Abnormal EEGs Flashcards
What is the difference between photoparoxysmal response and photoconvulsive response?
- Photoparoxysmal response = Generalized spike-wave discharges without clinical correlation
- Photoconvulsive response = Generalized spike-wave discharges with a clinical response
What is shown on this EEG and in what conditions can it be seen?
- Alpha coma (note lack of reactivity)
- Can be seen with anoxic brain injury (signals poor outcome)
- Can also be seen with head injury, brainstem stroke or TME
What is a photomyoclonic (photomyogenic) response?
Widespread muscle twitching timed to the stimulus representing an elevated brainstem-mediated reflex
Difference between spikes and sharp waves in relation to distance from the cortex
- Spike occur from synchronous depolarization of neurons within 6 cm of the cortex
- Sharp waves occur from synchronous depolarization of neurons further away from the cortex
What is the progression of EEG changes seen in CJD?
- Intermittent diffuse slowing
- Periodic sharp wave complexes
- More continuous diffuse slowing with periodic sharp complexes
- Loss of periodic sharp complexes with continuous slowing
In the setting of an intracranial tumor what does focal delta and or theta activity correlate with?
White matter involvement by the tumor
In the setting of an intracranial tumor IRDA suggests what?
Involvement of the thalamus or frontal deep white matter
In the setting of an intracranial tumor, background attenuation suggests what?
High grade glioma with thalamic involvement or with extensive peritumoral edema
FIRDA in adults suggest what?
It suggests acute or subacute diffuse cortical or subcortical gray matter dysfunction
Classic EEG abnormalities seen in Landau-Kleffner Syndrome
Spike or sharp wave activity with slow waves initially seen only during NREM sleep
Clinical picture of Landau-Kleffner Syndrome
- 3 - 10 years old with normally acquired language
- Develops auditory verbal agnosia (inability to comprehend speech)
- Infrequent nocturnal partial or secondarily generalized seizures
What is the clinical picture of SSPE?
- Ages 5 - 15 years old
- After a primary measles infection
- Progressive psychoneurological deterioration including personality changes and seizures
Diagnosis?
SSPE
EEG pattern in Subacute Sclerosing Panencephalitis
Periodic complexes composed of high amplitude, bisynchronous and symmetrical polyspike and sharp and slow wave complexes occuring every 4 to 15 seconds
Common causes for lateralized PDs (formerly PLEDs)?
HSV encephalitis
Acute/subacute stroke
Seizures
What does the downward green angle in the frontal head region represent?
Eye closure
Diagnosis?
PLEDs
seen in subacute strokes, HSV encephalitis, brain abscess or after a run of seizures
Diagnosis?
Hypsarrhythmia
note disorganized background with multi focal spikes
Diagnosis?
Centro temporal spikes
as seen in benign rolandic epilepsy
(different example below)
Diagnosis?
Photoparoxysmal response
- Outlasts photic stimulation
- Strong association with generalized epilepsies, especially JME
- Can sometimes see with alcohol or benzo withdrawal
- (another example below where activity outlasts photic stim by a few milliseconds
What is the general interpretation of photoparoxysmal response?
- It has a clinical correlation with photosensitivity and generalized epilepsy
- It can be an inherited disorder and not associated with epilepsy
- PPR beyond photic stimuli more frequently associated with epilepsy
