(127 days)
The Test of Variables of Attention (T.O.V.A.) provides healthcare professionals with objective measurements of attention and inhibitory control, which aid in the assessment of attention deficits, including attention-deficit/hyperactivity disorder (ADHD). T.O.V.A. results should only be interpreted by qualified healthcare professionals.
The Test of Variables of Attention (T.O.V.A.) is an accurate and objective continuous performance test (CPT) that measures the key components of attention and inhibitory control. The T.O.V.A. is used by qualified healthcare professionals in the assessment of attention deficits, including attention-deficit/hyperactivity disorder (ADHD), in children and adults.
The T.O.V.A. is a culture- and language-free, sufficiently long computerized test that requires no left/right discrimination or sequencing. Responses to visual or auditory stimuli are recorded with a specially designed, highly accurate (±1 ms) microswitch. The T.O.V.A. calculates response time variability (consistency), response time (speed), commissions (impulsivity), and omissions (focus and vigilance). These calculations are then compared to a large age- and gender-matched normative sample (over 1,700 individuals for the visual test, and over 2,500 individuals for the auditory test), as well as to a sample population of individuals independently diagnosed with ADHD. These comparison results are used to create an immediately available, easy-to-read report.
The T.O.V.A. system includes: a USB flash drive with software installer for Mac and Windows PCs, a T.O.V.A. USB device, a T.O.V.A. Microswitch, an Installation Guide, a User's Manual, a Clinical Manual, and accessory cables (USB, VGA, and audio cables).
Here's a breakdown of the acceptance criteria and study information for the Test of Variables of Attention (T.O.V.A.) version 9.0 device, based on the provided text:
Acceptance Criteria and Device Performance
The provided text focuses on the device's adherence to safety, essential performance, and electromagnetic compatibility (EMC) standards rather than clinical performance metrics for diagnosing ADHD. The acceptance criteria essentially stem from proving substantial equivalence to the predicate device, the Gordon Diagnostic System Model I (K854903), in these engineering and regulatory aspects.
| Acceptance Criterion (Test) | Reported Device Performance (Results) |
|---|---|
| IEC 60601-1:2005 "Medical electrical equipment - Part 1: General requirements for basic safety and essential performance" | The T.O.V.A. passed the state of the art for electrical safety and functional testing. It is considered equivalent or better in safety and functionality compared to the predicate GDS. |
| IEC 60601-1-2:2014 "Medical electrical equipment - Part 1-2: General requirements for basic safety and essential performance - Collateral Standard: Electromagnetic disturbances - Requirements and tests" | The T.O.V.A. passed the state of the art for electromagnetic compatibility and electromagnetic immunity testing. It is considered equivalent or better in electrical performance compared to the predicate GDS. |
| T.O.V.A. Verification Testing (Software functionality) | The T.O.V.A. functioned as intended, passing all major verification tests as described in "Section 16 – Software", specifically the "Verification and Validation Summary ("VVS01")". Minor unresolved anomalies were found and listed. The device is deemed equivalent or even more rigorously verified compared to the GDS (for which no equivalent verification tests were listed in its 1989 510(k)). |
Study Information Pertaining to Device Verification and Validation:
The document primarily describes a set of verification and validation activities rather than a clinical study evaluating diagnostic performance. The focus is on demonstrating that the T.O.V.A. 9.0 functions correctly and meets established engineering standards and design requirements.
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Sample Size used for the test set and data provenance:
- IEC 60601-1:2005 & IEC 60601-1-2:2014: These tests involve the physical device itself and do not typically use "patient samples." The "test set" here refers to the device prototypes subjected to standardized electrical and functional tests.
- T.O.V.A. Verification Testing: This involved the T.O.V.A. system (software and hardware). The "test set" refers to the various functions and modules of the software and hardware that were tested according to a detailed matrix of requirements. No human participant data is mentioned for these verification tests.
- Normative Data: While not a "test set" for performance evaluation against a gold standard in the context of device accuracy, the device's internal comparison data uses a large normative sample:
- Visual test: over 1,700 individuals
- Auditory test: over 2,600 individuals
- These normative samples were described as "age- and gender-matched" and "non-ADHD individuals." The provenance (country of origin, retrospective/prospective) is not specified in the provided text.
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Number of experts used to establish the ground truth for the test set and their qualifications:
- For the engineering and software verification tests described (IEC standards, T.O.V.A. Verification Testing), the "ground truth" is defined by the technical specifications of the standards and the design requirements. The "experts" would be the certified test engineers at the third-party facilities (UL, Inc. and Element, Inc.) and The TOVA Company's internal design and quality assurance teams, who assess compliance with these objective standards. Specific qualifications beyond being "third-party test facilities" are not detailed.
- Regarding the normative data used by the device (not to test the device's diagnostic accuracy directly), the text mentions "a sample population of individuals independently diagnosed with ADHD." However, it does not specify the number or qualifications of experts who established these independent ADHD diagnoses.
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Adjudication method for the test set:
- For the engineering and software verification tests, the adjudication method is typically direct assessment against the defined standard or requirement. There isn't an "adjudication method" in the sense of multiple experts reviewing cases to establish a clinical ground truth.
- For the normative data and the "independently diagnosed with ADHD" population, the adjudication method for the ADHD diagnosis itself is not described.
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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 MRMC comparative effectiveness study is mentioned in the provided text. The T.O.V.A. device provides objective measurements to aid in assessment by healthcare professionals; it is not described as an AI-assisted diagnostic tool where human readers improve with its assistance in the typical sense of interpreting images or complex data with AI overlays. Its function is to generate objective metrics for a clinician's interpretation.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- The T.O.V.A. is described as providing "objective measurements" that "aid in the assessment of attention deficits." It explicitly states that "T.O.V.A. results should only be interpreted by qualified healthcare professionals." This indicates it's designed as a tool for a human-in-the-loop workflow, not as a standalone diagnostic device. Therefore, a standalone performance study in a diagnostic capacity would not be applicable or described for this device.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For the engineering tests, the ground truth is compliance with the IEC 60601-1 and IEC 60601-1-2 standards and the device's own design specifications (for verification testing).
- For the context of the device's internal comparisons, it uses a "normative sample" of "non-ADHD individuals" and a "sample population of individuals independently diagnosed with ADHD." The ground truth for these populations is derived from clinical diagnosis (likely expert consensus or established diagnostic criteria for ADHD), though the specifics are not detailed.
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The sample size for the training set:
- The document does not describe a machine learning algorithm that requires a "training set" in the conventional sense. The T.O.V.A. functions by comparing an individual's performance to existing "normative data." This normative data could be considered analogous to a "training set" for establishing typical ranges.
- Visual normative data: 1,714 individuals
- Auditory normative data: 2,680 individuals
- The document does not describe a machine learning algorithm that requires a "training set" in the conventional sense. The T.O.V.A. functions by comparing an individual's performance to existing "normative data." This normative data could be considered analogous to a "training set" for establishing typical ranges.
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How the ground truth for the training set was established:
- For the normative data (analogous to a training set), the ground truth for these individuals was established as "non-ADHD individuals." This implies that they were clinically confirmed not to have ADHD. The specific diagnostic process or criteria used to classify these "non-ADHD" individuals are not detailed in the provided text. It is reasonable to assume this was established through standard clinical diagnostic procedures, excluding individuals with an ADHD diagnosis.
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