Adapting the Posterior Probability of Diagnosis Index to Enhance Evidence-Based Screening: An Application to ADHD in Primary Care

This study adapts the Posterior Probability of Diagnosis (PPOD) Index for use with screening data. The original PPOD Index, designed for use in the context of comprehensive diagnostic assessments, is overconfident when applied to screening data. To correct for this overconfidence, we describe a simple method for adjusting the PPOD Index to improve its calibration when used for screening. Specifically, we compare the adjusted PPOD Index to the original index and Naïve Bayes probability estimates on two dimensions of accuracy, discrimination and calibration, using a clinical sample of children and adolescents (N = 321) whose caregivers completed the Vanderbilt Assessment Scale to screen for Attention-Deficit/Hyperactivity Disorder (ADHD) and who subsequently completed a comprehensive diagnostic assessment. Results indicated that the adjusted PPOD Index, original PPOD Index, and Naïve Bayes probability estimates are comparable using traditional measures of accuracy (sensitivity, specificity, AUC) but the adjusted PPOD Index showed superior calibration. We discuss the importance of calibration for screening and diagnostic support tools when applied to individual patients

Objective Measurement of Hyperactivity Using Mobile Sensing and Machine Learning: Pilot Study

BackgroundAlthough hyperactivity is a core symptom of attention-deficit/hyperactivity disorder (ADHD), there are no objective measures that are widely used in clinical settings. ObjectiveWe describe the development of a smartwatch app to measure hyperactivity in school-age children. The LemurDx prototype is a software system for smartwatches that uses wearable sensor technology and machine learning to measure hyperactivity. The goal is to differentiate children with ADHD combined presentation (a combination of inattentive and hyperactive/impulsive presentations) or predominantly hyperactive/impulsive presentation from children with typical levels of activity. MethodsIn this pilot study, we recruited 30 children, aged 6 to 11 years, to wear a smartwatch with the LemurDx app for 2 days. Parents also provided activity labels for 30-minute intervals to help train the algorithm. Half of the participants had ADHD combined presentation or predominantly hyperactive/impulsive presentation (n=15), and half were in the healthy control group (n=15). ResultsThe results indicated high usability scores and an overall diagnostic accuracy of 0.89 (sensitivity=0.93; specificity=0.86) when the motion sensor output was paired with the activity labels. ConclusionsState-of-the-art sensors and machine learning may provide a promising avenue for the objective measurement of hyperactivity

Regulating digital therapeutics for mental health: Opportunities, challenges, and the essential role of psychologists

With so many promising digital therapeutics for anxiety and obsessive-compulsive (OC) spectrum problems, there is an urgent need to consider how evolving regulatory oversight of digital therapeutics is poised to shift how these tools are developed, evaluated, reimbursed, and delivered. In this commentary, we discuss both opportunities and potential pitfalls associated with emerging government regulations of digital therapeutics for mental health, and we consider how applying the traditional 'prescription-based' medical approval paradigm to digital therapeutics for mental health could ultimately undermine and limit the broad accessibility of these software-based innovations that have been explicitly designed to expand the accessibility of care. For example, the vast majority of behavioural and mental health providers do not have 'prescription privileges' (a term originally rooted in pharmacologic practices), and as a result, under current regulations in the U.S. would not be authorized to make FDA-cleared digital therapeutics available to their patients. This is particularly concerning given that most digital therapeutics for mental health are directly rooted in psychological and behavioural science, yet psychologists would not be authorized to incorporate these innovations into their practice. We consider how synchronizing regulatory standards across countries may prove useful, and we conclude by arguing that multidisciplinary teams making regulatory decisions concerning digital therapeutics for mental health must include representation from the discipline and practice of psychology. PRACTITIONER POINTS: Emerging government regulations of digital therapeutics for mental health present both opportunities and potential pitfalls Applying the traditional 'prescription-based' medical approval paradigm to digital therapeutics for mental health could ultimately undermine the broad accessibility of these software-based innovations. Synchronizing regulatory standards across countries may prove useful. Multidisciplinary teams making regulatory decisions concerning digital therapeutics for mental health must include representation from the field of psychology