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EEG and the anterior thalamic nucleus
Published in Hans O Lüders, Deep Brain Stimulation and Epilepsy, 2020
Thresholds for producing a visible recruiting rhythm were determined as a function of stimulation voltage, frequency and pulse width. A single American Board of Clinical Neurophysiology certified expert reader (BL) interpreted EEGs in the operating room for the presence of the recruiting rhythm. In one patient, the relationship between pulse width and recruiting rhythm threshold was documented. In two patients frequency-response of the recruiting rhythm was recorded. In all patients, recruiting rhythm was produced by monopolar stimulation at different electrode depths spanning the AN on each side, and correlated with stereotaxic coordinates to verify functional electrode placement in the AN. The electrode depths through which the recruiting rhythm was evoked were recorded and used to select the deep brain stimulation electrode contacts positioned at the same depths for chronic stimulation postoperatively.
Electrical Brain Stimulation to Treat Neurological Disorders
Published in Bahman Zohuri, Patrick J. McDaniel, Electrical Brain Stimulation for the Treatment of Neurological Disorders, 2019
Bahman Zohuri, Patrick J. McDaniel
However, the clinical significance of these distinctive patterns of brain wave activity is unknown. Thus, the role of quantitative EEG in diagnosis, evaluation of disease progression, and treatment of these conditions has yet to be elucidated. A report from the American Academy of Neurology and the American Clinical Neurophysiology Society concluded that quantitative EEG remains investigational for clinical use in post-concussion syndrome, mild-to-moderate head injury, learning disability, attention disorders, schizophrenia, depression, alcoholism, and drug abuse.
Evaluation of Balance
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Loud sounds can activate the vestibular labyrinth. If these sounds are brief in duration (clicks), the total amount of energy delivered to the ear is small and the procedure harmless. Using averaging techniques similar to those in brainstem auditory evoked potentials, an electromyographic (EMG) potential can be identified from neck muscles.148,149 The response is a sound-evoked vestibulocollic (or vestibulospinal) reflex and this is often called the cervical vestibular-evoked myogenic potential (cVEMP). The technique can be easily set up in any clinical neurophysiology or audiology department with access to calibrated sound generators, averaging equipment and surface recording electrodes and several devices are available commercially.
Comparison of nerve conduction velocity distribution methods by cold exposure and ischemia
Published in International Journal of Neuroscience, 2021
Kamil Savaş, Hilmi Uysal, Nazmi Yaraş
The assessment of peripheral nerve functions is essential in clinical neurophysiology in order to detect nerve conduction velocity (NCV) and conduction block at a subclinical stage [1, 2]. NCV studies are based on recording a compound action potential (CAP) from a peripheral nerve via surface or needle electrodes placed near the nerve bundle to calculate conduction velocity (CV), latency and duration. However, the information gained from clinical NCV studies generally applies to fast conducting fibers since they contribute more to CAP amplitude and duration than the slower ones. Consequently, no information is provided by current NCV methods with regard to slower conducting fibers or individual fiber groups. There is strong evidence to suggest that some diseases affect specific nerve groups. For example, diabetes mellitus [3] and uremic neuropathy [4] affect slower conducting sensory fibers earlier and more frequently than faster conducting sensory fibers. On this basis, the estimation of conduction velocity distribution (CVD) can provide a holistic comprehension of the pathophysiology of fibers affected by various neuropathies. It can also be used to monitor the efficacy of the applied treatment and healing process.
Evaluation of the effectiveness of valproic acid for treating cyanotic breath holding spells: A Pilot prospective study
Published in Expert Review of Clinical Pharmacology, 2020
Sherifa A. Hamed, Ali F. Elhadad, Hekma S. Farghaly
Echocardiography was performed for patients with M-mode measurements and conventional Doppler echocardiographic examinations according to the criteria of the American Society of Echocardiography (ASE) guidelines [38] using a S4-2 Broadband Sector (4- to 2-MHz phased-array transducer, Philips EnVisor C HD ultrasound system; Philips Medical Systems, Inc., Netherlands). EEG: was done for patients by employing scalp electrodes placed according to the international 10–20 system with bipolar and referential montages) [Nihon Kohden machine (4217)], Recording was done for 20–30 minutes. Photic stimulation was done as a provocative test. The EEG records were interpreted by the neurologists (SAH and AFH) according to definitions of the International Federation of clinical neurophysiology [39], Evaluation of autonomic nervous system function [40] testing was done for patients and healthy children. The following autonomic testing were repeated thrice at baseline and the average was included in the statistical analyses. They included: (a) Postural falls in blood pressure parameters [systolic (SBP), diastolic (DBP) blood pressures and mean arterial pressure (MAP)] were used as markers of dysfunction of the sympathetic cardiovascular reflexes: sustained drop in SBP (>20mm Hg), DBP (>10mm Hg) and MAP (>10mm Hg) without increase in heart rate were suggestive of an autonomic deficit. MAP was measured as follows: MAP = [(2 x diastolic) + systolic]/3].
Usefulness of intraoperative monitoring in microvascular decompression for hemifacial spasm: a systematic review and meta-analysis
Published in British Journal of Neurosurgery, 2022
Lyndon Sprenghers, Robin Lemmens, Johannes van Loon
Literature on BAEP monitoring is marked by a substantial amount of heterogeneity. Studies use different protocols for BAEP monitoring, different alarm criteria, different definitions of hearing loss and different ways of assessing postoperative hearing loss. For this reason, we did not use a bivariate approach of pooling data of the individual studies. We found an Area Under the Curve of 0.911 95%CI [0.753; 0.933]. This means that BAEP monitoring using the criteria of the ‘American Clinical Neurophysiology Society’ has good diagnostic accuracy. The wide confidence interval is also a consequence of the marked heterogeneity. This value is similar to the value of a previously published systematic review.71