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The Active Signal A SCOPE (or noise-immune stethoscope) is intended for medical diagnostic purposes only. It may be used for the detection and amplification of acoustic signals generated by physiologic activity in the body. In the presence of relatively mild ambient noise it is used in Acoustic Mode and functions as a passive electronic stethoscope to receive sounds produced by the heart, lungs, bowel and other internal organs. To retain audibility at higher sound levels it is switched to Doppler Mode where an audible tone is produced by the ultrasound frequency-shift caused by motion of the heart and lungs.

It can be used on any person undergoing a physical assessment. It is not intended to be used for diagnosis and treatment by unlicensed, untrained, or unqualified medical persons.

Active Signal's stethoscope combats noise intrusion through use of two modes of operation depending on the intensity of background noise:

1. In the presence of relatively benign ambient noise (loud accident scenes, ambulances, emergency rooms, civilian Medevac helicopters, etc.) the device is configured as an amplified electronic stethoscope employing a passive piezoelectric sensor. Noise rejection is imparted by design of the piezoelectric element and mass of the housing.

2. When the ambient sound levels exceed the passive sensing limit, an active Doppler mode is engaged. This transposes the detection of vital physiological sounds from the audio frequency range (used by conventional or electronic stethoscopes) where physiological sounds typically overlap the background noise and hence are swamped out, to ultrasound which puts the measurement into an entirely different frequency band.

DEVICE CONFIGURATION: The top section of the device is the battery compartment, which contains two 1.5V AA-cells.

The device is held between the index and middle fingers, with the thumb free to operate a 4-button control panel shown at here. The bottom section contains the stethoscope sensors and signal-processing electronics. For operation as a passive amplified electronic stethoscope (Mode 1, above), a tall column of piezoelectric ceramic material is used as the sensing element contacting the center of the front face. At the top, this column is pressed against the stethoscope's casing. For the active ultrasound-Doppler mode of operation (Mode 2, above), two semicircle-shaped disks, made of piezoelectric material, are embedded in the sensor head, where one functions as a transmitting and the other as a receiving transducer. Details of the mounting geometry, the gap size between the discs and the gap orientation, and also the carrier frequency, determine the width of the sound beam and its penetration depth.

A thumb-operated 4-button control panel allows the device to be turned on (press any mode button), the signal volume to be set (+ and - buttons in the horizontal plane), and the operating mode to be selected.

Here's an analysis of the provided text regarding the A SCOPE™ electronic stethoscope, focusing on acceptance criteria and the study details:

1. Table of Acceptance Criteria and Reported Device Performance:

The document primarily focuses on establishing "substantial equivalence" to predicate devices rather than defining specific quantitative acceptance criteria or performance metrics for the A SCOPE™ itself. The acceptance criteria described are largely related to meeting regulatory standards and demonstrating
that the device performs "as intended" and is comparable to existing devices for its stated use.

"In the presence of relatively mild ambient noise it is used in Acoustic Mode and functions as a passive electronic stethoscope to receive sounds produced by the heart, lungs, bowel and other internal organs. To retain audibility at higher sound levels it is switched to Doppler Mode where an audible tone is produced by the ultrasound frequency-shift caused by motion of the heart and lungs." |
| Safety Testing | "Testing of the A SCOPE™ included ISO 60601-X Standards as they apply, bench testing, testing to applicable FDA Guidance Documents, and U.S. Army qualification testing. The A SCOPE™ has successfully completed all required testing with positive end points." |
| Substantial Equivalence (to Predicate Devices) | "The A SCOPE™ is substantially equivalent to other electronic and Ultrasound devices in the market such as the IMEX Stethodop (K973336), Pocket DOP 3 (K910462 and E-Scope (K961301)."

"Based on testing and comparison to predicate devices, the A SCOPE™ has the same intended use, and is substantially equivalent to the predicated devices. The device performs as intended." |
| Performance (General) | "The device performs as intended." |
| Noise Immunity | Claimed ability to detect heart and lung returns in very high noise level environments with Doppler technology. (This is a claim of capability for comparison, not a quantified metric). |

Summary of Device Performance (as reported and implied):

The document broadly states that the A SCOPE™ successfully completed all required testing with "positive end points" and "performs as intended." It explicitly claims the ability to detect heart and lung sounds in high-noise environments using Doppler technology. However, it does not provide specific quantifiable performance metrics such as sensitivity, specificity, accuracy, signal-to-noise ratio measurements, or comparative audibility studies. The performance is primarily asserted through its adherence to standards and substantial equivalence to predicate devices, focusing on its operational modes and intended use.

Detailed Study Information:

The provided text describes a submission for a 510(k) premarket notification, which typically focuses on demonstrating substantial equivalence to a legally marketed predicate device rather than conducting a full-scale clinical efficacy trial with specific, granular performance metrics. As such, the information you're requesting for a "study" in the traditional sense (e.g., test set, training set, ground truth) is largely not present in the provided document.

Here's what can be extracted, and what is missing:

2. Sample size used for the test set and the data provenance:

• Sample Size for Test Set: Not specified. The document mentions "bench testing" and "U.S. Army qualification testing" but does not detail the number of subjects, cases, or recordings used for evaluation.
• Data Provenance (country of origin, retrospective/prospective): Not specified. While "U.S. Army qualification testing" is mentioned, details about the origin, nature, or type of data collected during this testing are absent.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

• Number of Experts: Not specified.
• Qualifications of Experts: Not specified.
  The document does not detail any expert-driven ground truth establishment for a specific test set.

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

• Adjudication Method: Not specified.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

• MRMC Study: Not indicated. The product is an electronic stethoscope that assists in detecting sounds, not an AI-driven image analysis tool for human readers. No MRMC study or AI assistance effect size is mentioned.

6. If a standalone (i.e., algorithm only without human-in-the-loop performance) was done:

• Standalone Performance: Not explicitly detailed. The device is an electronic stethoscope intended for human use ("human-in-the-loop"). The "testing" mentioned is for the device's functional performance, but not in the context of a standalone AI algorithm's performance.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):

• Type of Ground Truth: Not specified for performance validation. The document implies that the device's ability to detect physiological sounds (heart, lungs, bowel) is the ground truth for its function, but it doesn't detail how this was independently verified or quantified during testing. The primary ground truth for its regulatory acceptance is its substantial equivalence to predicate devices.

8. The sample size for the training set:

• Sample Size for Training Set: Not applicable/specified. This device predates widespread AI/ML applications in medical devices requiring distinct training sets as described. The device is a hardware/firmware product, not a trainable AI model.

9. How the ground truth for the training set was established:

• Ground Truth for Training Set: Not applicable/specified. See point 8.

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