1. To determine the activation timing of muscles. a) retraining of muscle activation b) coordination of muscle activation 2. An indication of the force produced by muscle a) control and maintenance of muscle contractions 3. For use in relaxation training and muscle re-education.
Device Story
Portable EMG device measures bioelectrical muscle signals via surface electrodes; processes signals to provide quantitative feedback. Features auto-ranging for signal scaling; custom LCD displays analog bar charts of muscle activity. Includes audible tone feedback for target muscle activity levels (within or exceeding limits). Used by healthcare professionals for muscle re-education, relaxation training, and coordination exercises. Provides real-time visual and auditory feedback to assist patients in controlling muscle tension; enables monitoring of training progress via stored session data.
Clinical Evidence
No clinical data provided; bench testing only. Comparative specifications provided against predicate devices regarding input impedance, CMRR, frequency ranges, and display features.
Technological Characteristics
Portable EMG monitor; 1 or 2 channels; 15Hz-300Hz frequency range (12dB/Octave filter); >100dB CMRR at 50/60Hz; >120dB CMRR over frequency; 1uV-2000uV input range; 1,000,000 M Ohm input impedance. Custom LCD display; silicone keypad controls; 3V battery power (AA cells).
Indications for Use
Indicated for patients requiring muscle re-education, relaxation training, coordination of muscle activation, and monitoring of muscle contraction force.
Regulatory Classification
Identification
A biofeedback device is an instrument that provides a visual or auditory signal corresponding to the status of one or more of a patient's physiological parameters (e.g., brain alpha wave activity, muscle activity, skin temperature, etc.) so that the patient can control voluntarily these physiological parameters.
Special Controls
*Classification.* Class II (special controls). The device is exempt from the premarket notification procedures in subpart E of part 807 of this chapter when it is a prescription battery powered device that is indicated for relaxation training and muscle reeducation and prescription use, subject to § 882.9.
Predicate Devices
The Prometheus Group Pathway II Electromyography (K891732)
{0}------------------------------------------------
Image /page/0/Picture/2 description: The image shows the seal for the Department of Health & Human Services - USA. The seal is circular, with the text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" arranged around the perimeter. In the center of the seal is a stylized eagle emblem, with three curved lines representing the eagle's body and wings. The emblem is black and white.
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
SEP 2 6 1997
Mr. Joe Elrod Manager of Regulatory Affairs Chattanooga Group, Inc. 4717 Adams Road P.O. Box 489 37343-0489 Hixson, Tennessee
K972487 Re : EMG Retrainer Trade Name: Regulatory Class: II 84HCC Product Code: June 5, 1997 Dated: Received: July 2, 1997
Dear Mr. Elrod:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 A substantially equivalent determination assumes compliance to 895. with the Good Manufacturing Practice for Medical Devices: General (GMP) requlation (21 CFR Part 820) and that, through periodic GMP inspections, the Food and Drug Administration (FDA) will verify such Failure to comply with the GMP regulation may result in assumptions. regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any
{1}------------------------------------------------
Page 2 - Mr. Joe Elrod
obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or requlations.
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4648. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or at (301) 443-6597.
Sincerely yours,
Thomas J. Callahion
Thomas J. Callanan, Ph.D. Director Division of Cardiovascular, Respiratory, and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
{2}------------------------------------------------
### 510(k) Number (if known): K972487
| Device Name: | Chattonooga Group, Inc. |
|----------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Indications For Use: | 1. To determine the activation timing of muscles.<br>a) retraining of muscle activation<br>b) coordination of muscle activation<br>2. An indication of the force produced by muscle<br>a) control and maintenance of muscle contractions<br>3. For use in relaxation training and muscle re-education. |
(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
Atte Heif for DB Stillman
(Division Sign-Off) Division of Cardiovascular, Respiratory, and Neurological Devices 510(k) Number K 972487
Over-The-Counter Use _________
Prescription Use X (Per 21 CFR 801.109)
OR
{3}------------------------------------------------
K972487
Sept. 26, 1997
**510(K) SUMMARY**
CHATTANOOGA
GROUP, INC.
June 5, 1997 Date: Contact Person: Joe Elrod EMG Retrainer Product: Diagnostic Electromyograph Classification Name: Class II Classification:
This 510(k) summary of safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990.
Substantial Equivalence: The new device is a stand alone portable device for the measurement of muscle activity. It is similar to The Prometheus Group Pathway II Electromyography (510(k) K891732), Verimed Myoexerciser II (510(k) K892649), Reference Comparative and Thought Technology Myotrac (510(k) K915858). Specifications on page 2-2}.
System Description: The EMG Retrainer is a device used to measure the bioelectrical signals produced by muscle activity. The main display will register activity and display the quantitative measurement with an analog bar display. Targets of muscle activity may be stored (utilizing audible signals on demand) configurable for activity that is within established limits or exceeding those limits depending on user preference. The EMG Retrainer also contains an auto-ranging function which eliminates manual scale adjustments unless that is the preference. The auto-ranging feature as well as the targeting function are not available on the other models and will be quite useful to the healthcare professional.
Intended Use: The EMG Retrainer measures electrical activity of the muscle . Since the electrical activity of the muscle increases as the muscle tension increases and decreases as muscle tension decreases, EMG can provide information about the state of muscle tension.
> Chattanooga Group, Inc. 4717 Adams Road P.O. Box 489 Hixson, TN 37343-0489 Phone: 423-870-2281 Fax: 423-874-0287
{4}------------------------------------------------
# COMPARATIVE SPECIFICATIONS
| Feature | VERIMED | Myotrac | Prometheus<br>Pathway | Chattanooga<br>Single & Dual<br>EMG |
|------------------------|----------------------------------------------------|-----------------------------------------------------------------|------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------|
| Product Name | Myoexerciser II | 4001 | MR20 | EMG |
| Pickup Config | individual electrodes | Triangular Pattern | DeLuca in-line<br>or Proprietary | Triangular or individual<br>electrodes |
| Active Head | No | Yes | Yes for Proprietary | No |
| Input Imped. | >10M ohm | 1,000,000 M ohm | unknown | 1,000,000 M Ohm with 4pF |
| Input Noise | | | | <1uV RMS |
| Display Type | 4 lines x 20 characters<br>5 lines x 25 characters | 13 LED Dot Bar chart | 16 char LCD histograms<br>with log output<br>4 LED s | Custom LCD, dual 25 Seg Bar<br>Chart<br>plus overflows, 3 by 7seg digit<br>signal level per channel, plus<br>volume, & progr. Select digit |
| Operator Controls | 12 Membrane Buttons | Volume & Gain Knobs<br>Range Slide Switch<br>Mode/On/Off switch | 6 Membrane Buttons | 5 Silicone Keypad Buttons;<br>On/Off;<br>Up, Down, Select & OK |
| Channels | 2 | 1 | 2 | 1 or 2 |
| Frequency Ranges | 25 to 1000Hz | 100 to 200Hz<br>20 to 500Hz | 20 to 500 Hz<br>"no notch filter" | 15Hz to 300Hz<br>(12db/Octave filter) |
| Buzzer | yes | Yes | Yes | 3 Tone |
| Output Voltage | yes | Yes 0 to 2V | No (data by comms) | No |
| CMRR<br>50 Hz, 60 Hz | 140dB | >180 dB | unknown | >100db |
| CMRR<br>over frequency | 120dB | >130 dB | >110 dB | >120db |
| Input Ranges<br>(rms) | 8 ranges | 0.8 to 20uV<br>0.8 to 200uV<br>0.8 to 2000uV | 1 to 800 uV<br>true RMS | 1uV to 2000uV<br>Internal auto gain selection<br>8 Ranges |
| Electrode Wire | 2 core + Screen | 2 core + Screen | 4 conductors | 2 core + Screen |
| Earpiece | yes | Yes, 2.5mm Phono<br>8 to 32 Ohm | Yes | Yes<br>2.5mm Phono |
| Threshold | | Above & Below | Above & Below<br>& Difference | Above, Below & At Target per<br>channel |
| Threshold<br>Features | | N/A | Separate Hi/Lo indicating<br>Leds | Bar Chart Dynamic Indication,<br>set by manual, direct activity or<br>% of activity. |
| Threshold Lock | | 4 seconds then switch to<br>deactivate | unknown | Yes, Dynamic Threshold<br>Setting |
| Continuous<br>Alarm | Yes, Varying pulse rates | Yes | unknown | Yes, Varying pulse rates |
| Stimulator | yes | No | Isolated Relay | No |
| Historical Record | yes | N/A | 32 Training Sessions | 9 training sessions |
| Battery Type | 9V | 9V | 9V | 3V Using AA cells |
| Battery<br>Compartment | Slide open | Slide open | Slide open | Slide open |
| Power<br>Consumption | | 6 to 11 mA<br>Alkaline for 50 hrs | unknown<br>Battery for 25Hrs | 10 mA w/ Management power<br>Carbon, Alkaline or Ni Cad |
| Dimensions | 85W*140L*30H | 61W*112L*28H | 117*69*38mm | 81W*84L*40D |
| Weight | 180g | 70 g+bat. | 280g | 150g |
| Pocket Clip | Yes | Yes | Yes | Yes |
ﺮ
{5}------------------------------------------------
Food and Drug Administration 9200 Corporate Boulevard Rockville MD 20850
SEP 2 6 1997
Mr. Joe Elrod Manager of Regulatory Affairs Chattanooga Group, Inc. 4717 Adams Road P.O. Box 489 Hixson, Tennessee 37343-0489
K972487 Re : EMG Retrainer Trade Name: Regulatory Class: II Product Code: 84HCC June 5, 1997 Dated: Received: July 2, 1997
Dear Mr. Elrod:
We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to 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). 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.
If your device is classified (see above) into either class II (Special Controls) or class III (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Good Manufacturing Practice for Medical Devices: General (GMP) regulation (21 CFR Part 820) and that, through periodic GMP inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note: this response to your premarket notification submission does not affect any
{6}------------------------------------------------
Page 2 - Mr. Joe Elrod
obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or regulations.
This letter will allow you to begin marketing your device as described in your 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
If you desire specific advice for your device on our labeling requlation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at (301) 594-4648. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at (301) 594-4639. Also, please note the requlation entitled, "Misbranding by reference to premarket notification" (21 CFR 807.97). Other general information on vour responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number (800) 638-2041 or at (301) 443-6597.
Sincerely yours,
Thomas J. Callahon
Thomas J. Callaman, Ph.D. Director Division of Cardiovascular, Respiratory, and Neurological Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
{7}------------------------------------------------
### 510(k) Number (if known): K972487
| Device Name: | Chattanooga Group, Inc. |
|----------------------|---------------------------------------------------------------------------------------------------------------------------------|
| Indications For Use: | 1. To determine the activation timing of muscles.<br>a) retraining of muscle activation<br>b) coordination of muscle activation |
| | 2. An indication of the force produced by muscle<br>a) control and maintenance of muscle contractions |
| | 3. For use in relaxation training and muscle re-education. |
## (PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation (ODE)
for DB Tillman
(Division Sign-Off) Division of Cardiovascular, Respiratory, and Neurological Devices 510(k) Number 972487
Prescription Use X (Per 21 CFR 801.109)
OR
Over-The-Counter Use_
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.