The Aspect Medical Systems, Inc. Zipprep™ Disposable EEG Sensor (hereafter referred to as the Aspect EEG Sensor, is a rectangular shaped, pre-gelled array of three (3) Zipprep electrodes that is applied to the patient's skin to record electro-physiological (such as EEG) signals. It is a low impedance, single patient use, disposable electrode sensor that is designed for application to the frontal/temporal area. The main body of the Aspect EEG Sensor, which houses two (2) electrodes, is placed on the forehead. The satellite, which houses one (1) electrode, is placed over the temple area.

AI/ML Overview

The provided text describes the Aspect Medical Systems, Inc. Zipprep EEG Sensor (K961821). Here's an analysis of the acceptance criteria and supporting studies based on the provided information:

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria Category	Specific Criteria	Reported Device Performance
Biocompatibility	Primary Skin Irritation	Pass; not a primary skin irritant
	Cytotoxicity	Pass; results indicate the device passes relative to its intended use
	Delayed Contact Sensitization	Results due May 31, 1996 (No final "pass" or "fail" reported in this document excerpt)
Electrical Performance	Adherence to American National Standard for Disposable ECG Electrodes (AAMI, ANSI Dec 1991)	Passed all testing in accordance with the Standard
Clinical Performance	Impedance evaluation	Performed in the manner intended
	Signal quality evaluation	Performed in the manner intended
	Usability evaluation	Performed in the manner intended
	Skin irritation evaluation	Performed in the manner intended

2. Sample Size Used for the Test Set and Data Provenance

The document mentions "A clinical evaluation was conducted at Ohio State University." However, it does not specify the sample size (number of participants/sensors) used for this clinical evaluation.

Regarding data provenance:

Country of origin: United States (Ohio State University)
Retrospective or prospective: The document does not explicitly state whether the clinical evaluation was retrospective or prospective. However, clinical evaluations are generally prospective studies designed to assess device performance in real-world or simulated clinical settings.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts

The document does not provide any information on the number of experts used or their qualifications for establishing ground truth in the clinical evaluation. The assessment of "impedance, signal quality, usability, and skin irritation" would likely involve clinicians and possibly technical experts, but their specific roles and expertise are not detailed.

4. Adjudication Method for the Test Set

The document does not describe any specific adjudication method (e.g., 2+1, 3+1, none) for the clinical evaluation. The results are summarized as indicating the sensor "performs in the manner in which it is intended," suggesting a direct assessment rather than a complex multi-reader adjudication process typically seen in image interpretation.

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

No. This document describes an EEG sensor, not an AI-powered diagnostic device or an imaging product. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable and was not performed.

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

No. The device is a physical EEG sensor, a medical accessory designed to acquire physiological signals. It does not have an "algorithm-only" performance in the sense of an AI model analyzing data. Its performance is entirely linked to its physical interaction with the patient and its ability to accurately transmit signals for human or automated interpretation.

7. The Type of Ground Truth Used

For the clinical evaluation, the "ground truth" for assessing impedance, signal quality, usability, and skin irritation would be based on:

Direct measurements: For impedance and signal quality (e.g., comparing to established benchmarks or expected physiological signals).
Clinical observation and assessment: For usability and skin irritation, likely involving qualified healthcare professionals observing application, removal, and patient skin response.
User feedback: For usability.

It is not explicitly stated as expert consensus, pathology, or outcomes data in the typical sense of AI algorithm validation.

8. The Sample Size for the Training Set

The document describes a physical medical device (an EEG sensor), not a machine learning model. Therefore, the concept of a "training set" for an algorithm is not applicable to this device. The development and testing focused on engineering specifications, biocompatibility, and clinical performance.

9. How the Ground Truth for the Training Set Was Established

As explained above, the concept of a "training set" and associated ground truth establishment is not applicable to this physical medical device.

Summary

{0}------------------------------------------------

K961821

510(k) SUMMARY Aspect Medical Systems, Inc. Zipprep EEG Sensor

Company Name

Aspect Medical Systems, Inc. 2 Vision Drive Natick, MA 01760-2059

Telephone: (508) 653-0603

Device Name/Classification

Proprietary Name:	Aspect Medical Systems Zipprep EEG Sensor
Common Name:	Electrode, Cutaneous Electrode

Cutaneous Electrodes have been classified by the Neurological Devices Panel as Class II devices. Refer to 21 CFR 882.1320.

Description

It is a low impedance, single patient use, disposable electrode sensor that is designed for application to the frontal/temporal area. The main body of the Aspect EEG Sensor, which houses two (2) electrodes, is placed on the forehead. The satellite, which houses one (1) electrode, is placed over the temple area.

Electrode Area of Sensor

The Zipprep electrode area of the Sensor is composed of a basepad with a pressure sensitive adhesive that contacts the skin. A pocket in the basepad houses the flexible tines disk, which adheres to a ring shaped piece of film. A polyurethane sponge is placed over the tines. The aqueous gel (hydrogel) is also placed in this area.

The Zipprep electrode is "self-prepping", in that no brisk skin or alcohol rub is necessary to prepare the skin to lower the impedance prior to applying the electrode. The flexible tines in the Zipprep electrodes part the outermost layer of skin while the gel flows around the tines and forms a conductive bridge with the skin.

{1}------------------------------------------------

Sensor

Two (2) Zipprep electrodes are mounted in a rectangular shaped basepad composed of polyethylene (PE) foam. The third Zipprep electrode (the satellite electrode) is mounted in a smaller, rectangular shaped basepad also composed of PE foam. On one side of the foam (the skin side) there is a pressure sensitive adhesive, which allows it to adhere to the skin with no additional taping necessary. On the other side of the PE foam there is a Mylar substrate. The electrode sections are connected by a thin strip of Mylar. Flexible circuit technology is utilized by printed silver/silver chloride ink on the Mylar substrate. A polyester insulator is used to restrict electrical contact to the element area.

The Aspect EEG Sensor has a flexible tab on one end, with a polypropylene housing designed to provide rigidity to the flexible tab.

Indications for Use

The Aspect EEG Sensor is applied directly to the patient's skin to enable recording of electro-physiological (such as EBG) signals.

Statement of Substantial Equivalence

The Aspect EEG Sensor is substantially equivalent to the following devices:

Aspect Medical Systems Zipprep™ Electrode, 510(k) #K940802 1)
NDM ECG Backpad, 510(k) #K761301 2)

Similarities

The Aspect EEG Sensor is similar to the 510(k) Aspect Zipprep Electrode in the 1) following ways:
- The indications for use are identical. O
- The technology is identical O
- Both use silver-silver chloride as the conducting material. In addition, the O following materials are the same:

Identical polyethylene basepad material Identical nylon flexible tines Identical liquid gel - hydrogel Identical silver-silver chloride conducting material

The Aspect EEG Sensor is similar to the NDM ECG Backpad in the following ways:

{2}------------------------------------------------

Fixed array of electrodes O
0 Pre-gelled
Flexible circuit technology 0

Differences

1. The Aspect EEG Sensor is different from the 510(k) Aspect Zipprep Electrode in the following minor ways:
- O The Aspect EEG Sensor has a polyurethane sponge over tines, whereas the Zipprep Electrode does not.
- The Aspect EEG Sensor has flexible Mylar circuitry with Ag/Ag Cl O conductors and a flexible tab for connection. The Zipprep Electrode has standard snap construction.
- O The Aspect EEG Sensor has no foam ring.
- 0 The Aspect EEG Sensor has a film ring located beneath the tines
- The Aspect EEG Sensor adhesive is slightly more adherent than the 0 adhesive used on the Zipprep Electrode.
1. The Aspect EEG Sensor is different from the NDM ECG Backpad in the following minor ways:
- The Aspect EEG Sensor has 3 electrodes. The NDM Backpad has 4. 0
- The Aspect Sensor is used for EEG recordings and is placed on the O forehead, whereas the NDM Backpad is used for ECG recordings and is placed on the back.
- The Aspect EEG Sensor is approximately 8.5" x 1.5". The NDM Backpad O is approximately 9" x 7".
- The Aspect EEG Sensor has Silver-silver chloride printed circuitry. The O NDM Backpad has Copper printed circuitry.

Testing

Biocompatibility testing was conducted in accordance with the International Standard ISO-10993, Biological Evaluation of Medical Devices Part I: Evaluation and Testing. Results are summarized as follows:

{3}------------------------------------------------

Primary Skin Irritation - Pass; not a primary skin irritant Cytotoxicity - Pass; results indicate the device passes relative to its intended use Delayed Contact Sensitization study - Results due May 31, 1996

Electrical testing was conducted in accordance with the American National 2) Standard for Disposable ECG Electrodes, developed by AAMI and approved in December, 1991 by ANSI. The Sensor passed all testing in accordance with the Standard.

A clinical evaluation was conducted at Ohio State University. Impedance, signal 3) quality, usability and skin irritation were evaluated. Results indicate the Aspect EEG Sensor performs in the manner in which it is intended.

રાજાતેર

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Regulation Number and Section

§ 882.1320 Cutaneous electrode.

(a)
Identification. A cutaneous electrode is an electrode that is applied directly to a patient's skin either to record physiological signals (e.g., the electroencephalogram) or to apply electrical stimulation.(b)
Classification. Class II (performance standards).