see Ten-Twenty System

A registration classification used by the US FDA in registering medical devices and products. Many types of products, including EEG and biofeedback equipment, are subject to mandatory 510(k) registration. A 510(k) is not an "approval." It is a registration that indicates that the product labeling meets federal requirements, and that the manufacturer is subject to FDA oversight.

Association for the Advancement of Medical Instrumentation. This professional and technical association sponsors publications, meetings, and standards. Certain US FDA regulations refer to AAMI standards for equipment safety and performance.

A method and scale of measurement in which the size of an EEG signal is expressed as an "absolute" number, generally microvolts

A measurement of EEG magnitude expressed as microvolts squared.

One of the two electrodes in a differential measurement. Generally on the head, it is the location you are interested in measuring and training.

see Silver Chloride

The instantaneous measure of a signal. EEG amplitude is expressed in microvolts.

American National Standards Institute

A measure of the difference in magnitude of two EEG sites. Generally asymmetry is expressed as some formula relating the magnitudes of the signals.

An EEG measurement taken between two (generally 10-20) locations on the scalp, designed to measure the brain activity in the regions near and between the two locations

A software system that replicates the capabilities of the Mind Mirror on a PC, using a suitable EEG amplifier.

A registration mark obtainable in Europe, required for a supplier to be able to legally market products in Europe. Registration includes review of the technical details and safety of the device.

A single EEG channel is a waveform recording taken either bipolar or monopolar. For one channel of recording, you need an active electrode, a reference electrode, and a ground. For two channels of recording, you need two active electrodes, two references (you can use the same reference for both channels), and a ground.

Also called "Pavlovian" conditioning. A manner of learning in which an organism learns to "pair" previously unpaired events. The first work in this area taught dogs to salivate in response to a bell that was paired with the presentation of food.

see Common Mode Rejection

A measure of how stable the phase relationship is between two sites. Reflects the amount of information shared between (or common to) two site, or between two sites and a third (or more) site(s). This is computed as a correlation coefficient between the channels, and varies from 0 to 1.0, or from 0 to 100%. Coherence training is important, as it allows neurofeedback to be used to train the amount of coupling or connection between brain locations, as the brain functions.

Also called "CMRR." A quality of a differential amplifier that reflects the ratio between the differential gain and the common-mode gain. In a differential amplifier, the former should be very large, and the latter should be very small. CMRR is often expressed in dB or decibels. A CMRR of 100 or above is sufficient for EEG amplifiers.

A metric that reflects how much two signals' magnitudes vary together. It is a Pearson Correlation Coefficient computed on the magnitudes of two signals over time. This metric was first described by Drs. Barry Sterman and David Kaiser.

Or "Component Band." An EEG signal after being filtered between defined frequency limits. Typical EEG component bands are 8-12 (alpha), 12-15 (low beta), and so on.

A way of learning, in which an organism learns to perform two or more tasks concurrently, that were not previous performed concurrently. Biofeedback training may involve concurrent learning in certain situations.

That property of a system that reflects control or communication between and among the component parts. Connectivity metrics include coherence, phase, asymmetry, spectral-correlation coefficient (SCC), comodulation, and synchrony

The outer layers of the brain, consisting of enfolded layers. The human Neocortex is the most recent brain development, consisting of the Frontal, Temporal, Parietal, and Occipital lobes.

Direct Current. A signal containing energy at 0 Hz, i.e. a steady potential. Since the potential is considered to slowly change, a working bandwidth of 0-0.1 Hz, for example, may be considered “DC.”

see Digital Clinical Norms

An electronic amplifier that measures the difference in potential between two sensor locations. One of the most important qualities of a differential amplifier is the common-mode rejection (CMRR).

also called "DCN". A reference database and software developed by John Demos for the analysis of MINI-Q data.

A filter (see Filter) for signal processing, that is implemented using digital techniques. Most digital filters are designed in software and implemented on a PC or other processor.

An international standards body for electronic equipment. The DIN standard is often used to specify electrical connectors. DIN 42-802 defines "touch-proof" connectors such as used in EEG and EKG. The US FDA refers to DIN standards in some of its guidance documents.

An electrical generator that has a positive and a negative pole. Cortical pyramidal cells produce dipoles by virtue of their postsynaptic potentials, then leading to the production of scalp EEG signals by Volume Conduction (qv).

see Dynamic Linked Library

A software method used by Microsoft to include code libraries into software products. Files are named e.g. "filename.dll". Software may require certain DLL's which, if absent, will cause failures. Windows includes hundreds of various DLLs. BrainMaster and other software also use DLL's to include code. The Z DLL is a software package that delivers Z Score training to the BrainMaster system via a DLL.

Electroencephalogram - the electrical activity of the brain as recorded from the head.

Electronics Industry Association

A metallic device used to make a connection to the scalp or body, to measure electrical potential.

A gel or liquid used to allow electrical potential to be measured from the body surface, using a metallic device. The electrolyte actually conducts the electrical signal from the skin surface to the electrode surface. There is one chemical reaction that occurs at the skin/electrolyte interface, and a different reaction at the electrolyte/sensor interface.

Also called "EMI". Any electromagnetic activity that interferes with the operation or use of an electrical device. EMI includes 60 Hz interference, RFI interference, and other sources of interference.

see Electromagnetic Interference

Food and Drug Administration. A branch of the US government chartered with protecting the public by overseeing the labeling, claims, and safety of food, medical products, and medical devices. Any product that is intended to be ingested, or to alter the anatomy or physiology of the body is subject to FDA oversight. Other countries also have their equivalent of the US FDA.

A device or algorithm that limits the frequency range of a signal according to specified limits. Filters may be "low pass," "high pass," "band pass," "band stop," or "notch," among other types. Many types of filters are possible, and filter design is an entire field in itself.

Code instructions used to control hardware. For example, devices such as the BrainMaster EEG modules, microwave ovens, IPods, and other devices are all controlled by internal firmware.

The rate at which a signal is changing or vibrating. EEG frequency is measured in cycles per second, also called "Hertz", abbreviated "Hz." Typical frequency ranges are Theta: 4-7, Alpha: 8-12, SMR or Low Beta: 12-15, Beta: 15-20, and High Beta: 20-30. Exact frequency ranges used for EEG training vary with the practitioner and protocol.

Good Manufacturing Practice - a structured set of rules and procedures used to ensure that the production of medical devices results in safe and properly labeled devices. The US FDA requires that manufacturers comply with GMP rules. The GMP regulations are very similar in content to the ISO 9000 standard.

The physical devices used in equipment, such as amplifiers, cables, and so on.

Hemoencephalography.

International Electronics Consortium. The IEC standards are often used for electrical safety and conformance. Medical devices often must conform to IEC 60601. This requirements exists in various US FDA regulations.

An electrical equipment safety and EMI standard published by the IEC.

Institute of Electrical and Electronics Engineers - A US based professional organization that publishes and conducts activities furthering the fields of electrical and electronic engineering. IEEE also publishes may industry standards. These include ethernet/networking standards such as 802.2 among others.

International Standards Organization. One of the most important ISO standards is the 9000 standards (9001, 9002 ,9003) that provide methods for ensuring that product development and production are conducted with documented quality control.

A quality control standard published by ISO. see ISO.

see Light Emitting Diode

see Low Energy Neurofeedback System

An electronic semiconductor device that produces light output under control of an electronic signal. LED devices include stimulator glasses or "goggles", LED displays, and LED indicator lights. LED's may produce visible or invisible (infrared) light.

A system incorporating various types of EEG-driven stimulation, developed by Dr. Len Ochs.

A measure of the size of a signal. Various metrics are used, including peak-to-peak (P-P) and root-mean-squared (RMS). P-P is a measure of the signal’s size measured from peak to valley. RMS is a measure of the signal’s energy. For pure sinewaves, there is a fixed ratio between P-P and RMS measurements (2.8). For other waveforms (square, triangle, EEG-like), the ratio will vary, depending on the wave shape. EEG amplitude is generally expressed in microvolts.

An EEG spectral analyzer and display developed by Maxwell Cade in England, primarily for use in meditation and personal development.

A method including equipment and software that allows one to acquire EEG from different sensor sites, using a small EEG (e.g. 1, 2, or 4 channel). MINI-Q is a registered trademark of BrainMaster Technologies, Inc.

An EEG measurement from an active (generally 10-20) location on the scalp, to a “neutral” reference such as an ear.

The arrangement of sensor positions and reference locations used to gather an EEG.

A form of biofeedback training that uses the EEG (Electroencephalogram), also known as the “brain wave” as the signal used to control feedback. Sensors applied to the trainee’s scalp record the brainwaves, which are converted into feedback signals by a human/machine interface using a computer and software. By using visual, sound, or tactile feedback to produce operant conditioning of the brain, it can be used to induce brain relaxation through increasing alpha waves. A variety of additional benefits, derived from the improved ability of the CNS (central nervous system) to relax, may also be obtained.

A QEEG software system developed by Dr. Robert Thatcher, and provided by Applied Neuroscience Inc. (ANI). www.appliedneuroscience.com

An instrument and software developed by Margaret Ayers for EEG biofeedback training.

A database of information that describes a normal population. There are standards for the creation of EEG normative databases.

Also called "Skinnerian" conditioning. A manner of learning, in which an organism learns to perform some behavior (including producing biological rhythms) in order to achieve a reward. Cats can be operantly conditioned to produce SMR waves, by rewarding with milk (Sterman). Humans can be operantly conditioned to alter their EEG waves through neurofeedback (EEG biofeedback) training. The psychologist B.F. Skinner used this method to study learning in animals.

A protocol method used with live Z Score training. This approach is incorporated into the BrainMaster 2.5 and 3.0 software when used with the ANI (Applied Neurosciences Inc) Live Z DLL.

A measure of the temporal relationship between two signals. Reflects the speed of information sharing between two sites, or between two sites and a third (or more) sites. Two sinewave signals are said to be “in phase” (have zero phase difference) when their peaks and valleys are aligned in time. Phase is generally measured in degrees, ranging from 0 degrees (in phase) to 180 degrees (out of phase).

A method in which light is used to stimulate the nervous system for various purposes. Common devices include LED glasses and strobe lights.

A set of controls, based upon a treatment plan or regimen that determines how neurofeedback training is done. This includes the enhance and inhibit settings, frequency bands, decision criteria, feedback signals, threshold adjustments, and decision points in the training.

A company providing EEG analysis and QEEG interpretation services.

Quality Assurance - policy and methods used to ensure that products meet stated quality standards.

Quantitative EEG - a method for analyzing EEG data that includes spectral analysis, and generally includes topographic mapping, and normative database analysis

A form of EMI (electromagnetic interference) that occurs at radio frequencies (above 1 MHz). This noise may produce distortions of electrical signals such as EEG. EMI can be reduced by moving equipment, improving sensor connections, filtering, or other methods.

The second of two electrodes in a differential measurement. Generally an ear or linked ears for monopolar (or “referential”) measurement, or can be a second scalp location for bipolar (or “differential”) measurement.

A method and scale of measurement in which the size of an EEG signal component band is expressed as an amplitude, in proportion to other component bands

An EEG measurement expressing the power in an EEG component band, in proportion to other bands.

See Radio Frequency Interference

A family of devices incorporating photic stimulation. Early Roshi devices are "EEG driven". Later devices including the pRoshi are "free-running". The Roshi devices are developed and produced by Chuck Davis.

see Spectral Correlation Coefficient

see Slow Cortical Potential

A way of learning, in chwich an organism learns to achieve theraputic efficacy through an internal mechanisms. Biofeedback training often includes self-efficacy as a means for remediation.

An EEG rhythm, generally between 12 and 15 Hz, that is recorded from the sensorimotor cortex (C3, Cz, C4). It has a characteristic waxing and waning pattern, and is generally larger when the body is relaxed and not moving. Dr. Barry Sterman conducted important research on SMR waves in cats and humans.

AgCl, a material often used for EEG or similar sensors, especially useful for low-noise and/or SCP or DC recordings. A common form is "Silver - Silver Chloride" or "Ag/AgCl" which is usually a sintered material incorporating both metallic silver and silver-chloride compound.

A specific EEG placement, e.g. T3 or C4.

Sterman Kaiser Imaging Laboratory - an educational and business entity that produces education, training, and software in the area of QEEG and neurofeedback.

An EEG signal typically considered to range between 0.05 Hz and 5 Hz. SCP’s are seen to vary with mental tasks, particularly planned movement. The Bereitzschaftpotential is a movement-related SCP.

see Sensorimotor Rhythm

An EEG connectivity metric first described by David Joffe and implemented in the Lexicor products such as the NRS-2D and NRS-24 using the BioLex software. It is defined as a Pearson Correlation Coefficient computed on the FFT magnitude spectra of the channels. This metric is used clinically by Dr. Kirtley Thornton, among others.

A measure of how time-locked two signals are. When training synchrony, this may also be referred to as “phase synchrony”

A system of locating positions (sites) on the scalp, for standard EEG recording. They are based on 10% and 20% of the distance across the head, hence the name. Standard charts and descriptions of the locations are freely available (include?).

Underwriters Laboratory - a testing and certification body in the US that tests and certifies the electrical safety of consumer and industrial devices. The UL-544 standard covers electrical safety achieved by methods including optical or magnetic isolation.

The phenomenon by which electrical fields are conducted through a medium such as salt water or biological tissue. Volume conduction of post synaptic potentials of cortical pyramidal cells to the surface of the scalp is the mechanism of genesis of the EEG (electroencephalogram).

A measure of how far a measurement is from a population mean. The Z Score is expressed as a value centered at 0, which may be positive or negative. The Z-Score may be interpreted as the "number of standard deviations away from the mean."

A statistical measure that tells how far a measurement is from the population mean. A z-score of 1, for example, means that the measurement is "1 standard deviation" above the mean. The z-score is defined as the observed measurement, minus the population mean, divided by the population standard deviation.