Exploring the evolution of CPT and ADHD

Throughout my decade-long journey in the medical field, it never fails to amaze me the number of healthcare professionals still unaware of well-validated, data-driven technology for ADHD. It’s important to note that there is not a single definitive test for identifying ADHD. It’s equally important to note there is over seven decades of research, innovation, and clinical application of this technology. All of which point to a significant improvement in a clinician’s ability to measure ADHD symptoms and more accurately determine the diagnosis when used with clinical interviews. These tests fall into the category known as continuous performance tests (CPT).

So, what is the history behind CPTs? What notable innovations have emerged in the last two decades? And how can you how can you determine which test is most suitable for your clinical practice? Let’s delve into the fascinating journey of attention and ADHD testing.

What is a continuous performance test?

The first evidence of CPTs dates back to the 1950s. A team of researchers used a presentation of stimuli for a long duration of time to identify challenges to attention in traumatic brain injury patients (TBI). This test included a continuously changing stream of symbols that infrequently would show a single symbol identified as a non-target that the test subject would react to.

The lapses in attention were calculated through error rates and response speeds. This provided a quantitative measure of ability to sustain attention over time. Now, you might think, “sounds boring, right?” Well, you’re not wrong.

It was boring back then, and guess what? It still is! It is intentionally designed that way. Over the next few decades, the concept of CPTs was used more. They were increased to include much larger clinical populations than those with TBIs. They existed in research studies until the 1980s.

The first commercially available CPT

Fast forward to 1983 and enter the Gordon Diagnostic System (GDS). A trailblazer in CPTs used as part of the diagnostic assessment for ADHD in children. The fundamental principles of the original 1950s CPTs existed – click when you spot a target symbol and resist the urge when presented with a non-target symbol.

This commercially available device brought with it an expansion of child normative data. Nearly 500 normative samples and almost 900 children with ADHD (combined and inattentive type).

CPTs in the clinical landscape gives valuable insight into patient symptoms

The advent of CPTs in the clinical world marked a groundbreaking moment. Especially as the world was just starting to unravel the complexities of ADHD. Rating scales/questionnaires were used the most at the time.

This data gave valuable insight into patients’ symptoms. However, clinicians struggled with the challenge of making clinical decisions in the absence of additional objective data. These challenges include:
• Difficulties patients have in assessing their own symptoms.
• Low correlations between different raters.
• Difficulty collecting consistent data over time.

The evolution begins

As our clinical understanding of ADHD evolved throughout the early to late 1990s, so did CPTs. We saw the start of IVA-2, introducing an extra auditory dimension, T.O.V.A, which included tasks with variable symbol presentation, and the Conners CPT.

The focus on diagnosing ADHD centered on children in the ’80s and ’90s. However, there was a shift as our understanding of this condition grew to include adults. The early commercially available tests then broadened their normative database and included adults of different ages.

The history of QbTest

In the late 1990s, as our grasp of ADHD continued to grow. Hyperactivity became a recognized aspect of the diagnosis – revealing a gap in objective testing. To bridge this gap, researchers led by Marty Teisher in the US and Fredrik Ulberstad in Sweden, collaborated to improve CPT measures. Research showed that tracking activity through an infrared camera could improve the accuracy of ADHD diagnosis with high sensitivity and specificity.

Adding activity-based metrics to a CPT was groundbreaking. It provided a first glimpse of objective measures as an ADHD standard of care. The Swedish team developed QbTest, getting its first FDA clearance in 2004 to aid ADHD diagnosis in children aged 6-12.

Clinical use in children brought huge advancements in ADHD evaluations. The condition began to be recognized outside of childhood onset. This led to the creation of an adolescent and adult task, incorporating CPT principles and introducing a “one-back” task. This increased the cognitive load, improving identification accuracy in adolescents and adults by including a continually changing target.

This unique feature in QbTest remains a key factor in producing well-validated results in patients today. The adolescent/adult test received FDA clearance in 2012 to aid in diagnosis.

CPT results were stagnant for years before Qbtech

CPTs were born out of research and commercialized for clinical use in the late 1980s, early 1990s. However, the evolution of results had remained stagnant for years.

Qbtech was the first to introduce a patient-centric report. Not only did we provide clinicians with digestible results but also enhanced patient discussions. Long-time QbTest user Dr. Angie LaRosa notes, “saves 10,000 words” in diagnostic consultations by presenting a visual layout of the patient’s performance compared to other non-ADHD individuals of the same age and gender.

Study after study showed that QbTest could accurately measure responses to medication and non-medication treatments.

The 2014 FDA clearance for QbTest in treatment monitoring gave clinicians the confidence to use objective data across their entire clinical process. From diagnosis to treatment optimization.

Using QbCheck to measure ADHD symptoms remotely

In 2016 we saw the FDA clearance of QbCheck. This was an innovative milestone that allows us to track hyperactivity via a web camera. It is not dependent on external hardware in a clinic.

We would later come to realize that this innovation would play a pivotal role in ADHD care during the COVID-19 pandemic that nobody could have seen coming.

As 2020 approached, Qbtech prepared to introduce remote access for QbCheck. Extensive research into facial tracking technology through webcams allowed patients to assess ADHD symptom severity from the comfort of their homes, all under professional medical supervision.

Despite the initial subdued demand for telehealth testing, there was a shift in March 2020. The global response to the pandemic remote testing is all the more important. Over 70,000 patients worldwide have now benefited from remote testing during their ADHD evaluation, an innovation unthinkable during the CPT’s first invention in the 1950s.

The future of CPTs

The journey is far from over. Further research into objective data is an ongoing pursuit, progressing year after year. Starting as a simple measurement tool for TBI patients in the 1950s, it has now sparked a clinical revolution in ADHD care.

Objective data shouldn’t be used as a standalone tool. It is a well-validated, data-driven companion to subjective measurement. Qbtech proudly stands at the forefront of objective ADHD testing and management. We continue to contribute to the continued mission of enhancing the lives of ADHD patients worldwide.

Contact us to find out more about CPTs like QbTest

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