ACNS Guideline 4: Recording Clinical EEG on Digital Media

Vocabulary flashcards based on the ACNS guidelines for digital EEG recording.

Digital EEG Recording Systems

Widely available and relatively inexpensive systems offering advantages like higher fidelity recording, signal postprocessing, automated detection, and efficient data storage.

Montage Control (Digital EEG)

A feature of digital EEG acquisition that allows the reviewer to view the EEG record with control over the montage.

Filter Settings Control (Digital EEG)

A feature of digital EEG acquisition that allows the reviewer to view the EEG record with control over the filter settings.

Gain Control (Digital EEG)

A feature of digital EEG acquisition that allows the reviewer to view the EEG record with control over the gain.

Horizontal Scaling Control (Digital EEG)

A feature of digital EEG acquisition that allows the reviewer to view the EEG record with control over the seconds of EEG recording viewed per screen page.

HIPPA Compliant Storage

Secure storage of digital video-EEG recordings on a central server, adhering to Health Insurance Portability and Accountability Act regulations.

Patient Information (EEG)

Electronically recorded information including patient name, date of birth, test date, and relevant identification numbers.

Calibration Signals (EEG)

Signals recorded at the beginning of each EEG recording, as per conventional EEG practices.

Event Codes (EEG)

Codes recorded with EEG data to represent common events like eye closure, hyperventilation, and patient state.

Sampling Rate (Digital EEG)

Minimum rate of 256 samples per second for acquiring EEG data onto a digital storage medium.

Aliasing (Digital EEG)

Artifact prevented by using higher sampling rates (e.g., 512 Hz) on modern high-resolution computer screens.

Digitization Resolution (EEG)

Resolution of at least 16 bits per sample, including any sign bit, for EEG digitization.

Dynamic Range (EEG)

The maximum allowed excursion based on mV resolution and bit analog-to-digital conversion; a range of voltage the EEG recording system can accurately measure.

Interchannel Crosstalk

Should be less than 1%, i.e., 40 dB down or better. Represents the interference between EEG channels.

Common Mode Rejection Ratio (CMRR)

Should be at least 90 dB for each of the EEG channels to reject unwanted noise.

EEG Noise Level

Additional noise in the recording should be less than 1 mV peak to peak at any frequency 0.5 to 100 Hz, including at 60 Hz.

Video Synchronization (EEG)

Synchronization of video recording with EEG to facilitate review, especially for artifact and clinical event identification.

Optical Storage (Digital EEG)

Acceptable for outpatient routine EEG recordings, but newer technologies are recommended due to potential damage and obsolescence.

Digital Server System (EEG)

Recommended for inpatient long-term recordings (24 hours or more) to facilitate remote review and backup.

HIPAA Compliance (Server Storage)

Achieved by using a server storage solution that records a full audit trail of every person who accesses the patient record.

EEG Recording Formats

Should be able to store EEG signal data, technologist comments, and event codes.

Nonproprietary Data Formats (EEG)

Publicly available data formats (e.g., EDF or EDF-plus) for storing EEG data to ensure compatibility across different systems.

Stand-alone Viewer (EEG)

A method for outputting studies with a viewer so the recording can be viewed on any computer.

Horizontal Scaling (EEG Display)

Standard scaling where 1 second occupies between 25 and 35 mm, with a minimum resolution of 128 data points/second.

Horizontal Resolution (EEG)

Minimum resolution of at least 1,280 pixels for a 10-second page on the screen.

Vertical Scaling (EEG Display)

Standard vertical scaling with a minimum spacing of 10 mm per channel for a display of up to 21 channels.

Post Hoc Digital Filtering

Ability to digitally filter recorded EEG data after the recording is complete.

Simultaneous Display (EEG)

The action of displaying multiple segments of EEG for side-by-side visual comparison.

Raw EEG Data Access

Reviewers should always have easy access to view the raw EEG data, even with EEG processing results displayed.

Montage Consistency (EEG)

Montages available for review should be consistent with standard laboratory use and ACNS recommendations.

Playback Systems (EEG)

Should be able to display channel designations, gain or filter settings, technologist comments, and event markers.

Time Stamp (EEG)

Essential on each screen or page of EEG data.

Digital EEG

Electroencephalography recorded and stored using digital technology.

Analog EEG

Older method of EEG recording using paper-based systems.

Signal Postprocessing

The ability to manipulate and analyze EEG signals after they have been recorded.

Automated Detection

Using computer algorithms to automatically identify specific EEG patterns.

Efficient Data Storage

Storing large amounts of EEG data in a compact and organized manner.

Continuous Monitoring

Recording EEG data over an extended period of time, often in a hospital setting.

Central Server

A computer system used to store and manage EEG data from multiple sources.

Remote Sites

Locations away from the main EEG recording facility where data can be accessed and reviewed.

Calibration Signals

Standard signals used to ensure the accuracy of EEG recordings.

Technologist Comments

Notes made by the EEG technologist during the recording to document important events.

Free-Text Comments

Custom notes that can be added to the EEG recording to provide additional information.

Impedance Values

Measurements of the electrical resistance between the electrodes and the patient's scalp.

Amplifier Control Settings

Parameters that control how the EEG signals are amplified and filtered.

Sampling Rate

The number of times per second that the EEG signal is measured.

High-Frequency Filter

A filter that removes high-frequency noise from the EEG signal.

Resolution

The level of detail captured in the EEG recording.

Analog-to-Digital Conversion

The process of converting the analog EEG signal into a digital format.

Clipping

Distortion of the EEG signal that occurs when the signal exceeds the recording system's limits.

Optical Storage Devices

Storage media such as CD-ROMs and DVD-ROMs used for storing EEG data.

USB Flash Drives

Portable storage devices that can be used to store and transfer EEG data.

Network Access Servers

Centralized storage systems that can be accessed over a network.

Data Storage Redundancy

Duplicating data across multiple storage devices to prevent data loss.

Data Backup

Creating copies of data to protect against data loss.

Audit Trail

A record of who has accessed the patient's EEG data.

European Data Format (EDF)

A standard file format for storing EEG data.

Proprietary Data Formats

File formats that are specific to a particular EEG recording system.

Playback Systems

Software or hardware used to review EEG recordings.

Temporal Resolution

The ability to distinguish events that occur close together in time.

Spatial Resolution

The ability to distinguish events that occur in different locations on the scalp.

Channel Spacing

The distance between EEG channels on the display.

Bipolar Reconstruction Techniques

A method of re-referencing EEG data to enhance certain features.

Scalp

Skin covering the head.

Clinical Neurophysiology

The subspecialty of neurology that focuses on the study of the nervous system through physiological recordings such as EEG, EMG, and evoked potentials.

Electroencephalography (EEG)

A neurophysiologic test that records electrical activity of the brain using electrodes placed on the scalp.

Digital Media

Electronic media that are used for creating, storing, and viewing digital EEGs.

Analog/Paper Systems

Older EEG recording systems that use paper to record brain electrical activity.

Higher Fidelity Recording

More accurate data signals compared to analog methods.

Automated Detection

Automated recognition of EEG patterns, such as seizures, spikes, or artifacts, using computer algorithims.

Efficient Data Storage

The process of efficiently storing and organizing data in data bases.

HIPAA Complaince

Complying with the Health Insurance Portability and Accountability Act, which aims to protect sensitive health information.

Notation of Information

Information that can describe events, codes, and patient states during the EEG recording.

American Clinical Neurophysiology Society (ACNS)

An organization that sets guidelines and standards for clinical neurophysiology practice, including EEG recording.

Nonerasable

Cannot be erased or altered.

Erasable

Capable of being erased or cleared.

Outpatient

Medical treatment without admittance to a hospital.

Routine

Daily procedures or normal, mundane tasks.

Ambulatory

Relating to or adapted for walking; not bedridden.

Inpatient

Admitted to a hospital overnight.

Medical Records

Statutes governing medical records in each of the individual states, and the existence of local or hospital statutes regarding EEG record storage. These govern the duration of storage, and in some instances, they may also dictate whether magnetic or optical storage is allowed.

Filter Settings

The manipulation of a band of frequencies.

Gain Settings

The act of amplifying certain voltages.

Horizontal

Parallel to the plane of the horizon; level.

Vertical

At right angles to a horizontal plane; in a direction, or having an alignment, such that the top is directly above the bottom.