EEG Flashcards
How early can the driving response be seen?
3-4 months
Photo driving is best seen at what flash frequency in children 3-5 years?
Below 8 Hertz
What flash frequency is best seen in children 6-12 years?
6-16 Hz
Photo paroxysmal response is more likely to occur in school age children or adolescents?
School age children- including normal children
Can healthy adolescents exhibit photomyoclonic and photic convulsive responses?
Yes
At what age do vertex waves and K-complexes appear?
5 months
Early ages of vertex waves can be located?
Frontally
What is another name for frontal vertex waves?
F-waves
In school-ages children can vertex waves be asymmetrical?
Yes
What are frontal arousal rhythm?
Prolonged rhythmic sharp or spiky activity over the midline frontal region that can be seen in children 2-4 years
What is SREDA?
Seen in older adults, location is in the temporoparietal region, sharply contoured theta frequency, occurs at rest, drowsiness or HV.
Burst suppression pattern can be seen in two generalized states?
Brain inactivation ((general anesthesia, coma, hypothermia) and severe brain injury (anoxic/hypoxia, infantile encephalitis)
What is the bio marker of the epileptogenic zone?
Pathological high-frequency oscillations
Do EEG findings of spikes, slowing, or attenuation localize to the epileptogenic zone?
Does not localize consistently
What are delta brushes?
Normal feature in preterm babies less than 37 weeks gestation
When do delta brushes first appear?
At about 26weeks conceptual age
Prior to 32weeks how frequency is the fast component?
18 - 22 Hz
After 32weeks what is the frequency of the fast component of the delta brush?
8 - 12 Hz
Before 32 weeks where is the delta brush located?
Central regions
After 32 weeks delta brushes are located where?
Temporal- occipital regions
Are delta brushes seen after 36 weeks?
Usually not in healthy neonate
When does it become possible to stage sleep?
31-32 weeks
In what stage of sleep are delta brushes more commonly seen?
NREN > R.E.M.
What are SIRPIDs?
Stimulated-induced repetitive ictal discharges
When are SIRPIDs are seen in what conditions?
Waveform elicited in critically ill patients
What is the length of EEG monitoring to detect most of the seizures in non-comatose patients?
24 hours
What is the percentage of patients in the ICU have sub clinical seizures?
19% of critically ill patients
What is the percentage of seizures found in the first 24 hours of monitoring?
88%
What are the risk factors for electrographic seizures in critically ill?
Coma, age < 18 years, history of epilepsy and convulsive seizures
To evaluate AEDs to treat neonatal seizures why is cEEG needed?
Proving the clinical event or electrographic events are actually seizures and the frequency of short electrographic seizures
What is another term for frontal sharp transients in neonatal EEG?
Encoches frontales
What are frontal sharp transients in neonate?
Normal and noted especially during indeterminate sleep in term babies
Frontal sharp transients are usually most common in what age range?
Most common in babies of 32-42 weeks gestation and are usually synchronous and symmetric
During what stages are frontal sharp transients seen?
Most commonly in transitional or indeterminate sleep, and early quiet sleep and less commonly in active sleep
What AEDs have been shown NOT to induce apoptosis in the developing brain?
LEV and CBZ
What type of EEG finding can be associated with onset of seizures?
High frequency rhythmic activity
Continuous EEG is useful for what clinical scenario?
To detect subtle or seizures with no motor components in patient in coma.
What is the percentage of seizures not seen at bedside in the critical ill patient?
75%
In cardiac arrest what is an unfavorable predictable finding?
Unfavorable EEG pattern- burst suppression or ISO-electric, absence of pupillary response at 48hours, bilateral absent somatosensory evoked potentials at 72 hours.
Is there a different EEG pattern between hypoxia-ischemia and metabolic encephalopathies?
Hypoxia-ischemia is usually periodic while metabolic is usually triphasic
What is the significance of rhythmic lateralized delta activity?
Is associated with 50%-60% risk of seizures, which is similar to lateralized periodic discharges
What is the dynamic range of local field potentials recorded by intracranial EEG?
DC to 600 or higher Hz
When EEG is performed on critically ill patients with acute neurological disorders electrographic seizures are found in what percentage?
10%-40%
What is considered to be high frequency?
80 - 500 Hz
What frequencies are considered ripples?
80 - 250 Hz
What frequencies are considered fast ripples?
> 250 Hz
What frequencies are considered very high oscillations?
> 1000 Hz
What other activity occurs with HFO?
Interdict also spikes, with only 19% seen completely independent of spikes.
HFO are specific for seizure onset?
Yes, fast ripples has sensitivity of 52% and spikes only 33%
