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Severe encephalopathy: Complete disrupt the thalamocortical connection
-> No reactivity, No state change
Burst Suppression
/ Attenuation
> 50% but <90% periods of suppression (<10 uv) or
attenuation (>10 uv but <50% comparing background
activity)
If the burst contains 2 or more spike/sharp waves = with
epileptiform activity.
Alpha/Theta Coma (more
common)
Predominant with the frequencies – abnormal A-P
distribution ie alpha in frontal, beta in posterior
Beta Coma (rare)
Spindle Coma (most
common)
Extreme Delta Brush in
adults: commonly associated
with NMDA encephalitis
Generalized rhythmic delta waves with superimposed fast
activity (20-30 Hz)
“Generalized” Polymorphic
Delta Activity (PDA)
Generalized non-rhythmic delta – the prognosis based on the
degree of reactivity
Moderate encephalopathy Some degree, it disrupt the thalamocortical connection
-> No PDR, Maintain reactivity , Have -but abnormal state
change
Triphasic Waves/ GPDs +TW Generalized or frontal-predominant three phase -dominate
downward positive phase with A-P lag
Stimulation can trigger or attenuate this activity
SIRPID Stimulation induces RDA, PDs, SW, burst, BIRDS, IIC, Seizure
FIRDA, OIRDA, TIRDA Rhythmic delta activity is predominant in the frontal
/occipital/temporal region – usually diminished by stimuli
Cycling Alternating Pattern
of Encephalopathy (CAPE)
Mimic NREM but brief than 60s: need each pattern > 10s
Mild encephalopathy PDR is slow, normal reactivity and state change
Mild generalized slowing PDR < 8 Hz or PDR is within the normal range of frequencies;
however, there is an increase in slower frequencies such as
theta in the state of awake.
“Focal” continuous
polymorphic delta
Indicate focal subacute/chronic brain lesion such as a tumor,
ischemia, or abscess than encephalopathy (30-50 % no lesion
in imaging)
