Abnormal EEG brain in neurological disease แพทย์หญิง กาญจนา พิทักษ์วัฒนานนท์ อายุรแพทย์ผู้เชี่ยวชาญระบบประสาท แพทย์ประจำศูนย์สมอง โรงพยาบาลสมิติเวชศรีราชา

10 – 20 system

Records the difference between two Active scalp electrodes Bipolar montage

Referential montage Active scalp electrode Inactive scalp / ear electrode : A1 , A2 Referential montage

Reference / Bipolar montage

If the voltage input from electrode 2 is relatively “ positive ” compared to electrode 1 , then the pen will deflect “ up ” If electrode 2 is relatively “ negative ” compared to electrode 1 , then the pen will deflect “ down ” If electrode 1 equal to electrode 2 , then the pen stay “ baseline ” Polarity

Different Montage : Polarity

EEG interpretation Identify background rhythms ( frequency ) Alpha 8 -13 Hz Beta 13 – 40 Hz Theta 4 – 8 Hz Delta < 4 Hz Mu 7 – 11 Hz Sleep stage ( awake , NREM , REM ) Identify any abnormal patterns Slow patterns Diffusely , Focally Symmetry , Asymmetry Paroxysms Spike , spike and wave complex , sharp wave Triphasic waves PLEDs ( Periodic lateralizing epileptiform discharges ) Localize those abnormal patterns Maximum amplitude ( Referential montage ) Phase reversal / Reciprocal changes ( Bipolar montage ) EEG interpretation

Background rhythm / frequency

Sleep stage : Background

Epilepsy

Factor lowering seizure threshold Common Sleep deprivation , Alcohol withdrawal , Television flicker , Systemic infection , Head trauma , Recreational drugs , antiepileptic drug , Menstruation Occasional Dehydration , Barbiturate / Benzodiazepine withdrawal , Hyperventilation , Flashing lights , Diet and missed meals , Specific reflex trigger , Stress , Intense exercise Factor lowering seizure threshold

Activation tecniques ( EEG ) Rountine electroencephalograms Hyperventilation Photic stimulation Sleep-deprivation Prolonged ambulatory recording Video – EEG telemetry Magnetoencephalography : Research Activation tecniques ( EEG )

Seizure

Epileptiform discharge / Spike

Focal seizure : spike ( phase reversal )

Herpes simple encephalitis PLEDs ( Periodic lateralizing epileptiform discharges ) Herpes simple encephalitis

Ictal EEG : Spike and waves complexs

Generalized seizure

Absence seizure 3 Hz spike and wave complexs

Syndrome of epilepsy

Syndrome of epilepsy

CJD – Mad cow disease Diffused slow pattern : encephalopathy

Prion encephalitis Triphasic waves

Severe dementia Triphasic waves : degenerative disease

Encephalopathy

Comatose

Brain death

Sleep or Death

Sleep Spindle

Sleep spindle / K complex

Sleep

Sleep Lab / Polysomnography

Hypnogram

Eye Blink Artifact

Artifact