Search

We quantified intraneural blood flow (INBF) using perfusion measurement software (PixelFlux), and compared it with the qualitative method of counting blood vessels (vessel score) in a cohort of carpal tunnel syndrome (CTS) patients., Methods: Forty-seven patients (67 wrists) with a clinical and electrophysiological diagnosis of CTS, and 20 healthy controls (40 wrists) were enrolled. Median nerve ultrasound (US) was performed at the carpal tunnel inlet to measure the cross-sectional area (CSA) and vessel score. Power Doppler sonograms from nerves with detectable INBF were processed with PixelFlux to obtain the maximum perfusion intensity (MPI)., Results: Forty-nine percent of CTS patients had detectable INBF compared with none in the control group (P < 0.0001). MPI correlated significantly with vessel score (r = 0.945, P < 0.0001), CSA (r = 0.613, P < 0.0001), and electrophysiological severity (r = 0.440, P < 0.0001). MPI had higher intra- or interobserver reliability compared with vessel score (0.95 vs. 0.47)., Conclusion: MPI is a better method for quantification of INBF. Muscle Nerve, 2016 Muscle Nerve 55: 77-83, 2017., (© 2016 Wiley Periodicals, Inc.)

Objective: To investigate the effects of fampridine on nerve excitability, the present study utilized peripheral axonal excitability techniques in 18 MS patients receiving treatment with fampridine., Methods: Studies were performed at baseline and repeated 3months after institution of fampridine at standard dosing., Results: Following treatment with fampridine there were significant changes in axonal excitability for those parameters associated with fast K(+) channels that shifted towards normal control values. Specifically, increases were noted in the peak superexcitability of recovery cycle (fampridine, -25.6±1.6%; baseline -22.8±1.7%; p<0.004), peak depolarizing threshold electrotonus (fampridine, 69.1±1.0%; baseline 67.0±1.4%; p<0.004), and depolarizing threshold electrotonus between 40 and 60ms after onset of depolarization (fampridine, 52.8±1.3%; baseline 49.9±1.4%; p=0.02)., Conclusion: The present study has established that fampridine at standard doses exerts effects on peripheral nerve function that may be mediated by reduction of fast K(+) conductances., Significance: Modulation of fast K(+) conductances by fampridine may contribute to the improvement observed in MS symptoms including motor fatigue., (Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

This article forms part of our 'Tests and results' series for 2011 which aims to provide information about common tests that general practitioners order regularly. It considers areas such as indications, what to tell the patient, what the test can and cannot tell you, and interpretation of results.

Introduction: Threshold tracking paired-pulse transcranial magnetic stimulation (TTTMS) examines cortical function and is useful for diagnosis of motor neuron disorders. Differences in cortical function have been identified between dominant and non-dominant limbs using constant stimulus methods, but they remain unclear, potentially due to methodological differences. In this study we aimed to clarify differences in cortical function between dominant and non-dominant limbs using TTTMS.Methods: Single-pulse TMS, TTTMS, and nerve conduction studies were performed in 25 healthy, right-handed participants by recording from the abductor pollicis brevis muscle.Results: There were no side-to-side differences observed in resting motor threshold, motor evoked potential (MEP) amplitude, MEP latency, central motor conduction time, cortical silent period, short-interval intracortical inhibition and facilitation, compound muscle action potential (CMAP) amplitude, CMAP latency, F-wave latency, or neurophysiological index.Conclusions: These findings suggest that, when using TTTMS, there are no differences in cortical function between dominant and non-dominant hemispheres. Muscle Nerve 55: 424-427, 2017. [ABSTRACT FROM AUTHOR]

• Taxanes produce significant peripheral neuropathy. • Variations in chemotherapy-induced peripheral neuropathy (CIPN) phenotypes associated with taxane-treatment exist. • Understanding the CIPN phenotype may inform treatment decisions. To comprehensively describe patient-reported, functional and neurophysiological outcomes to elucidate the phenotypic profile of taxane-induced neuropathy. Taxane-treated patients (n = 47) completed cross-sectional bilateral clinical and sensory assessments and nerve conduction studies. Patients reported symptom severity via Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx13) questionnaire. Symptoms of neuropathy were reported by 81% of patients. On clinical examination, 62% had 2 or more abnormalities, with 20% indicating significant symptomatic and objective neuropathy. Nerve conduction studies were consistent with a sensory predominant axonal neuropathy. However, features more typical of entrapment neuropathy were also present in > 50%, which were not associated with overall severity of chemotherapy-induced peripheral neuropathy (CIPN) or clinical risk factors. There is considerable variation in CIPN phenotypes associated with taxane-treatment. Understanding their clinical associations may assist in identification of patients at risk of severe neurotoxicity. This would enable treatment modification decisions but also limit early cessation of effective anti-cancer treatment in patients with less severe neurological sequelae. Understanding the CIPN phenotype may inform treatment decisions which could impact clinical and survival outcomes. [ABSTRACT FROM AUTHOR]

Objective Recently, the utility of threshold tracking paired-pulse transcranial magnetic stimulation (TTTMS), to measure changes in cortical excitabilitability, has been established for diagnostic purposes across a range of neurological diseases. However, the impact of healthy aging on the GABA-ergic intracortical inhibitory system remains unclear. To improve the clinical applicability, TTTMS was performed across an age spectrum. Methods TTTMS, single-pulse TMS and nerve conduction studies (NCS) were performed in 113 healthy subjects aged between 20 and 83 years (57 male and 56 female). Results Prolonged motor evoked potential (MEP) latency, increased central motor conduction time, decreased compound muscle action potential (CMAP) amplitude, prolonged F-wave latency and decreased neurophysiological index (NI), calculated from CMAP amplitude, latency and F-wave frequency, were observed as subjects aged. In contrast, short interval intracortical inhibition (SICI) and facilitation did not change. Compared to females, males exhibited a reduced SICI and NI along with longer MEP, CMAP with prolonged F-wave latencies. Multivariate analyses revealed similar results. Conclusion Utilizing clinically applicable TTTMS protocols, findings suggest that GABA mediated intracortical inhibition may be greater in females but does not significantly change with age. Significance These findings may better inform the interpretation of diagnostic TTTMS studies in the clinical setting. [ABSTRACT FROM AUTHOR]