K974496 · Aspect Medical Systems, Inc. · OLW · Feb 6, 1998 · Neurology
Device Facts
Record ID
K974496
Device Name
A-2000 EEG MONITOR WITH BIS
Applicant
Aspect Medical Systems, Inc.
Product Code
OLW · Neurology
Decision Date
Feb 6, 1998
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 882.1400
Device Class
Class 2
Indications for Use
The Aspect A-2000 EEG Monitor with BIS is intended to monitor the state of the brain by data acquisition of EEG signals in the intensive care unit, operating room and for clinical research. The BIS, a processed EEG variable, may be used as an aid in monitoring the effects of certain anesthetic agents.
Device Story
The A-2000 EEG Monitor is a bedside device used in ORs, ICUs, and research settings to monitor brain state. It utilizes a Digital Signal Converter (DSC-2) to acquire raw EEG signals from the patient. The device processes these signals to calculate the Bispectral Index (BIS), a parameter used to monitor the effects of anesthetic agents. It displays raw EEG waveforms, Density Modulated Spectral Array (DSA), trend plots, BIS numbers, signal quality, EMG indicators, and suppression ratios. The monitor performs automatic and manual self-tests to ensure hardware and software integrity. Clinicians use the real-time display and optional thermal strip printer to assess patient depth of anesthesia, potentially facilitating faster emergence and improved recovery. It includes audible and visual alarms for patient conditions, lead connections, and equipment errors.
Clinical Evidence
No clinical data was generated specifically for this 510(k) submission. The device relies on bench testing, including software, environmental, mechanical, electrical, and EMC validation. A hazard analysis was performed to mitigate identified risks. The document references a published clinical study (Gan et al., 1997) to support the clinical utility of the BIS parameter in monitoring anesthetic effects.
Technological Characteristics
The device is an EEG monitor featuring a high-gain, isolated DSC-2 amplifier. It processes EEG signals at a 16,384 Hz sampling rate. The system includes a display for raw EEG, DSA, and trend parameters (BIS, SR, SQI, EMG). It supports optional thermal strip printing. The device performs automated power-up self-tests and manual hardware/filter diagnostics. It is designed for clinical environments (OR/ICU).
Indications for Use
Indicated for monitoring brain state via EEG signal acquisition in ICU, OR, and clinical research settings; serves as an aid in monitoring effects of specific anesthetic agents in anesthetized or sedated patients.
Regulatory Classification
Identification
An electroencephalograph is a device used to measure and record the electrical activity of the patient's brain obtained by placing two or more electrodes on the head.
Predicate Devices
Aspect Medical Systems EEG Monitor, Model A-1050 with BIS (K963644)
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FEB 6 1998
K974496
## II 510(k) SUMMARY OF SAFETY AND EFFECTIVENESS INFORMATION
510(k) SUMMARY
Date Prepared: November 26, 1997
### Company Name and Address
Aspect Medical Systems, Inc.
2 Vision Drive
Natick, MA 01760-2059
Contact People:
Christine Morgida
Manager, Regulatory Affairs
Paul J. Manberg, PhD
Vice President, Clinical and Regulatory Affairs
### Device Name
Proprietary Name: A-2000™ EEG Monitor with BIS. Common Name: EEG Monitor
### Classification
Electroencephalograph (EEG) monitors have been classified by the Neurological Devices Panel as Class II devices (21 CFR 882.1400)
### Predicate Device
Aspect Medical Systems EEG Monitor, Model A-1050 with BIS™.
This 510(k), #K963644, received FDA clearance October 8, 1996.
### Device Description
The Aspect A-2000 Monitor dimensions are 7 inches wide x 6.8 inches high x 4 inches deep. The active display area is 3.4 inches high x 4.5 inches wide, and displays Raw EEG waveforms, Density Modulated Spectral Array (DSA) (includes spectral edge frequency), Trend plots of processed EEG parameters in real time, Current BIS number, Signal quality and EMG indicators, and Suppression Ratio.
The Aspect A-2000 Monitor performs automatic self tests upon power up to ensure that the monitor and its components are functioning properly. A quick test of the DSC-2 is conducted upon first detection of the DSC-2.
In addition, comprehensive self tests can be initiated manually from the service menu. Results are reported on the display, and printed automatically if a printer is connected.
A-2000 and BIS are trademarks of Aspect Medical Systems, Inc.
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# Digital Signal Converter (DSC-2)
The DSC-2 is used in the A-2000 system, and is identical to the digital signal converter used with the A-1050 system (510(k) #K952347, FDA clearance date 1/16/96). It is an electrically isolated, low noise, high gain amplifier.
Its dimensions are: 2.50 x 3.75 x 1.00", and its weight is 4.5 ounces.
# Printer
A two inch thermal strip printer is optional. When printing is initiated, an 8-10 second real time EEG strip is printed. When the monitor is displaying a trend, the printer outputs a horizontal trend plot of the entire case at the same scale as the main display.
# Intended Use
The Aspect A-2000 EEG monitor with BIS is intended to monitor the state of the brain by data acquisition of EEG signals in the intensive care unit, operating room and for clinical research.
The BIS, a processed EEG variable, may be used as an aid in monitoring the effects of certain anesthetic agents.
Gan TJ, Glass PS, Windsor A, Payne F, Rosow C, Sebel P, Manberg P. Bispectral Index (BIS) Monitoring Allows Faster Emergence and Improved Recovery From Propofol, Alfentanil and Nitrous Oxide Anesthesia. Anesthesiology October 1997; (4) 87: 808-15.
# Summary of Technological Characteristics Compared to Predicate Device
## Similarities
Both devices are EEG machines that monitor the state of the brain by data acquisition of EEG of the anesthetized or sedated patient in the intensive care unit, operating room and for clinical research. Also, both are indicated for use as an aid in monitoring the effects of certain anesthetic agents by use of the processed parameter BIS.
The A-2000 and A-1050 Monitors with BIS have the same basic functions. The hardware systems are similar, the A-2000 Monitor having more highly integrated components. They have similar hardware and software designs, signal flow, self-test capabilities (automatic and manual), alarms, and identical Digital Signal Converters (DSC-2).
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The A-2000 and A-1050 alarm capabilities include:
**System Error Message Alarms** for patient condition (i.e. EEG Isoelectric), lead connection (i.e. DSC Disconnected) and equipment messages (i.e. Software Errors). Both the A-1050 and A-2000 Monitors have written messages. Both have audible alarms associated with error messages.
**Numeric Display Limit Alarms** for the primary trend. Both the A-1050 and A-2000 Monitors have 3 ascending tones when the high limit is reached, and three descending tones when the low limit is reached.
A description of the System Error Message Alarms can be found in Section VII of the Operator’s Manual. A description of the Numeric Display Limit Alarms can be found in Section II of the Operator’s Manual.
- Printer support - Both the A-1050 and A-2000 Monitors have printer support capabilities.
- Self tests (automatic and manual) - Both monitors have automatic testing upon start up. Both monitors have manual testing of the DSC-2, as well as the hardware filter performance.
- DSC-2 (digital signal converter) - The A-2000 Monitor DSC-2 is identical to the A-1050 Monitor DSC-2 (other than a color change to the case).
- Trend BIS, SR, SQI, EMG - Both the A-1050 and A-2000 Monitors can trend all 4 of the above processed EEG variables. Both prominently display the primary trend in the graphic display.
- Data sampling rate (16,384 samples per second) - Identical
## Minor Differences
There are 3 minor differences that occur in the following areas:
- Processed Parameters
### CSA and DSA
The Aspect A-2000 Monitor has processed EEG displayed as DSA (Density Spectral Array) whereas the Aspect A-1050 Monitor with BIS graphically displays processed EEG as CSA and DSA. Both are graphic representations of the same thing, i.e. power spectra.
### Median Frequency
The Aspect A-2000 Monitor does not have median frequency because this parameter is not used widely by anesthesiologists. Median frequency is defined as the frequency at which 50% of the total power lies to either side of it.
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* Alarms
System Error Message Alarms
Both the A-2000 and the predicate device have written messages for 3 categories of errors (i.e. patient condition, lead connection and equipment messages). The differences are that the written messages may differ slightly (i.e. "DSC Power Regulation Fault" in the A-1050 with BIS will read "DSC Power Regulation" in the A-2000 Monitor). Also, with regard to the audible alarm, the Aspect A-1050 Monitor with BIS has a single tone alarm, whereas the A-2000 Monitor has a two tone alarm.
Numeric Display Limit Alarms
In both the Aspect A-2000 and A-1050 Monitors, this alarm occurs for those variables that are primary trended. For the A-2000 Monitor, these high and low limit alarms occur for the BIS. In the predicate device, the auxiliary alarms, i.e. EMG, Suppression Ratio and Signal Quality can be primary trended in addition to the BIS.
The following tests have been conducted: software, environmental, mechanical and electrical validation testing, as well as EMC testing. The Reviewer Guidance for Premarket Notification Submissions (1993) was followed (other than packaged product storage test - Appendix A, section (i) (6) (ii); this test will be completed once the package is finalized) and all test results are acceptable. Also, a hazard analysis was completed, and this document indicates Aspect has made diligent efforts to identify all the potential hazards that could be anticipated, and have found ways to mitigate them by various hardware and software designs, including labeling.
Aspect Medical Systems believes the A-2000 EEG Monitor with BIS is substantially equivalent to the Aspect A-1050 EEG Monitor with BIS, and is safe for its intended use.
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DEPARTMENT OF HEALTH & HUMAN SERVICES
Public Health Service
Food and Drug Administration
10903 New Hampshire Avenue
Document Control Room -WO66-G609
Silver Spring, MD 20993-0002
Ms. M. Christine Morgida
Manager, Regulatory Affairs
Aspect Medical Systems, Inc.
2 Vision Drive
Natick, MA 01760-2059
APR - 9 2012
Re: K974496
Trade/Device Name: Aspect Medical System A-2000 EEG Monitor with BIS
Regulation Number: 21 CFR 882.1400
Regulation Name: Electroencephalograph
Regulatory Class: II
Product Code: OLW, OMC, ORT, OLT
Dated (Date on orig SE ltr): November 26, 1997
Received (Date on orig SE ltr): November 28, 1997
Dear Ms. Morgida:
This letter corrects our substantially equivalent letter of February 6, 1998.
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
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Page 2 - Ms. M. Christine Morgida
Please be advised that FDA’s issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act’s requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please go to http://www.fda.gov/AboutFDA/CentersOffices/CDRH/CDRHOffices/ucm115809.htm for the Center for Devices and Radiological Health’s (CDRH’s) Office of Compliance. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm for the CDRH’s Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Kesia Alexander
Malvina B. Eydelman, M.D.
Director
Division of Ophthalmic, Neurological, and Ear, Nose and Throat Devices
Office of Device Evaluation
Center for Devices and Radiological Health
Enclosure
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2-05-1998 2:42PM FROM ASPECT MEDICAL SYTMS 508 653 6788 P. 3
Page ___ of ___
510(k) NUMBER (IF KNOWN): K974496
DEVICE NAME: Aspect Medical Systems EEG Monitor with BIS, Model A-2
INDICATIONS FOR USE:
The Aspect A-2000 EEG Monitor with BIS is intended to monitor the state of the brain by data acquisition of EEG signals in the intensive care unit, operating room and for clinical research. The BIS, a processed EEG variable, may be used as an aid in monitoring the effects of certain anesthetic agents.
Gan TJ, Glass PS, Windsor A, Payne F, Rosow C, Sebel P, Manberg P. Bispectral Index (BIS) Monitoring Allows Faster Emergence and Improved Recovery From Propofol, Alfentanil and Nitrous Oxide Anesthesia... Anesthesiology October 1997; (4) 87: 808-15
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED.)
Concurrence of CDRH, Office of Device Evaluation (ODE)
M. (Division Sign Off) Division of Cardiovascular, Respiratory, and Neurological Devices
Prescription Use X 510(k) Number K974496 OR (Per 21 CFR 801.109) Over-The-Counter-Use (Optional Format 1-2-96)
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.