This software is intended for use by qualified research and clinical professionals with specialized training in the use of EEG and PSG recording instrumentation for the digital recording, playback, and analysis of physiological signals. It is suitable for digital acquisition, display, comparison, analysis, and archiving of EEG potentials and other rapidly changing physiological parameters.
Device Story
TWin PLUS software functions as a universal review and analysis platform for EEG/PSG systems. It collects, formats, and displays real-time physiological waveforms and numeric data; records synchronized video/audio of patients. Operates on Windows OS; interfaces with various hardware amplifiers via digital interface cards or USB. Features include: real-time seizure/spike event marking (SZAC algorithm), semi-automatic sleep staging, and automated analysis of SaO2, respiration, and EMG (periodic leg movements). Data stored in TUFF format on local/network disks or archived to CD-ROM. Used by trained medical professionals in clinical/research settings. Output provided as waveform displays, numeric reports, and event markers. Healthcare providers review all automated markers; no diagnostic classification is made by the software. Benefits include efficient data management, synchronized review of EEG and video, and streamlined analysis of long-term recordings for epilepsy and sleep disorders.
Clinical Evidence
Bench testing only. No clinical data provided. The device relies on proven algorithms from previously cleared predicate devices (e.g., SZAC seizure analysis, SASSY sleep scoring).
Technological Characteristics
Software-based EEG/PSG review system. Operates on Windows 98/2000. Supports up to 136 channels, 1000 Hz max sample rate. Connectivity via RS232 or digital interface cards. Data storage in proprietary TUFF format. Features include digital filtering, frequency/amplitude measurement, potential mapping, and spectral analysis. No specific material standards or sterilization required as it is a software-only device.
Indications for Use
Indicated for use by qualified research and clinical professionals for digital recording, playback, and analysis of EEG and PSG physiological signals, including epilepsy diagnosis and sleep studies.
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.
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K 012976
2-12-02
# EXHIBIT A
Grass-Telefactor Division
Astromed-Med, Inc.
#### West-Warwick, RI 02893 USA
Tel: (401) 828-4000
Fax: (401) 822-2430
Contact Person: Jim Bryan
August 15, 2001
#### 1. Identification of the Device
Classification Name: Electroencephalograph, 84GWQ, Reg. #882.1400 (1)
Common/Usual Name: EEG Review Software
Proprietary-Trade Name: Grass-Telefactor TWin PLUS Software
## 2. Equivalent Legally Marketed Devices
This software is functionally equivalent in design and function to that of the GRASS GAMMA software package and the Telefactor BEEHIVE, and the Telefactor SZAC Seizure Analysis Computer.
## 3. Indications for Use
This software is intended for use by qualified research and clinical professionals with specialized training in the use of EEG and PSG recording instrumentation for the digital recording, playback, and analysis of physiological signals. Its specifications and features are especially well suited to electroencephilography, polysomnographic sleep recordings, and long term recordings used in epilepsy diagnosis.
## 4. Theory of Operation and Description of the Device
TWin PLUS will become the universal review package for all GRASS-Telefactor EEG systems. Further the TWin PLUS software package is intended for use with a number of hardware EEG inourterlices. It utilizes the windows operating system to manage four or more simultaneous ongoing tasks which include:
- Real-time collection and formating of real time EEG and other physiological parameters ●
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- Real-time display of the foregoing parameters in waveform or numeric format as the data and user . may require.
- . Real time analysis of EEG waveform data to identify events which may be epileptoform in nature and hence require special attention from professionals in attendance - SZAC analysis.
- Data collection and recording to disk of real time video and audio data, usually an image of the patient ● being monitored.
- Review and analysis of previously recorded data including the ability to look-back to old data while ● real-time recording of ongoing data is in progress.
#### EEG Input Ampliffers:
The TWin PLUS software package is intended to work with a number of different amplifier systems with various digital interface modes. Each of these hardware devices have or will have their own separate 510(k) marketing authority, ---
These amplifiers choices include:
- Current BEEHIVE amplifiers which use a special purpose digital interface card for already digitized . data.
- The same BEEHIVE amplifiers using a USB interface for the data. .
- GRASS-Telefactor TS amplifiers using a computer resident card for A to D conversion of their . multiplexed analog data stream.
#### Data Formatting and Storage:
All data is stored in a format (TUFF) as near the original input as possible at sample rates appropriate for the data type. Primary storage is either local or remote hard disk (network server). Provisions exist for archiving to several appropriate digital archive media, most frequently CD ROM.
#### Montaging Capability:
The TWIN PLUS software has provision for labeling data channels with electrode names and then displaying waveforms as the algebraic difference of any electrode pair. The playback montage also specifies default digital filter settings.
#### Analysis;
Specific sections of data can be selected easily for further analysis including frequency and amplitude measurement, potential mapping, spectral analysis, and frequency band mapping.
#### Flagging of Epileptoform EEG Data Sequences (SZAC):
The SZAC program module uses the identical software algorithm developed and proven in the SZAC Computer previously marketed by Telefactor (K870450) This system is in wide use in the medical community, particularly in epilepsy centers around the world. Grass-Telefactor makes no claims for diagnostic accuracy of this algorithm, it is merely a device which marks particular EEG passages for diagnostic consideration either as seizures or as spikes.
#### EEG Data BASE:
An EEG data base feature associates stored EEG data with patient name, date and appropriate clinical parameters entered by the operator, and provides convenient means for accessing that data for review.
#### Digital Video Recording:
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TWIN software uses the output of an appropriate video capture card in the host computer to digitize, compress and store patient image data. Provision is included to play back video data synchronized with the EEG waveform display.
## Semi Automatic Sleep Scoring:
TWin PLUS includes the next iteration of the Semi Automatic Sleep Scoring System (SASSY K860219). This system functions to display polysomnographic data in standard page sizes and provides means a review operator to assign a sleep stage notation to each page.
Report generation and printout are provided for each study with reported parameters which can be tailored by the particular laboratory using the device.
A software option is provided for automatic analysis of SaO2 and respiration data to mark apnea and desaturation events for professional review and classification. A similar module analyzes EMG waveforms to mark periodic leg movements. In each case no diagnostic classification is made without a decision based on the review of a qualified professional.
These routines are supplied without any claims for accuracy and the professional can use or ignore them at his own discretion. In each case decision thresholds are adjustable and can be set by the person reviewing the data.
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### 5 Comparison Matrix
| Technical<br>Characteristic | GRASS-Telefactor<br>TWin PLUS | GRASS<br>GAMMA | Telefactor<br>SZAC 16<br>Seizure Analysis<br>Computer | Telefactor<br>BEEHIVE 64 |
|-------------------------------|-------------------------------|------------------------------|-------------------------------------------------------|------------------------------|
| Device Class | CLASS II | CLASS II | CLASS II | CLASS II |
| Intended User | Medical<br>Professional | Medical<br>Professional | Medical<br>Professional | Medical<br>Professional |
| Operating System | Windows 98 or<br>2000 | Windows 98 Or<br>2000 | DOS | DOS |
| Max Channels | 136 | 36 | 16 | 64 (128 for other<br>models) |
| Sample Rate | 1000 Hz Max | 1000 Hz Max | 200 | 200 |
| Amplifier control | RS232 | RS232 | Manual | RS232 |
| Recorder Update<br>Mode | Wiper Bar | Wiper Bar | Scrolled Display | Scrolled Display |
| Monitor<br>Resolution | 1600 x 1200 | 1600 x 1200 | 1024 x 440 | 1024 x440 |
| Data Storage | Local or Remote<br>hard disk | Local or remote<br>hard disk | Local or remote<br>hard disk | Digital VCR |
| Primary Data<br>Access | Random | Random | Random | VCR sequential |
| User Input | Mouse/keyboard | Mouse/keyboard | Keyboard | Keyboard |
| Synchronized<br>Patient Video | Yes | | | Yes |
| Seizure Event<br>Marking | Yes | | Yes | |
| Spike Event<br>Marking | Yes | | Yes | |
| Apnea Event<br>Marking | Yes | Yes | | |
| Desaturation Event<br>Marking | Yes | Yes | | |
| PLM Marking | Yes | Yes | | |
| Staging/scoring<br>method | Manual/computer<br>assisted | Manual/computer<br>assisted | | |
| Sleep Report<br>Parameters | Yes | Yes | | |
| Epilepsy<br>Parameters | Yes | | Yes | Beehive 7 |
#### 6 Discussion:
The TWin PLUS software is primarily a composite of the three referenced substantially equivalent devices with enhanced capacity permitted by the state-of-the-art in electronic data handling. Faster computers, less expensive disk capacity and multi-tasking operating systems have permitted combining all the figatives, of the referenced products into a single useful modular software package.
None of the products features have any impact on the safety of the patient or operator. Although both TWin PLUS and GRASS GAMMA (NIGHT VISION) have the capability to control the data aquisition
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amplifier settings, neither are required for the safe operation of the amplifiers that they are designed to control, nor are they capable of impacting on the safety of the amplifier systems.
All of the products are designed to be operated by trained medical professionals and the data collected is reviewed in its entirety by trained medical professionals. None of the products claims to be in and of itself "diagnostic".
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Image /page/5/Picture/1 description: The image shows the logo for the Department of Health & Human Services USA. The logo consists of a stylized eagle with three stripes forming its body and wing. The eagle is facing right. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES USA" is arranged in a circular fashion around the eagle.
Food and Drug Administration 10903 New Hampshire Avenue Document Control Room -WO66-G609 Silver Spring. MD 20993-0002
Mr. John B. Chatten President Grass-Telefactor Division Astro-Med, Inc. West-Warwick. Rhode Island 02893
Re: K012976
Trade/Device Name: Grass-Telefactor Twin PLUS Software Regulation Number: 21 CFR 882.1400 Regulation Name: Electroencephalograph Regulatory Class: II Product Code: OLV, GWQ Dated (Date on orig SE ltr): December 7, 2001 Received (Date on orig SE Itr): December 11, 2001
APR - 9 2012
Dear Mr. Chatten:
This letter corrects our substantially equivalent letter of February 12, 2002.
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 - Mr. John B. Chatten
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/CDRHQffices/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/ReportalProblem/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/Resourcesfor You/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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12012976 510(k) Number (if known):
Device Name: _TWIN_Plus
Indications for Use:
This software is intended for use by qualified research and clinical professionals with specialized training in the use of EEG and PSG recording instrumentation for the digital recording, playback, and analysis of physiological signals. It is suitable for digital acquisition, display, comparison, analysis, and archiving of EEG potentials and other rapidly changing physiological parameters.
(PL.FASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IIT NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODDE)
Miriam C. Provost
(Division Sign-Off) Division of General, Restorative and Neurological Devices
510(k) Number K012976
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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.