Electroencephalography (EEG) Overview
57 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does EEG stand for?

Electroencephalography

What is the main utility of EEG?

  • Evaluating dynamic cerebral functioning
  • Assessing the depth of anesthesia
  • Monitoring for potential complications
  • All of the above (correct)

What are the characteristic EEG alterations during an epileptic seizure called?

  • Ictal (correct)
  • Interictal
  • Epileptiform
  • All of the above

What is the primary generator of EEG signals?

<p>Cortical pyramidal neurons (A)</p> Signup and view all the answers

EEG can directly record the momentary local field potential changes arising from neuronal action potentials.

<p>False (B)</p> Signup and view all the answers

What is a common artifact encountered during EEG?

<p>All of the above (D)</p> Signup and view all the answers

What is the principle behind differential amplification in EEG?

<p>Recording voltage differences between different points using a pair of electrodes.</p> Signup and view all the answers

MEG is more sensitive to biological filters than EEG.

<p>False (B)</p> Signup and view all the answers

What is meant by the term "calibration" in EEG?

<p>Passing a known voltage through the system to ensure that each amplifier for each channel handles this known signal identically.</p> Signup and view all the answers

What is meant by biocalibration?

<p>An additional step to ensure the fidelity of the cerebral signal, commonly involving having the patient open and close their eyes.</p> Signup and view all the answers

What does "10-20" refer to in the 10-20 electrode placement strategy?

<p>Standard intervals of measurement of either 10 or 20 percent for positioning electrodes over the anterior-posterior dimension.</p> Signup and view all the answers

What are the two main types of EEG montages?

<p>All of the above (D)</p> Signup and view all the answers

What is the term for a standard arrangement and selection of channel pairs and chains for display and review?

<p>Montage</p> Signup and view all the answers

What are the different EEG frequency bands?

<p>All of the above (G)</p> Signup and view all the answers

What is meant by the term "background" in EEG?

<p>The predominant frequencies of the EEG.</p> Signup and view all the answers

What is the term for a normal background EEG in patients with eyes closed?

<p>Posterior dominant alpha rhythm</p> Signup and view all the answers

Alpha rhythm is typically highly symmetrical in amplitude.

<p>True (A)</p> Signup and view all the answers

Where is the alpha generator thought to be located?

<p>Within the occipital lobes.</p> Signup and view all the answers

What is the term for independent alpha activity over the temporal regions, often seen in older patients?

<p>Temporal alpha (A)</p> Signup and view all the answers

The mu rhythm is reactive to eye opening or closure.

<p>False (B)</p> Signup and view all the answers

Excess beta activity is always pathological.

<p>False (B)</p> Signup and view all the answers

Generalized background slowing is always pathological.

<p>False (B)</p> Signup and view all the answers

Focal slowing is always indicative of a focal brain lesion.

<p>False (B)</p> Signup and view all the answers

Triphasic waveforms are considered to be ictal.

<p>False (B)</p> Signup and view all the answers

What is the term for nearly continuous periodic epileptiform complexes that repeat at a slower frequency than those of NCSE, usually 1 Hz or less?

<p>LPDs (A)</p> Signup and view all the answers

Generalized periodic discharges (GPDs) are considered to represent NCSE.

<p>False (B)</p> Signup and view all the answers

What are the three main types of psychogenic nonepileptic spells?

<p>All of the above (D)</p> Signup and view all the answers

What are the two main types of epileptic seizures?

<p>Both A and B (A)</p> Signup and view all the answers

What is the term for absence seizures?

<p>3-Hz generalized spike and wave</p> Signup and view all the answers

What is the term for a sudden loss of postural tone, which may lead to falls?

<p>All of the above (D)</p> Signup and view all the answers

Tonic seizures are always a hallmark of generalized epilepsy.

<p>False (B)</p> Signup and view all the answers

What are the two phases of a tonic-clonic seizure?

<p>Both A and B (A)</p> Signup and view all the answers

Focal seizures always involve impairment of consciousness.

<p>False (B)</p> Signup and view all the answers

What is the term for seizures with no subjective or objective clinical accompaniment?

<p>Subclinical (A)</p> Signup and view all the answers

Focal seizures always result in a change in EEG activity.

<p>False (B)</p> Signup and view all the answers

Generalized slowing on EEG always indicates a focal brain lesion.

<p>False (B)</p> Signup and view all the answers

EEG can be used to confirm a diagnosis of brain death.

<p>True (A)</p> Signup and view all the answers

What is the term for a lack of any detectable brain activity on EEG?

<p>Electrocerebral silence</p> Signup and view all the answers

Who is credited with discovering the electrical properties of the brain?

<p>Richard Caton</p> Signup and view all the answers

Who is credited with recording the first human EEGs?

<p>Hans Berger</p> Signup and view all the answers

What is the term for the 10 or 20 percent intervals used to position electrodes on the scalp for EEG recordings?

<p>10-20 system</p> Signup and view all the answers

Digital EEG is the only type of EEG recording method used today.

<p>False (B)</p> Signup and view all the answers

EEG is considered a very safe procedure.

<p>True (A)</p> Signup and view all the answers

EEG can be used to help determine the depth of anesthesia.

<p>True (A)</p> Signup and view all the answers

EEG is often used during the evaluation of patients with suspected seizures.

<p>True (A)</p> Signup and view all the answers

Video-EEG monitoring is always necessary when performing a routine EEG.

<p>False (B)</p> Signup and view all the answers

Video-EEG monitoring is most appropriately reserved for patients needing event characterization or seizure localization in preparation for epilepsy surgery.

<p>True (A)</p> Signup and view all the answers

Interictal EEG findings alone can always be used to determine the diagnosis of epilepsy.

<p>False (B)</p> Signup and view all the answers

EEG recordings can be used to monitor the effectiveness of anti-epileptic drug treatment.

<p>True (A)</p> Signup and view all the answers

EEG abnormalities cannot be used to differentiate between convulsive and nonconvulsive status epilepticus.

<p>False (B)</p> Signup and view all the answers

Video-EEG monitoring has a very high yield, and therefore should be performed routinely on all patients with epilepsy.

<p>False (B)</p> Signup and view all the answers

Video-EEG monitoring can differentiate between psychogenic spells and epileptic seizures.

<p>True (A)</p> Signup and view all the answers

The use of computerized seizure and spike detection software is a highly accurate and reliable method for interpreting video-EEG data.

<p>False (B)</p> Signup and view all the answers

Sleep deprivation is never used as a provocative technique in video-EEG monitoring.

<p>False (B)</p> Signup and view all the answers

Video-EEG monitoring is always the best choice for diagnosing epilepsy.

<p>False (B)</p> Signup and view all the answers

Video-EEG monitoring is not helpful for characterizing spells that are non-epileptic in nature.

<p>False (B)</p> Signup and view all the answers

Video-EEG monitoring is highly specific, meaning that it can reliably distinguish between epileptic and nonepileptic events.

<p>False (B)</p> Signup and view all the answers

Flashcards

Electroencephalography (EEG)

A neurophysiological technique that records electrical activity in the brain using electrodes placed on the scalp.

Ictal EEG

The electrical activity of the brain during a seizure.

Interictal EEG

The electrical activity of the brain between seizures.

Epileptiform Discharges (IEDs)

Abnormal electrical discharges in the brain that can be seen on an EEG.

Signup and view all the flashcards

Spike

A rapid electrical discharge in the brain lasting less than 70 milliseconds.

Signup and view all the flashcards

Wave

A slow electrical wave that follows a spike on the EEG.

Signup and view all the flashcards

Ripples

Electrical discharges in the brain lasting greater than 100 milliseconds and often associated with epileptic activity.

Signup and view all the flashcards

EEG Background

The overall pattern of electrical activity in the brain.

Signup and view all the flashcards

Alpha Rhythm

Alpha rhythm is the dominant brainwave activity in a relaxed, eyes-closed state.

Signup and view all the flashcards

Alpha Reactivity

Alpha rhythm is suppressed (reduced in amplitude) when the patient opens their eyes or focuses on something.

Signup and view all the flashcards

Normal Alpha Rhythm

A prominent, symmetrical, and reactive alpha rhythm is usually considered a normal finding on an EEG.

Signup and view all the flashcards

Theta Rhythm

A type of brainwave activity that is slower than alpha rhythm.

Signup and view all the flashcards

Delta Rhythm

A type of brainwave activity that is even slower than theta rhythm.

Signup and view all the flashcards

Drowsy Burst

A normal burst of theta activity that is often seen in children, adolescents, and young adults during drowsiness.

Signup and view all the flashcards

Provocation Techniques

The use of techniques to trigger brain activity and help detect potential abnormalities on an EEG.

Signup and view all the flashcards

Hyperventilation

A technique used to trigger brain activity by having the patient breathe deeply and rapidly.

Signup and view all the flashcards

Photic Stimulation

A technique used to trigger brain activity by exposing the patient to flashing lights.

Signup and view all the flashcards

Photic Driving

A rhythmic response to photic stimulation in the EEG.

Signup and view all the flashcards

REM Sleep

A desynchronized EEG pattern with low-voltage activity, rapid eye movements, and sawtooth waves.

Signup and view all the flashcards

Slow Eye Movement (SEM)

A slow, rolling eye movement artifact seen on EEG during drowsiness and stage 1 sleep.

Signup and view all the flashcards

Stage 1 Sleep (N1)

The first stage of non-REM sleep, characterized by SEMs, theta and delta frequencies, and vertex waves.

Signup and view all the flashcards

Vertex Wave

A sharp, pointed wave seen on EEG during stage 1 sleep, mainly over the frontal lobes.

Signup and view all the flashcards

Stage 2 Sleep (N2)

The second stage of non-REM sleep characterized by spindles, K-complexes, and POSTS.

Signup and view all the flashcards

Sleep Spindle

A burst of high-frequency activity seen on EEG during stage 2 sleep.

Signup and view all the flashcards

K-Complex

A sharp, negative waveform seen on EEG during stage 2 sleep.

Signup and view all the flashcards

Posterior Occipital Sharp Transient of Sleep (POSTS)

A transient, sharp wave seen on EEG during stage 2 sleep, mainly over the occipital lobes.

Signup and view all the flashcards

Slow Wave Sleep (SWS) or Stage 3-4 Sleep (N3-4)

The third stage of non-REM sleep, characterized by high-amplitude delta activity.

Signup and view all the flashcards

Conceptional Age (CA)

The age of a premature baby, calculated by adding the gestational age and the chronological age after birth.

Signup and view all the flashcards

Neonatal EEG

The EEG recording specifically designed for newborns and infants.

Signup and view all the flashcards

Neonatal Montage

A standard electrode placement system used for neonatal EEGs, focusing on coverage of central brain regions.

Signup and view all the flashcards

Study Notes

Electroencephalography (EEG)

  • EEG is an electrophysiological technique for recording electrical activity arising from the human brain.
  • It's useful for evaluating dynamic cerebral functioning, especially in suspected seizures, epilepsy, and unusual spells.

Editors and Contributors

  • Erik K. St. Louis, MD, Mayo Clinic College of Medicine, Rochester, Minnesota
  • Lauren C. Frey, MD, University of Colorado, Denver, Colorado
  • Additional contributors listed include various medical professionals with diverse expertise.

License

  • Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International Public License (BY-NC-SA)
  • Proper citation of figures, tables, and images necessary when reusing or repurposing content

Table of Contents

  • Covers topics like introduction, background, analysis techniques, normal and abnormal EEG patterns in different age groups, and treatment of acute seizures.
  • Includes appendices on EEG generation in the brain, digital EEG principles, electrical safety, common artifacts, EEG standards, and history.

Introduction

  • The first neurophysiologic recordings of animals were by Richard Caton in 1875.
  • Hans Berger pioneered EEG in humans in 1924.

Calibration

  • Technologists use a known voltage during EEG recording for checking amplifier fidelity.
  • Biocalibration further ensures the fidelity of the cerebral signal (often by having patients open and close their eyes).

Electrode Placement and Montages

  • The International 10-20 system for electrode placement is a standard strategy.
  • Both bipolar and referential montages are used for different purposes (bipolar connects neighboring electrodes, referential connects each active to a distant reference.)
  • A Laplacian or "source derivation" montage is also a common approach for evaluating electrical potentials to localize areas of activity.

Frequency Bandwidths

  • EEG waveforms categorized into different frequency bands (e.g., delta, theta, alpha, beta, low and high gamma).
  • Ripples refer to frequencies generally over 100Hz.

Common Physiological Artifacts

  • Eye movement, blinking, swallowing, and muscle movements create artifacts.
  • Posterior dominant rhythm (PDR) - a common, symmetrical, low-amplitude rhythmic pattern seen when eyes are closed (especially in relaxed wakefulness)
  • Other normal background rhythms (theta and delta) are also present but can be focal or generalized.

Drowsiness and Sleep

  • Drowsiness and sleep characterized by slow frequencies (theta and delta).
  • Slow eye movements (SEMS) are a marker for the transition to deeper sleep stages.
  • Defining features of sleep stages with their respective EEGs are summarized in a table.

Developmental EEG

  • Specialized considerations for monitoring premature, neonatal, infant, and children EEGs.
  • Particular note for electrode placement, patient state, and external factors.
  • Techniques for assessing development, maturity, and response to treatment are detailed.

EEG in Epilepsies

  • Routine interictal EEG in epilepsy used for seizure type diagnosis.
  • Interictal epileptiform discharges are helpful, but need to be differentiated from benign variants to avoid misdiagnosis.

Focal and Generalized Slowing

  • Focal slowing can be due to a number of pathologies
  • Generalized slowing can be due to various etiologies.

Encephalopathy/Delirium

  • Characterized by reversible generalized confusion.
  • Often manifested as diffuse slowing or epileptiform patterns.

Dementias

  • Early stages might be normal appearing.
  • Later stages (especially second to third month of symptoms) can include periodic sharp-wave activity, often associated with myoclonus.

Anesthetic Patterns

  • EEG commonly used to assess anesthetic depth in surgical procedures, especially cardiovascular and associated surgeries.
  • Variations such as unilateral increased slowing or voltage reduction can suggest adjustments for surgical procedure.

Ictal EEG

  • Applications of using EEG during surgical procedures are described.
  • Long-term monitoring with subdural electrodes is detailed.

Urgent and Emergent EEG

  • Urgent cases require particular caution in interpretation given systemic/neurologic conditions.

Pre-Lorazepam and Post-Lorazepam

  • Used as an example for assessing the impact of drugs on EEG activity and treatment efficacy for seizure conditions.

Common Artifacts

  • Eye movements, tongue movements, and muscle artifacts addressed.
  • Electrode related issues like electrode "pop" and sweat artifacts also considered.

EEG Standards and Examples for the Determination of Brain Death

  • Criteria and details necessary for confirming brain death using EEG.

Brief History of EEG

  • Provides background on the development of the technique.
  • Key contributors and milestones are highlighted.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Electroencephalography (EEG): An Introductory Text and Atlas of Normal and Abnormal Findings in Adults, Children, and Infants PDF

Description

This quiz provides an overview of Electroencephalography (EEG), an important technique for recording brain's electrical activity. It covers its applications, especially in evaluating seizures and abnormal brain functioning, as well as the analytical techniques used. Explore the normal and abnormal EEG patterns and their significance in various age groups.

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser