Outline at least two (2) examples of both mechanical and physiological artifacts. Describe each in detail. Describe any unusual artifacts that you have encountered at your current clinical site. Discu

Polysomnography Artifacts
Name
Institution

Physiological Artifacts
Movement Artifact
These artifacts can obscure tracing if large movements are involvement. Small movement artifacts are evident on EEG and EOG channels, and they are attributed to a patient’s movement of his or her head only or to the high sensitivity that is typical of these recording channels. Thereby, they can be easily resolved if movement stops.
Respiration Artifact
Disruption of the signal, largely attributed to changes in body movements and position of the belts are associated with the occurrence of these artifacts. This kind of disruption gives rise to slow and rhythmic types of respiratory artifacts. On the other hand, there are slow or sharp waves that are attributed to the electrodes. Other than reducing movements and ensuring that the belts are fastened appropriately (Butkov, 2016).
Mechanical Artifacts
60 Hz Artifact
Various reasons give rise to this artifact including, lack of a ground electrode on the patient, poor electrode application, and high electrode impedance. These can be considered as the internal sources while ancillary equipment that has ungrounded circuits, fluorescent lighting, and tangled power cords lying next to the patient or jackbox cable are outside sources. The patient room should be well-shielded from these external sources while proper grounding of the electrodes is also beneficial.
Electrode Bridge Artifact
This artifact occurs when a substance, such as sweat, exacerbates low-impedance between two electrodes causing them to connect physically.

It is mechanical in nature due to the fact that disruption of the electrical connection results in low-impedance electrical bridges. Unlike the other artifacts that can be readily viewed on recorded data, pairwise comparisons help to identify identical or nearly identical channels via the “superimposition of two EEG/ERP waveforms” (Alschuler, Tenke, Bruder, & Kayser, 2013, p. 485). These artifacts can be avoided by close monitoring and screening for blink artifacts.

References
Alschuler, D. M., Tenke, C. E., Bruder, G. E., & Kayser, J. (2014). Identifying electrode bridging from electrical distance distributions: a survey of publicly-available EEG data using a new method. Clinical Neurophysiology : Official Journal of the International Federation of Clinical Neurophysiology, 125(3), 484–490. Retrieved on 12 December 2016.
Butkov, N. (2007). Polysomnography recording systems. In N. Butkov, & T. L. Lee-Chiong (Eds.), Fundamentals of sleep technology. Philadelphia, PA: Wolters Kluwer. Retrieved on 12 December 2016.