*1.4.4 Motion artifact*

The movement of the patient or even disturbance just during the electrodes settling could become the cause of electrode pops variations of the conduction between electrodes and the skin. Linguistically these signals appear either in the form of single or multiple sharp waveforms due to abrupt variations in the impedance. It can be easily identified by its characteristic appearance and its usual distribution, which is restricted to a single electrode [4]. In usual manners, sharp transients which occur at a single electrode should be considered artifacts, until it has not been proven. **Figure 9a** and **Figure 9b** present the pure EEG signal and motion artifact contaminated EEG signal. **Figure 9b** shows the high amplitude broad spectrum distribution because of motion artifact in the EEG signal.

**Figure 9a** shows the original EGG signal and (b) represents the motion artifact contaminated EEG signal. **Figure 9b** presented the motion artifacts contamination on the EEG signal.

**Figure 9.** *(a) Original EEG signal (b) EEG signal contaminated with motion artifact.* *Effective EEG Artifact Removal from EEG Signal DOI: http://dx.doi.org/10.5772/intechopen.102698*

#### *1.4.5 Power lines*

Alternating Currents, ranging from 50 to 60 Hz, that is strong signals from Alternating Current (A/C) power supplies could also corrupt EEG data since it gets transferred to a recording device from the scalp electrodes. Issues co-related to power lines-based artifacts come into the picture when an active electrode has a higher impedance than impedance between the electrodes and the amplifier's ground. In such kinds of scenarios, the amplifier's ground starts to work as an active electrode which solely depends upon its location and implements/generates 50–60-Hz artifact. Usually for removal of these artifact notch filters are used, but still, it could produce a problem of useful information removal, furthermore lower frequency line noise and harmonics are undesirable [10]. If the line noise or harmonics produce in frequency bands of interest it interferes with EEG signals which occur in the same frequency band [9].

Power line noise as shown in **Figure 10** can be presented mathematically as:

$$P(t) = \beta\_0 \sin\left(2\pi \* \mathbf{60} \* t\right) \tag{4}$$

In the above equation *β*<sup>0</sup> represents power line noise weight.
