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QbTest provides clinicans with objective measurements of hyperactivity, and inatention to aid in the clinical assessment of ADHD (Attention Deficit Hyperactivity Disorder) an interentions in patients with ADHD. QbTest results should be interpreted only by qualified professionals.

QbTest is a non-invasive test that has been developed to provide precise quantitative assessment of the capacity of an individual to pay attention to visual stimuli and inhibit impulses. There are three cardinal disturbances in Attention-Deficit Hyperactivity Disorder (ADHD): impaired attention, hyperactivity and impulsivity. QbTest provides an accurate and reproducible measure of an individual's capacity in each of these three domains by utilizing a consistent challenge paradigm coupled with detailed real-time measurements of behavior and performance. The fundamental core of QbTest is a computer-assisted attention and impulse control task and simultaneous recording of activity using an infrared camera for motion measurements.

The system consists of the following components:

• · Client software
• · Responder button (also referred to as responder unit)
• · Infrared camera
• · Reflective motion marker
• · User manual
• Technical manual
• · Stimulus card
• · Camera stand
• · Measuring tape
• · QbTest Behavior Rating Scale
• · In addition, the user must have access to a remote server that generates test reports

Here's a breakdown of the acceptance criteria and the study information for the QbTest device, based on the provided 510(k) summary:

QbTest Acceptance Criteria and Performance Study Summary

1. Table of Acceptance Criteria and Reported Device Performance

The 510(k) summary does not explicitly state formal "acceptance criteria" in terms of predefined thresholds for performance metrics. Instead, it presents the results of clinical studies to demonstrate the device's ability to measure treatment effects in ADHD. The key performance indicators used are Effect Size (ES) and Agreement (NPA, PPA) with established clinical rating scales.

Important Note: The document explicitly states: "Although the ES in the above studies all show large treatment effects they must be interpreted with caution since two of the studies did not include a concurrent control arm." It also mentions, "The registry study showed statistically significant but low correlations between QbTest and the clinically validated rating scales (RS)." This suggests that while effects are detectable, agreement is not perfect, necessitating clinical evaluation alongside QbTest results.

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

The "test set" in this context refers to the data used for the clinical performance evaluation for the expanded intended use (evaluation of treatment interventions).

• Registry Study (comparing QbTest with Rating Scales):

  • Pooled Cohort: 115 patients (42 children/adolescents + 73 adults)
  • Child Cohort: 42 children/adolescents (mean age 11.5, 35 male, 7 female)
  • Adult Cohort: 73 adults (mean age 35, 41 male, 32 female)
  • Data Provenance: Retrospective, from clinical centers. The child cohort consisted of Swedish children, and the adult cohort consisted of Dutch adults.

• Other Published Clinical Studies (evaluating responsiveness/effect size):

  • Study 5 (Atomoxetine vs. Placebo): 128 children with ADHD (mean age 9.0)
  • Study 6 (Methylphenidate, Dexamphetamine vs. Placebo): 36 medication-naïve children (aged 9-14 years)
  • Study 7 (Methylphenidate in Adults): 23 adults

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

• The ground truth for the Effect Size (ES) was based on the change from baseline in QbTest metrics itself or in the ADHD Rating Scales (RS). The clinical diagnosis of ADHD and assessment of treatment response using rating scales would have been performed by "qualified professionals" as stated in the intended use.
• For the Agreement with Rating Scales, the "ground truth" for the rating scales (RS) was implicitly established by the application of those scales by clinicians.
• The document does not specify the number or specific qualifications (e.g., number of years of experience) of the experts/clinicians who established the diagnoses or administered the rating scales in these studies. It only refers to "qualified professionals."

4. Adjudication Method for the Test Set

• The document does not describe an explicit adjudication method for establishing ground truth from multiple experts for the clinical studies mentioned.
• For the comparison between QbTest and Rating Scales, the methods are compared directly, meaning the "ground truth" for each is independently derived (QbTest metrics vs. RS scores). The agreement (NPA/PPA) is essentially a comparison rather than an adjudication.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and the Effect Size of How Much Human Readers Improve with AI vs. Without AI Assistance

• No, an MRMC comparative effectiveness study was not described. The QbTest is described as a diagnostic aid that provides "objective measurements" to supplement clinical assessment, not as an AI system assisting human readers/clinicians in interpreting other data. The studies focused on the device's standalone ability to detect treatment effects and its correlation with traditional rating scales.

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

• Yes, a standalone performance assessment was done in the sense that QbTest's measurements and the derived "Q-scores" are direct outputs of the device's algorithms based on patient behavior and performance during the task. The effect sizes reported for QbTest are based solely on these objective measurements, demonstrating its standalone capacity to detect changes due to treatment.
• The comparison with Rating Scales in the registry study also assesses the standalone performance of QbTest against another established standalone method (RS).

7. The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc.)

• The primary "ground truth" in these studies consists of clinical diagnoses of ADHD (DSM-IV criteria mentioned) and changes in symptoms and behavior due to treatment, as measured by:
  • QbTest's objective metrics (Time active, Distance, Area, Microevents, Reaction Time Variation, Omission Errors, Commission Errors).
  • Clinically validated Rating Scales (RS) for ADHD, with a specific, clinically-derived threshold for "meaningful response" (-30% change).
  • In placebo-controlled studies, the "ground truth" for treatment effect is the difference in outcomes between the active treatment group and the placebo group.

8. The Sample Size for the Training Set

• The document does not explicitly describe a "training set" for the QbTest device's core algorithms. The QbTest is presented as a system that provides quantitative measurements based on standardized tasks and infrared motion tracking.
• The studies mentioned are for the validation of the device's ability to measure treatment effects, not for training a machine learning model. The algorithms for calculating QbTest metrics and Q-scores are expected to be established during the device's development, prior to these clinical validation studies.

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

• As no explicit training set for a machine learning model is mentioned, there is no information provided on how ground truth for a training set was established.

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