Epilepsy & EEG Flashcards
(42 cards)
What are the three definitions of epilepsy?
- At least two unprovoked seizures more than 24 hrs apart
- One unprovoked seizure + probability of another (EEG records and real time brain waves recorded)
- At least two seizures in setting of reflex epilepsy
How does epilepsy differ from a seizure?
In epilepsy there is an enduring predisposition to generate epileptic seizures–> neurobiological, cognitive, psychological, social consequences
A simple seizure is paroxysmal and transient
Generalized seizures
Starts on both sides:
Originates within and rapidly involves bilaterally distributed networks (cortical and subcortical)
Focal seizures:
Originated from network restricted to one hemisphere; may be discrete or wider distribution
How are EEGs useful?
Distinguish between focal or generalized seizure
What are the uses for continuous video EEG? (2)
- Distinguish between epilepsy and non-epileptiform events
- Rule out subclinical seizure in critically ill patients
How is seizure treatment customized?
Based on ONSET not spread
What are the shortcomings of 30 minute outpatient EEG?
- Limited sleep state (jaw muscle artifact)
- Misses some frontal lobe seizures
What is the ideal method to get maximum yield from an EEG?
- Done within 24-48 hrs of seizure
- Sleep deprivation and recorded sleep state
What is the proper method for placing EEG leads?
10%-10% of patient’s measurement and placement of leads accordingly; as long as head shape doesn’t change due to trauma or suture bulging, as long as you follow the system the leads will be put in the same place
Scalp location is surrogate for brain location
What are the Hz values for Alpha, beta, delta, and gamma waves
8-12 Hz = alpha
13+ Hz = beta
4-6 Hz= Delta
1-4 Hz= gamma
How do eye blinks appear on EEG? What is “Bell’s phenomenon”?
Negative vector is up, positive is down
Eye blinks are the cornea with a humongously positively charge touching the frontal region = “Bells phenomenon” causes the downward dip on EEG due to cornea rolling
Which leads change with maturity?
Occipital leads– you will see a posterior dominant background
What will you see with hyperventilation on EEG?
Diffuse slowing throughout all leads.
Caused by dip in CO2
**Note that if you saw focal slowing, you’d think focal brain lesion
In terms of spike and wave activity, what constitutes a seizure?
Lasts longer than ten seconds
What are the three types of focal seizures?
- simple partial (no LOC)
- complex partial (LOC / awareness)
- secondary generalization (w bilateral convulsions)
What are the 4 types of generalized seizures?
- Absence
- Myoclonic
- Tonic-Clonic
- Atonic
What are the typical EEG findings associated with generalized absence seizures?
What is a primary characteristic of absence epilepsy?
3 hz spike and wave discharge, generalized absence seizure
**No postectal confusion
What are the 4 classifications for epilepsy etiology?
- Genetic (especially frontal lobe)
- Structural/ metabolic (DKA, Hypernatremia)
- Unknown
- Immune/ Inflammatory mediated
Neonatal epilepsy is commonly caused by…
Benign familial neonatal epilepsy
What are two common causes of infantile seizures?
West syndrome
Dravet Syndrome
What is Benign Epilepsy with centrotemporal spikes?
At what age does it manifest?
What are the clinical features?
“Rolondic epilepsy”
Manifests after 1 yoa with twitching mouth and drooling
What are infantile spasms? What is the triad?
- EEG Hipsarrythmia
- Spasms
- Arrested psychomotor development
6 potential causes of infantile spasms:
- Malformations
- TS
- Chromosomal abnormalities
- Genetic mutations
- Inborn error of metabolism
- Hypoxic ischemic encephalopathy
