Neonatal EEG Patterns

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

1. Neonatal EEG
Dr. Rahul Kumar

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. 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

5. •Activity discontinuous in early life
•Long periods of electrical silence
•Presen in both sleep and awake records
•Seen till 30
th
week CA
•This pattern is referred to as
‘Trace Discontinua’

7. •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 10-
15 seconds
•Present upto 5-6 weeks of age

11. 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

12. •EEG activity asynchronous till 28 weeks CA
•Degree of asynchrony decreases with age,
mature brain has minimal asynchrony

13. 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

14. •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

16. 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

17. •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

19. 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

20. •Bilaterally synchronous
•Present from 35 week CA, up to 44 weeks, till
6weeks post term
•50-150 µv
•Resemble vertex sharp waves

21. 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, SleepRuns, 1Hz, unilateral, awake
Following slow wave Absent Present

22. 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

23. •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

24. 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

25. •Distinction clear by 36
th
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

26. Summary …

27. 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

33. 1 sec
50 mV
Fp1-A1
Fp2-A2
C3-A1
C4-A2
T5-A1
T6-A2
O1-A1
O2-A2
Hypnagogic Hypersynchrony

34. 34
Roffwarg, Muzio, and Dement. Science, 1966