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The IB-Stim is a percutaneous electrical nerve field stimulator (PENFS) system intended to be used in patients 11-18 years of age with functional abdominal pain associated with irritable bowel syndrome (IBS). The IB-Stim is intended to be used for 120 hours per week up to 3 consecutive weeks, through application to branches of Cranial Nerves V, VII, IX and X, and the occipital nerves identified by transillumination, as an aid in the reduction of pain when combined with other therapies for IBS.

The IB-Stim is a device that delivers electrical stimulation through percutaneous electrodes to areas usually innervated by branches of occipital nerves and cranial nerves V, VII, IX and X that are located by transillumination. The device consists of (1) a percutaneous electrical nerve field stimulator (PENFS), (2) a multi-pin wire harness percutaneous electrode array, and (3) a pen light for use in the transillumination technique that aids in positioning of the percutaneous electrodes (Figure 1).

The wire harness percutaneous electrode array consists of 4 leads. The 1-1-1-4 configuration consists of three single-needle leads, and one 4-needle array (Figure 2).

The stimulator is placed behind the ear and the percutaneous electrodes are positioned utilizing the transillumination function of the device (Figure 1). The transillumination technique assists in the visualization of the vasculature of the ear to aid in the placement of the percutaneous electrodes near the nerve branches in the ear.

The provided text describes the regulatory evaluation of the IB-Stim device, a non-implanted nerve stimulator for functional abdominal pain relief associated with Irritable Bowel Syndrome (IBS) in adolescents. The document outlines the studies conducted to establish the device's safety and effectiveness.

It is important to note that the IB-Stim is a medical device performing nerve stimulation, not an AI/ML powered device. Therefore, typical acceptance criteria and study designs for AI/ML devices (e.g., mMRMC studies, stand-alone algorithm performance, ground truth establishment through expert consensus or pathology for image classification, separate training and test sets the way an AI/ML device would need them, etc.) are NOT directly applicable to this device.

The "acceptance criteria" for the IB-Stim are essentially the demonstration of safety and clinical effectiveness as outlined by the FDA's De Novo classification process, largely evidenced through a randomized, double-blind, sham-controlled clinical trial and various non-clinical tests.

Here's an attempt to structure the information according to your request, adapting the concepts to fit a medical device rather than an AI/ML system:

Acceptance Criteria and Device Performance for IB-Stim

The acceptance criteria for the IB-Stim device are based on demonstrating its safety and effectiveness for its intended use, as required by FDA for a De Novo classification. This is primarily achieved through non-clinical testing and a pivotal clinical trial.

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size and Data Provenance

• Clinical Trial Test Set Sample Size:
  • Total randomized: 115 subjects (60 active treatment, 55 sham treatment).
  • Completed the trial (primary analysis cohort): 104 subjects (57 active, 47 sham).
  • IBS Subgroup Analysis (post-hoc, for final indication): 51 subjects met Rome III criteria for IBS at baseline. 50 of these completed the study (27 active IB-Stim, 23 sham). This IBS subgroup formed the basis for the specific indication granted.
• Data Provenance: The study was a randomized, double-blind, sham-controlled clinical trial. It is stated to be published in Lancet Gastroenterol Hepatol in 2017, suggesting it was a prospective clinical trial. The location of the clinical trial (country of origin) is not explicitly stated in the provided text, but the authors listed (K. Kovacic, etc.) typically indicate US-based research centers.

3. Number of Experts and Qualifications for Ground Truth

• The "ground truth" in this context refers to the patient-reported outcomes of pain and symptom scores (e.g., worst pain, PFSD, SRS). These are direct measures from the participants themselves, not interpretations by experts.
• The diagnosis of functional abdominal pain, including IBS, was based on established clinical criteria (Rome III criteria for IBS) by the clinicians conducting the study. The number or specific qualifications of these clinicians are not detailed as "experts establishing ground truth" in the way it would be for, e.g., image annotation.

4. Adjudication Method for the Test Set

• Adjudication methods (e.g., 2+1, 3+1) are typically used for establishing ground truth in AI/ML model training or evaluation where human reviewers provide labels or assessments that need to be reconciled.
• This was a clinical trial with patient-reported outcomes. While there would be standard operating procedures for data collection and monitoring, there was no "adjudication" in the sense of reconciling disagreeing expert labels. The "ground truth" was the direct patient report and clinical diagnosis.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• An MRMC study evaluates the performance of multiple human readers on multiple cases, often comparing performance with and without AI assistance.
• No MRMC study was performed as this is a medical device for direct patient treatment, not an AI-based diagnostic tool that assists human readers in interpreting data or images. The study design was a standard randomized controlled trial comparing the device to a sham control.

6. Standalone (Algorithm Only) Performance

• "Standalone performance" refers to the performance of an algorithm without human-in-the-loop.
• Not applicable to this device. The IB-Stim is a physical medical device that delivers electrical stimulation to a patient. Its functionality is inherently tied to its application to a patient's body under clinical guidance. There is no "algorithm only" component that could be evaluated for standalone performance.

7. Type of Ground Truth Used

• The primary ground truth for effectiveness was patient-reported outcome data (pain scores, symptom improvement) collected during the clinical trial.
• The patient cohort was defined by clinical diagnostic criteria (Rome III for IBS) established by medical professionals.

8. Sample Size for the Training Set

• Not applicable in the context of AI/ML. The IB-Stim design and functionality are based on medical principles and prior devices, not on machine learning from a "training set." The clinical trial data (the "test set" in your original framework) was used to demonstrate safety and effectiveness for regulatory approval.

9. How Ground Truth for Training Set was Established

• Not applicable as there is no "training set" for an AI/ML model. The device's design and parameters (e.g., electrical characteristics, duty cycle) were based on existing medical understanding of nerve stimulation and were verified through bench testing. The clinical trial then assessed the device's efficacy in a target patient population.

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The NSS-2 BRIDGE is a percutaneous nerve field stimulator (PNFS) system, that can be used as an aid to reduce the symptoms of opioid withdrawal, through application to branches of Cranial Nerves V, VII, IX and X, and the occipital nerves identified by transillumination.

NSS-2 BRIDGE is a device that electrically stimulates branches of Cranial Nerves V. VII. IX and X, and the occipital nerves identified by transillumination through percutaneous electrodes to aid in the reduction of opioid withdrawal symptoms. The device consists of (1) a percutaneous nerve field stimulator (PNFS; Figure 1), (2) a multi-pin wire harness percutaneous electrode array (Figure 2), and (3) a pen light for use in the transillumination technique that aids in positioning of the percutaneous electrodes (Figure 3).

Acceptance Criteria and Study for NSS-2 BRIDGE

1. Table of Acceptance Criteria and Reported Device Performance

2. Sample Size for Test Set and Data Provenance

• Sample Size: 73 patients.
• Data Provenance: Retrospective study. Data was collected from participating outpatient drug treatment clinics located across five US states: St. Louis, MO (27 patients), Liberty, IN (13), Florence, KY (12), Anchorage, AK (9), Rising Sun, IN (6), Richmond, IN (2), Dayton, OH (2), and Indianapolis, IN (2).

3. Number of Experts and Qualifications for Ground Truth

The study does not mention the use of experts to establish ground truth for the test set. The ground truth for opioid withdrawal symptoms was established through the Clinical Opioid Withdrawal Scale (COWS) scores, which were recorded as part of the treatment protocol in the participating clinics. These scores are obtained by medical professionals (e.g., clinicians, nurses), but the study does not specify their exact qualifications or the number of individuals involved in scoring each patient. The COWS is a standardized, subjective assessment tool.

4. Adjudication Method for the Test Set

The study does not mention any specific adjudication method for the COWS scores in the test set. Scores were "recorded" and "extracted from the medical chart," implying a single assessment per time point per patient.

5. Multi Reader Multi Case (MRMC) Comparative Effectiveness Study

No, a Multi Reader Multi Case (MRMC) comparative effectiveness study was not done. The study was a single-arm, open-label retrospective study, evaluating the device's effect without a direct comparison to human readers' performance with and without AI assistance or a control group receiving no intervention/placebo in the same manner.

6. Standalone (Algorithm Only) Performance Study

No, a standalone (algorithm only) performance study was not done. The device (NSS-2 BRIDGE) is a hardware device that electrically stimulates nerves; it does not involve an AI algorithm to analyze data or provide a diagnosis. Its performance is directly tied to its physical application and electrical stimulation.

7. Type of Ground Truth Used

The ground truth used was expert assessment using a standardized clinical scale, specifically the Clinical Opioid Withdrawal Scale (COWS). The COWS is a widely recognized tool for assessing the severity of opioid withdrawal symptoms, typically administered by trained healthcare professionals. While not "pathology" or "outcomes data" in the direct sense of a biological marker, it represents a clinical judgment based on observable signs and reported symptoms.

8. Sample Size for the Training Set

The document does not define a "training set" in the context of this device's effectiveness study. The NSS-2 BRIDGE is a medical device, not an AI/machine learning algorithm requiring a distinct training phase with a dedicated dataset. The clinical study described served as the primary evidence for its efficacy for regulatory purposes.

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

As there was no distinct "training set" for an AI/ML algorithm, this question is not applicable. The device's mechanism of action is electrical stimulation, not a learned algorithm.

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