Purpose: An increase in resting motor threshold (RMT), prolonged cortical silent period duration (CSP), and reduced short-latency afferent inhibition (SAI), confirmed with previous transcranial magnetic stimulation (TMS), suggest decreased cortical excitability in obstructive sleep apnea syndrome (OSAS). The present study included MRI of OSAS patients for navigated TMS assessment of the RMT, as an index of the threshold for corticospinal activation at rest, and SAI as an index of cholinergic neurotransmission. We hypothesize to confirm findings on SAI and RMT with adding precision in the targeting of motor cortex in OSAS.
Subjects And Methods: After acquiring head MRIs for 17 severe right-handed OSAS and 12 healthy subjects, the motor cortex was mapped with nTMS to assess the RMT and SAI, with motor evoked potentials (MEPs) recorded from the abductor-pollicis brevis (APB) muscle. The 120%RMT intensity was used for the SAI by a paired-pulse paradigm in which the electrical stimulation to the median nerve is followed by magnetic stimulation of the motor cortex at inter-stimulus intervals (ISIs) of 18-28 ms (ISIs). The SAI control condition included a recording of MEPs without peripheral stimulation. Latency and amplitude of MEP at RMT at 120%RMT for eleven different at ISIs were analyzed.
Results: The study showed a significantly lower percentage deviation of MEP amplitude at ISIs from the control condition between OSAS and healthy subjects (U=44.0, p=0.01). The intensity of stimulation at RMT was significantly higher in OSAS subjects (U=55.0, p=0.04*). Correlation analysis showed that BMI significantly negatively correlated (=-0.47) with MEP amplitude percentage deviation in OSAS patients.
Conclusion: The nTMS study results in increased RMT, and reduced cortical afferent inhibition in OSAS patients for SAI at ISIs, confirming previous findings of impaired cortical afferent inhibition in OSAS. Future nTMS studies are desirable to elucidate the role of RMT and SAI in diagnostics and treatment of OSAS, and to elucidate the usefulness of nTMS in OSAS research.
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http://dx.doi.org/10.2147/NSS.S253281 | DOI Listing |
Biomed Phys Eng Express
January 2025
Children's Hospital of Eastern Switzerland, Claudiusstrasse 6, St.Gallen, 9006, SWITZERLAND.
Mapping the myomagnetic field of a straight and easily accessible muscle after electrical stimulation using triaxial optically pumped magnetometers (OPMs) to assess potential benefits for magnetomyography (MMG). Approach: Six triaxial OPMs were arranged in two rows with three sensors each along the abductor digiti minimi (ADM) muscle. The upper row of sensors was inclined by 45° with respect to the lower row and all sensors were aligned closely to the skin surface without direct contact.
View Article and Find Full Text PDFJAMA Neurol
January 2025
Department of Neural and Pain Sciences, University of Maryland School of Dentistry, Baltimore.
Importance: Biomarkers would greatly assist decision-making in the diagnosis, prevention, and treatment of chronic pain.
Objective: To undertake analytical validation of a sensorimotor cortical biomarker signature for pain consisting of 2 measures: sensorimotor peak alpha frequency (PAF) and corticomotor excitability (CME).
Design, Setting, And Participants: This cohort study at a single center (Neuroscience Research Australia) recruited participants from November 2020 to October 2022 through notices placed online and at universities across Australia.
Cerebrospinal fluid (CSF) dynamics, driven by sensory stimulation-induced neuronal activity, is crucial for maintaining homeostasis and clearing metabolic waste. However, it remains unclear whether such CSF flow is impaired in age-related neurodegenerative diseases of the visual system. This study addresses this gap by examining CSF flow during visual stimulation in glaucoma patients and healthy older adults using functional magnetic resonance imaging.
View Article and Find Full Text PDFEClinicalMedicine
February 2025
Department of Neurosurgery, King's College Hospital Foundation Trust, London, UK.
Background: Supratentorial function-eloquent brain tumour surgeries challenge the balance between maximal tumour resection and preservation of neurological function. This study aims to evaluate the efficacy of preoperative and intraoperative mapping techniques on resection outcomes and post-operative deficits.
Methods: This systematic review and meta-analysis examined literature up to March 2023, sourced from PubMed, Embase, and Medline.
J Pain Res
January 2025
School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.
Purpose: Complex regional pain syndrome (CRPS) is a debilitating chronic pain condition characterized by sensory, motor, and autonomic dysfunction with a world-wide prevalence of 26.2 per 100,000 people per year and is 3 to 4 times more prevalent in females. Repetitive transcranial magnetic stimulation (rTMS) has shown to be beneficial for pain relief in neuropathic pain and initial evidence in CRPS is promising, but studies are limited.
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