A biosignal is any
signal
A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology.
In ...
in living
being
Existence is the state of having being or reality in contrast to nonexistence and nonbeing. Existence is often contrasted with essence: the essence of an entity is its essential features or qualities, which can be understood even if one do ...
s that can be continually
measured and
monitored. The term biosignal is often used to refer to bioelectrical signals, but it may refer to both electrical and non-electrical signals. The usual understanding is to refer only to time-varying signals, although spatial parameter variations (e.g. the nucleotide sequence determining the
genetic code) are sometimes subsumed as well.
Electrical biosignals
Electrical biosignals, or bioelectrical time signals, usually refers to the change in
electric current
An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge c ...
produced by the sum of an
electrical potential difference across a specialized tissue, organ or cell system like the
nervous system
In biology, the nervous system is the complex system, highly complex part of an animal that coordinates its behavior, actions and sense, sensory information by transmitting action potential, signals to and from different parts of its body. Th ...
. Thus, among the best-known bioelectrical signals are:
*
Electroencephalogram (EEG)
*
Electrocardiogram (ECG)
*
Electromyogram
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyo ...
(EMG)
*
Electrooculogram (EOG)
*
Electroretinogram (ERG)
*
Electrogastrogram (EGG)
*
Galvanic skin response (GSR) or
electrodermal activity (EDA)
EEG, ECG, EOG and EMG are measured with a
differential amplifier which registers the difference between two electrodes attached to the skin. However, the galvanic skin response measures
electrical resistance and the
Magnetoencephalography (MEG) measures the
magnetic field
A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular ...
induced by electrical currents (
electroencephalogram) of the brain.
With the development of methods for remote measurement of electric fields using new sensor technology, electric biosignals such as EEG
and ECG
can be measured without electric contact with the skin. This can be applied, for example, for remote monitoring of brain waves and heart beat of patients who must not be touched, in particular patients with serious burns.
Electrical currents and changes in
electrical resistances across tissues can also be measured from plants.
Biosignals may also refer to any non-electrical signal that is capable of being monitored from biological beings, such as mechanical signals (e.g. the
mechanomyogram or MMG), acoustic signals (e.g. phonetic and non-phonetic utterances, breathing), chemical signals (e.g.
pH,
oxygenation) and optical signals (e.g. movements).
Use in artistic contexts
In recent years, the use of biosignals has gained interest amongst an international artistic community of performers and composers who use biosignals to produce and control sound. Research and practice in the field go back decades in various forms and have lately been enjoying a resurgence, thanks to the increasing availability of more affordable and less cumbersome technologies. An entire issue of ''eContact!'', published by the
Canadian Electroacoustic Community in July 2012, was dedicated to this subject, with contributions from the key figures in the domain.
''eContact! 14.2 — Biotechnological Performance Practice / Pratiques de performance biotechnologique''
(July 2012). Montréal: CEC.
See also
* Bioindicator
* Biomarker
* Biosignature
* Molecular marker
* Multimedia information retrieval
References
Bibliography
*Donnarumma, Marco.
Proprioception, Effort and Strain in "Hypo Chrysos": Action art for vexed body and the Xth Sense
" ''eContact! 14.2 — Biotechnological Performance Practice / Pratiques de performance biotechnologique'' (July 2012). Montréal: CEC.
*Tanaka, Atau.
The Use of Electromyogram Signals (EMG) in Musical Performance: A Personal survey of two decades of practice
" ''eContact! 14.2 — Biotechnological Performance Practice / Pratiques de performance biotechnologique'' (July 2012). Montréal: CEC.
*
External links
;Applications:
Using electroencephalograph signals for task classification and activity recognition Microsoft
NASA scientists use hands-off approach to land passengers jet
;Hardware:
University of Vienna : cours Biomedical Engineering, Electromyography (EMG)
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Biology terminology
Electrophysiology