calcium channels located on T-tubule membranes are the voltage sensors of ECC. The dihydropyridine receptor (DHPR) contains the pore forming basic functional elements of these calcium channels and is encoded by the <i>CACNA1S</i> gene. Recessive mutations in the <i>CACNA1S</i> gene have been recently reported with a severe congenital myopathy and facial involvement. We describe two sisters with compound heterozygous mutations involving the <i>CACNA1S</i> gene. Both had neonatal hypotonia, muscle weakness, and delayed motor milestones. Prior to one year of age, periodic paralysis was evident as episodic flaccidity and loss of postural control. Periodic paralysis episodes continued to occur most notably with cold exposure, lasting around 10 minutes each. Lab evaluation revealed normal CPK. Electrophysiological evaluation revealed normal motor and sensory nerve conduction studies, and normal long exercise testing. Limb cooling and cold provocation led to clinical weakness and a drop in motor amplitude. Magnetic resonance imaging of the older sister showed symmetrical tigroid pattern fat replacement and atrophy of bilateral gluteus maximus muscles. Targeted next generation sequencing revealed two variants in the <i>CACNA1S</i> gene: both c.3526-2A>G and c.2831G>A (p.Cys944Tyr) are not described in the gnomAD database. Both variants co-segregated into affected sisters and Sanger sequencing revealed that c.3526-2A>G was inherited from the unaffected mother and c.2831G>A from the unaffected father, thus revealing a recessive pattern of inheritance. The c.3526-2A>G is expected to disrupt the acceptor splice site of intron 27 by <i>in silico</i> analysis, whereas the c.2831G>A variant replaces a highly conserved cysteine residue with tyrosine at codon 944 in the DIII-S5 of the Cav1.1 protein. This novel phenotype of a milder congenital recessive myopathy and early onset periodic paralysis expands the phenotypic spectrum of <i>CACNA1S</i> gene mutations.

Ultrasound Findings in Patients with Normal Nerve Conduction despite Clinical Signs and Symptoms Consistent with Carpal Tunnel Syndrome.

Confirmatory methods such as nerve conduction studies are often performed to support a clinical carpal tunnel syndrome diagnosis and to rule out other upper extremity pathologies. Ultrasonography provides another diagnostic option, especially when nerve conduction studies are discordant with history and physical examination. The authors explored the correlation of ultrasound findings with clinical carpal tunnel syndrome diagnosis in patients with normal nerve conduction study results. A database of 220 patients with carpal tunnel syndrome was analyzed retrospectively to reveal 24 patients (28 hands) with a clinical diagnosis and normal nerve conduction study results. Patient demographics and nerve conduction study and ultrasound findings were compared with those of a control group of patients without carpal tunnel syndrome (42 patients, 52 hands). Median nerve cross-sectional area was recorded; values of 10 mm 2 or greater were considered positive for carpal tunnel. Statistical and correlation analyses were performed between control and carpal tunnel groups comparing key measures of interest. Mean cross-sectional area was significantly increased in patients with carpal tunnel syndrome with normal nerve conduction study results compared with controls. The proportion of carpal tunnel-positive, nerve conduction study-negative patients with cross-sectional area measurements greater than 10 mm 2 was significantly greater than the proportion for control patients. Neither age nor body mass index correlated with cross-sectional area measurements. Nerve conduction study latencies and amplitudes did not correlate with ultrasound abnormalities. Patients diagnosed clinically with carpal tunnel syndrome with normal nerve conduction study results were found to have clinically significant median nerve cross-sectional area on ultrasound (10.1 ±2.1 mm 2 , p < 0.001). Cross-sectional area measurements on ultrasound did not correlate with nerve conduction study measures. These results suggest that ultrasound holds a unique diagnostic utility in the evaluation of carpal tunnel syndrome, especially when nerve conduction studies are negative. Diagnostic, II.

Guillain–Barré Syndrome with Normal Nerve Conduction Study Associated with COVID-19 Infection in a Child: Correspondence

Guillain–Barré Syndrome with Normal Nerve Conduction Study Associated with COVID-19 Infection in a Child: Correspondence

The impacts of poor glycemic control and disease duration on peripheral nerves in children and adolescents with type 1 diabetes mellitus

Objective: To evaluate the risk factors of subclinical neuropathy, and the nerve conduction study (NCS) results in children, and adolescents with type 1 diabetes mellitus (T1DM). Methods: A total of 81 patients without neuropathy symptoms were studied. Demographical features, pubertal stage, disease duration, NCS results, lipid profile results in the last 2 years, HbA1c results in the last 5 years, and the types of treatments (multiple-dose and insulin pump therapy) were recorded. Results: The median age was 14 (5) years, 49.3 % (n=40) of the study group was female and 81.5 % (n=66) of the patients were pubertal. Of the patients, 16.04% had abnormal NCS results. There were no significant differences between patients with normal and abnormal NCS results in terms of demographical features, pubertal stage, disease duration, lipid profiles, and dysglycemia. No significant differences were found between the types of treatment in terms of NCS results. The proximal and distal compound muscle action potential (CMAP) amplitudes of the median nerve were significantly lower in patients with poor glycemic control than in those with well-glycemic control. Sensory nerve action potential (SNAP) amplitudes of sural nerve were significantly lower in patients whose disease durations were ≥60 months than in those &lt;60 months. Conclusions: About a sixth of the T1DM has subclinical neuropathy. CMAP amplitudes of the median nerve are the most affected measurement from poor-glycemic control. Additionally, SNAP amplitudes of the sural nerve are the values most affected by longer disease duration.