EEG Maturation

From Infancy to Adolescence

Dendritic Spreading

11

2233

33

33

2211

11

ContinuityInterhemispheric

synchronyDifferentiation of

waking and sleepingPosterior basic (alpha)

rhythmSlow activity (awake)

Temporal thetaOccipital theta

Fast activity (awake)Low voltage

HyperventilationIntermittent photic

stimulation

DrowsinessTracé alternant

SpindlesVertex waves and K complexes

Positive occipital sharp transients of sleep

Slow and fast activity in sleepREM sleep

Rhythmical frontal theta activity (6–7/sec)

14 and 6/sec positive spikesPsychomotor variant (marginal

abnormality)Sharp waves, spikes

Full Term (36-41 week)Continuity Continuous except for tracé alternant in non-

REM (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 Disappearing or absentOccipital theta AbsentFast activity (awake) Decreasing ripples, sparse fast activity

Low voltage Very low-voltage records are due to severe cerebral pathology; prognosis ominous

Hyperventilation Not feasibleIntermittent photic stimulation Driving response below 4 flashes/sec may occur,

not easily elicited

Drowsiness UndifferentiatedTracé alternant Present in non-REM (quiet) sleep

Full Term (36-41 week), contd…

Spindles None (but scanty ripples)Vertex waves and K complexes None

Positive occipital sharp transients of sleep None

Slow and fast activity in sleep Much delta and theta activity, continuous in REM sleep

REM sleep Continuous slow activity, REM in EOG (more REM or “active†than non-REM �

sleep)

Rhythmical frontal theta activity (6–7/sec)

None

14 and 6/sec positive spikes NonePsychomotor variant (marginal

abnormality)None

Sharp waves, spikes Some minor sharp transients (normal) (abnormal spikes more consistent and

prominent)

Infancy (2-12 months)Continuity Continuous

Interhemispheric synchrony No significant asynchronyDifferentiation of waking and sleeping Good

Posterior basic (alpha) rhythm Starting at age 3–4 mos at 4/sec, reaching about 6/sec at 12 mos

Slow activity (awake) ConsiderableTemporal theta NoneOccipital theta None

Fast activity (awake) Very moderateLow voltage Uncommon, usually abnormal

Hyperventilation Not feasibleIntermittent photic stimulation Improving driving to low flash rates after age 6

mosDrowsiness Around age 6 mos, appearance of rhythmical

theta

Infancy (2-12 months), contd…

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 of sleep None

Slow and fast activity in sleep Much diffuse 0.75–3/sec activity with posterior maximum; moderate fast activity

REM sleep REM portion decreasing; mostly slow activity

Rhythmical frontal theta activity (6–7/sec) None

14 and 6/sec positive spikes NonePsychomotor variant (marginal abnormality) None

Sharp waves, spikes Essential as abnormal phenomena

9 months

9 months

10 months

Early Childhood (12 to 36 months)

Continuity ContinuousInterhemispheric synchrony No significant asynchrony

Differentiation of waking and sleeping Good

Posterior basic (alpha) rhythm Rising from 5–6/sec to 8/sec (seldom 9/sec)

Slow activity (awake) ConsiderableTemporal theta NoneOccipital theta None

Fast activity (awake) Mostly moderateLow voltage Uncommon, usually abnormal

Hyperventilation Mostly not feasibleIntermittent photic stimulation Often good driving response to low flash

ratesDrowsiness Marked “hypnagogic†rhythmical theta �

(4–6/sec)Tracé alternant None

Early Childhood (12 to 36 months) contd…Spindles In 2nd yr, sharp and shifting, then

symmetrical with vertex maximum

Vertex waves and K complexes Large, becoming more pointed

Positive occipital sharp transients of sleep Poorly defined

Slow and fast activity in sleep Marked posterior maximum of slow activity; often a good deal of fast activity

REM sleep Mostly slow, starting to become more desynchronized

Rhythmical frontal theta activity (6–7/sec)

Seldom in 3rd yr of life

14 and 6/sec positive spikes RarePsychomotor variant (marginal

abnormality)None

Sharp waves, spikes Spikes in seizure-free children, mainly occipital (mild abnormalities)

Pre School Age (3 to 5 yrs)Continuity Continuous

Interhemispheric synchrony No significant asynchronyDifferentiation of waking and sleeping Good

Posterior basic (alpha) rhythm Rising from 6–8/sec to 7–9/sec

Slow activity (awake) Marked admixture of posterior slow activity (to alpha rhythm)

Temporal theta NoneOccipital theta None

Fast activity (awake) Mostly moderateLow voltage Uncommon, usually abnormal

Hyperventilation Often marked delta response

Intermittent photic stimulation Often good driving response to low flash rates

Drowsiness Rhythmical theta gradually vanishing, other types of slow activity predominant

Tracé alternant None

Pre School Age (3 to 5 yrs), contd…

Spindles Typical vertex maximumVertex waves and K complexes Large with an increasingly impressive

sharp component

Positive occipital sharp transients of sleep

Poorly defined

Slow and fast activity in sleep Predominant slowing but less prominent posterior maximum

REM sleep Slow activity with some desynchronization

Rhythmical frontal theta activity (6–7/sec)

May occur, not very common

14 and 6/sec positive spikes May occur, not very commonPsychomotor variant (marginal

abnormality)Probably none

Sharp waves, spikes Spikes in seizure-free children, mainly occipital, also Rolandic (slight

abnormalities)

Older Children (6-12 years)Continuity Continuous

Interhemispheric synchrony No significant asynchronyDifferentiation of waking and sleeping Good

Posterior basic (alpha) rhythm Reaching 10/sec at age 10 yr

Slow activity (awake) Varying degree of posterior slow activity mixed with alpha

Temporal theta NoneOccipital theta None

Fast activity (awake) Mostly moderateLow voltage Seldom as variant of normalcy

Hyperventilation Often marked delta response

Intermittent photic stimulation Often good driving response, chiefly at medium flash rates (8–16/sec)

Drowsiness Gradual alpha dropout with increasing slow activity

Tracé alternant None

Older Children (6-12 years) contd…

Spindles Typical vertex maximumVertex waves and K complexes Large with a prominent sharp component

Positive occipital sharp transients of sleep

Still poorly defined but gradually evolving

Slow and fast activity in sleep Much diffuse slowing, slightly decreasing voltage

REM sleep Less slowing and increasing desynchronization

Rhythmical frontal theta activity (6–7/sec)

A bit more common

14 and 6/sec positive spikes Fairly commonPsychomotor variant (marginal

abnormality)Uncommon

Sharp waves, spikes Spikes in seizure-free children, mainly Rolandic (central-mid-temporal), slight to

moderate abnormalities; physiological occipital spikes in congenitally blind

children

Adolescents Continuity Continuous

Interhemispheric synchrony No significant asynchronyDifferentiation of waking and sleeping Good

Posterior basic (alpha) rhythm Averaging 10/sec

Slow activity (awake) Posterior slow activity diminishing

Temporal theta NoneOccipital theta None

Fast activity (awake) Moderate, except for low voltage fast records

Low voltage Occasionally and (at end of teenage period more often) as variant of normalcy

Hyperventilation Delta responses become less impressive

Intermittent photic stimulation Often good driving response, chiefly at medium flash rates

Drowsiness Gradual alpha dropout with low-voltage stretches (mainly slow)

Tracé alternant None

Adolescents, contd…

Spindles Typical vertex maximumVertex waves and K complexes Not quite as large, sharp component not

quite as prominent

Positive occipital sharp transients of sleep Often very well developed

Slow and fast activity in sleep Much diffuse slowing with further attenuation of voltage

REM sleep Mature desynchronizationRhythmical frontal theta activity

(6–7/sec)A bit more common, declining at end of

period14 and 6/sec positive spikes Fairly common

Psychomotor variant (marginal abnormality)

More common (although relatively rare)

Sharp waves, spikes Benign Rolandic spikes usually disappear before beginning of this period

ContinuityInterhemispheric

synchronyDifferentiation of

waking and sleepingPosterior basic (alpha)

rhythmSlow activity (awake)

Temporal thetaOccipital theta

Fast activity (awake)Low voltage

HyperventilationIntermittent photic

stimulation

DrowsinessTracé alternant

SpindlesVertex waves and K complexes

Positive occipital sharp transients of sleep

Slow and fast activity in sleepREM sleep

Rhythmical frontal theta activity (6–7/sec)

14 and 6/sec positive spikesPsychomotor variant (marginal

abnormality)Sharp waves, spikes