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Quantitative Electroencephalography
Quantitative electroencephalography (qEEG or QEEG) is a field concerned with the numerical analysis of electroencephalography (EEG) data and associated behavioral correlates. Details Techniques used in digital signal analysis are extended to the analysis of electroencephalography (EEG). These include wavelet analysis and Fourier analysis, with new focus on shared activity between rhythms including phase synchrony (coherence, phase lag) and magnitude synchrony (comodulation/correlation, and asymmetry). The analog signal comprises a microvoltage time series of the EEG, sampled digitally and sampling rates adequate to over-sample the signal (using the Nyquist principle of exceeding twice the highest frequency being detected). Modern EEG amplifiers use adequate sampling to resolve the EEG across the traditional medical band from DC to 70 or 100 Hz, using sample rates of 250/256, 500/512, to over 1000 samples per second, depending on the intended application. QEEG can be per ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electroencephalography
Electroencephalography (EEG) is a method to record an electrogram of the spontaneous electrical activity of the brain. The biosignals detected by EEG have been shown to represent the postsynaptic potentials of pyramidal neurons in the neocortex and allocortex. It is typically non-invasive, with the EEG electrodes placed along the scalp (commonly called "scalp EEG") using the International 10-20 system, or variations of it. Electrocorticography, involving surgical placement of electrodes, is sometimes called " intracranial EEG". Clinical interpretation of EEG recordings is most often performed by visual inspection of the tracing or quantitative EEG analysis. Voltage fluctuations measured by the EEG bioamplifier and electrodes allow the evaluation of normal brain activity. As the electrical activity monitored by EEG originates in neurons in the underlying brain tissue, the recordings made by the electrodes on the surface of the scalp vary in accordance with their orientation and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wavelet Transform
In mathematics, a wavelet series is a representation of a square-integrable (real number, real- or complex number, complex-valued) function (mathematics), function by a certain orthonormal series (mathematics), series generated by a wavelet. This article provides a formal, mathematical definition of an orthonormal wavelet and of the integral wavelet transform. Definition A function \psi \,\in\, L^2(\mathbb) is called an orthonormal wavelet if it can be used to define a Hilbert space#Orthonormal bases, Hilbert basis, that is a orthonormal basis, complete orthonormal system, for the Hilbert space L^2\left(\mathbb\right) of Square-integrable function, square integrable functions. The Hilbert basis is constructed as the family of functions \ by means of Dyadic transformation, dyadic translation (geometry), translations and dilation (operator theory), dilations of \psi\,, :\psi_(x) = 2^\frac \psi\left(2^jx - k\right)\, for integers j,\, k \,\in\, \mathbb. If under the standard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fourier Transform
A Fourier transform (FT) is a mathematical transform that decomposes functions into frequency components, which are represented by the output of the transform as a function of frequency. Most commonly functions of time or space are transformed, which will output a function depending on temporal frequency or spatial frequency respectively. That process is also called ''analysis''. An example application would be decomposing the waveform of a musical chord into terms of the intensity of its constituent pitches. The term ''Fourier transform'' refers to both the frequency domain representation and the mathematical operation that associates the frequency domain representation to a function of space or time. The Fourier transform of a function is a complex-valued function representing the complex sinusoids that comprise the original function. For each frequency, the magnitude (absolute value) of the complex value represents the amplitude of a constituent complex sinusoid with that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry Nyquist
Harry Nyquist (, ; February 7, 1889 – April 4, 1976) was a Swedish-American physicist and electronic engineer who made important contributions to communication theory. Personal life Nyquist was born in the village Nilsby of the parish Stora Kil, Värmland, Sweden. He was the son of Lars Jonsson Nyqvist (b. 1847) and Katrina Eriksdotter (b. 1857). His parents had eight children: Elin Teresia, Astrid, Selma, Harry Theodor, Amelie, Olga Maria, Axel Martin and Herta Alfrida. He emigrated to the USA in 1907. Education He entered the University of North Dakota in 1912 and received B.S. and M.S. degrees in electrical engineering in 1914 and 1915, respectively. He received a Ph.D. in physics at Yale University in 1917. Career He worked at AT&T's Department of Development and Research from 1917 to 1934, and continued when it became Bell Telephone Laboratories that year, until his retirement in 1954. Nyquist received the IRE Medal of Honor in 1960 for "fundamental contributions to a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EEGLAB
EEGLAB is a MATLAB toolbox distributed under the free BSD license for processing data from electroencephalography (EEG), magnetoencephalography (MEG), and other electrophysiological signals. Along with all the basic processing tools, EEGLAB implements independent component analysis (ICA), time/frequency analysis, artifact rejection, and several modes of data visualization. EEGLAB allows users to import their electrophysiological data in about 20 binary file formats, preprocess the data, visualize activity in single trials, and perform ICA. Artifactual ICA components may be subtracted from the data. Alternatively, ICA components representing brain activity may be further processed and analyzed. EEGLAB also allows users to group data from several subjects, and to cluster their independent components. History In 1997, a set of data processing functions was first released on the Internet by Scott Makeig in the Computational Neurobiology Laboratory directed by Terry Sejnowski at the Salk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encephalopathy
Encephalopathy (; from grc, ἐνκέφαλος "brain" + πάθος "suffering") means any disorder or disease of the brain, especially chronic degenerative conditions. In modern usage, encephalopathy does not refer to a single disease, but rather to a syndrome of overall brain dysfunction; this syndrome has many possible organic and inorganic causes. Signs and symptoms The hallmark of encephalopathy is an altered mental state or delirium. Characteristic of the altered mental state is impairment of the cognition, attention, orientation, sleep–wake cycle and consciousness. An altered state of consciousness may range from failure of selective attention to drowsiness. Hypervigilance may be present; with or without: cognitive deficits, headache, epileptic seizures, myoclonus (involuntary twitching of a muscle or group of muscles) or asterixis ("flapping tremor" of the hand when wrist is extended). Depending on the type and severity of encephalopathy, common neurological sym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traumatic Brain Injury
A traumatic brain injury (TBI), also known as an intracranial injury, is an injury to the brain caused by an external force. TBI can be classified based on severity (ranging from mild traumatic brain injury TBI/concussionto severe traumatic brain injury), mechanism ( closed or penetrating head injury), or other features (e.g., occurring in a specific location or over a widespread area). Head injury is a broader category that may involve damage to other structures such as the scalp and skull. TBI can result in physical, cognitive, social, emotional and behavioral symptoms, and outcomes can range from complete recovery to permanent disability or death. Causes include falls, vehicle collisions and violence. Brain trauma occurs as a consequence of a sudden acceleration or deceleration within the cranium or by a complex combination of both movement and sudden impact. In addition to the damage caused at the moment of injury, a variety of events following the injury may result in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurofeedback
Neurofeedback (NFB), also called neurotherapy, is a type of biofeedback that presents real-time feedback from brain activity in order to reinforce healthy brain function through operant conditioning. Typically, electrical activity from the brain is collected via sensors placed on the scalp using electroencephalography (EEG), with feedback presented using video displays or sound. The effectiveness of neurofeedback is disputed. While studies and reviews have often found neurofeedback treatment to be beneficial for the patient, it has yet to be shown these effects are directly caused by the neurofeedback technique applied. Placebo-controlled trials have often found the control group to show the same level of improvement as the group receiving actual neurofeedback treatment, which suggests these improvements may be caused by secondary effects instead. Despite this controversy and never having gaining prominence in the medical mainstream, it has been practiced for over four decades. NFB ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biofeedback
Biofeedback is the process of gaining greater awareness of many physiology, physiological functions of one's own body by using Electronics, electronic or other instruments, and with a goal of being able to Manipulation (psychology), manipulate the body's systems at will. Humans conduct biofeedback naturally all the time, at varied levels of consciousness and intentionality. Biofeedback and the biofeedback loop can also be thought of as Emotional self-regulation, self-regulation. Some of the processes that can be controlled include Electroencephalography, brainwaves, muscle tone, skin conductance, heart rate and pain perception. Biofeedback may be used to improve health, performance, and the physiological changes that often occur in conjunction with changes to thoughts, emotions, and behavior. Recently, technologies have provided assistance with intentional biofeedback. Eventually, these changes may be maintained without the use of extra equipment, for no equipment is necessaril ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinical Neurophysiology (journal)
''Clinical Neurophysiology'' is a monthly peer reviewed medical journal published by Elsevier. It was established in 1949 as ''Electroencephalography and Clinical Neurophysiology'' and obtained its current title in 1999. The journal covers all aspects of neurophysiology, especially as relating to the pathophysiology underlying diseases of the central and peripheral nervous system. It is the official journal of the International Federation of Clinical Neurophysiology, the Brazilian Society of Clinical Neurophysiology, the Czech Society of Clinical Neurophysiology, the Italian Clinical Neurophysiology Society, and the International Society of Intraoperative Neurophysiology. Abstracting and indexing The journal is abstracted and indexed in: According to the ''Journal Citation Reports'', the journal has a 2017 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
