China
Africa
Explore chapters and articles related to this topic
Study and Analysis of the Visual P300 Speller on Neurotypical Subjects
Published in Mridu Sahu, G. R. Sinha, Brain and Behavior Computing, 2021
Mridu Sahu, Vyom Raj, Shreya Sharma, Samrudhi Mohdiwale
Brainwaves are classified according to their frequencies and have been labelled under five different categories according to the division of bandwidth [44,45]. These are described herewith:Infra low waves (frequency range less than 0.5 Hz). They are the basic rhythms that underlie all our brain functions. They have not been studied deeply because of their low frequency which makes them difficult to detect.Delta waves (frequency range 0.5–3 Hz). They are low frequency and highly penetrating waves that are observed during deep meditation and dreamless sleeps. Healing and regeneration are stimulated in this state.Theta waves (frequency range 3–8 Hz). They are the semi-awake state waves and the times of drifting to sleep or getting awake.Alpha waves (frequency range 8–12 Hz). They regulate over-all mental coordination, calmness, and alertness. They basically determine the relaxed attentive states.Beta waves (frequency range 12–38 Hz). They dominate our nor-mal waking state of consciousness. They direct attentiveness towards cognitive works and the outer world.
Protocol and Process of EEG Data Acquisition
Published in Narayan Panigrahi, Saraju P. Mohanty, Brain Computer Interface, 2022
Narayan Panigrahi, Saraju P. Mohanty
The EEG signal is closely related to the level of consciousness of the person. As the activity increases, the EEG shifts to a higher dominating frequency and lower amplitude. When the eyes are closed, the alpha waves begin to dominate the EEG. When the person falls asleep, the dominant EEG frequency decreases. In a certain phase of sleep, rapid eye movement (REM), the person dreams and has active movements of the eyes, which can be seen as a characteristic EEG signal. In deep sleep, the EEG has large and slow deflections called delta waves. No cerebral activity can be detected from a patient with complete cerebral death. An example of each of the mentioned waveforms is depicted in Figure 5.2.
Diagnostic Devices
Published in Laurence J. Street, Introduction to Biomedical Engineering Technology, 2016
Delta waves are the highest in amplitude but lowest in frequency, about 1.5–4 Hz. Periods of sleep show delta wave activity, with frequency corresponding to depth of sleep—deeper sleep means lower frequencies. Delta waves can be analyzed to indicate depth of unconsciousness during general anesthesia.
Using brain waves to assess the colour effect on promoting spirituality in the mosque architecture
Published in Architectural Science Review, 2022
As previously stated, EEG signals are categorized into five various wave types ‘alpha, beta, theta, delta, and gamma’ (Basar 2012). Delta waves are located in a range of 0.5-3 Hz. People in the delta wave state are lethargic, immobile, inattentive, and have a low level of arousal. Theta waves, the rate of changes is between 4 and 7 Hz. Theta waves are slow waves with a sinus rhythm. Theta is associated with emotion, creativity, deep thinking. The alpha signals’ frequency is from 8-12 Hz. Alpha waves are associated with relaxation, alertness, and concentration. They are often characterized by creativity and dream thinking. This wavelength is observed when a person is relaxed. Beta waves are created in a range of 13-30 Hz. The beta frequency wave is also the fastest and most active form of short-wave brain waves and is related to intellectual activity, concentration, and attention. The gamma waves fluctuate in frequencies beyond 30 Hz and are observed more during the cross quality of sensory processing. It is also known to accommodate short-term memory of objects, sounds, or sense of touch using gamma rays. (Kamal, Mahmood, and Zakaria 2013)
Brain–Computer Interface Games Based on Consumer-Grade EEG Devices: A Systematic Literature Review
Published in International Journal of Human–Computer Interaction, 2020
Gabriel Alves Mendes Vasiljevic, Leonardo Cunha de Miranda
Brain waves consist of a set of signals that can be divided into five bands, i.e., delta, theta, alpha, beta and gamma waves, classified according to its frequency (Munck, Gonçalves, Mammoliti, Heethaar, & Da Silva, 2009; Nowack, 1995). Each band is associated with certain mental states, and the value definition for each band can vary among studies (Gerrard & Malcolm, 2007). The delta waves (below 4 Hz) are low-frequency waves associated with deep, dreamless sleep and profound meditation states (Nicolas-Alonso & Gomez-Gil, 2012). Their amplitude decreases as the baby human ages and is unusual in awake adult persons, being associated with neurological diseases in such cases (Kübler, Kotchoubey, Kaiser, & Birbaumer, 2001).