BCIA Neurofeedback Exam: Demos study guide Day
- with Complete Solutions
Describe how electrical activity coming from the scalp is transformed into the EEG - Correct Answer Electrodes detect signals (in microvolts) coming from the scalp that are amplified and transformed via digital or analog processing. The EEG is an analog representation of electrical activity coming from the scalp.Morphology - Correct Answer The visible shapes and contours of the EEG waveform that give its visual appearance Name some important aspects of the EEG signal - Correct Answer Amplitude, frequency distribution, patterns of waxing and waning, changes due to sensory stimulation or task, distribution across the scalp Explain bandpass filters - Correct Answer A way of letting some frequencies through while blocking others. They can be analog hardware or digital software.Explain Fast Fourier Transform (FFT) - Correct Answer Like a prism- separates raw EEG into smaller parts - frequencies. There are many types of bandpass filters and many ways of implementing Fourier or other transforms.Explain bins - Correct Answer A way of gathering outputs from transforms where the frequency data is organized into useful bands like the bandwidth of a digital filter Explain sampling rate - Correct Answer Reflects how fast the signal is sampled. Optimum ratio is 4:1.For example if a system was recording 32 Hz activity, a sampling rate of 128 would be preferable.Name common bandwidths - Correct Answer Delta, theta, alpha, beta, SMR, high beta, gamma Delta - Correct Answer 1-4 hz. Sleep, repair, brain injury Theta - Correct Answer 4-8 hz. Creativity, insight, deep states, distraction Alpha - Correct Answer 8-12 hz. Alert and peaceful, readiness, meditation, effortlessness 1 / 2
Beta - Correct Answer 13-21 hz. Thinking, focusing, sustained attention, problem solving, busy thoughts SMR - Correct Answer 12-15 hz. Mentally alert, physically relaxed, stillness, intention to remain still High beta - Correct Answer 20-32 hz. Intensity, hyper alert, anxious, agitated Gamma - Correct Answer 38-42 hz. Cognitive processing, learning, integrated thoughts Which 3 basic factors can potentially distort the EEG? - Correct Answer Biological, equipment, environmental Which biological factors can distort the EEG? - Correct Answer Muscles anywhere in body, e.g.Blinking, clenched jaw, raised eyebrows, breathing, coughing What is electromyography (EMG)? - Correct Answer Electrical activity coming from muscles What is surface electromyography (SEMG) biofeedback? - Correct Answer Records the electrical activity of muscles coming from the surface of the skin. General range of SEMG is 20-200 hz.How can SEMG cause artifact? - Correct Answer EEG and SEMG have some overlapping Hz in the beta range (EEG 0-40); (SEMG 20-200). Best way to identify EMG is by observing the analog EEG.Which areas of the scalp are most affected by SEMG? - Correct Answer Prefrontal and temporal What is electro-ocular artifact (low frequency invasion)? - Correct Answer Blinking or eye movements can show as high amplitudes of delta. Identify by looking at the EEG.Explain the effect of sweating and salt bridges. - Correct Answer Excessive sweating can cause large, slow, up and down movements of the EEG, perhaps due to the loosening of the electrodes. Salt bridges can come from sweating or clients who have wet or damp hair. A salt bridge refers to unwanted electrical conductivity between two or more scalp sensors.
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