Systematic Review, and Meta-Analysis: Clinical Utility off Continuous Performance Tests for the identification of ADHD
Commentary by *Dr. Geraldine Farrelly
The purpose of the study was to quantify the clinical usefulness of CPT for diagnosis of ADHD compared to a clinical diagnosis in children and adolescents.
CPTs were first developed in 1956 and have been used in both clinical practice and research for decades. According to this new systematic review and meta-analysis, the use of these tests is on the increase and some healthcare providers are overly reliant on them in clinical practice. They are easy to use, require a shorter time to diagnose ADHD than a lengthy, clinical interview and are perceived as “objective” versus more “subjective” rating scales and interviews. However, the authors point out that neither CPTs nor rating scales have ever been recommended as a standalone measure in clinical practice.
The authors selected 19 studies using commercially available CPTs out of 8,507 screened for eligibility. The Conners CPT (CCPT) was the most frequently used commercial CPT used in the studies, others included the Integrated Visual and Auditory (IVA+) CPT, and the Test of Variables of Attention (TOVA). The authors indicated that the use of different tools and thresholds across the primary studies was an issue.
Participants were between the ages of 3 and 18, with 72% under 13 and more males than females. The objective was to compare the diagnostic accuracy of CPT as a standalone tool to a reference standard. The accepted reference standards were a clinical diagnosis with evidence from parent interview, child observation and independent evidence of pervasiveness (teacher reports /etc.); a research diagnosis with parent interview; a clinical diagnosis based on codes (ICD / DSM) in medical records/registries; or clinical diagnosis methods not otherwise specified.
The authors excluded a diagnosis of ADHD based solely on rating scales. Any type of CPT was accepted as well as any temporal differences between clinical diagnosis and use of CPT.
The approach used by the authors differs from previous meta-analysis and, to their knowledge, this is the first meta-analysis of measures of clinical usefulness of CPT in ADHD. They see their results as more easily translatable into clinical practice in mental health settings and useful in developing clearer, best practice guidelines.
The meta-analysis found that performance of the CPT against a clinical diagnosis is “not strong”. The Area Under the Curve (AUC), sensitivity and specificity of the CPTs are in the lower range of what is typically considered acceptable, hovering around the value of 0.7. As a result, the authors say that these results support previous recommendations not to use CPT as a standalone screening tool in population or clinical settings.
Overall, Arrondo et al stressed that their findings supported the best current practice recommendations and corresponded to the results found in relation to symptom rating scales for ADHD. They recommend future studies should be done to assess whether combining the CPT with other measures would improve sensitivity and specificity. The authors feel their study provides an easy-to-interpret benchmark for future comparisons.
They conclude by stating that despite all the research literature on CPT measures in ADHD, they show “limited clinical utility in the differentiation between individuals with and without ADHD”.
Abstract
Objective: We aimed to quantify the clinical utility of continuous performance tests (CPTs) for the diagnosis of attention-deficit/hyperactivity disorder (ADHD) compared to a clinical diagnosis in children and adolescents.
Method: Four databases (MEDLINE, PsycINFO, EMBASE, and PubMed) were screened until January 2023. Risk of bias of included results was judged with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). We statistically pooled the area under the curve, the sensitivity, and the specificity of 3 commonly used CPTs subscales: omission/inattention, commission/impulsivity, and total number of errors/ADHD subscales (PROSPERO registration: CRD42020168091).
Results: A total of 19 studies using commercially available CPTs were identified. Results from up to 835 control individuals and 819 cases were combined in the summary receiver operating characteristic (ROC) curve analyses (sensitivity and specificity pooling), and up to 996 cases and 1,083 control individuals in the area under the curve (AUC) analyses. Clinical utility as measured by AUCs could be considered as barely acceptable (between 0.7 and 0.8) for the most part, with the best results for the total/ADHD score, followed by omissions/inattention, and poorest for commission/impulsivity scores. A similar pattern was found when pooling sensitivity and specificity: 0.75 (95% CI = 0.66-0.82) and 0.71 (0.62-0.78) for the total/ADHD score; 0.63 (0.49-0.75) and 0.74 (0.65-0.81) for omissions; and 0.59 (0.38-0.77) and 0.66 (CI = 0.50-0.78) for commissions.
Conclusion: At the clinical level, CPTs as a stand-alone tool have only a modest to moderate ability to differentiate ADHD from non-ADHD samples. Hence, they should be used only within a more comprehensive diagnostic process.
Geraldine Farrelly MD, FRCPC * is a Developmental/Behavioral pediatrician and Clinical Associate Professor with joint appointments in Pediatrics and Psychiatry, Department of Medicine, University of Calgary Alberta Canada.
Reviewer disclosure: Dr. Farrelly is a clinician, not a researcher, and has not been trained in the use of Continuous Performance Tests (CPTs).
Journal articles are selected based on their clinical relevance. The commentary reflects the reviewer’s own opinion and is not approved, or necessarily representative, of the opinion of the CADDRA Board.