Diagnosing ADHD has traditionally relied on clinical history, questionnaires, and observational reports. These are valuable but subjective. Enter the QbTest—a computer-based assessment that provides objective, quantifiable measures of attention, impulsivity, and activity. It doesn’t replace the psychiatrist’s clinical judgment, but it adds a scientific layer of data that enriches diagnosis and monitoring.

What is the QbTest?

The QbTest (Quantified Behavior Test) is an FDA- and CE-cleared computerized test designed to support the assessment of ADHD in children, adolescents, and adults.

It combines a Continuous Performance Test (CPT) with a motion-tracking system:

• CPT component: Measures attention and impulse control by requiring the patient to respond to certain stimuli and inhibit responses to others.

• Motion tracking: An infrared camera tracks a reflective headband to quantify hyperactivity in real time.

This integration allows clinicians to see how inattention, impulsivity, and hyperactivity interact during a structured task.

What Does the QbTest Measure?

The test produces three key domains:

1. Attention

   • Number of correct vs. missed targets.

   • Reaction time and variability.

   • Ability to sustain focus over time.

2. Impulsivity

   • Number of incorrect responses (commission errors).

   • Premature responses or difficulty inhibiting actions.

3. Activity (Hyperactivity)

   • Degree, frequency, and pattern of head movements.

   • Quantitative measure of restlessness during the task.

The results are compared against normative data from age- and sex-matched control groups.

Clinical Uses of the QbTest

1. Diagnosis Support

• Helps distinguish ADHD from conditions with overlapping symptoms (anxiety, depression, learning difficulties).

• Provides a visual report that parents, teachers, and patients can easily understand.

2. Treatment Monitoring

• Before and after medication initiation, QbTest can show objective changes in attention and activity.

• Particularly useful when families are uncertain if medication is “working.”

3. Motivational Tool

• Visual feedback helps children and adults see the difference treatment makes, improving adherence.

4. Research Utility

• Provides standardized outcome measures in clinical trials of ADHD treatments.

Advantages of QbTest

• Objective data reduces sole reliance on questionnaires.

• Time-efficient (takes about 15–20 minutes).

• Engaging for children due to its game-like format.

• Trackable across multiple sessions for long-term monitoring.

• Validated in multiple studies and approved by regulatory bodies.

Limitations of QbTest

• Not a standalone diagnostic tool: ADHD remains a clinical diagnosis based on history, collateral reports, and functional impairment.

• Influenced by context: Poor sleep, anxiety, or unfamiliarity with computers can affect performance.

• Cost and availability: Requires specific equipment and licensing, not universally available.

• Cultural/educational bias: Normative data may not perfectly fit all populations, especially outside Europe/North America.

Evidence Base

• Studies show QbTest has moderate to high sensitivity and specificity in differentiating ADHD from controls.

• NICE (2018) acknowledges QbTest as a supportive tool in ADHD diagnosis and monitoring, but not a substitute for comprehensive evaluation.

• In medication monitoring, QbTest often shows clear reductions in hyperactivity and impulsivity scores after stimulant treatment, aligning with clinical impressions.

A Typical Clinical Workflow

1. Initial consultation: history, rating scales, clinical interview.

2. QbTest administered in clinic (~20 minutes).

3. Immediate generation of visual report (graphs, comparison with norms).

4. Integration of QbTest results with clinical assessment.

5. Repeat QbTest after starting or adjusting medication to measure treatment effects.

Conclusion

The QbTest represents the future of ADHD assessment—bringing objectivity into a field long dominated by subjective reports. While it cannot diagnose ADHD on its own, it offers clinicians and families tangible, data-driven insights into attention, impulsivity, and hyperactivity. When combined with thorough clinical evaluation, QbTest improves diagnostic confidence, supports shared decision-making, and enhances treatment monitoring.

✦ About the Author
I’m Dr. Srinivas Rajkumar T, MD (AIIMS, New Delhi), Consultant Psychiatrist in Chennai. At my Mind and Memory Clinic (Apollo Clinic, Velachery, Opp. Phoenix Mall), I integrate objective tools like QbTest with clinical expertise, alongside medications, psychotherapy, lifestyle strategies, and advanced neuromodulation (rTMS, tDCS, neurofeedback, ketamine therapy).

📍 Mind and Memory Clinic, Apollo Clinic, Velachery, Chennai (Opp. Phoenix Mall)
📞 +91 85951 55808