New objective diagnostic tests for ADHD in adults

Attention deficit hyperactivity disorder (ADHD) is one of the most common childhood disorders that often continues into adulthood. While ADHD is a treatable disorder, it is underdiagnosed in adults. Conventional methods to diagnose ADHD also make it challenging for doctors to determine if someone has ADHD because it requires self-reporting of symptoms that sometimes can be subjective and exaggerated.

Professor Roger Ho, Principal Investigator from the NUS Institute for Health Innovation and Technology (iHealthtech), together with his team, designed a series of tests to enhance the current diagnostic process for ADHD, making it more objective.

The team developed a new combination of three objective tests consisting of an infrared brain scan, an eye tracker test, and a continuous performance test. These tests were designed to be conducted along with the usual clinical interviews and self-report questionnaires carried out by a medical professional.

Prof Ho and his team started working on this new objective diagnostic process for ADHD in June 2021, when they studied how infrared brain scans could determine whether an adult had ADHD.

In an interview with The Straits Times, Prof Ho shared, “Psychiatry is the only medical discipline that diagnoses patients without objective diagnostic tools. So, this brain scan and eye tracker are like the prick test. There’s a predetermined value, and it’s objective. No one can change that. If you’re below or close to this value, you may have ADHD.”

Since July 2022, the research team has performed the new diagnostic process on about 250 adults at iHealthtech, of which 240 were diagnosed with ADHD. Prof Ho shared that most of these patients reported suffering from ADHD symptoms for years and consulted him for a diagnosis.

As part of the three objective tests, the client will undergo an infrared brain scan to detect the oxygen level in the brain while performing simple mental exercises. Lower oxygen level in the brain’s frontal lobe is commonly seen in adults with ADHD. Then, an eye tracker test will measure eye movement when the client is instructed to look at or away from a dot on the screen. Adults with ADHD may have a longer reaction time or turn to look in the wrong direction before being given instruction. Lastly, the client will undergo the Conners’ Continuous Performance Test to identify any brain and hand coordination issues. People with moderate to high risk of ADHD will tend to make many mistakes or have an inconsistent reaction time.

Overall, the full assessment for ADHD will take about 90 minutes. Each of the three objective tests has an accuracy of about 70 percent, which adds to the overall accuracy of the ADHD diagnosis process. Following the comprehensive diagnostic process, the patient will receive a diagnostic report.

Prof Ho and his team are currently working towards expanding the use of these diagnostic tools for ADHD in adults in developing countries like Vietnam.

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