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 1 st 3 months of life EEG patterns during 1 st 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 Fp1 Fp3 Fp2 Fp4 F7 CH3 F3 Fz F4 F8 CH1 CH5 CH7 T3 C3 Cz C4 T4 CH9 CH10 CH11 CH12 T5 P3 Pz P4 T6 CH4 CH2 CH6 CH8 O1 O2
Developmental EEG Characteristics of premature and term baby CA (wk) Continuity of Background Activity Awake Quiet sleep Active sleep Synchrony of Background Activity Awake Quiet sleep Active sleep EEG Difference between Arousal and Sleep Appearance and Disappearance of Specific Waveforms and Patterns 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
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 Interhemispheric synchrony Differentiation of waking and sleeping Posterior basic alpha rhythm Slow activity (awake) Temporal theta burst Occipital theta Fast activity (awake) Low voltage Tracé alternant Spindles Vertex waves and K complexes Positive occipital sharp transients Discontinuous, long flat stretches Short bursts in synchrony Undifferentiated None Very slow high voltage bursts Present and increasing Prominent Very little beta activity Long flat stretches None None None None (tracé discontinu) Slow and fast activity in sleep REM sleep Slow activity of high voltage, little slow activity Undifferentiated Niedermeyer E Electroencephalography 1999
M / GA 26 wk Tracé discontinu
M / GA 27 wk Tracé discontinu
EEG of Premature (28-31 Weeks) Continuity Interhemispheric synchrony Differentiation of waking and sleeping Posterior basic alpha rhythm Slow activity (awake) Temporal theta burst Occipital theta Discontinuous Mostly asynchronous Undifferentiated None Very slow activity predominant Prominent (temporal sawtooth waves) Decreasing (tracé discontinu) Fast activity (awake) Low voltage Tracé alternant Spindles Vertex waves and K complexes Positive occipital sharp transients Slow and fast activity in sleep REM sleep Frequent ripples or brushes around 16/sec (delta brushes) Flat stretches, mainly asynchronous None None (but ripples present) None None Much slow activity, more irregular, little fast activity Undifferentiated 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 Interhemispheric synchrony Differentiation of waking and sleeping Posterior basic alpha rhythm Slow activity (awake) Temporal theta burst Occipital theta Fast activity (awake) Low voltage Tracé alternant Spindles Vertex waves and K complexes Positive occipital sharp transients Slow and fast activity in sleep REM sleep Continuous in waking and REM, discontinuous in NREM Partly synchronous, especially in occipital leads Waking distinguished from sleep early in the period None Slow (delta) with occipital maximum Decreasing and disappearing Decreasing Frequent ripples or brushes (16-20/sec) Low voltage records suspect of serious cerebral pathology Present in NREM (quite) sleep None (but ripples present) None None Irregular slow activity of occipital predominance 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 Interhemispheric synchrony Differentiation of waking and sleeping Posterior basic alpha rhythm Slow activity (awake) Temporal theta burst Occipital theta Fast activity (awake) Low voltage Tracé alternant Spindles Vertex waves and K complexes Positive occipital sharp transients Slow and fast activity in sleep REM sleep Continuous except for tracé alternant in NREM (quiet) sleep Minor asynchronies still present Good None Slow (delta) mostly of moderate voltage Disappearing or absent Absent Decreasing ripples, sparse fast activity Very low voltage records due to serious cerebral pathology Present in NREM (quite) sleep None (but scanty ripples) None None Much delta and theta activity, continuous in 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 Temporal Alpha Bursts Occipital Dominant Alpha Rhythm Temporal Theta Bursts Vertex Transients Beta Delta Complex Sleep Spindles 26 28 30 32 34 36 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 Interhemispheric synchrony Differentiation of waking and sleeping Posterior basic alpha rhythm Slow activity (awake) Temporal theta burst Occipital theta Fast activity (awake) Low voltage Tracé alternant Spindles Vertex waves and K complexes Positive occipital sharp transients Slow and fast activity in sleep REM sleep Continuous No significant asynchrony Good Starting at 3-4 mos (4/sec) reaching about 6/sec at 12 mos Considerable None None Very moderate Uncommon, usually abnormal Disappears in 1 st (seldom 2 nd ) mo Appear after 2 nd mo (12-15/sec, sharp, shifting) Appear mainly at 5 mos, fairly large, blunt None Much diffuse 0.75-3/sec activity with posterior maximum 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 Interhemispheric synchrony Differentiation of waking and sleeping Posterior basic alpha rhythm Slow activity (awake) Temporal theta burst Occipital theta Fast activity (awake) Low voltage Tracé alternant Spindles Vertex waves and K complexes Positive occipital sharp transients Slow and fast activity in sleep REM sleep Continuous No significant asynchrony Good Rising from 5-6/sec to 8/sec Considerable None None Mostly moderate Uncommon, usually abnormal None In 2 nd yr sharp and shifting, then symmetrical with vertex max Large, becoming more pointed Poorly defined Marked posterior maximum of slow activity 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
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