Peripheral Nerve Abnormalities Research Articles

Comparison of High Resolution Ultrasonography with Clinical Examination in the Assessment of Peripheral Nerve Involvement in Leprosy.

Context:Assessment of peripheral nerves in leprosy by clinical methods is subject to considerable inter-observer variability. High resolution ultrasonography (HRUS) can assess peripheral nerves more objectively.Aims:To compare the findings of peripheral nerve involvement in newly diagnosed cases of leprosy by clinical and sonological methods.Settings and Design:Cross sectional study in a tertiary care teaching hospital.Subjects and Methods:Four pairs of peripheral nerves of 40 newly diagnosed patients with leprosy were examined clinically and by HRUS.Statistical Analysis Used:Agreement between clinical examination and HRUS using kappa statistic; sensitivity; specificity; and predictive values.Results:Of the 320 nerves examined, 71 (22.18%) were abnormal clinically and 63 (19.7%) sonologically. Sonological abnormalities were increased cross sectional area (n = 63; 100%), hypoechogenicity with loss of fascicular architecture (n = 46; 73%) and increased vascularity (n = 35; 55.6%). There was moderate agreement (Cohen's Ḳ = 0.59) between clinical and sonological findings. HRUS findings were abnormal in 18 (7.2%) nerves that were clinically normal. HRUS was normal in 26 (36.6%) nerves which were clinically abnormal. Sensitivity of HRUS compared to clinical examination was 63%; specificity 92.7%; positive predictive value 71.4%; and negative predictive value 89.9%. Increased cross sectional area agreed with clinical findings the most.Conclusions:HRUS has low sensitivity (63%) and high specificity (92.7%) to identify abnormal peripheral nerves in leprosy, compared to clinical examination. It could detect abnormality of some (n = 18, 7.2%) clinically normal nerves, but showed normal findings of some nerves (n = 26, 36.6%), which were considered clinically abnormal.

RAGE signaling is required for AMPA receptor dysfunction in the hippocampus of hyperglycemic mice

Diabetes in humans has been associated for a long time with cognitive dysfunction. In rodent animal models, cognitive dysfunction can manifest as impaired hippocampal synaptic plasticity. Particular attention has been concentrated on the receptor for advanced glycation end products (RAGE), which is implicated in multiple diabetic complications involving the development of vascular and peripheral nerve abnormalities. In this study, we hypothesize that RAGE signaling alters glutamate receptor function and expression, impairing synaptic transmission in the hippocampus. Using preparations of hippocampal slices from male mice, we show a RAGE-dependent decrease in long-term potentiation (LTP) and an increase in paired-pulse facilitation (PPF) following streptozotocin (STZ)-induced diabetes. Consistently, in hippocampal cultures from male and female neonatal mice, high glucose caused a RAGE-dependent reduction of AMPA- but not NMDA-evoked currents, and an increase in cytosolic reactive oxygen species (ROS). Consistently, when cultures were co-treated with high glucose and the RAGE antagonist FPS-ZM1, AMPA-evoked currents were unchanged. Hippocampi from STZ-induced hyperglycemic wild type (WT) mice showed increased RAGE expression concomitant with a decrease of both expression and phosphorylation (Ser 831 and 845) of the AMPA GluA1 subunit. We found these changes correlated to activation of the MAPK pathway, consistent with decreased pJNK/JNK ratio and the JNK kinase, pMEK7. As no changes in expression or phosphorylation of regulatory proteins were observed in hippocampi from STZ-induced hyperglycemic RAGE-KO mice, we report a RAGE-dependent impairment in the hippocampi of hyperglycemic WT mice, with reduced AMPA receptor expression/function and LTP deficits.

Routine knee MRI: how common are peripheral nerve abnormalities, and why does it matter?

To evaluate the frequency, MRI appearance, and clinical significance of peripheral nerve abnormalities encountered on routine knee MRI. A retrospective review was performed to identify consecutive patients who underwent routine knee MRI from March 2015-2018 and had peripheral nerve abnormalities. MRIs were reviewed for the presence of tibial (TN) and common peroneal nerve (CPN) abnormalities (including hyperintensity, bulbous enlargement, discontinuity, architectural distortion, skeletal muscle denervation). The presence or absence of concomitant meniscal, cruciate, and collateral ligament tears was documented. Patient demographics and clinical outcomes were recorded. Descriptive statistics were reported. The search yielded 8125 MRIs, of which 50 knee MRIs (patient age (years): 44+19) had peripheral nerve abnormalities (hyperintensity (TN: 30%(15/50), CPN: 80%(40/50)), bulbous enlargement (TN: 10%(5/50), CPN: 30%(15/50)), discontinuity (TN: 0, CPN: 4%(2/50)), architectural distortion (TN: 4%(2/50), CPN: 18%(9/50)), and skeletal muscle denervation (TN: 14%(7/50), CPN: 28%(14/50)). Medial meniscus (TN: 12% (6/50), CPN: 36%(18/50)), ACL (TN: 4%(2/50), CPN: 32%(16/50)), PCL (TN: 2%(1/50), CPN: 20%(10/50)), and lateral meniscus (TN: 12%(6/50), CPN: 24%(12/50)) tears were frequently present. Of these, 32% (16/50) were treated for peripheral nerve injury (PNI), characterized as high-grade (n = 7/16) or low-grade (n = 9/16). Nerve discontinuity, architectural distortion, and denervation were encountered more in high-grade PNI than low-grade PNI. Five patients were recalled for follow-up imaging and operative management was performed in 36% of cases (18/50). Although uncommon (frequency = 0.6%), peripheral nerve abnormalities (CPN more common than TN) are encountered on routine knee MRI and affect patient management, with 36% requiring surgical treatment.

Correlation Between Thioredoxin-Interacting Protein and Nerve Conduction Velocity in Patients With Type 2 Diabetes Mellitus

Aims: To investigate the correlation between thioredoxin-interacting protein (TXNIP) and peripheral nerve conduction velocity (NCV) in patients with type 2 diabetes mellitus.Methods: In total, 338 patients with type 2 diabetes mellitus (T2DM) were included in this study. We collected the clinical data and measured the motor conduction velocities of the bilateral ulnar nerve, median nerve, tibial nerve, and common peroneal nerve, and the sensory conduction velocities of the ulnar nerve, median nerve, sural nerve, and superficial peroneal nerve. According to the results, the patients were divided into two groups: normal peripheral nerve conduction group (NCVN group) and abnormal peripheral nerve conduction group (NCVA group). The two groups were then compared in terms of the conventional biochemical index and the sugar metabolic index as well as the serum levels of TXNIP, reduced glutathione (GSH), total superoxide dismutase (SOD), malondialdehyde (MDA), and tumor necrosis factor alpha (TNF-α). The correlation between TXNIP and NCV was also analyzed.Results: Compared with the NCVN group, the TXNIP and MDA values were significantly increased in the NCVA group (P < 0.05). Among the patients with T2DM, age, fasting glucose, SDBG, and TXNIP were risk factors for NCV abnormality, while vitamin D3 was a protective factor. After adjusting for related confounding factors, TXNIP was significantly correlated with NCV (P < 0.05). Among the patients with T2DM, TXNIP was an independent risk factor for left ulnar motor conduction velocity (MCV), right ulnar MCV, left median MCV, and right median MCV. TNF-α was identified as a positive influencing factor for serum TXNIP, while serum TXNIP was a positive factor for TNF-α and MDA (both P < 0.05).Conclusion: Serum TXNIP is related to NCV in T2DM patients. In combination with oxidative stress and inflammation, TXNIP may affect diabetic peripheral neuropathy (DPN).

Multifocal, hypoechogenic nerve thickening in Cerebrotendinous Xanthomatosis

ObjectiveTo characterize peripheral nerve morphology in cerebrotendinous xanthomatosis (CTX) patients using high-resolution ultrasound (HRUS) in vivo. We hypothesized that nerve enlargements might be present in CTX as a result of accumulation of abnormal lipids with deposition also in peripheral nerves. MethodsFour CTX patients were examined using HRUS to assess morphological abnormalities of peripheral nerves as well as cervical nerve roots 5 and 6. ResultsHRUS revealed mild to moderate, hypoechogenic thickening of sensorimotor nerves (ulnar nerve in 1/4, tibial nerve in 3/4, median nerve 4/4 patients) as well as mild enlargement of pure sensory nerves (sural nerve in 2/3, superficial FN in 2/4 patients). The vagal nerve was moderately enlarged in one patient, cervical roots showed moderate enlargements of C5 in two patients, one of which also showing thickening of C6 as well as in another patient. UPSS score was slightly to moderately abnormal in all patients. The Homogeneity score was not increased suggesting regional to inhomogeneous nerve enlargement. ConclusionsHRUS shows multifocal, hypoechogenic nerve thickening of peripheral nerves and nerve roots in CTX. SignificanceHRUS might serve as a valuable, additive and non-invasive bedside tool to assess peripheral nerve morphology in future clinical studies on CTX patients.

Use of Magnetic Resonance Neurography for Evaluating the Distribution and Patterns of Chronic Inflammatory Demyelinating Polyneuropathy.

ObjectiveTo evaluate the distribution and characteristics of peripheral nerve abnormalities in chronic inflammatory demyelinating polyneuropathy (CIDP) using magnetic resonance neurography (MRN) and to examine the diagnostic efficiency.Materials and MethodsThirty-one CIDP patients and 21 controls underwent MR scans. Three-dimensional sampling perfections with application-optimized contrasts using different flip-angle evolutions and T1-/T2- weighted turbo spin-echo sequences were performed for neurography of the brachial and lumbosacral (LS) plexus and cauda equina, respectively. Clinical data and scores of the inflammatory Rasch-built overall disability scale (I-RODS) in CIDP were obtained.ResultsThe bilateral extracranial vagus (n = 11), trigeminal (n = 12), and intercostal nerves (n = 10) were hypertrophic. Plexus hypertrophies were observed in the brachial plexus of 19 patients (61.3%) and in the LS plexus of 25 patients (80.6%). Patterns of hypertrophy included uniform hypertrophy (17 [54.8%] brachial plexuses and 21 [67.7%] LS plexuses), and multifocal fusiform hypertrophy (2 [6.5%] brachial plexuses and 4 [12.9%] LS plexuses) was present. Enlarged and/or contrast-enhanced cauda equina was found in 3 (9.7%) and 13 (41.9%) patients, respectively. Diameters of the brachial and LS nerve roots were significantly larger in CIDP than in controls (p < 0.001). The largest AUC was obtained for the L5 nerve. There were no significant differences in the course duration, I-RODS score, or diameter between patients with and without hypertrophy.ConclusionMRN is useful for the assessment of distribution and characteristics of the peripheral nerves in CIDP. Compared to other regions, LS plexus neurography is more sensitive for CIDP.

CHRONIC KIDNEY DISEASE, MUSCLE WEAKNESS, AND MOBILITY LIMITATION

Objectives: Chronic kidney disease (CKD) is associated with increased mobility limitation. Prior research has documented that peripheral nerve abnormalities occur early in CKD and progressively worsen. Loss of balance, impaired muscle strength, and slow gait predispose older adults to falls and frailty. However, the current literature is limited by a lack of nationally representative data that includes objective measures of kidney disease and physical functioning. Thus, this research examines whether CKD is associated with muscle strength, balance, gait, and self-reported mobility limitations. Methods: Data come from the 2016 Health and Retirement Study (HRS). Estimated GFR, a measure of kidney functioning derived from creatinine levels in the blood, was used to classify CKD (i.e, eGFR<45 or Stage 3b CKD). Logistic and linear regression models were generated to examine the association of CKD with physical functioning, net of demographic characteristics (i.e., age, sex, race, and education) and comorbidities (i.e., obesity, pain, and number of diagnosed medical conditions). Results: In unadjusted models, CKD was significantly associated (p<0.05) with more mobility limitations, slower walking speeds, stronger grip strengths, and non-participation in balance tests. After adjusting for covariates, CKD (β=-1.43, p=0.01) was negatively associated with grip strength. In sex-stratified models, CKD was associated with slower walking speeds among men, whereas CKD was associated with more mobility limitations among women. Discussion: In a nationally representative sample of older adults, CKD was associated with poorer physical functioning on multiple measures. After adjusting for demographic characteristics and comorbidities, CKD was associated with increased muscle weakness.

Technological Advancements in Magnetic Resonance Neurography.

Magnetic resonance neurography (MRN) is being increasingly used as a problem-solving tool for diagnosis and management of peripheral neuropathies. This review is aimed at summarizing important technological advances, including MR pulse sequence and surface coil developments, which have facilitated MRN's use in clinical practice. The most recent research in MRN focuses on its clinical applications, with concomitant development of three-dimensional, parallel imaging and vascular suppression techniques that facilitate higher spatial resolution and depiction of small nerve branches arising from the brachial and lumbosacral plexi as well as fascicular abnormalities of more distal extremity nerves. Quantitative diffusion tensor imaging (DTI) has been studied as a tool to detect microstructural abnormalities of peripheral nerves and more precisely define grades of nerve injury but will require additional investigation to determine its role in daily clinical practice. MRN continues to evolve due to technological improvements and awareness by the medical community of its capabilities. Additional technological developments related to surface coil designs and vascular suppression techniques will be needed to move the field forward.

Magnetic resonance neurography of traumatic pediatric peripheral nerve injury: beyond birth-related brachial palsy.

Traumatic peripheral nerve injury occurs more frequently in the pediatric population than previously recognized. High-resolution magnetic resonance (MR) imaging in the form of MR neurography can serve as a powerful noninvasive tool for detecting and characterizing peripheral nerve injury in children. In this review article we briefly discuss optimal methods of MR neurography image acquisition, highlighting core MR sequences necessary to characterize peripheral nerve injury. In addition, we illustrate the MR neurography appearance of normal and abnormal peripheral nerves in children, with emphasis on commonly used Seddon and Sunderland classification schemes to characterize peripheral nerve injury severity. The primary and secondary features associated with peripheral nerve injury including skeletal muscle denervation are reviewed in addition to key distinctive features that can impact operative versus nonoperative management of children. We include a checklist approach to interpreting MR neurography for the assessment of peripheral nerve injury.

Corneal subbasal nerve plexus changes in patients with episodic migraine: an in vivo confocal microscopy study.

Background and purpose: It has been generally thought that activation and sensitization of the trigeminovascular system may contribute to the pathogenesis of migraine. Nevertheless, there is little evidence on abnormalities in peripheral trigeminal afferent nerves from humans in vivo. Alterations of corneal nerves from the ophthalmic branch of the trigeminal nerve may support the notion that trigeminal afferent nerves are involved in migraine pathophysiology. The aim of the present study was to investigate the structural changes in corneal subbasal nerve plexus in patients with episodic migraine (EM) with in vivo confocal microscope (IVCM).Methods: In this cross-sectional observational study, 10 EM patients and 10 age- and sex-matched healthy controls were included. Analysis of IVCM images with Image J software was performed to quantify the changes in the corneal subbasal nerve plexus.Results: EM patients showed an increase in nerve fiber length (25.0±2.65 vs 22.3±2.41 mm/mm2, p=0.047) and nerve fiber density (36.3±7.29 vs 30.5±6.19 fibers/mm2, p=0.104) as compared with normal controls, but this difference was not statistically significant. Nerve branching and tortuosity were significantly increased in the EM subjects compared to the normal subjects (91.3±13.8 vs 75.0±14.2 branches/mm2, p=0.030 and 2.30±0.46 versus 1.63±0.52, p=0.011, respectively). In addition, nerve sprouts and increased number of Langerhans cells were observed in the EM patients.Conclusion: The morphologic changes of corneal subbasal nerve plexus and Langerhans cell aggregation suggest the presence of nerve regeneration and inflammation in EM. Furthermore, the alterations of corneal nerves from the ophthalmic branch of the trigeminal nerve offer support for the hypothesis that the peripheral trigeminal system may be involved in the pathogenesis of migraine.

Ultrasound Imaging of Disorders of Small Nerves of the Extremities: Less Recognized Locations.

Ultrasound is a well-proven imaging modality for showing peripheral nerve disorders and guiding perineural injections. The aim of this review is to focus on small peripheral nerve abnormalities, which are usually not recognized by sonologists. In fact, most of these small nerves have a tiny diameter (<2 mm), and their anatomy is less familiar. We describe the most common causes of small peripheral nerve disorders, providing an accurate description of their anatomic locations and relationships with adjacent structures; we also focus on technical hints that may help in their evaluation.

Nerve ultrasound characterizes AMN polyneuropathy as inhomogeneous and focal hypertrophic

ObjectiveHigh-resolution nerve ultrasound (HRUS) is a painless tool to quickly evaluate peripheral nerve morphology in vivo. This study set out to characterize peripheral nerve involvement in X-linked adrenomyeloneuropathy (AMN) by HRUS.MethodsThirteen adults with genetically proven AMN were examined using the Ultrasound pattern sum score (UPSS) to evaluate morphological abnormalities of peripheral nerves, vagal nerves, as well as cervical nerve roots. Ultrasound results were correlated with clinical findings and nerve conduction studies.ResultsUPSS was increased in six out of 13 patients. Nerve enlargement was mostly inhomogeneous and regional. The median, ulnar, and vagal nerves presented with more prominent alterations than nerves of the lower limbs. The proximal-to-distal ratio was significantly enlarged for the median nerve. HRUS findings matched nerve conduction studies, but identified one patient with enlarged nerves and yet normal conduction velocities. Sonographic findings did not correlate with disease duration or disease severity as assessed by the spastic paraplegia rating scale.ConclusionHRUS reveals significant multifocal regional nerve swellings with reduced echo intensity as the morphological equivalent of electrophysiological peripheral nerve affection in AMN patients. Ultrasound and NCS characteristics in AMN seem to differ from other demyelinating neuropathies like CIDP or CMT1a.Trial registrationGerman clinical-trial-register (DRKS) (DRKS-ID 00005253) Registered 15 October 2013.

Peripheral nerve abnormality in HIV leprosy patients.

BackgroundThe geographical overlap of HIV (human immunodeficiency virus) and leprosy infection has become increasingly frequent and worrying, bringing many clinical issues. Peripheral neuropathy is very frequent in leprosy because of the predilection of its etiologic agent by Schwann cells of the peripheral nervous system, and it also affects individuals with HIV as one of the most common neurological manifestations.Methodology/Principal findingsThe present study compared a cohort of 63 patients diagnosed with leprosy and coinfected with HIV with a cohort of 64 patients with leprosy alone, who were followed at the outpatient clinic of the Nucleus of Tropical Medicine of the Federal University of Pará, Brazil. We observed that HIV-coinfected leprosy patients presented greater odds of overall peripheral nerve damage (nerve function impairment—NFI) than patients with leprosy alone. More sensitive damage was observed, especially in patients coinfected with multibacillary forms. Leprosy patients coinfected with HIV presented higher chances of motor damage with improvement over time using multidrug therapy (MDT) and highly active antiretroviral therapy (HAART), along with a greater extent of damage and occurrence of neuritis. The data suggest that in addition to patients presenting possible damage caused by leprosy, they also had a greater damage gradient attributable to HIV disease, but not related to HAART because most of these patients had been on the treatment for less than a year. Neuritis was treated with prednisone at doses recommended by the WHO, and coinfected patients had the highest rate of clinical improvement in the first 60 days.Conclusions/SignificanceThe clinical characteristics of the two diseases should be considered in leprosy patients coinfected with HIV for better diagnosis and treatment of peripheral neuropathy. We suggest that new simplified assessment tools that allow the evaluation of the NFI of these patients be developed for use in the service.

Correlation between markers of peripheral nerve function and structure in type 1 diabetes.

Clinical and experimental studies in patients with type 1 and type 2 diabetes have demonstrated changes in ion channel function and nerve structure. In this study, we investigated the relationship between axonal dysfunction and morphological change in diabetic polyneuropathy by using neuromuscular ultrasound and nerve excitability techniques. We also explored possible differences in this relationship between type 1 and type 2 diabetes. Nerve ultrasound and corresponding motor excitability studies were undertaken in 110 diabetes patients (50 type 1; 60 type 2) and 60 age-matched controls (30 for each group). Neuropathy severity was assessed by using total neuropathy score. Median and tibial nerve cross-sectional areas were measured at nonentrapment sites by using high-resolution linear probe. Median and tibial nerve cross-sectional areas were significantly higher in diabetes patients compared with controls: type 1 (median=7.6±0.2mm2 vs 6.3±0.1mm2 ; tibial=14.5±0.7mm2 vs 10.8±0.3mm2 , P<.05) and type 2 (median=9.1±0.3mm2 vs 7.2±0.1mm2 ; tibial=18.5±1.0mm2 vs 12.8±0.5mm2 , P<.05). In the type 1 cohort, significant correlations were found between nerve cross-sectional area and excitability parameters including resting current-threshold slope (median: r=0.523, P<.0001; tibial: r=-0.571, P=.004) and depolarizing threshold electrotonus at 90 to 100ms (median: 0.424, P<.01; tibial: r=0.435, P=.030). In contrast, there was no relationship between excitability values and nerve cross-sectional area in the type 2 cohort. This study has identified correlation between markers of axonal membrane function and structural abnormalities in peripheral nerves of type 1 diabetes patients. The differential relationship in nerve function and structure between type 1 and type 2 diabetes provides clinical evidence that different pathophysiological mechanisms underlie the development of neuropathy in these patient groups.

S97. Clinical and electrophysiological characteristics of multiple myeloma eripheral neuropath: Aretrospective study in thirty-five patients

To analyze the symptoms and signs in thirty-five multiple myeloma eripheral neuropath (MMPN) patients retrospectively. Characteristics of eleetrophysiological examinations were investigated. Thirty-five MM patients were reviewed and information gathered regarding clinicalcomplains neurological symptoms, and other concomitant disease. The records showed that nerve conduction velocity and skin sympathetic response and repetitive nelwestimulaljon(RNS) were performed in all patient. Needleelectromyography(EMG) and skin sympathetic response were also performed in all patients. (1) The mean age of neurological clinical onset age was (60.23 ± 4.8) years old. The most common symptoms peripheral nerve system damage: sensory abnormalities (25 cases), the radicular pain (3 cases), dyskinesia (15 cases), the most common neurological signs reduced to lower extremity or distal upper extremity pain (18 cases), double knee jerk or ankle reflex to reduce or disappear (13 cases) and dry mouth or constipation or diarrhea patients or autonomic symptoms (20 cases); The first symptoms varied, such as dizziness, fatigue, increased foam in the urine, numbness of the limbs, back pain, etc. (2) Electrophysiological examination: there was no significant increase in high-frequency stimulation of ulnar nerve in all patients. Sensory nerve conduction velocity (SCV) abnormalities or motor nerve conduction velocity (MCV) abnormalities or SCV combined with MCV were found in 29 patients (83%). All patients underwent SSR and 17 (85%) abnormalities were detected. The most common peripheral nerve system impairment in MM is the sensation of “socks and gloves” distributed, paresthesia, paresthesia and numbness, severe movement disorders, autonomic nerve can also be involved. All the patients were no abnormal repetitive nerve stimulation, but abnormal electrophysiological system MM in patients with peripheral nerve abnormalities and autonomic nerve, suggesting that clinical manifestations may cause neurological or autonomic neuropathy mixed with. Electrophysiological examination of SSR can also be used for screening autonomic neuropathy in MMPN patients.

Whole-mount Confocal Microscopy for Adult Ear Skin: A Model System to Study Neuro-vascular Branching Morphogenesis and Immune Cell Distribution.

Here, we present a protocol of a whole-mount adult ear skin imaging technique to study comprehensive three-dimensional neuro-vascular branching morphogenesis and patterning, as well as immune cell distribution at a cellular level. The analysis of peripheral nerve and blood vessel anatomical structures in adult tissues provides some insights into the understanding of functional neuro-vascular wiring and neuro-vascular degeneration in pathological conditions such as wound healing. As a highly informative model system, we have focused our studies on adult ear skin, which is readily accessible for dissection. Our simple and reproducible protocol provides an accurate depiction of the cellular components in the entire skin, such as peripheral nerves (sensory axons, sympathetic axons, and Schwann cells), blood vessels (endothelial cells and vascular smooth muscle cells), and inflammatory cells. We believe this protocol will pave the way to investigate morphological abnormalities in peripheral nerves and blood vessels as well as the inflammation in the adult ear skin under different pathological conditions.

Extraneural findings during peripheral nerve ultrasound: Prevalence and further assessment.

In this study we evaluated the frequency and further assessment of extraneural findings encountered during peripheral nerve ultrasound (US). Our retrospective review identified 278 peripheral nerve US examinations of 229 patients performed between December 2014 and December 2015. Reports were reviewed to assess the number of studies without peripheral nerve abnormalities and the frequency and further assessment of extraneural findings. A total of 107 peripheral nerve US examinations of 90 patients (49 men and 41 women, mean age 55 ± 16 years) did not report peripheral nerve abnormalities. Extraneural findings were observed in 24 of 107 (22.4%) studies. Fifteen of the 278 [5.4% (95% confidence interval 2.7%-8.1%)] studies led to a recommendation for additional imaging or clinical evaluation of an extraneural finding. At least 5.4% (15 of 278) of peripheral nerve US studies led to additional clinical or imaging assessment. Muscle Nerve 57: 65-69, 2018.

Modulation of diet-induced mechanical allodynia by metabolic parameters and inflammation.

Dietary-associated diseases have increased tremendously in our current population, yet key molecular changes associated with high-fat diets that cause clinical pre-diabetes, obesity, hyperglycemia, and peripheral neuropathy remain unclear. This study examines molecular and metabolic aspects altered by voluntary exercise and a high-fat diet in the mouse dorsal root ganglion. Mice were examined for changes in mRNA and proteins encoding anti-inflammatory mediators, metabolic-associated molecules, and pain-associated ion channels. Proteins involved in the synaptosomal complex and pain-associated TRP ion channels decrease in the dorsal root ganglion of high-fat exercise animals relative to their sedentary controls. Exercise reversed high-fat diet induced mechanical allodynia without affecting weight gain, elevated blood glucose, and utilization of fat as a fuel source. Independent of weight or fat mass changes, high-fat exercised mice display reduced inflammation-associated mRNAs. The benefits of exercise on abnormal peripheral nerve function appear to occur independent of systemic metabolic changes, suggesting that the utilization of fats and inflammation in the peripheral nervous system may be key for diet-induced peripheral nerve dysfunction and the response to exercise.

Neonatal Hypoxia Results in Peripheral Nerve Abnormalities

Although the adverse effects of neonatal hypoxia associated with premature birth on the central nervous system are well known, the contribution of hypoxic damage to the peripheral nervous system (PNS) has not been addressed. We demonstrate that neonatal hypoxia results in hypomyelination and delayed axonal sorting in mice leading to electrophysiological and motor deficits that persist into adulthood. These findings support a potential role for PNS hypoxic damage in the motor impairment that results from premature birth and suggest thattherapies designed to protect the PNS may provide clinical benefit.

The relationship between auditory brainstem response, nerve conduction studies, and metabolic risk factors in type II diabetes mellitus

Few studies have reported a correlation between auditory brainstem response (ABR) findings and nerve conduction studies (NCSs). The correlation between ABR findings and the metabolic profile of these patients is not well documented in previous studies. The present study was designed to investigate the impact of the disturbed metabolic profile (hyperglyceridemia and hyperlipidemia) in diabetic patients on the peripheral nervous system as well as the auditory brainstem response. The present study aimed to detect the effect of diabetic control on the presence of abnormal ABR and/or peripheral nerve affection in Egyptian diabetic patients. The study was conducted on two groups: the diabetic group (n=68) and the control group, which was matched for age, sex, blood pressure, and BMI (n=60). All participants were subjected to clinical assessment, basic audiologic assessment, brainstem auditory evoked potential, NCS, and metabolic profile [serum level of glycated hemoglobin (HbA1c%) and lipid profile]. There was a significant increase in absolute wave latencies of ABR and interpeak latencies (IPLs) in the diabetic group compared with the control group. Twenty-six (38.2%) patients had abnormal ABR values. IPLs (I–III and III–V) were significantly negatively correlated with sensory conduction velocity of the sural, median, and ulnar nerves as well as F-wave latency of the posterior tibial, median, and ulnar nerves (P=0.01 and 0.001, respectively). Moreover, IPL III–V and sural sensory conduction velocity were significantly correlated with HbA1c% and total cholesterol, as well as triglyceride serum levels. Brainstem dysfunction and ABR changes are common in patients with type II diabetes mellitus. These changes are significantly correlatedto NCS parameters on one hand and serum HbA1c% and lipid profile (total cholesterol and triglycerides) on the other hand.