Abnormal EEGs

Question 1

What is the difference between photoparoxysmal response and photoconvulsive response?

Answer 1

• Photoparoxysmal response = Generalized spike-wave discharges without clinical correlation
• Photoconvulsive response = Generalized spike-wave discharges with a clinical response

Question 2

What is shown on this EEG and in what conditions can it be seen?

Answer 2

• 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

Question 3

What is a photomyoclonic (photomyogenic) response?

Answer 3

Widespread muscle twitching timed to the stimulus representing an elevated brainstem-mediated reflex

Question 4

Difference between spikes and sharp waves in relation to distance from the cortex

Answer 4

• 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

Question 5

What is the progression of EEG changes seen in CJD?

Answer 5

• Intermittent diffuse slowing
• Periodic sharp wave complexes
• More continuous diffuse slowing with periodic sharp complexes
• Loss of periodic sharp complexes with continuous slowing

Question 6

In the setting of an intracranial tumor what does focal delta and or theta activity correlate with?

Answer 6

White matter involvement by the tumor

Question 7

In the setting of an intracranial tumor IRDA suggests what?

Answer 7

Involvement of the thalamus or frontal deep white matter

Question 8

In the setting of an intracranial tumor, background attenuation suggests what?

Answer 8

High grade glioma with thalamic involvement or with extensive peritumoral edema

Question 9

FIRDA in adults suggest what?

Answer 9

It suggests acute or subacute diffuse cortical or subcortical gray matter dysfunction

Question 10

Classic EEG abnormalities seen in Landau-Kleffner Syndrome

Answer 10

Spike or sharp wave activity with slow waves initially seen only during NREM sleep

Question 11

Clinical picture of Landau-Kleffner Syndrome

Answer 11

• 3 - 10 years old with normally acquired language
• Develops auditory verbal agnosia (inability to comprehend speech)
• Infrequent nocturnal partial or secondarily generalized seizures

Question 12

What is the clinical picture of SSPE?

Answer 12

• Ages 5 - 15 years old
• After a primary measles infection
• Progressive psychoneurological deterioration including personality changes and seizures

Question 13

Diagnosis?

Answer 13

SSPE

Question 14

EEG pattern in Subacute Sclerosing Panencephalitis

Answer 14

Periodic complexes composed of high amplitude, bisynchronous and symmetrical polyspike and sharp and slow wave complexes occuring every 4 to 15 seconds

Question 15

Common causes for lateralized PDs (formerly PLEDs)?

Answer 15

HSV encephalitis

Acute/subacute stroke

Seizures

Question 16

Periodic discharges are found in what percent of patients with CJD?

Answer 16

Approximately 60%

Question 17

What is the most specific CSF test for CJD?

Answer 17

RT- QuIC

(Real Time Quaking Induced Conversion)

Question 18

What does the downward green angle in the frontal head region represent?

Answer 18

Eye closure

Question 19

Diagnosis?

Answer 19

PLEDs

seen in subacute strokes, HSV encephalitis, brain abscess or after a run of seizures

Question 20

Diagnosis?

Answer 20

Hypsarrhythmia

note disorganized background with multi focal spikes

Question 21

Diagnosis?

Answer 21

Centro temporal spikes

as seen in benign rolandic epilepsy

(different example below)

Question 22

Diagnosis?

Answer 22

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

Question 23

What is the general interpretation of photoparoxysmal response?

Answer 23

• 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