EEG Reporting: ACNS Guideline 7 Summary

EEG Reporting Guideline Summary

• ACNS Guideline 7 aims to structure EEG reports for routine adult electroencephalography (EEG).
• The goal is to enhance interrater reliability for clinical and research purposes through standardized reporting.
• Documentation of patient history is expanded to include pertinent clinical details affecting EEG recording and interpretation.
• Technical condition recommendations now include post hoc review parameters and the type of EEG recording.
• The guideline seeks to standardize terminology for clinical and research utility, advocating an organized approach to EEG reporting.
• It is designed to define EEG recording conditions and parameters, offering a record description and summarizing visual analysis.
• The framework aids clinicians in general neurologic care, including primary care, who may lack expertise in EEG technical aspects or terminology.
• Proper result interpretation requires adherence to minimum technical standards for EEG performance.
• Higher interobserver agreement occurs with a forced-choice paradigm using a limited set of EEG terms.
• The guideline presents a framework for categorizing EEG features as normal or abnormal and specifying clinical importance to clinicians.
• Specialized EEGs or recordings in specific settings/durations may need modified formats with enhanced technical details.
• Institutions using research indexing may need additional reporting means beyond these guidelines.
• Standardized clinical neurophysiologic procedure reporting has been successfully implemented.
• This guideline supplements previous guidelines on "Writing an EEG Report" and non-routine recording situations.

Format for Reporting

• A standard rsEEG report should contain these five sections: History, Technical Description, EEG Description, Impression, and Clinical Correlation.

History Section

• This section aids in interpreting the rsEEG by providing relevant clinical information and patient/EEG recording identification.
• Templates should include patient demographics, medical record number, and EEG record number.
• Specify the EEG's purpose, such as evaluating altered consciousness or classifying epileptiform discharges.
• The person preparing the recording should input necessary information.
• Worksheets should include relevant medical history (including medications), imaging results, operations, and previous EEGs.

Technical Description Criteria

• This section should detail the recording's conditions and parameters, including the acquisition and interpretation dates/locations.
• Technical parameters should include the number of electrodes used and their placement according to the 10-20 or 10-10 International System.
• Report technical standards and use of additional/special electrodes, as well as modifications to the 10-20/10-10 systems.
• Include any special parameters used during post hoc review.
• Specify the duration of the recoding, especially if deviates from the minimum technical requirements.
• A statement regarding premedication, including the drug and dose, should be provided.
• Conditions that can influence the EEG, like sleep deprivation or dietary influences, should be documented.
• Document the patient's state of consciousness, as helps guide interpretation and electroclinical correlation.

EEG Description Requirements

• A description of the background electrocerebral activity, detailing all essential waveform characteristics
• Should use complex EEG signals, with clinically relevant features extracted through integration and interpretation of various bandwidths
• Objective analysis for review using technical terminology and metrics to detail waveforms over the recording's duration
• A complete orderly description of the state of the patient, the background activity, and the salient EEG features
• Identification/description of normal variants and stating the degree of any abnormality
• It should begin with a complete description of the background activity, including the posterior dominant rhythm and special feature.
• Report the posterior dominant rhythm, it's frequency in Hertz, amplitude in microvolts, when the patient is alert
• Should reflect recordings obscured by artifacts, recordings in infants, and those without a defined past dominant frequency.
• Note the response or reactivity to external stimuli, identify non-dominant background activity with principal frequencies, symmetry, and morphology
• Use numerical measures to quantify nondominant background activity, including beta, theta, and delta activity.
• Document state changes, level of alertness, EEG background frequency/amplitude organization, and spatial features.
• Report all sleep stages, abnormal patterns such as rapid sleep cycling, and asymmetry in sleep elements.
• Should note hyperventilation and intermittent photic stimulation.
• Document any special characteristics in the background using terminology to describe morphology, voltage, and laterality.
• Note salient abnormal features following identification of state and background activity.
• Should document where interictal epileptiform discharges or present including the location, morphology, ect
• Describe the frequency and pattern of occurrence and some abnormal finding may be influenced by external stimulation.
• Quantifying paroxysmal abnormalities, and provide snapshots of any reported abnormality
• Should include description of the electrographic onset, field of propagation, and postictal period when electroclinical seizure or electrographic seizures are present.

Other EEG Elements

• Artifacts get reported when they mimic cerebral activity, or are unusual/excessive.
• Include a single-channel electrocardiogram in every EEG, and variation is reporting depends on the interpretere's expertise
• Report other channels such as respiration, EMG, and noncephalic monitors when applicable

Video Recording

• It is a routine part of most systems for performing rsEEG.
• It should provide additional information involving electroclinical episodes and seizures, while assessing artifacts.
• Document a description of the clinical event, terminology used by the International League Against Epilepsy seizure classification systems, and the level of responsiveness.

Impression Elements

• Is a synthesis of the EEG findings, that is written primarily for the clinician, and be succinct.
• It should include an initial, clear summary statement as to whether it is a normal or an abnormal record.
• List clear and concise line items to simplify and compare abnormalities among successive records.
• State findings succinctly in layman's terms, and be restricted to salient and minimum findings with no more than 3 to 4
• The impression should avoid confusing terminology and technical jargon, but "epileptiform discharges" are universally accepted terms.

Clinical Correlation Description

• It integrates the EEG referral reason and findings to assist with patient management, where relevance should be clear.
• Avoiding technical terminology helps convey the message to the least experienced clinician.
• A good litmus test means that the section should be understandable to a general practitioner or nurse.
• Phrases such as "no focal or lateralizing abnormality" are helpful in the clinical correlation where the clinical request is explicit
• Examples of clinical correlations include indicating if an EEG supports/excludes the diagnosis of epilepsy, or suggests underlying lesions.
• Should avoid therapeutic suggestions
• Should note if previous EEGs are available, the current record should be compared to previous tracings
• If a combined report is used, it should start with the neurophysiologic findings, followed by comments about the clinical significance.
• Implementation will facilitate interobserver reliability of EEG reporting for clinical care, while increasing consistency for research studies.