Abstract
Purpose:
ADHD is a common neurobehavioral disorder. ADHD is diagnosed by clinicians using subjective tools, sometimes supported by a computerized test. However, since this diagnosis requires visiting a clinic and is affected by external factors such as intelligence and fatigue, many cases remain undiagnosed through adulthood. There is a societal burden associated with undiagnosed ADHD, creating a need for objective tools for ADHD preliminary self-assessment, prompting seeking professional clinical diagnosis if relevant.<br /> Here we aimed at testing whether we can manipulate spatial and temporal stimulation to identify ADHD symptoms in adults. To this end, we used a short, self-administered tool based on dynamic crowded visual stimulation to identify ADHD symptoms. Various studies demonstrated the usefulness of crowded conditions for measuring visual performance in aging adults and children.
Methods:
Measurements using a prototype dynamic digital assessment tool, currently developed by GlassesOff™, on smartphones, which reliably measure functional near visual acuity (VA), were compared between diagnosed-ADHD and control groups: 24 ADHD subjects (aged 16-28 years, with an ADHD diagnosis performed by a neurologist or psychiatrist) and 18 controls (aged 20-30 years), all corrected to normal vision (worst binocular VA 0.04 logMAR). Stimuli consisted of matrices composed of 25 letters "E" (5×5), each with a randomly chosen orientation having 4 options. Two variations of inter-letter-spacing within the matrix were used (0.4 and 1 letter size). Participants were requested to identify the orientation of the central letter. VA thresholds were determined using a staircase measuring the minimal detectable letter size, under crowding conditions and the stimulus presentation ranged from 34 to 120 msec.
Results:
Despite normal VA on the clinical static ETDRS chart, our self-administered test showed a large and significant VA reduction in ADHD subjects compared with controls: 62, 79, and 64% for 34, 60, and 120 msec, respectively, equivalent to about 2 ETDRS lines. Similar results were obtained for 0.4-letter spacing.
Conclusions:
Our self-administered dynamic digital tool may be used for objective assessment of ADHD symptoms. We suggest that under-development of visual functions, which is present in children under regular conditions, persist in adults with ADHD symptoms and that this becomes apparent under spatial and temporal loading conditions.