EEG of Newborn
and Infants
Ki Joong Kim MD PhD
Pediatric Neurology
Seoul National University Children’s Hospital
Seoul, Korea
Maturation of EEG
• Maturation of EEG patterns parallels brain development
• Anatomical and physiological development of brain
• Development of age-specific waking and sleep patterns
• Most dramatic EEG changes occur between premature
age and 1st 3 months of life
• EEG patterns during 1st 6 months closely correlate with
conceptual age (CA)
Neonatal EEG
• Function of actual age of brain
• CA = gestational age + legal (chronological) age
• A number of age-specific normal EEG features for only
several weeks at a time
• Different clinical implication when seen at later ages
• Persistence or reappearance of patterns with immature
features (dysmaturity) means cerebral dysfunction
• More mature EEG pattern than expected is usually due
to underestimated CA
Neonatal montage
F7
Fp1
Fp2
Fp3
Fp4
F3
CH3
CH1
T3
CH9
T5
CH4
C3
CH10
P3
CH2
O1
F4
Fz
F8
CH5
Cz
Pz
CH11
C4
CH7
CH12
P4
CH6
O2
T4
T6
CH8
Developmental EEG Characteristics of premature and term baby
Continuity of
Background Activity
Synchrony of
Background Activity
Awake
Quiet
sleep
Active
sleep
Awake
Quiet
sleep
Active
sleep
EEG
Difference
between
Arousal and
Sleep
27-28
-
D
D
-
++++
++++
No
29-30
D
D
D
0
0
0
No
1. Temporal theta bursts
2. Beta-delta complexes in central region
3. Occipital very slow activity
No
1. Beta-delta complexes in TO region
2. Rhythmic 1.5Hz activity in frontal leads in
transitional sleep
3. Temporal alpha bursts replace 4-5 Hz bursts
No
1. Frontal sharp transients
2. Extremely high voltage beta activity during
beta-delta complexes
3. Temporal alpha bursts disappear
CA
(wk)
31-33
34-35
D
C
D
D
C
C
+
+++
+
+
++
+++
Appearance and Disappearance of
Specific Waveforms and Patterns
36-37
C
D
C
++++
++
++++
Yes
1. Continuous bioccipital delta activity with
superimposed 12-15Hz activity during active
sleep
2. Central beta-delta complexes disappear
38-40
C
C
C
++++
+++
++++
Yes
1. Occipital beta-delta complexes decrease and
disappear by 39wk
2. Trace alternant pattern (NREM sleep)
Mizrahi EM et al Atlas of Neonatal EEG 2004
EEG change in newborn
Less than 29 wks
Tracé discontinu (continuously discontinuous and bilaterally synchronous)
Delta brush emerge at 26 weeks
29-31 weeks
Greater periods of continuous activity, suppression periods les than 30 sec
Frequent delta brushes, temporal theta burst pattern
32-34 weeks
EEG reactivity to stimulation established
Periods of diffuse attenuation less than 15 sec
Abundant multifocal sharp transients and delta brushes
34-37 weeks
Delta brushes appear less often and multifocal sharp transients less frequent
Frontal sharp transients appear
Tracé discontinu pattern is replaced by tracé alternant
After 38 weeks
Low voltage irregular (LVI) in waking and active sleep
Mixed voltage (MV) pattern in waking, transitional and active sleep
High voltage slow (HVS) in quiet sleep
Tracé alternant (TA) in quiet sleep
Fisch BJ EEG Primer 1999
EEG of Premature ( GA 24-27 Weeks)
Continuity
Discontinuous, long flat stretches
Interhemispheric synchrony
Short bursts in synchrony
Differentiation of waking and sleeping
Undifferentiated
Posterior basic alpha rhythm
None
Slow activity (awake)
Very slow high voltage bursts
Temporal theta burst
Present and increasing
Occipital theta
Prominent
Fast activity (awake)
Very little beta activity
Low voltage
Long flat stretches
Tracé alternant
None
Spindles
None
Vertex waves and K complexes
None
Positive occipital sharp transients
None
Slow and fast activity in sleep
Slow activity of high voltage, little slow activity
REM sleep
Undifferentiated
(tracé discontinu)
Niedermeyer E Electroencephalography 1999
M / GA 26 wk
Tracé discontinu
M / GA 27 wk
Tracé discontinu
EEG of Premature (28-31 Weeks)
Continuity
Discontinuous
Interhemispheric synchrony
Mostly asynchronous
Differentiation of waking and sleeping
Undifferentiated
Posterior basic alpha rhythm
None
Slow activity (awake)
Very slow activity predominant
Temporal theta burst
Prominent (temporal sawtooth waves)
Occipital theta
Decreasing
Fast activity (awake)
Frequent ripples or brushes around 16/sec (delta brushes)
Low voltage
Flat stretches, mainly asynchronous
Tracé alternant
None
Spindles
None (but ripples present)
Vertex waves and K complexes
None
Positive occipital sharp transients
None
Slow and fast activity in sleep
Much slow activity, more irregular, little fast activity
REM sleep
Undifferentiated
(tracé discontinu)
Niedermeyer E Electroencephalography 1999
M / GA 28 wk
Tracé discontinu
F / GA 29 wk
Temporal theta
F / GA 29 wk
Delta brush
M / GA 30 wk
Ripples including delta brush
M / GA 31 wk
Ripples
EEG of Premature (32-35 Weeks)
Continuity
Continuous in waking and REM, discontinuous in NREM
Interhemispheric synchrony
Partly synchronous, especially in occipital leads
Differentiation of waking and sleeping
Waking distinguished from sleep early in the period
Posterior basic alpha rhythm
None
Slow activity (awake)
Slow (delta) with occipital maximum
Temporal theta burst
Decreasing and disappearing
Occipital theta
Decreasing
Fast activity (awake)
Frequent ripples or brushes (16-20/sec)
Low voltage
Low voltage records suspect of serious cerebral pathology
Tracé alternant
Present in NREM (quite) sleep
Spindles
None (but ripples present)
Vertex waves and K complexes
None
Positive occipital sharp transients
None
Slow and fast activity in sleep
Irregular slow activity of occipital predominance
REM sleep
Continuous slow activity
Niedermeyer E Electroencephalography 1999
M / GA 32 wk
Discontinuity
M / GA 32 wk
Asymmetry and asynchrony
M / GA 32 wk
Continuity
F / GA 33 wk
Continuity
F / GA 33 wk
Asynchrony
M / GA 34 wk
Status change
F / GA 34 wk
Ripples and frontal sharp transient
F / GA 35 wk
Continuity
F / GA 35 wk
Trace alternant
EEG of Full-term Newborn (36-41 Weeks)
Continuity
Continuous except for tracé alternant in NREM (quiet) sleep
Interhemispheric synchrony
Minor asynchronies still present
Differentiation of waking and sleeping
Good
Posterior basic alpha rhythm
None
Slow activity (awake)
Slow (delta) mostly of moderate voltage
Temporal theta burst
Disappearing or absent
Occipital theta
Absent
Fast activity (awake)
Decreasing ripples, sparse fast activity
Low voltage
Very low voltage records due to serious cerebral pathology
Tracé alternant
Present in NREM (quite) sleep
Spindles
None (but scanty ripples)
Vertex waves and K complexes
None
Positive occipital sharp transients
None
Slow and fast activity in sleep
Much delta and theta activity, continuous in REM sleep
REM sleep
Continuous slow activity
Niedermeyer E Electroencephalography 1999
M / GA 36 wk
F / GA 37 wk
M / GA 38 wk
Tracé alternant
F / GA 39 wk
Frontal sharp transient
F / GA 40 wk
M / GA 40 wk
Anterior dysrhythmia
M / GA 42 wk
Appearance and disappearance of developmental EEG landmarks
Trace Alternant
Frontal Sharp Transients
Occipital
Dominant
Alpha Rhythm
Temporal
Alpha Bursts
Vertex Transients
Temporal Theta Bursts
Beta Delta Complex
26
28
30
32
34
36
Sleep Spindles
38
40
42
44
46
48
50
52
54
Conceptual Age (weeks)
Mizrahi EM et al Atlas of Neonatal EEG 2004
F / GA 38 wk
Excessive suppression in HIE
F / GA 38 wk
Rhythmic epileptiform activity in HIE
F / GA 38 wk
Rhythmic epileptiform activity in HIE
F / GA 41 wk
Focal spike discharges
F / GA 40 wk
FST vs. epileptiform spike
F / GA 40 wk
Repetitive spike discharges
F / GA 40 wk
Neonatal seizures
F / GA 40 wk
Neonatal seizures
F / GA 40 wk
Neonatal seizures
M / GA 33 wk
Neonatal seizures
M / GA 33 wk
Neonatal seizures
M / GA 33 wk
Neonatal seizures
Early Infantile Epileptic Encephalopathy
with Suppression-bursts (EIEE)
• Pseudoperiodical suppression-bursts pattern
• High amplitude bursts alternating with and nearly flat
suppression phases
• Bursts of irregular 150-350 µV high voltage slow waves
mixed with spikes for 1-3 seconds
• Suppression phase for 3-4 seconds
• Burst-burst interval 5-10 seconds
• Appearance regardless of waking and sleep states
F / 1 mo
Burst suppression in EIEE
F / 1 mo
Burst suppression in EIEE
Normal EEG in Infancy
• Delta and theta equally prominent
• Transient asymmetries
• Central rhythms develop during the 1st year
• Posterior rhythms equivalent to alpha of older age
during eye closure
• V waves of higher voltage and briefer than in adults
(spike-like) begins at 3-4 months
• Spindles of more numerous and longer than later
expressed at 3-4 months
EEG of Infancy (2-12 Months)
Continuity
Continuous
Interhemispheric synchrony
No significant asynchrony
Differentiation of waking and sleeping
Good
Posterior basic alpha rhythm
Starting at 3-4 mos (4/sec) reaching about 6/sec at 12 mos
Slow activity (awake)
Considerable
Temporal theta burst
None
Occipital theta
None
Fast activity (awake)
Very moderate
Low voltage
Uncommon, usually abnormal
Tracé alternant
Disappears in 1st (seldom 2nd) mo
Spindles
Appear after 2nd mo (12-15/sec, sharp, shifting)
Vertex waves and K complexes
Appear mainly at 5 mos, fairly large, blunt
Positive occipital sharp transients
None
Slow and fast activity in sleep
Much diffuse 0.75-3/sec activity with posterior maximum
REM sleep
REM portion decreasing
Niedermeyer E Electroencephalography 1999
M / 1 mo
M / 3 mo
M / 5 mo
Sleep spindle
M / 8 mo
A-P gradient
West Syndrome (Infantile Spasms)
• Hypsarrhythmia
• Disorganized and chaotic background activity
• Irregular high amplitude 1-3 Hz slow waves with
multifocal asynchronous spikes or sharp waves
• Appear during awake and light sleep states
• Modified or atypical hypsarrhythmia possible
• Electrodecremental event (EDE)
M / 6 mo
Hypsarrhythmia in IS
M / 13 mo
Hypsarrhythmia in IS
Changing EEG Patterns from SB through H to SSW
Awake
SB
H
H
SSW
SSW
Sleep
SB
SB
H
H
SSW
F / 2 mo
Early phase of IS
F / 2 mo
EEG progression of IS
Patterns of Atypical Hypsarrhythmia
• Asymmetrical or unilateral hypsarrhythmia
• Hypsarrhythmia with constant focal discharges
• Hypsarrhythmia comprising primary, high-voltage,
bilateral asynchronous slow activity with minimal
epileptiform potentials
• Hypsarrhythmia with partial conservation of basal
rhythm and focal or generalized sharp and slow waves
• Hypsarrhythmia similar to suppression-bursts
F / 15 mo
Asymmetric hypsarrhythmia
F / 7 mo
Hypsarrhythmia with constant focal discharges
M / 3 mo
Hypsarrhythmia with constant focal discharges
M / 3 mo
Hypsarrhythmia with constant focal discharges
M / 4 yr
Hypsarrhythmia with prominent fast activity
HF 12Hz
M / 16 mo
Hypsarrhythmia with rare epileptiform discharges
M / 7 mo
Hypsarrhythmia with prominent slow activity
F / 4 mo
Hypsarrhythmia with conservation of normal BG
F / 10 mo
Hypsarrhythmia with normal BG due to status change
F / 2 mo
Hypsarrhythmia like burst-suppression
F / 4 mo
Hypsarrhythmia like burst-suppression
F / 10 mo
Electrodecremental event (EDE)
F / 7 mo
Ictal EEG in IS
EEG of Early Childhood (12-36 Months)
Continuity
Continuous
Interhemispheric synchrony
No significant asynchrony
Differentiation of waking and sleeping
Good
Posterior basic alpha rhythm
Rising from 5-6/sec to 8/sec
Slow activity (awake)
Considerable
Temporal theta burst
None
Occipital theta
None
Fast activity (awake)
Mostly moderate
Low voltage
Uncommon, usually abnormal
Tracé alternant
None
Spindles
In 2nd yr sharp and shifting, then symmetrical with vertex max
Vertex waves and K complexes
Large, becoming more pointed
Positive occipital sharp transients
Poorly defined
Slow and fast activity in sleep
Marked posterior maximum of slow activity
REM sleep
Mostly slow, starting to become more desynchronized
Niedermeyer E Electroencephalography 1999
M / 13 mo
Vertex sharp transient
Summary
• Within broad normal limits of variability for age
• Marginal patterns should be interpreted in a prudent
manner
• Rash link between brain and psyche do more harm
• Deviation from normal, immaturity or structural insult ?
• Careful correlation with clinical status for significance
Thank You for Your Attention