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Neonatal EEG Patterns

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This pattern discusses the various EEG patterns seen in term as well as pre term neonates. Normal Variations as well as pathological traces are discussed

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Neonatal EEG Patterns

  1. 1. Neonatal EEG Dr. Rahul Kumar
  2. 2. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  3. 3. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  4. 4. • • • • Activity discontinuous in early life Long periods of electrical silence Presen in both sleep and awake records Seen till 30th week CA • This pattern is referred to as ‘Trace Discontinua’
  5. 5. • EEG activity becomes continuous during waking by 34 weeks CA • EEG activity becomes continuous during NREM by 37 weeks CA • However, semi-periodic, voltage attenuation still seen during NREM sleep, lasting for 1015 seconds • Present upto 5-6 weeks of age
  6. 6. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  7. 7. • EEG activity asynchronous till 28 weeks CA • Degree of asynchrony decreases with age, mature brain has minimal asynchrony
  8. 8. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  9. 9. • Beta-delta waveforms are composed of random wave forms • 0.3-1.5 Hz frequency, superimposed on fast frequency • Fast frequency in two frequency bands • 8-12 Hz and 18-22 Hz • Voltage <75 • Also known as spindle delta bursts, ripples of prematurity, etc
  10. 10. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  11. 11. • Appear by 26 weeks CA • 4.5-6 Hz, 20-200 µv • Occur independently for short bursts, <2 sec • Expressed maximally at 30-32 weeks CA, then decline in frequency • Used to determine CA, replaced by alpha rhythm
  12. 12. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  13. 13. • Bilaterally synchronous • Present from 35 week CA, up to 44 weeks, till 6weeks post term • 50-150 µv • Resemble vertex sharp waves
  14. 14. Parameter Normal Abnormal Amplitude 50-150 µv > 150 µv Duration <100 msec >150 msec Initial Polarity Surface negative Surface positive or negative Phase Mono or diphasic Polyphasic Occurrence Random, bilateral, Sleep Runs, 1Hz, unilateral, awake Following slow wave Absent Present
  15. 15. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  16. 16. • Response easily identifiable by 37 weeks CA • Generalised attenuation or rarely augmentation of voltage to loud sounds seen by 34 th week • If background is high voltage delta, response is attenuation • If background is low voltage theta, response is augmentation
  17. 17. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  18. 18. • Distinction clear by 36th week CA • Till that age, Beta Delta complexes dominate • These change to random, semi arrhythmic activity at 4-8 Hz • Trace alternans seen during 36-38 weeks
  19. 19. Summary …
  20. 20. Road Map for the Session • • • • • • • Continuity Inter-hemispheric Synchrony Beta-Delta Complexes Temporal Theta Bursts Frontal Sharp Waves Reactivity to Stimulus Differentiation between sleep and awake eeg
  21. 21. Hypnagogic Hypersynchrony Fp1-A1 Fp2-A2 C3-A1 C4-A2 O1-A1 O2-A2 T5-A1 T6-A2 50 µV 1 sec
  22. 22. Roffwarg, Muzio, and Dement. Science, 1966 34

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