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
T3 C3 Cz C4 T4
O1 O2
Pz
Fz
Fp3 Fp4
Fp1 Fp2
F3 F4 F8F7
T5 P3 P4 T6
CH1
CH2
CH3
CH4
CH5 CH7
CH6 CH8
CH9 CH10 CH11 CH12
Neonatal montage
Developmental EEG Characteristics of premature and term baby
CA
(wk)
Continuity of
Background Activity
Synchrony of
Background ActivityEEG
Difference
between
Arousal and
Sleep
Appearance and Disappearance of
Specific Waveforms and Patterns
Awake Quiet
sleep
Active
sleepAwake
Quiet
sleep
Active
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
31-33 D D C + + ++ 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
34-35 C D C +++ + +++ No
1. Frontal sharp transients
2. Extremely high voltage beta activity during
beta-delta complexes
3. Temporal alpha bursts disappear
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
Less than 29 wksTracé discontinu (continuously discontinuous and bilaterally synchronous)
Delta brush emerge at 26 weeks
29-31 weeksGreater 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 change in newborn
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
EEG of Premature ( GA 24-27 Weeks)
Niedermeyer E Electroencephalography 1999
(tracé discontinu)
M / GA 26 wk Tracé discontinu
M / GA 27 wk Tracé discontinu
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
EEG of Premature (28-31 Weeks)
Niedermeyer E Electroencephalography 1999
(tracé discontinu)
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
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
EEG of Premature (32-35 Weeks)
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
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
EEG of Full-term Newborn (36-41 Weeks)
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
26 28 30 32 34 36 38 40 42 44 46 48 50 52 54
Beta Delta Complex
Temporal Theta Bursts
Frontal Sharp Transients
Trace Alternant
Temporal
Alpha Bursts
Occipital
Dominant
Alpha Rhythm
Conceptual Age (weeks)
Mizrahi EM et al Atlas of Neonatal EEG 2004
Sleep Spindles
Vertex Transients
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 µµµµV 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
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
EEG of Infancy (2-12 Months)
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
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
EEG of Early Childhood (12-36 Months)
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
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