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EEG artifacts

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BASICS OF EEG ARTIFACTS

EEG artifacts

  1. 1. EEG ARTIFACTS DR SRIRAMA ANJANEYULU RESIDENT,NEUROLOGY KING GEORGE HOSPITAL,VIZAG
  2. 2. Introduction • Unwanted electrical activity arising from different sources, other than cerebral activity. • EEG -highly sensitive recording device, easily interrupted by other electrical activity of very high voltages . • Some readily distinguished, others closely resemble cerebral activity that their interpretation is taxing even to the most experienced eletroencephalographer.
  3. 3. CLASSIFICATION Physiological : from patient’s own,generator sources other than the brain. – Eye movement – Muscle ( EMG ) – Movement – Cardiogenic – Sweat • Extraphysiological : Externally generated e.g. instrumental & environmental. - IV drip, -ventilator
  4. 4. Cardiac artifacts • ECG artifact-poorly formed QRS complex , left temporal leads.(BETS,IED,PLEDS) • Ballistocardiographic-movement of head or body with cardiac contractions. • Pacemaker-generalized across scalp , shorter duration. • Pulse-electrode resting on vessel , frontal and temporal leads , follows ECG artifact.
  5. 5. Cardiac artifact
  6. 6. Cardiac artifact
  7. 7. Pacemaker artifact
  8. 8. Pulse artifact
  9. 9. ELECTRODE ARTIFACT-TYPES • Two forms-brief transients limited to one electrode , low frequency rhythms across scalp region. • Electrode pop-spontaneous discharges. • Electrode contact-poor contact. • Electrode/lead movement. • Perspiration-undulating waves >2 sec. • Salt bridge-lower amplitude. • Movement artifact.
  10. 10. Electrode pop
  11. 11. Electrode Movement artifact
  12. 12. Lead movement
  13. 13. Sweat artifact
  14. 14. Salt bridge artifact
  15. 15. EXTERNAL DEVICE ARTIFACT • 50/60 HZ ambient electrical noise • Intravenous drip • Electrical devices-intravenous pumps, telephone • Mechanical artifacts-ventilators,circulator pumps
  16. 16. 60 Hz artifact
  17. 17. IV drip
  18. 18. Electrical motor
  19. 19. Mechanical ventilator
  20. 20. Circulatory pump
  21. 21. MUSCLE ARTIFACT • Glossokinetic • Photomyogenic • Surface EMG
  22. 22. Muscle artifact
  23. 23. Muscle and movement artifact
  24. 24. EMG artifact
  25. 25. Photomyogenic artifact
  26. 26. OCULAR ARTIFACT • Blink • Eye flutter • Lateral gaze • Slow/rowing eye movements • Lateral rectus spike
  27. 27. Blink artifact
  28. 28. Eye flutter artifact
  29. 29. Eye flutter artifact
  30. 30. Lateral eye movement
  31. 31. Slow roving eye movement
  32. 32. Lateral rectus spike
  33. 33. Thank you

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