EEG random facts Flashcards
At what age do vertex waves and K complexes first appear?
Age 5 months
What EEG frequencies are seen during active sleep in a 37 week gestational age patient?
Continuous theta and delta. At 38 weeks you will see fater frequencies mixing in
What is the pattern of active sleep seen in a 37 week gestational age patient?
Tracé alternant pattern
What is the background EEG rhythm from ages 1 -3 years?
1,2,3 years
6, 7, 8 Hz
(10 Hz by 10 years)
What areas are recorded as EEG activity on the scalp electrodes?
- Superficial excitatory activity (cortical layers 2 and 3)
- Deep inhibitory activity (cortical layer 5)
- This results in surface negative extra cellular potential at the scalp
Describe posterior slow waves of youth
They occur in wakefulness as delta waves interrupting the posterior dominant rhythm
What does the EEG background look like in Angelman syndrome?
Hypsarrhythmia. It does not show fragmentation during sleep, unlike true hypsarrhythmia.
What are the typical ages of onset for childhood absence epilepsy?
4 to 10 years of age
What are the 3 seizure types seen in JME?
- Absence seizures
- Myoclonic seizures
- Generalized tonic clinic seizures
Name 3 behaviors that can be seen in a person having an absence seizure
- Rhythmic eye blinking
- Oral automatisms
- Head retropulsion
- They will not lose postural control but may sway
What is the frequency of the EEG PDR from infancy to adolescence?
3 Hz by 3 months
6 Hz by 12 months
8 Hz by 3 years
10 Hz by 10 - 15 years
What is the difference between atypical vs typical absence seizures on the EEG?
- Atypical absence = 2 Hz spike and wave
- Typcial absence = 3 Hz spike and wave
What is the typical background EEG seen in West Syndrome?
Hypsarrhythmia and this is not an ictal pattern
What are the seizure characteristics in benign rolandic epilepsy?
- Centrotemporal spikes
- Seizures are focal and involve
- Hemifacial sensory-motor symptoms
- Oropharyngolaryngeal symptoms
- Speech arrest
- Hypersalivation
Hypersalivation seizure could be coming from or associated with what 3 conditions or areas?
- Benign rolandic epilepsy
- Temporal lobe seizures
- Insular seizures
What pattern is present on EEG in neonates starting at 29 weeks conception?
Tracé discontinu
What is OIRDA associated with?
It is more commonly seen in children and is associated with absence epilepsy
What are CIRDA and GIRDA associated with?
Both are likely related to a non-specific dysfunction.
Some evidence that GIRDA could increase risk for seizures, especially in critically ill patients.
What are the associated EEG findings?
Eyelid myoclonia with absences
Occurs immediately after eyelid closure
More frequent in bright light (never in dark)
Brief, bilateral spike-wave discharges
What are the associated EEG findings?
Progressive myoclonic epilepsies (like Infantile ceroid lipofuscinosis)
Occipital spikes elicited by photic stimulation
What are the associated EEG findings?
West Syndrome
- High amplitude, disorganized slow activity with multifocal spikes (called hypsarrhythmia) and generalized electrodecrements
- When associated with a clinical spasm, there is a generalized spike/sharp wave followed by diffuse EEG attenuation
- Can progress into LGS
What are the associated EEG findings?
LGS
- Presents with slow spike-wave discharges
- Can have faster beta range activity in sleep, some of which may be associated with clinical tonic seizures
Charge of the cornea in relation to the retina
Cornea = + charge
Retina = - charge
What are the associated EEG findings?
Dravet syndrome
- Generalized polyspike-wave complexes
- May be prominent unilaterally and occur in clusters
What is the earliest age that active sleep and quiet sleep can be distinguished?
35 weeks
Initially, infants transition directly from wake to REM sleep. At what age does this change?
At 3 months they transition from wake to NREM sleep
Enflurane at high doses can show what on the EEG?
A spike-wave pattern
EEG eyes closed and open. What leads are affected and what will you see?
Fp1 and Fp2
Closed –> eyes look up (Bells) –> Fp1 and Fp2 will be positive (downgoing wave)
Open is the opposite
EEG eyes look left and right. What EEG leads and what will you see?
F7 and F8
Look left –> F7 positive (downgoing wave), F8 negative (upgoing wave)
Look right is opposite
What is this pattern what is the approximate start and stop in age?
Hypnagogic hypersynchrony
- Early drowsiness and arousal from deeper sleep
- Starts and 2-3 months and usually resolves by age 12
Define synchrony
Bursts of activity happening at the same time in both sides of the brain
Define EEG symmetry
The degree to which EEG activity on both sides of the brain is the same amplitude and frequency
Define discontinuity on EEG
Areas of flat activity between bursts of activity
Difference between trace discontinu pattern and trace alternans pattern in quiet sleep
Amplitude
Trace discontinu = < 25 mcv
Trace alternans = > 25 mcV
What are the post conception ages for trace discontinu to trace alternans to slow wave sleep?
TD —► TA = 34 weeks
TA —►SWS = 38 weeks
At what post menstrual or post conception age do you start to see differences in the EEG between awake and sleep
About 30 weeks. Prior to that it looks the same
