ACNS 3 (PDs and SWs)

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Questions and Answers

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?

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

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

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

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

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

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

Two consecutive changes must happen in the same category. Signup and view all the answers

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

High Signup and view all the answers

What distinguishes electroclinical seizures from other types of seizures?

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

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

BIRDs must have a known normal pattern associated. Signup and view all the answers

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

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

Which of the following is a characteristic of evolving BIRDs?

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

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

BIRDs may occur with no clinical correlate at all. Signup and view all the answers

What determines the number of phases in a signal?

The total number of baseline crossings Signup and view all the answers

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

Below the imaginary baseline Signup and view all the answers

Which statement correctly describes spontaneous phases?

They are never clearly induced or improved by stimulation Signup and view all the answers

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

Sharpness and greatest voltage Signup and view all the answers

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

A change from one phase to another Signup and view all the answers

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

The frequency of the signal Signup and view all the answers

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

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

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

Those influenced by sensory stimulation Signup and view all the answers

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

It should be specified for both dominant and sharpest phases Signup and view all the answers

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

It counts as additional phases Signup and view all the answers

What does PDs1R refer to?

Periodic Discharges with fast activity in one hemisphere only Signup and view all the answers

Which condition qualifies as BIPDs1F?

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

What type of fast activity is characterized as RDA1F?

Fast activity with a stereotyped relationship to delta waves Signup and view all the answers

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

Fast activity occurring independently from periodic discharges Signup and view all the answers

Which one of the following describes a Deﬁnite EDB condition?

Fast activity that is continuous or abundant Signup and view all the answers

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

Can occur frequently but should not be occasional Signup and view all the answers

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

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

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

Fast activity that persists even with dormant periodic discharges Signup and view all the answers

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

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

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

It indicates fast activity that is abundant and patterned Signup and view all the answers

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

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

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

Possible electrographic SE Signup and view all the answers

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

20% 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?

5 continuous minutes Signup and view all the answers

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

ECSz has less stringent duration criteria than ECSE. Signup and view all the answers

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

Using the RPP modiﬁers Signup and view all the answers

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

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

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

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

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

There are ambiguous findings needing further investigation. Signup and view all the answers

When is an electroclinical seizure (ECSz) considered valid?

If detected solely using EEG without clinical correlates. Signup and view all the answers

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

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

Which duration category corresponds to continuous activity in EEG patterns?

90% or more of the record. Signup and view all the answers

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

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

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

Each pattern must be individually recorded for prevalence. Signup and view all the answers

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

1 to 2.5 Hz. Signup and view all the answers

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

19 mV Signup and view all the answers

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

At least two different locations Signup and view all the answers

What characterizes the voltage measurement for absolute voltage in PDs?

It compares highest voltage to background voltage in the same channel Signup and view all the answers

What defines evolution in frequency specifically for PDs?

A single frequency that must persist for three cycles Signup and view all the answers

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

High Signup and view all the answers

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

Fast activity superimposed on periodic discharges Signup and view all the answers

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

Independent periodic discharges must occur in both hemispheres Signup and view all the answers

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

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

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

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

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

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

Which condition is required for a classification as RDA1S?

The presence of sharp spikes with rhythmic delta activity Signup and view all the answers

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

A characteristic feature of generalized delta activity Signup and view all the answers

What distinguishes 1F from patterns classified as PD1R?

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

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

There is noted independence between delta activities across hemispheres Signup and view all the answers

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

Distinct sharp waves or spikes within the recorded activity 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.