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The CRI Zmachine is a single-channel, EEG acquisition and analysis system, designed for use in the home or clinical environments. This device is intended to be used by qualified healthcare practitioners to monitor the wake and sleep states of adult patients and as an adjunct to their diagnosis of sleep disorders.

The CRI Zmachine is a battery-operated, single-channel, EEG acquisition and analysis system. The Zmachine system includes the Zmachine device, disposable EEG sensors, sensor cable, and a wall charger. The device operates on data from the differential-mastoid EEG channel to determine the wake and sleep states (wake, light sleep, deep sleep and REM) of the patient every 30 seconds.

Here's the breakdown of the acceptance criteria and study information for the Zmachine DT-200, based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria for the Zmachine DT-200 are implicitly established by demonstrating substantial equivalence to predicate devices, particularly the Sleep Profiler (K120450). The performance metrics used for comparison are P1 (sensitivity) and P2 (positive predictive value) for each sleep stage.

Note: "Similar to Predicate" is the implicit acceptance criterion. The document states, "The P1 and P2 values obtained during clinical validation of the Zmachine Algorithm are similar to those obtained by the predicate Sleep Profiler algorithm."

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

• Sample Size: 99 subjects (52 female / 47 male, 18-60 years, median age 32.7 years).
• Data Provenance: The document does not explicitly state the country of origin. It indicates the study subjects included those reporting normal sleep and those with complaints consistent with various sleep disorders. The study is described as "clinical," suggesting it's prospective, but this is not explicitly stated. It is a clinical study in which overnight laboratory polysomnographic (PSG) data was acquired.

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

• Number of Experts: Two to four (2-4) certified polysomnographic technologists.
• Qualifications of Experts: Certified polysomnographic technologists.

4. Adjudication Method for the Test Set

• Adjudication Method: Majority voting rule. The individual score files from the 2-4 technologists were combined, on a 30-second epoch basis, using a majority voting rule to generate a single score file per subject ("Human Scores").

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 MRMC comparative effectiveness study was done involving human readers with and without AI assistance. This study focused on the standalone performance of the Zmachine algorithm compared to human consensus.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done

• Yes, a standalone study was done. The Zmachine Algorithm's performance was evaluated by directly comparing its output to the "Human Scores" (ground truth). The objective was to assess the algorithm's ability to determine wake and sleep states independently.

7. The Type of Ground Truth Used

• Type of Ground Truth: Expert consensus. The ground truth, referred to as "Human Scores," was established by comparing the Zmachine Algorithm's output against the scores generated by multiple certified polysomnographic technologists using a majority voting rule, based on standard PSG channels. The scoring guidelines used were Rechtschaffen and Kales (R&K) visual sleep staging guidelines.

8. The Sample Size for the Training Set

• The document does not provide information regarding the sample size used for the training set for the Zmachine DT-200. It focuses on the clinical performance testing sample.

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

• The document does not provide information on how the ground truth for any training set was established for the Zmachine DT-200.

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