Intro to EEG Nicholas J. Beimer, MD

Lead placement 10-20 system

Common montages longitudinal bipolar transverse

Normal 20 year old

Normal 20 year old

Normal 20 year old

Normal 20 year old

Frequency ranges of EEG 0.5-3.999 Hz Delta 4-7.999 Hz Theta 8-12.999 Hz Alpha >13 Hz Beta * Difference between alpha frequency and alpha rhythm

(posterior dominant rhythm) Normal 20 year old 10 Hz PDR (posterior dominant rhythm)

Normal PDR by age 3-4 Hz 3-4 months 5-6 Hz 1 year 7 Hz 2 years

Normal

Normal Eye closure

Normal

Alpha squeak: transient increase in alpha rhythm after eye blink Normal Alpha squeak: transient increase in alpha rhythm after eye blink

Normal

Lambda waves: sharply contoured, occipital, occur with visual scanning Normal Lambda waves: sharply contoured, occipital, occur with visual scanning

Normal

POSTS: positive occipital sharp transients of sleep Normal POSTS: positive occipital sharp transients of sleep

Normal

Normal Sleep spindles: about 13 Hz, 0.5 sec burst, characteristic of stage II sleep

Normal

Normal K complex: Negative sharp wave, then slower positive component, associated with spindles

Normal

Normal Vertex waves

Normal

Posterior slow waves of youth (prominent in ages 3-10) Normal Posterior slow waves of youth (prominent in ages 3-10)

If this is normal, how old is the patient?

Normal 75 year old Age >65: Focal temporal delta slowing once every several minutes Increase in frontal beta PDR still 8.5 hz or greater

Normal

Normal Hypnagogic hypersynchrony: 4-5 Hz rhythmic bursts in young children, a marker of drowsiness and transitional sleep

Rapid lateral eye movements Normal Rapid lateral eye movements

Sawtooth waves: theta frequency, sawtooth shape Normal Sawtooth waves: theta frequency, sawtooth shape

REM

Provocative measures

Provocative measures Photic driving

Provocative measures Photic driving

Slowing with hyperventilation Provocative measures Slowing with hyperventilation

Benign variants

Benign variants Mu: frontocentral alpha rhythm that disappears when pt. opens and closes contralateral hand

Benign variants

RMTTD: rhythmic temporal theta of drowsiness Benign variants RMTTD: rhythmic temporal theta of drowsiness

Benign variants

BETS: benign epileptiform transients of sleep Benign variants BETS: benign epileptiform transients of sleep

Benign variants

Benign variants Wicket spikes

Benign variants 14 and 6 positive bursts 14 and/or 6 Hz 6 Hz more common in early childhood 14 Hz more common in late childhood/adolescence

Benign variants 14 and 6 positive bursts 14 and/or 6 Hz 6 Hz more common in early childhood 14 Hz more common in late childhood/adolescence