Fisch EEG Primer Chapter 19 Flashcards
Electrographic seizure patterns, pseudoperiodic patterns, and pseudoepileptiform patterns
rythmical focal or multifocal EEG abnormalities often without spike and sharp waves components are features of…
ictal patterns in neonates; frequently occurs without clinical correlates
These three conditions of neonates have features of both focal and generalized epileptiform activity, appear in infants and young children as the result of a variety of organic brain disorders…(3)
- Hypsarrythmia
- slow-spike-and-wave
- multifocal independent spikes
How do you characterized pseduoperiodic patterns?
fairly regular recurrence of various paroxysmal forms of activity
ictal patterns without spikes and sharps are seen in…
patients that also have focal and generalized interictal epileptiform patterns
What is the relationship of pseudoepileptogenic (PLEDs, periodic generalized sharp waves, periodic generalized complexes, suppresion-burst, triphasic waves) patterns to seizures or epilepsy?
There is no proven relationship to epilepsy or seizures
READ 19.1 Neonatal seizures
READ 19.1 Neonatal seizures
READ 19.2 Infantile patterns of hypsarrythmia, slow spike and wave….
READ 19.2 Infantile patterns of hypsarrythmia, slow spike and wave….
pseudoperiodic complexes are simliar to eachother in that they
1) consist of complexes which recur at fairly regular intervals on a background of slow waves of usually low amplitude
2) most are generalzied or widespread in distribution and synchronous with timing and produce a myoclonic seizure manifestations
Periodic Lateralizing epileptiform discharges (PLEDs) and bilateral indenpendent periodic lateralized epileptiform dischares (BIPLEDs)…(morphology, distribution
di- or multiphasic sharp waves and may include a slow wave; often lateralized but can have a mirror focus
Periodic generalized sharp waves (mono-to-multiphasic) are often associated with which disease
creutzfeld jakob disease, seen usually within 12 weeks of symptom onset and are present in 90% of those with fully developed disease
What are the two ways that an electrographic seizure pattern may evolve from PLEDs?
- focal seizure evolves directly from PLEDs
- seizure pattern develops alongside ongoing PLEDs (usually only persist for seconds before disappearing as seizure continues)
Why might PLEDs represent an interictal pattern rather than an ictal pattern?
PLEDs often coexist with simultaneous and independent electrographic seizure patterns
NOTE: PLED patterns is generally considered a highly epileptogenic interictal pattern
What is the setting PLEDs are usually found?
stroke (38%), neoplasm (20%), epilepsy (17%), misc (34%)–hsv, sickle cell, metabolic, sdh, tuberculoma
NOTE: recently reported with mitochondrial encephalopathies (MERRF, MELAS) and CJD.
What are some features special to PLEDs
-rarely reactive to stimuli changes in state; persist into sleep
Myoclonic jerking that occurs in PLEDs often is seen…
contralateral to the electrographic seizure pattern
What is the typical time course of PLEDs
in general considered to be continuous and invariant but may transiently attenuate during state changes. Patterns simplifys over weeks or months but may last for years.
BIPLEDs are commonly seen in…
diffuse or bilateral multifocal cerebral diseases such as HSV encephalitis, epilepsy, sickle cell anemia, anoxic encephalopathy - their presence indicates a guarded prognosis
What is a potential trigger for the Periodic generalized sharp waves seen in CJD
Startling stimuli caused by light flashes
Which other disorders can have a similar Periodic generalized sharp waves as seen in CJD
- Post anoxic encephalopathy
- cerebral fat embolism
Periodic generalized complexes are often associated with which disorder?
Subacute slerosing panencephalitis (SSPE)
What are the EEG features of SSPE?
periodic generalized complexes of high voltage (300 - 1500microV) with sharp and delta waves, not usually enhanced by sensory stimuli, sleep may enhance or obscure, clinically appears as myoclonic jerking
Which other disorders can have a similar Periodic generalized complexes as seen in SSPE?
Postanoxic encephalopathy, head injury, drug intoxication, lipidoses, HSV encephalitis, tuberous sclerosis
What are conditions in which suppression-burst pattern would be encountered?
comatose patients with reversible conditions (general anesthesia, hypothermia, Reye’s syndrome) or irreversible conditions (cardiopulmonary arrest, acute stroke, wernicke’s disease and encephalopathy, and encehpalitis)
What are the suspected underlying physiolgical changes associated with suppression burst pattern?
cortical neuronal inactivity followed by depolarization and hyperpoloarization; anesthesia likely modifies thalamocortical interactions through GABAergic inhibition
