Objective: To investigate motor axonal excitability in multifocal motor neuropathy (MMN) associated with involuntary muscle activity.
Methods: Two MMN patients with continuous involuntary finger movements (MMNifm) were compared to 11 patients without movements (MMNnfm). Clinical examination, EMG of the abductor pollicis brevis muscle, nerve conduction studies, motor unit number estimation, excitability studies, and mathematical modeling were conducted in the patients with MMN and compared to controls.
Results: Weakness, axonal loss, conduction block, or both occurred in the median nerve in the MMNifm and the MMNnfm patients. Ultrasound studies (US) in MMNifm showed enlargement of the nerves at the axilla/brachial plexus at the site of the conduction block. In MMNifm, EMG and the US showed continuous involuntary contractions, and excitability studies of the median nerve at the wrist showed increased threshold reduction during early depolarizing electrotonus and at early recovery cycle (superexcitability). Mathematical modeling was consistent with reduced fast K current more pronounced in MMNifm than in MMNnfm.
Conclusions: MMN may have a spectrum of changes associated with instability of the axonal membrane which may be due to paranodal myelin loosening.
Significance: In addition to motor conduction block and axonal loss, MMN has pathophysiological changes that suggest more widespread involvement of motor myelinated fibers.
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http://dx.doi.org/10.1016/j.clinph.2024.12.019 | DOI Listing |
Heart Rhythm
January 2025
Geisinger Heart Institute, Geisinger Wyoming Valley Medical Center, MC 36-10, 1000 E Mountain Blvd, Wilkes-Barre, PA 18711.
J Electrocardiol
January 2025
Victorian Heart Institute, Monash University, Clayton, VIC, Australia; Victorian Heart Hospital, Clayton, VIC, Australia. Electronic address:
Introduction: This study evaluates various formulae used to correct the QT interval in patients with wide QRS complexes to calculate corrected QT (QTc) following Cardiac Resynchronisation Therapy (CRT).
Methods: We included patients with severe heart failure and left bundle branch block, presenting with a QRS duration of at least 120 milliseconds, who underwent successful CRT implantation. Patients were excluded if they had non-lateral left ventricular lead placement, metabolic disorders, atrial fibrillation, atrial tachycardia, or high-degree atrioventricular block prior to implantation.
Int J Environ Res Public Health
January 2025
Study Design and Scientific Writing Laboratory, Centro Universitario FMABC, Santo André 09060-870, SP, Brazil.
The trained heart adapts through geometric changes influenced by concentric and eccentric hypertrophy, depending on the predominance of the isometric or dynamic components of the exercise performed. Additionally, alterations in heart rhythm may occur due to increased vagal system activity. Cardiological evaluation with an electrocardiogram (ECG) aims to identify cardiac conditions that could temporarily or permanently disqualify an athlete from competition.
View Article and Find Full Text PDFClin Neurophysiol
January 2025
Department of Clinical Neurophysiology, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine and Neuroscience, University of Copenhagen, Denmark; Department of Neurology, Rigshospitalet, Copenhagen, Denmark.
Objective: To investigate motor axonal excitability in multifocal motor neuropathy (MMN) associated with involuntary muscle activity.
Methods: Two MMN patients with continuous involuntary finger movements (MMNifm) were compared to 11 patients without movements (MMNnfm). Clinical examination, EMG of the abductor pollicis brevis muscle, nerve conduction studies, motor unit number estimation, excitability studies, and mathematical modeling were conducted in the patients with MMN and compared to controls.
Br J Anaesth
January 2025
Department of Anaesthesiology, Peking University First Hospital, Beijing, China; Outcomes Research Consortium, Cleveland, OH, USA.
Background: The Qnox index is a novel monitor to quantify intraoperative nociception based on an electroencephalographic algorithm. We evaluated the ability of the Qnox index to discriminate noxious from non-noxious stimuli, respond to stimuli, and discriminate different levels of analgesia in patients under propofol anaesthesia with neuromuscular block.
Methods: Qnox was compared with heart rate and mean arterial pressure with five designated stimuli: tetanic stimulations without (tetanic 1) and with sufentanil (tetanic 2), skin incision, tracheal intubation, and a non-noxious period.
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