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Brain Topography Sep 2018Paired-pulse depression (PPD) has been widely used to investigate the functional profiles of somatosensory cortical inhibition. However, PPD induced by somatosensory...
Paired-pulse depression (PPD) has been widely used to investigate the functional profiles of somatosensory cortical inhibition. However, PPD induced by somatosensory stimulation is variable, and the reasons for between- and within-subject PPD variability remains unclear. Therefore, the purpose of this study was to clarify the factors influencing PPD variability induced by somatosensory stimulation. The study participants were 19 healthy volunteers. First, we investigated the relationship between the PPD ratio of each component (N20m, P35m, and P60m) of the somatosensory magnetic field, and the alpha, beta, and gamma band changes in power [event-related desynchronization (ERD) and event-related synchronization (ERS)] induced by median nerve stimulation. Second, because brain-derived neurotrophic factor (BDNF) gene polymorphisms reportedly influence the PPD ratio, we assessed whether BDNF genotype influences PPD ratio variability. Finally, we evaluated the test-retest reliability of PPD and the alpha, beta, and gamma ERD/ERS induced by somatosensory stimulation. Significant positive correlations were observed between the P60m_PPD ratio and beta power change, and the P60m_PPD ratio was significantly smaller for the beta ERD group than for the beta ERS group. P35m_PPD was found to be robust and highly reproducible; however, P60m_PPD reproducibility was poor. In addition, the ICC values for alpha, beta, and gamma ERD/ERS were 0.680, 0.760, and 0.552 respectively. These results suggest that the variability of PPD for the P60m deflection may be influenced by the ERD/ERS magnitude, which is induced by median nerve stimulation.
Topics: Adult; Brain-Derived Neurotrophic Factor; Cortical Synchronization; Electric Stimulation; Electrophysiological Phenomena; Evoked Potentials, Somatosensory; Female; Genotype; Healthy Volunteers; Humans; Magnetoencephalography; Male; Median Nerve; Polymerase Chain Reaction; Polymorphism, Genetic; Reproducibility of Results; Somatosensory Cortex; Young Adult
PubMed: 29737438
DOI: 10.1007/s10548-018-0648-5 -
Surgical and Radiologic Anatomy : SRA Sep 2023This report describes a bilateral persistent median artery (PMA) originating from the ulnar artery and terminating at different levels of the upper limb. The PMA...
PURPOSE
This report describes a bilateral persistent median artery (PMA) originating from the ulnar artery and terminating at different levels of the upper limb. The PMA coexisted with a bilateral bifid median nerve (MN) and two bilateral interconnections (ICs characterized with the symbol -) of the MN with the ulnar nerve (UN) (MN-UN) and a unilateral reverse IC (UN-MN). Emphasis was given to the artery's developmental background.
METHODS
The PMA was identified in an 80-year-old formalin-embalmed donated male cadaver.
RESULTS
The right-sided PMA terminated at the wrist, posterior to the palmar aponeurosis. Two neural ICs were identified: the UN joined the MN deep branch (UN-MN), at the forearm's upper third, and the MN deep stem joined the UN palmar branch (MN-UN), at the lower third (9.7 cm distally to the 1st IC). The left-sided PMA ended in the palm giving off the 3rd and 4th proper palmar digital arteries. An incomplete superficial palmar arch was identified by the contribution of the PMA, radial, and ulnar arteries. After the MN bifurcation into superficial and deep branches, the deep branches formed a loop, that was penetrated by the PMA. The MN deep branch communicated with the UN palmar branch (MN-UN).
CONCLUSIONS
The PMA should be evaluated as a causative factor of carpal tunnel syndrome. The modified Allen's test and the Doppler ultrasound may detect the arterial flow and the angiography may depict the vessel thrombosis in complex cases. PMA could also be a "salvage" vessel for the hand supply, in radial and ulnar artery trauma.
Topics: Humans; Male; Aged, 80 and over; Median Nerve; Ulnar Nerve; Hand; Carpal Tunnel Syndrome; Ulnar Artery; Cadaver
PubMed: 37368116
DOI: 10.1007/s00276-023-03183-y -
Disease Markers 2023To evaluate the effect of wrist dorsiflexion/palmar flexion on median nerve excursion and cross-sectional area in patients with carpal tunnel syndrome.
OBJECTIVE
To evaluate the effect of wrist dorsiflexion/palmar flexion on median nerve excursion and cross-sectional area in patients with carpal tunnel syndrome.
METHODS
From November 2019 to December 2021, 85 patients (110 affected wrists) who presented to our department and were diagnosed with carpal tunnel syndrome were collected and classified by severity as mild to moderate. Twenty-five healthy controls were selected during the same period, with a total of 50 healthy wrists. All patients and healthy volunteers underwent high-frequency ultrasonography to measure the vertical deviation between the median nerve and the transverse carpal ligament during wrist dorsiflexion/palmar flexion and the changes in the cross-sectional area of the median nerve in the pisiform plane. All patients with carpal tunnel syndrome underwent neurophysiological testing to measure median nerve sensory conduction velocity, sensory latency time, and sensorimotor point fluctuation amplitude.
RESULTS
The mean age of the patients was 50 ± 8 years, the proportion of males was 18%, and the disease course was 2.3 ± 1.2 years. In terms of severity grading, 38 patients (34.5%) had mild carpal tunnel syndrome, 30 patients (27.3%) had moderate carpal tunnel syndrome, and 42 patients (38.2%) had severe carpal tunnel syndrome. Compared with the control group, the distance between the proximal median nerve and the transverse carpal ligament, the distance between the distal median nerve and the transverse carpal ligament, and the cross-sectional area were decreased in the carpal tunnel syndrome group compared with those during wrist dorsiflexion, and the differences were statistically significant ( < 0.05). Compared with the control group, there were significant differences in the vertical distance and cross-sectional area between the median nerve and the transverse carpal ligament at the proximal and distal ends in the mild, moderate, and severe groups ( < 0.05). The proximal vertical distance of the median nerve was positively correlated with sensory latency ( < 0.05) and negatively correlated with sensory conduction velocity ( < 0.05). The vertical distance of the distal end of the median nerve was also significantly positively correlated with sensory latency ( < 0.05) and significantly negatively correlated with sensory conduction velocity ( < 0.05).
CONCLUSION
Wrist dorsiflexion/palmar flexion can affect median nerve deviation and cross-sectional area in patients with carpal tunnel syndrome. High-frequency ultrasound is helpful to detect such an effect and can also help determine the severity of carpal tunnel syndrome, which is worthy of clinical promotion.
Topics: Male; Humans; Adult; Middle Aged; Median Nerve; Carpal Tunnel Syndrome; Wrist; Ultrasonography; Healthy Volunteers
PubMed: 36776922
DOI: 10.1155/2023/3631193 -
Clinical Neurophysiology : Official... Jun 2020A very high-resolution (70 MHz) ultrasound device (VHRUS) has recently been approved for use in humans. The aim of this study was to use VHRUS to collect data on...
OBJECTIVE
A very high-resolution (70 MHz) ultrasound device (VHRUS) has recently been approved for use in humans. The aim of this study was to use VHRUS to collect data on healthy subjects to propose some reference values for the digital branches of the median nerves of the hand.
METHODS
A VHRUS with 70 MHz linear array transducer was used to measure the cross sectional area of the median nerve at the wrist (CSA) and digital branches (CSA), largest and smallest fascicles, the fascicles number (N), the fascicle density (FD), the flattening ratio (FR) and CSA/CSA.
RESULTS
Data from 20 healthy subjects were obtained for both hands. The median nerve at the wrist and digital branches were properly identified without anatomical alterations. No differences were found between the right and the left hand. In the dominant hand, CSA was 9.35 mm (4.57-12.35) and N was 24 (18-38). FD and FR were respectively 2.94 (2.47-4.91) and 2.74 (1.70-4.90).
CONCLUSION
VHRUS technology can visualize the median nerves at the wrist, their internal structure and their small branches at the fingers, providing both a qualitative and quantitative assessment. Results from this study provide preliminary reference values in a young healthy sample.
SIGNIFICANCE
Most conventional ultrasound devices are not able to properly visualize the distal branches of the median nerve. In contrast, VHRUS allows to detect and measure smaller structures of the nerve, assisting in clinical practice.
Topics: Adult; Female; Hand; Humans; Male; Median Nerve; Ultrasonography; Young Adult
PubMed: 32302945
DOI: 10.1016/j.clinph.2020.03.013 -
Annals of African Medicine 2022Despite the usefulness of ulnar nerve conduction studies in identifying disorders of ulnar nerves, there is a lack of normative values for the ulnar nerve in Nigerian...
BACKGROUND
Despite the usefulness of ulnar nerve conduction studies in identifying disorders of ulnar nerves, there is a lack of normative values for the ulnar nerve in Nigerian population.
OBJECTIVE
The objective of the study was to generate normative values for motor and sensory ulnar nerve conduction studies (NCSs) in Nigerian population and to determine the influence of gender and height on ulnar nerve conduction velocity (NCV).
MATERIALS AND METHODS
A total of 200 healthy volunteers were selected after clinical evaluation to exclude common causes of ulnar neuropathy. We carried out NCS of ulnar nerves on all the healthy volunteers according to a standardized protocol. The NCS parameters included in the final analysis were amplitude, latency, NCV, and f-wave latency. Ethical approval was obtained for the study.
RESULTS
The mean ulnar nerve sensory velocity was 55.22 ± 5.67 with 2.5 and 97.5 percentile of 46.9 and 70.1, respectively. The mean latency of the ulnar nerve (sensory) was 2.97 ± 0.62 with 2.5 and 97.5 percentile of 2.00 and 4.52, respectively. The mean amplitude of the ulnar nerve (sensory) was 35.56 ± 9.97 with 2.5 and 97.5 percentile of 15.9 and 57.7, respectively). The ulnar NCV was significantly (P = 0.0202) higher in male. Mild inverse correlation (r = 0.2) was found between ulnar NCV and height of the participants (P = 0.0089).
CONCLUSION
In the Nigerian population, normative values of motor and sensory ulnar nerve conduction parameters are similar to the existing values in the literature. The ulnar NCV appeared to be influenced by height and gender.
Topics: Humans; Male; Median Nerve; Neural Conduction; Nigeria; Ulnar Nerve
PubMed: 35313404
DOI: 10.4103/aam.aam_74_20 -
Musculoskeletal Science & Practice Aug 2021With medical information widely available, patients often have preconceived ideas regarding diagnostic procedures and management strategies.
BACKGROUND
With medical information widely available, patients often have preconceived ideas regarding diagnostic procedures and management strategies.
OBJECTIVES
To investigate whether expectations, such as beliefs about the source of symptoms and knowledge about diagnostic tests, influence pain perception during a clinical diagnostic test.
DESIGN
Cross-sectional study.
METHODS
Pain was induced by intramuscular hypertonic saline infusion in the thenar muscles. In line with sample size calculations, fifteen participants were included. All participants received identical background information regarding basic median nerve biomechanics and basic concepts of differential diagnosis via mechanical loading of painful structures. Based on different explanations about the origin of their induced pain, half of the participants believed (correctly) they had 'muscle pain' and half believed (incorrectly) they had 'nerve pain'. Pain intensity and size of the painful area were evaluated in five different positions of the median nerve neurodynamic test (ULNT1 ). Data were analysed with two-way analyses of variance.
RESULTS
/findings: Changes in pain in the ULNT1 positions were different between the 'muscle pain' and 'nerve pain' group (p < 0.001). In line with their expectations, the 'muscle pain' group demonstrated no changes in pain throughout the test (p > 0.38). In contrast, pain intensity (p ≤ 0.003) and size of the painful area (p ≤ 0.03) increased and decreased in the 'nerve pain' group consistent with their expectations and the level of mechanical nerve loading.
CONCLUSION
Pain perception during a clinical diagnostic test may be substantially influenced by pain anticipation. Moreover, pain was more aligned with beliefs and expectations than with the actual pathobiological process.
Topics: Attitude to Health; Cross-Sectional Studies; Decision Making; Diagnostic Tests, Routine; Humans; Median Nerve; Motivation; Pain; Physician-Patient Relations
PubMed: 33991785
DOI: 10.1016/j.msksp.2021.102387 -
Clinics in Orthopedic Surgery Dec 2022The interest in ultrasonography (US) and magnetic resonance imaging (MRI) assessment of the patients with carpal tunnel syndrome (CTS) is growing. This paper aimed to...
BACKGROUND
The interest in ultrasonography (US) and magnetic resonance imaging (MRI) assessment of the patients with carpal tunnel syndrome (CTS) is growing. This paper aimed to find the correlation of postoperative changes in these modalities' parameters with clinical outcomes.
METHODS
Boston CTS questionnaire-symptom severity (BQ-SS), Boston CTS questionnaire-functional status (BQ-FS), and visual analog scale (VAS) questionnaires (for pain, paresthesia, and grip weakness assessment) were used to evaluate clinical outcomes. Various imaging parameters of the median nerve and carpal tunnel were evaluated using US and MRI at two levels of the hook of the hamate (distal) and the pisiform (proximal) once preoperatively and then 3 months postoperatively. Corresponding US and MRI parameter measures were compared, and correlational analysis was performed between alteration of imaging findings and changes in clinical parameters postoperatively.
RESULTS
Patients' functional status (BQ-FS score) was positively correlated with the nerve width both in US and MRI at the proximal level ( = 0.457 and = 0.453, respectively) and also with the MRI nerve circumference at the distal level ( = -0.482). Correlation between paresthesia and the nerve width was notable in MRI at the distal hook of the hamate level ( = -0.403). Grip weakness VAS score was correlated with the nerve width-to-height ratio (WHR) in US at the distal level ( = 0.432).
CONCLUSIONS
Changes in US and MRI parameters of the median nerve width, circumference, and WHR were associated with clinical changes in patients with CTS after surgery.
Topics: Humans; Carpal Tunnel Syndrome; Paresthesia; Median Nerve; Ultrasonography; Magnetic Resonance Imaging
PubMed: 36518939
DOI: 10.4055/cios22031 -
NeuroImage. Clinical 2020There is an unmet need to develop robust predictive algorithms to preoperatively identify pediatric epilepsy patients who will respond to vagus nerve stimulation (VNS)....
There is an unmet need to develop robust predictive algorithms to preoperatively identify pediatric epilepsy patients who will respond to vagus nerve stimulation (VNS). Given the similarity in the neural circuitry between vagus and median nerve afferent projections to the primary somatosensory cortex, the current study hypothesized that median nerve somatosensory evoked field(s) (SEFs) could be used to predict seizure response to VNS. Retrospective data from forty-eight pediatric patients who underwent VNS at two different institutions were used in this study. Thirty-six patients ("Discovery Cohort") underwent preoperative electrical median nerve stimulation during magnetoencephalography (MEG) recordings and 12 patients ("Validation Cohort") underwent preoperative pneumatic stimulation during MEG. SEFs and their spatial deviation, waveform amplitude and latency, and event-related connectivity were calculated for all patients. A support vector machine (SVM) classifier was trained on the Discovery Cohort to differentiate responders from non-responders based on these input features and tested on the Validation Cohort by comparing the model-predicted response to VNS to the known response. We found that responders to VNS had significantly more widespread SEF localization and greater functional connectivity within limbic and sensorimotor networks in response to median nerve stimulation. No difference in SEF amplitude or latencies was observed between the two cohorts. The SVM classifier demonstrated 88.9% accuracy (0.93 area under the receiver operator characteristics curve) on cross-validation, which decreased to 67% in the Validation cohort. By leveraging overlapping neural circuitry, we found that median nerve SEF characteristics and functional connectivity could identify responders to VNS.
Topics: Adolescent; Afferent Pathways; Child; Connectome; Drug Resistant Epilepsy; Evoked Potentials, Somatosensory; Female; Humans; Magnetoencephalography; Male; Median Nerve; Retrospective Studies; Somatosensory Cortex; Support Vector Machine; Treatment Outcome; Vagus Nerve Stimulation
PubMed: 32070812
DOI: 10.1016/j.nicl.2020.102205 -
The Journal of International Medical... Nov 2022To identify whether median nerve stimulation (MNS) may be a potential candidate for the treatment of consciousness disorders via a systematic review and meta-analysis. (Meta-Analysis)
Meta-Analysis
OBJECTIVE
To identify whether median nerve stimulation (MNS) may be a potential candidate for the treatment of consciousness disorders via a systematic review and meta-analysis.
METHODS
PubMed, Cochrane Library, China National Knowledge Infrastructure, Chinese VIP Information, Wanfang, and SinoMed databases were searched. Risk of bias was assessed using the Cochrane Collaboration's tool. The Glasgow Coma Scale (GCS), Disability Rating Scale (DRS), electroencephalogram (EEG), days in the Intensive Care Unit (ICU), and cerebral blood flow measures were compared between the median nerve stimulation and control groups. The meta-analysis was conducted using Review Manager software.
RESULTS
We identified 2244 studies, of which 23 (with data from 1856 patients) qualified for the analysis. MNS improved GCS scores (mean difference [MD] = 2.15), EEG scores (MD = 1.61), cerebral mean blood flow velocity (MD = 4.23), and cerebral systolic blood flow velocity (MD = 10.51). Furthermore, it decreased DRS scores (MD = -1.77) and days in the ICU (MD = -2.02). The effects of MNS on GCS scores increased with longer treatments (1 week, MD = 1.03; 1 month, MD = 2.35) and were better with right MNS (right, MD = 2.36; bilateral, MD = 1.72).
CONCLUSIONS
MNS may promote recovery from consciousness disorders.
Topics: Humans; Consciousness Disorders; Median Nerve; Electric Stimulation; Electroencephalography; Asian People
PubMed: 36448965
DOI: 10.1177/03000605221134467 -
Hand (New York, N.Y.) Nov 2019Ultrasound (US) measurement of cross-sectional area (CSA) of the median nerve has emerged as a viable alternative to electromyography/nerve conduction studies (EMG/NCS)... (Comparative Study)
Comparative Study Observational Study
Ultrasound (US) measurement of cross-sectional area (CSA) of the median nerve has emerged as a viable alternative to electromyography/nerve conduction studies (EMG/NCS) for diagnosis of carpal tunnel syndrome (CTS). The purpose of this study is to compare CSA of the median nerve between US and MRI using current MRI and US technology. The null hypothesis is there is no difference between US and MRI CSA measurements. : The study design was an observational cohort, enrolling patients presenting to clinic with MRI of the wrist. Participants with clinical signs and symptoms of CTS were excluded. The CSA measurements of the median nerve on MRI T1-weighted axial images were performed by a hand fellow blinded to results of US measurements, and US measurement of median nerve CSA was performed by a hand fellowship trained surgeon blinded to results of the MRI measurements. Results were analyzed via percent error, Pearson correlation, and tests. Twenty participants were enrolled with mean age of 29.4 years. Four left wrists and 16 right wrists were measured. The US mean CSA of the median nerve was 6.8 mm (±2.330 mm). The MRI mean CSA of the median nerve was 6.8 mm (±2.153 mm), = .442. Pearson correlation between modalities was 0.93, suggesting near-perfect correlation. Mean percent error was 8.8%. : Results of this study suggest that US is an accurate method to measure CSA of the median nerve at the carpal tunnel inlet. The mean difference between US and MRI was unlikely to be clinically significant.
Topics: Adult; Carpal Tunnel Syndrome; Female; Humans; Magnetic Resonance Imaging; Male; Median Nerve; Neurologic Examination; Prospective Studies; Sensitivity and Specificity; Ultrasonography; Wrist
PubMed: 29799270
DOI: 10.1177/1558944718777833