Solutions
Transverse Montage A montage consisting of derivations from pairs along coronal
(transverse) arrays.
Also called a Coronal Bipolar Montage.
Longitudinal Montage A montage consisting of derivations from pairs of electrodes along
longitudinal, usually anterior to posterior, arrays.
Reference Montage An arrangement of derivations in which one input 2 is common to all
channels.
Derivation A pair of electrodes recorded in the EEG.
Polarity The sign of potential different between an electrode affected by the given
potential and another electrode.
, Definitions for EEG – EEG Test Banks With
Solutions
Artefact Any potential difference due to an extracerebral source (either physiological or
mechanical) recorded in EEG tracings.
Frequency The rhythmic repetitive activity or the equivalent frequency of isolated waves.
Rhythmic A constant frequency.
Arrhythmic A sequence of waves of inconstant frequency.
Voltage The amplitude of a waveform. Refers to the average voltage or peak voltage of
EEG activity.
Attenuation The reduction of amplitude of EEG activity resulting from decreased voltage.
Hypersynchrony An increase in voltage and regularity of rhythmic activity.
Paroxysmal Activity that emerges from the background with a rapid onset.
, Definitions for EEG – EEG Test Banks With
Solutions
Morphology The shape of a waveform.
Monomorphic One dominant waveform.
Polymorphic Multiple frequencies that combine to form a complex waveform.
Sinusoidal Waves resembling sine waves. Monomorphic activity is usually sinusoidal.
Transient An isolated wave or pattern that is distinctly different from the background
activity.
Spike A transient waveform with a pointed peak and duration of 20-70 milliseconds.
Sharp wave A transient waveform with a pointed peak and duration of 70-200
milliseconds.