39 Questions
What is the most common cause of lesions that lead to LPDs?
Ischemic strokes
What modifier is used to represent additional features that make an EEG pattern 'more ictal-appearing'?
What is the prognosis of LPDs dependent on?
The underlying etiology
What is the characteristic of BIPDs that distinguishes them from LPDs?
Bilateral occurrence
What is the mortality rate associated with BIPDs?
61%
What is the condition most recently associated with GPDs?
Anoxic-ischemic coma
What is the characteristic of LPDs+ that distinguishes them from LPDs?
Rhythmic buildup
What is the stage of convulsive status epilepticus in which the EEG may appear as GPDs?
Final stage
What percentage of patients experienced a seizure during the cEEG monitoring in a retrospective study?
18%
How often should critical care continuous EEG be reviewed and interpreted by neurophysiologist/intensivist/neurologist?
Every 12 hours
What type of seizures were experienced by all patients in the retrospective study?
Subclinical seizures
What is the association between generalized periodic discharges and neurological outcomes?
Generalized periodic discharges are associated with poor neurological outcomes
What is the interval at which periodic discharges typically occur?
0.3- several seconds
What type of periodic discharges are seen unilaterally and occur periodically or pseudo-periodically?
Lateralized periodic discharges
What should be done if frequent nonconvulsive seizures or nonconvulsive status epilepticus are identified during cEEG monitoring?
Increase the frequency of cEEG monitoring
What is the recommended frequency for reviewing cEEG for patients at risk for acute ischemic stroke?
Every hour while the patient is asleep
What is the predictive value of specific pathologic or physiologic EEG patterns in patients with postanoxic encephalopathy following cardiac arrest?
They can accurately predict either a poor or good outcome
What is the significance of deep coma in the first hours after cardiac arrest?
It does not necessarily preclude full functional recovery
What is the significance of lack of clinical improvement after several days in patients with unconsciousness after cardiac arrest?
It is associated with a poor prognosis
What is the significance of recovery towards continuous, physiologic EEG rhythms within 12 hours?
It is associated with a good prognosis
What is the significance of absence of relevant improvement within 24 hours, with persistent isoelectric, low voltage or burst suppression with identical burst patterns?
It is associated with a poor prognosis
What is the significance of EEG monitoring in patients with aneurysmal SAH?
It can be successfully applied to detection of DCI with a good sensitivity
What is the EEG signal in relation to brain function?
It is a sensitive measure of brain function
What is the primary benefit of using EEG monitoring in ICU patients?
To detect small changes in neurologic function before they become severe
What is the purpose of trending quantified EEG features in ICU patients?
To monitor for changes in neurologic function and prevent further damage
What is the primary limitation of quantified EEG summaries in ICU patients?
They are subject to technical artifacts such as head movement and muscle activity
What is the importance of reviewing the actual raw EEG data in ICU patients?
It is necessary to ensure that technical artifacts are identified and corrected
What is the significance of frontally predominant brief 2/second generalized rhythmic delta activity in ICU EEG recordings?
It is a sign of a patient's physiologic state
What is the purpose of identifying pseudo-periodic LPDs in ICU EEG recordings?
To identify the patient's physiologic state
What is the significance of TWs in ICU EEG recordings?
They are a sign of a patient's physiologic state
Why is it necessary to document all equipment attached to the patient during EEG monitoring?
To identify potential sources of technical artifacts
What is the primary source of neurologic co-morbidity after Subarachnoid Hemorrhage (SAH)?
Vasospasm
What is the median incidence of vasospasm after SAH?
38%
What can be used to detect vasospasm and guide therapy methods?
Transcranial Doppler (TCD)
What is the outcome of patients with SAH who have persistently poor EEG variability and reactivity?
Poor neurologic outcome
What is a marker for altered cerebral function accompanying vasospasm in SAH patients?
Decreased relative alpha variability
When should EEG monitoring be continued for patients with SAH?
All of the above
What is the optimal duration of monitoring for ischemia in patients with crescendo transient ischemic attack?
24–48 hours
What is the suggested method to identify ischemia in at-risk patients?
Critical care cEEG
Study Notes
Seizures in TBI Patients
- 18% of TBI patients experience seizures during cEEG monitoring, all of which are subclinical seizures.
- 8% of TBI patients develop non-convulsive status epilepticus (NCSE).
Critical Care Continuous EEG Monitoring
- cEEG monitoring should be reviewed as often as logistically and technically feasible.
- Interpretation should be done by a neurophysiologist/intensivist/neurologist at least twice daily.
- More frequent interpretation should be provided if frequent NCS or NCSE are identified until seizures are controlled.
- If clinical events are recorded, cEEG should be interpreted as soon as possible after the event to determine whether the events are ictal or non-ictal.
Periodic Discharges and Patterns on the Ictal-Interictal Continuum
- Periodic discharges (PDs) are associated with poor neurological outcomes and are strongly associated with NCS and NCSE.
- Generalized PDs are associated with NCS and NCSE.
- Lateralized PDs are associated with structural or focal lesions, such as ischemic strokes, and may co-occur with seizures.
- Bilateral independent PDs arise from more morbid conditions and have a worse prognosis.
- Rhythmic buildup of LPDs+ is thought to precede seizures.
ICU-EEG Monitoring
- cEEG monitoring is suggested as an adjunct method to identify ischemia in at-risk patients.
- EEG monitoring should be continued until the window for vasospasm has passed (day 14) or the patient is considered no longer at risk for vasospasm.
- The optimal duration of monitoring for ischemia in other patient groups has not been established and should be individualized for the specific clinical situation.
Cerebral Ischemia, Subarachnoid Hemorrhage (SAH), and Delayed Cerebral Ischemia (DCI)
- Vasospasm is a primary source of neurologic co-morbidity after SAH, with an incidence of 8-68% with a median of 38%.
- cEEG ICU monitoring can track cerebral activity continuously and identify changes suggestive of impending ischemia before infarction occurs.
- Decreased relative alpha variability is a marker for altered cerebral function accompanying vasospasm.
Outcome Prediction in Post-Anoxic Encephalopathy
- Specific pathologic or physiologic EEG patterns can accurately predict either a poor or good outcome of patients with post-anoxic encephalopathy following cardiac arrest.
- Deep coma in the first hours after cardiac arrest does not necessarily preclude full functional recovery, and improvement of brain function is possible even if the EEG is initially isoelectric.
- Lack of clinical improvement after several days is associated with a poor prognosis if the patient is off sedation.
Quantified EEG Analysis
- Automated extraction and trending of quantified EEG features can assist staff in monitoring EEG.
- Features commonly chosen for monitoring include percentage of alpha activity, total power or amplitude, ratio between alpha and delta activity, and spectral edge or mean frequency.
- Caution: Quantified summaries of EEG activity are subject to technical artifacts, including head movement, muscle activity, and electrocardiogram (ECG).
This quiz covers the occurrence of seizures in Traumatic Brain Injury (TBI) patients, particularly during continuous EEG monitoring, and the importance of frequent interpretation by neurophysiologists. It also touches on the development of non-convulsive status epilepticus.
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