The difficulty lies, in part, in recognizing artifacts and also in being able to differentiate normal variants from abnormalities. Single waves that are specially shaped include, for instance spikes or sharp waves - waves that rise rapidly to a point and fall away equally dramatically with a base that is small compared to the wave's amplitude. Specially shaped waves 2.
Artifacts are disturbances caused by technical defects - usually transitory.
Included are such things as electrode movement, with loss of contact, muscle activity obscuring the EEG, movements of the head, scratching the scalp, sweating etcetera. Some of these wave types will be discussed and illustrated by clicking below. There are several waves or patterns of waves which are unusual in appearance yet are not significant for abnormality or disease. These waves can be misinterpreted. Some of these wave types will be discussed and illustrated by clicking below.