ACNS 3 (PDs and SWs)
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What is the minimum required change in frequency to qualify as evolution in frequency?

  • Frequency must change while maintaining the same voltage.
  • The highest voltage component must remain unchanged.
  • At least two consecutive changes must occur in different categories.
  • A single frequency must persist for at least three cycles. (correct)

    • How is the highest voltage component categorized for PDs?

  • High: 100 to 200 mV
  • Very low: less than 20 mV (correct)
  • Low: 20 to 49 mV (correct)
  • Medium: 50 to 149 mV

    • What measurement method is specified for evaluating voltage components?

  • Peak to peak
  • Peak to trough (correct)
  • Peak to baseline
  • Average to baseline

    • What defines evolution in location regarding voltage changes?

    <p>It must spread into at least two different electrode locations.</p> Signup and view all the answers

    Which of the following is a required ratio for relative voltage in PDs?

    <p>It must measure the voltage of the typical discharge against background.</p> Signup and view all the answers

    What is the timeframe required to qualify a frequency change as evolution?

    <p>The first frequency must last for at least 3 cycles.</p> Signup and view all the answers

    To qualify for evolution in morphology, what is required concerning changes?

    <p>Two consecutive changes must happen in the same category.</p> Signup and view all the answers

    What is the voltage classification for a measurement of 150 mV?

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

    What distinguishes electroclinical seizures from other types of seizures?

    <p>They are time-locked to EEG patterns and correlate clinically.</p> Signup and view all the answers

    Which statement about Brief Potentially Ictal Rhythmic Discharges (BIRDs) is NOT true?

    <p>BIRDs must have a known normal pattern associated.</p> Signup and view all the answers

    In the context of electroencephalogram (EEG) interpretations, what does the term 'nonconvulsive' signify?

    <p>It indicates seizures that do not exhibit pronounced motor activity.</p> Signup and view all the answers

    Which of the following is a characteristic of evolving BIRDs?

    <p>They can be distinguished by a varying morphology over time.</p> Signup and view all the answers

    When considering BIRDs and their relationship to clinical signs, what is important to note?

    <p>BIRDs may occur with no clinical correlate at all.</p> Signup and view all the answers

    What determines the number of phases in a signal?

    <p>The total number of baseline crossings</p> Signup and view all the answers

    In the context of baseline crossings, how is phase 2 categorized?

    <p>Below the imaginary baseline</p> Signup and view all the answers

    Which statement correctly describes spontaneous phases?

    <p>They are never clearly induced or improved by stimulation</p> Signup and view all the answers

    When categorizing phases, what aspect must be specified for the dominant phase?

    <p>Sharpness and greatest voltage</p> Signup and view all the answers

    What does a baseline crossing indicate in the context of phases?

    <p>A change from one phase to another</p> Signup and view all the answers

    In the provided context, what is not a part of the criteria for categorizing phases?

    <p>The frequency of the signal</p> Signup and view all the answers

    Which of the following represents a feature of a phase in this context?

    <p>It can be clearly defined as above or below the baseline</p> Signup and view all the answers

    What type of phases should not be classified under spontaneous categories?

    <p>Those influenced by sensory stimulation</p> Signup and view all the answers

    What is a characteristic of phase sharpness as described in the content?

    <p>It should be specified for both dominant and sharpest phases</p> Signup and view all the answers

    What occurs when a signal has more than one crossing of the baseline?

    <p>It counts as additional phases</p> Signup and view all the answers

    What does PDs1R refer to?

    <p>Periodic Discharges with fast activity in one hemisphere only</p> Signup and view all the answers

    Which condition qualifies as BIPDs1F?

    <p>Bilateral Independent Periodic Discharges with fast activity in one hemisphere only</p> Signup and view all the answers

    What type of fast activity is characterized as RDA1F?

    <p>Fast activity with a stereotyped relationship to delta waves</p> Signup and view all the answers

    Which of the following does NOT qualify as part of the RDA or PD pattern?

    <p>Fast activity occurring independently from periodic discharges</p> Signup and view all the answers

    Which one of the following describes a Definite EDB condition?

    <p>Fast activity that is continuous or abundant</p> Signup and view all the answers

    What is a possible characteristic of extreme delta brush (EDB)?

    <p>Can occur frequently but should not be occasional</p> Signup and view all the answers

    In terms of fast activity, what does the term 'periodic delta brushes' imply?

    <p>Fast activity that associates with periodic discharges in a structured manner</p> Signup and view all the answers

    What does it mean if the fast activity is described as continuous in the context of RDA?

    <p>Fast activity that persists even with dormant periodic discharges</p> Signup and view all the answers

    When fast activity is recorded, what is necessary for it to classify as part of the PD pattern?

    <p>It should occur without any time-lock concerning periodic discharges</p> Signup and view all the answers

    What defines a '1F' activity in a clinical neurophysiology context?

    <p>It indicates fast activity that is abundant and patterned</p> Signup and view all the answers

    What is the duration requirement for Electroclinical Status Epilepticus (ECSE) to be classified as such?

    <p>10 continuous minutes or a total of 20% in 60 minutes</p> Signup and view all the answers

    Which of the following terms is synonymous with 'possible electrographic seizure'?

    <p>Possible electrographic SE</p> Signup and view all the answers

    What percentage of a 60-minute recording does an ongoing seizure need to occupy to qualify as ECSE?

    <p>20%</p> Signup and view all the answers

    What is the minimum duration an ongoing seizure with bilateral tonic-clonic activity must meet to be classified as ECSE?

    <p>5 continuous minutes</p> Signup and view all the answers

    What is the primary distinction between Electroclinical Seizure (ECSz) and Electroclinical Status Epilepticus (ECSE)?

    <p>ECSz has less stringent duration criteria than ECSE.</p> Signup and view all the answers

    How should the Electroclinical Seizure (ECSz) pattern be described for standardized reporting?

    <p>Using the RPP modifiers</p> Signup and view all the answers

    What does the term 'possible ECSE' refer to in clinical settings?

    <p>It qualifies for the IIC with EEG improvement but without clinical improvement.</p> Signup and view all the answers

    In the context of seizures, what does the term 'ictal-interictal continuum' (IIC) indicate?

    <p>A classification system for seizure-related EEG patterns.</p> Signup and view all the answers

    What is indicated when an EEG shows patterns consistent with 'possible electrographic seizure'?

    <p>There are ambiguous findings needing further investigation.</p> Signup and view all the answers

    When is an electroclinical seizure (ECSz) considered valid?

    <p>If detected solely using EEG without clinical correlates.</p> Signup and view all the answers

    What defines the prevalence of a pattern in the context of EEG recording?

    <p>The percentage of record or epoch that includes the pattern.</p> Signup and view all the answers

    Which duration category corresponds to continuous activity in EEG patterns?

    <p>90% or more of the record.</p> Signup and view all the answers

    What is the meaning of an abundant duration classification in EEG patterns?

    <p>Patterns that are present in 50% to 89% of the record.</p> Signup and view all the answers

    What implication does the presence of multiple patterns have on their categorization?

    <p>Each pattern must be individually recorded for prevalence.</p> Signup and view all the answers

    Which frequency range is typically associated with defining abnormal patterns in EEG?

    <p>1 to 2.5 Hz.</p> Signup and view all the answers

    What is classified as very low voltage according to the categorization?

    <p>19 mV</p> Signup and view all the answers

    To qualify as evolution in location, how many electrode locations must be involved?

    <p>At least two different locations</p> Signup and view all the answers

    What characterizes the voltage measurement for absolute voltage in PDs?

    <p>It compares highest voltage to background voltage in the same channel</p> Signup and view all the answers

    What defines evolution in frequency specifically for PDs?

    <p>A single frequency that must persist for three cycles</p> Signup and view all the answers

    Which voltage category is assigned to readings of 150 mV and above?

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

    What does the notation '1FR' signify in the context of periodic discharges (PDs)?

    <p>Fast activity superimposed on periodic discharges</p> Signup and view all the answers

    To classify a pattern as BIPDs1F, what condition must be met regarding the presence of independent discharges?

    <p>Independent periodic discharges must occur in both hemispheres</p> Signup and view all the answers

    Which statement accurately represents the conditions for classifying a pattern as 1S?

    <p>Associated sharp waves or spikes must appear with rhythmic delta activity</p> Signup and view all the answers

    In the classification system, when should a pattern be coded as PDs1R instead of RDA1S?

    <p>When a pattern indicates both rhythmic discharges and sharp waves in one hemisphere</p> Signup and view all the answers

    What must occur for a pattern to be classified as EDB according to established guidelines?

    <p>Theta or faster activity must be present along with delta contributions</p> Signup and view all the answers

    Which condition is required for a classification as RDA1S?

    <p>The presence of sharp spikes with rhythmic delta activity</p> Signup and view all the answers

    When categorizing waveforms, what does the absence of fast activity during RDA qualify as?

    <p>A characteristic feature of generalized delta activity</p> Signup and view all the answers

    What distinguishes 1F from patterns classified as PD1R?

    <p>Continuous fast frequencies cannot be part of spike-wave complexes</p> Signup and view all the answers

    What is a condition that allows a pattern to qualify for the designation of RDA?

    <p>There is noted independence between delta activities across hemispheres</p> Signup and view all the answers

    In EEG classification, what does the term 'sharp contour' refer to?

    <p>Distinct sharp waves or spikes within the recorded activity</p> Signup and view all the answers

    Study Notes

    Categorization of Voltage Components

    • Highest voltage component for periodic discharges (PDs) should be measured from peak to trough.
    • Key voltage categories:
      • Very low: < 20 mV
      • Low: 20 to 49 mV
      • Medium: 50 to 149 mV
      • High: ≥ 150 mV

    Frequency Evolution

    • At least two consecutive voltage changes in the same category are required to qualify as evolution.
    • Single frequency must persist for at least three cycles, e.g., 1 Hz for 3 seconds.
    • Examples of acceptable frequency changes include:
      • 3 Hz for ≥ 1 second, then 2 Hz for ≥ 1.5 seconds, followed by 1.5 Hz for ≥ 2 seconds.

    Morphology and Location Evolution

    • Morphological evolution requires at least two consecutive changes to a novel morphology.
    • Evolution in location is determined by sequential spreading into or out of at least two different standard 10-20 electrode locations.

    Baseline Crossings and Phases

    • Phases are defined by the number of baseline crossings of the typical discharge.
    • A phase corresponds to a segment of the signal above or below an imaginary baseline.
    • Total phases can be calculated by counting baseline crossings.

    Spontaneous Discharges

    • Spontaneous discharges are not clearly induced, exacerbated, improved, or terminated by stimuli.
    • Categories include clinical patterns that are spontaneous with no clear triggers.

    Electroclinical Seizure (ECSz) Criteria

    • ECSz is defined by specific EEG patterns that show a clinical correlate such as face twitching or eye deviation.
    • Nonconvulsive seizures are characterized by electrographic activity without overt motor activity.

    Electroclinical Status Epilepticus (ECSE)

    • Defined as an electroclinical seizure lasting ≥ 10 continuous minutes or 20% of any 60-minute recording period.
    • Bilateral tonic-clonic motor activity must be present for ≥ 5 minutes for classification as ECSE.

    Brief Potentially Ictal Rhythmic Discharges (BIRDs)

    • BIRDs are focal or generalized rhythmic activity lasting ≥ 0.5 to < 10 seconds at a rate of at least 4 Hz.
    • Must not be consistent with a known normal pattern or benign variant, and lack clear clinical correlate.
    • Include evolution in their definitions (evolving BIRDs) as a form of definite BIRDs.

    Extreme Delta Brush (EDB)

    • EDB is characterized by abundant or continuous fast activity associated with periodic delta waves.
    • Differentiate between definite EDB (abundant or continuous) and possible EDB (occasional or frequent).

    Periodic Discharges (PDs) and Spike/Sharp Waves (SW)

    • PDs involve monitoring voltage components, specifically the highest voltage from any discharge.
    • SWs are characterized by voltage spikes and sharp waves, requiring measurement from peak to trough.

    Voltage Categorization

    • Voltage classification for PDs:
      • Very low: < 20 mV
      • Low: 20 to 49 mV
      • Medium: 50 to 149 mV
      • High: ≥ 150 mV
    • For Relative PDs, both absolute and relative voltage measurements are necessary.

    Evolution Criteria

    • Evolution in frequency: Change must occur in the same frequency direction of at least 0.5 Hz, persisting for at least three cycles.
    • Evolution in morphology: Requires at least two consecutive changes leading to a new morphology.
    • Evolution in location: Must spread or retreat to at least two different 10-20 electrode locations.

    Prevalence of EEG Patterns

    • Prevalence classification includes:
      • Continuous: ≥ 90%
      • Abundant: 50% to 89%
      • Frequent: 10% to 49%
      • Occasional: 1% to 9%
      • Rare: < 1%

    Duration and Frequency Measurements

    • Typical frequency categorization: Measures in Hz include ranges 0.5, 1, 1.5, 2, and 2.5.
    • For very brief durations, includes 3, 3.5, and 4 Hz.
    • Time gaps between PDs contribute to the overall pattern duration.

    Terminology for Patterns

    • Suggested terms to describe patterns include:
      • If multiple patterns exist, document presence and prevalence.
      • Terms must be concise, specifying whether patterns are indicative of electrographic seizures if ≥ 10 seconds.

    Fast Activity and Duration Definitions

    • Specific fast activity categorizations include:
      • “1F”: associating fast activity with PDs, defined as theta or faster.
      • “1R”: rhythmic delta activity applied only to PDs.
      • “1S”: sharp waves or spikes associated solely with RDA.

    Extreme Delta Brush (EDB)

    • EDB defined as a subtype of 1F, classified under specific criteria:
      • Abundant or continuous RDA with stereotyped fast activity.
      • Does not meet criteria for electrographic seizures (ESz) if falls under occasional or frequent activity.

    Treatment Indicators

    • Improved EEG with parenteral antiseizure medications may indicate an electrographic seizure (ECSz) or possible enhanced clinical significance (ECSE).
    • Stimulus-induced patterns require the “SI-” prefix for classification, indicating responsiveness to alerting stimuli.

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    Description

    This quiz focuses on the principles of electrophysiology, particularly analyzing the characteristics of PDs (periodic discharges) and SWs (spike/wave complexes). Participants will explore frequency measurement and voltage profiling related to these phenomena. Test your understanding and deepen your knowledge in this critical area of neuroscience.

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