Development of a novel rodent rapid serial visual presentation task reveals dissociable effects of stimulant versus nonstimulant treatments on attentional processes.

The rapid serial visual presentation (RSVP) task and continuous performance tasks (CPT) are used to assess attentional impairments in patients with psychiatric and neurological conditions. This study developed a novel touchscreen task for rats based on the structure of a human RSVP task and used pharmacological manipulations to investigate their effects on different performance measures. Normal animals were trained to respond to a target image and withhold responding to distractor images presented within a continuous sequence. In a second version of the task, a false-alarm image was included, so performance could be assessed relative to two types of nontarget distractors. The effects of acute administration of stimulant and nonstimulant treatments for ADHD (amphetamine and atomoxetine) were tested in both tasks. Methylphenidate, ketamine, and nicotine were tested in the first task only. Amphetamine made animals more impulsive and decreased overall accuracy but increased accuracy when the target was presented early in the image sequence. Atomoxetine improved accuracy overall with a specific reduction in false-alarm responses and a shift in the attentional curve reflecting improved accuracy for targets later in the image sequence. However, atomoxetine also slowed responding and increased omissions. Ketamine, nicotine, and methylphenidate had no specific effects at the doses tested. These results suggest that stimulant versus nonstimulant treatments have different effects on attention and impulsive behaviour in this rat version of an RSVP task. These results also suggest that RSVP-like tasks have the potential to be used to study attention in rodents.

Review of Studies on Incremental Validity of Assessment Measures Used in Psychological Assessment of Attention-Deficit Hyperactivity Disorder.

Few studies have summarized the literature relevant to the incremental validity of tools and procedures for the assessment of attention-deficit hyperactivity disorder (ADHD). The current project reviewed such studies published in the prior 18 years. Results from studies on the incremental validity of measures used in the assessment of ADHD were reviewed. Measures included symptom reports, clinical interviews, behavioral observation, continuous performance and other psychomotor tasks, intelligence tests, and measures of executive function. Twenty-nine published studies and two reviews were identified from 2004 to 2022. Incremental validity was determined using various statistics including R2, classification metrics, odds ratios, and post-test probabilities. Findings suggest that symptom reports from a collateral source and continuous performance test measures have incremental validity over self-reports and clinical interviews. Measures of intellectual and executive functioning did not show incremental validity in the diagnosis of ADHD. Findings are relevant to the practitioner, as they bear on the optimization of both the cost-effectiveness and the diagnostic accuracy of combined procedures in the assessment of ADHD.

The Continuous Matching Task (CMT) - real-time procedural stimulus generation for adaptive testing of attention.

The Continuous Matching Task (CMT) is a novel paradigm designed to measure sustained attention and alertness. It is a special type of Continuous Performance Task (CPT) that utilizes truly continuous stimulus material. Stimuli are generated in real-time by a procedural algorithm which also enables adaptive testing. The task is highly flexible and can be used in either single or dual-task configurations that also allow for task mixing. The functionality of the algorithm and applications are presented. The viability of the CMT is tested and results are compared with similar tasks, i.e. Stroop-Task and Conner's CPT (CCPT), as well as self-reports of ADHD in adults in a Multi-Trait-Multi-Method approach in a sample of N = 122 participants. Self-reports and measurements of heart rate variability during testing are analyzed to infer and compare mental workload during tasks. Overall, variants of the CMT induce a higher mental workload than the other tasks, and employing the dual-task CMT with adaptive difficulty resulted in the highest reliability and validity. Results indicate that the CMT is primarily a measure of alertness and processing speed and benefits from adaptive testing.

Cognitive Developmental Trajectories in Adult ADHD Patients and Controls: A Comparative Study.

OBJECTIVE: There is an updated conceptualization of whole-lifespan attention-deficit hyperactivity disorder (ADHD), promoted by awareness of probable persistence of impairment into adulthood. We investigated cognition trajectories from adolescence to mid-adulthood in ADHD. METHOD: Data of 240 patients with ADHD and 244 healthy controls (HCs) were obtained; clinical symptoms and neuropsychological functions were assessed using the various tests. RESULTS: Compared to HCs, patients with ADHD except 35 to 44 age interval showed lower full scale intelligence quotient. They showed decreased verbal comprehensive scores except in the 35 to 44 age interval and working memory scores in all intervals. In the Comprehensive Attention Test, patients with ADHD showed increased working memory error frequencies except in the 15 to 17 age interval and divided attention omission error in all intervals. CONCLUSION: Adults with ADHD showed deficits not in simple attention but in complex attention, including divided attention and working memory.

Post-Error Slowing in Patients With ADHD: A Meta-Analysis.

OBJECTIVE: Post-error slowing (PES) is a cognitive mechanism for adaptive responses to reduce the probability of error in subsequent trials after error. To date, no meta-analytic summary of individual studies has been conducted to assess whether ADHD patients differ from controls in PES. METHOD: We identified 15 relevant publications, reporting 26 pairs of comparisons (ADHD, n = 1,053; healthy control, n = 614). Random-effect meta-analysis was used to determine the statistical effect size (ES) for PES. RESULTS: PES was diminished in the ADHD group as compared with controls, with an ES in the medium range (Cohen's d = 0.42). Significant group difference was observed in relation to the inter-stimulus interval (ISI): While healthy participants slowed down after an error during long (3,500 ms) compared with short ISIs (1,500 ms), ADHD participants sustained or even increased their speed. CONCLUSION: The pronounced group difference suggests that PES may be considered as a behavioral indicator for differentiating ADHD patients from healthy participants.

Comparison of the effectiveness of Conners' CPT and the CPT-identical pairs at distinguishing between smokers and nonsmokers with schizophrenia.

Sustained attention deficits and high rates of smoking are often observed in patients with schizophrenia. This has led to the hypothesis that patients may smoke as an attempt to ameliorate cognitive deficits related to abnormal nicotinic structure and function. Continuous performance tasks (CPT) are often used to index sustained attention deficits in patients with schizophrenia, however, there are important differences between tasks that may impact performance in smokers and nonsmokers with schizophrenia differently. The Conners' CPT (C-CPT) has a high signal-to-noise ratio and is commonly used to assess impulsivity. The CPT-Identical Pairs (CPT-IP) has a low signal-to-noise ratio and is commonly used to assess negative symptoms in patients with schizophrenia. We sought to determine whether there were differences of sustained attention between patient smokers vs. nonsmokers, and if one CPT would provide a better separation of sustained attention between groups. Results revealed that both instruments detect more impaired sustained attention deficits in patient smokers compared to nonsmokers. Patient smokers performed significantly worse on the majority of the CPT-IP composite scores compared to the C-CPT composite scores. These results do not support the self-medication theory, as patient smokers performed worse than patient nonsmokers. Researchers studying sustained attention in schizophrenia may wish to consider the CPT-IP over the C-CPT, as well as control for smoking status.