Music and movement therapy improves quality of life and attention and associated electroencephalogram changes in patients with attention-deficit/hyperactivity disorder

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurobehavioral disorder. Treatments for ADHD include pharmacological and nonpharmacological therapy. However, pharmacological treatments have side effects such as poor appetite, sleep disturbance, and headache. Moreover, nonpharmacological treatments are not effective in ameliorating core symptoms and are time-consuming. Hence, developing an alternative and effective treatment without (or with fewer) side effects is crucial. Music therapy has long been used to treat numerous neurological diseases. Although listening to music is beneficial for mood and cognitive functions in patients with ADHD, research on the effects of music and movement therapy in children with ADHD is lacking.

METHODS

The present study investigated the effects of an 8-week music and movement intervention in 13 children with ADHD. The Pediatric Quality of Life Inventory (PedsQL) was used to evaluate changes in participants' quality of life. Conners' Kiddie Continuous Performance Test (K-CPT 2) and the Swanson, Nolan, and Pelham rating scale (SNAP-IV) were used to assess core symptoms. Electroencephalogram (EEG) recordings were analyzed to determine neurophysiological changes.

RESULTS

The results revealed that the participants' quality of life increased significantly after the 8-week intervention. Furthermore, the participants' hit reaction times in the block 1 and block 2 tests of K-CPT 2 decreased significantly after the intervention. EEG analysis demonstrated an increase in alpha power and Higuchi's fractal dimension and a decrease in delta power in certain EEG channels.

CONCLUSION

Our music and movement intervention is a potential alternative and effective tool for ADHD treatment and it can significantly improve patients' quality of life and attention.

A systematic review of the utility of continuous performance tests among adults with ADHD

OBJECTIVE

The clinical utility of continuous performance tests (CPTs) among adults with attention-deficit/hyperactivity disorder (ADHD) has increasingly been brought under question. Therefore, the objective of this study was to systematically review the literature to investigate the clinical utility of various commercially available CPTs, including the Conner's Continuous Performance Test (CCPT), Test of Variables of Attention (TOVA), Gordon Diagnostic System (GDS), and Integrated Visual and Auditory Continuous Performance Test (IVA) in the adult ADHD population.

METHODS

This systematic review followed the a priori PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Articles were gathered from PsycINFO, PsycARTICLES, Academic Search Complete, and Google Scholar on 11 April 2022. Sixty-nine articles were included in the final review. Risk of bias was assessed using the National Institute of Health Quality Assessment Took for Observational Cohort and Cross-Sectional Studies.

RESULTS

Most articles demonstrated high risk of bias, and there was substantial heterogeneity across studies. Overall, the reviewed CPTs appeared to have limited diagnostic utility and classification accuracy. Although many studies showed differing scores between adults with ADHD and comparison groups, findings were not consistent. Characteristics of CPT performances among adults with ADHD were mixed, with little consistency and no evidence of a clear profile of performances; however, CCPT commission errors appeared to have the most utility when used a treatment or experimental outcome measure, compared to other CCPT scores.

CONCLUSION

Overall, CPTs should not be used in isolation as a diagnostic test but may be beneficial when used as a component of a comprehensive assessment.

Is the Conners' continuous performance test helpful for assessing attention deficit hyperactivity disorder in a clinical setting?

BACKGROUND

Despite lacking validation for Norwegian populations, the Conners Continuous Performance Test II (CCPT-II) is applied to almost one-third of children receiving an ADHD diagnosis. However, evidence of the CCPT-II's ability to differentiate between children with and without ADHD is contradictory. Thus, this study examines how CCPT-II results correlate with ADHD symptoms reported by mothers and teachers in a sample representing ordinary child and adolescent mental health services and explores the extent to which the CCPT-II influences the diagnostic result.

METHODS

Correlations between CCPT-II results and ADHD Rating Scale scores and a clinical diagnosis of ADHD were analysed in children aged 6-15 years (N = 69) referred to a child and adolescent psychiatric outpatient clinic.

RESULTS

Total ADHD symptom scores rated by mothers correlated with hit reaction time (HRT) block change (.260), HRT inter-stimulus interval (ISI) change (.264) and CCPT-II overall index (.263), while hyperactivity subscale scores correlated with omissions (.285), HRT (.414) and variability (.400). In teachers' ratings, total ADHD and both subscale scores correlated with commissions (.280-.382), while hyperactivity scores correlated with variability (.265). A higher number of commissions was the only significant difference in CCPT-II performance between children diagnosed with and children without ADHD.

CONCLUSIONS

Correlations between CCPT-II results and ADHD symptoms were all small to moderate. As such, CCPT-II results should be interpreted with caution, because they correspond to a limited degree with other sources of information.

Driving impairment due to psychoactive substances and attention deficit disorder: A pilot study

Objective

Attention disorder and substance use disorder are linked to driving impairment and increased road crash involvement. This study explores attention deficits in a population of drivers found driving under the influence (DUI) of psychoactive substances.

Methods

A case-control study was conducted comparing subjects with a previous DUI episode (cases) to subjects who were negative for DUI offenses (controls). Personal, socio-demographic, and DUI data were collected for both groups. All subjects were administered the Continuous Performance Test-third edition (CPT-3), which measures dimensions of attention, including inattentiveness, impulsivity, sustained attention, and vigilance. Possible associations with a previous DUI episode, the use of illicit substances or excessive alcohol use, and road crash involvement were analyzed statistically.

Results

Overall, the study included 147 subjects (100 cases, 47 controls). The parameter distributions of detectability, probability of ADHD, and inattentiveness indicated statistical differences between the two groups. No attention deficits predicted substance use disorder or excessive alcohol consumption. Inattentiveness was an independent risk factor for previous road collision involvement.

Conclusions

The results suggest that alterations exist in some attention dimensions in a population of DUI subjects who were users of alcohol or other psychoactive substances and involved in road traffic crashes. The CPT-3 had successfully distinguished between the two study groups, and after validation, it could be useful in the process of reinstating a driver's license. Future research should expand the study sample to better understand the relevance of the proposed methodological approach in terms of prevention, rehabilitation, and the monitoring of subjects evaluated for driving eligibility requirements.

Sex-Dependent Attentional Impairments in a Subchronic Ketamine Mouse Model for Schizophrenia

Background

The development of more effective treatments for schizophrenia targeting cognitive and negative symptoms has been limited, partly due to a disconnect between rodent models and human illness. Ketamine administration is widely used to model symptoms of schizophrenia in both humans and rodents. In mice, subchronic ketamine treatment reproduces key dopamine and glutamate dysfunction; however, it is unclear how this translates into behavioral changes reflecting positive, negative, and cognitive symptoms.

Methods

In male and female mice treated with either subchronic ketamine or saline, we assessed spontaneous and amphetamine-induced locomotor activity to measure behaviors relevant to positive symptoms, and used a touchscreen-based progressive ratio task of motivation and the rodent continuous performance test of attention to capture specific negative and cognitive symptoms, respectively. To explore neuronal changes underlying the behavioral effects of subchronic ketamine treatment, we quantified expression of the immediate early gene product, c-Fos, in key corticostriatal regions using immunofluorescence.

Results

We showed that spontaneous locomotor activity was unchanged in male and female subchronic ketamine-treated animals, and amphetamine-induced locomotor response was reduced. Subchronic ketamine treatment did not alter motivation in either male or female mice. In contrast, we identified a sex-specific effect of subchronic ketamine on attentional processing wherein female mice performed worse than control mice due to increased nonselective responding. Finally, we showed that subchronic ketamine treatment increased c-Fos expression in prefrontal cortical and striatal regions, consistent with a mechanism of widespread disinhibition of neuronal activity.

Conclusions

Our results highlight that the subchronic ketamine mouse model reproduces a subset of behavioral symptoms that are relevant for schizophrenia.

Effects of psilocybin, the 5-HT2A receptor agonist TCB-2, and the 5-HT2A receptor antagonist M100907 on visual attention in male mice in the continuous performance test

RATIONALE

Neuropsychiatric disorders such as depression are characterized in part by attention deficits. Attention is modulated by the serotonin (5-HT) neurotransmitter system. The 5-HT2A agonist and hallucinogen psilocybin (PSI) is a promising treatment for disorders characterized by attention changes. However, few studies have investigated PSI's direct effect on attention.

OBJECTIVE

Using the rodent continuous performance task (CPT), we assessed PSI's effect on attention. We also evaluated the impact of 5-HT2A receptor agonist TCB-2 and antagonist M100907 for comparative purposes.

METHODS

In the CPT, mice learned to distinguish visual targets from non-targets for milkshake reward. Performance was then tested following injections of PSI (0.3, 1, and 3 mg/kg), TCB-2 (0.3, 1, and 3 mg/kg), or M100907 (0.1, 0.3, and 1 mg/kg). Subsequently, drug effects were then evaluated using a more difficult CPT with variable stimulus durations. Mice were then tested on the CPT following repeated PSI injections. Drug effects on locomotor activity were also measured.

RESULTS

In the CPT, all three drugs reduced hit and false alarm rate and induced conservative responding. PSI also reduced target discrimination. These effects were seen primarily at doses that also significantly reduced locomotor activity. No drug effects were seen on the more difficult CPT or following repeated PSI injections.

CONCLUSIONS

Psilocybin, TCB-2, and M100907 impaired performance of the CPT. However, this may be in part due to drug-induced locomotor changes. The results provide little support for the idea that psilocybin alters visual attention, or that 5-HT2A receptors modulate this process.

Association of the Comprehensive Attention Test and the Korean Wechsler Intelligence Scale for Children-Fourth Edition in Children and Adolescents With Attention-Deficit/Hyperactivity Disorder

Objectives

This study aimed to investigate the correlation between the Comprehensive Attention Test, Korean-Wechsler Intelligence Scale for Children-Fourth Edition, and Attention-Deficit/Hyperactivity Disorder (ADHD) Rating Scale-IV scores in children and adolescents with ADHD.

Methods

Fifty-five children and adolescents diagnosed with ADHD and not taking psychiatric medications were included in this retrospective study. A correlation analysis was performed.

Results

Although simple visual and auditory selective attention have diagnostic value in traditional continuous performance tests, this study revealed that inhibition-sustained attention and interference-selective attention are also effective in evaluating ADHD. Furthermore, the correlation between the attention and intelligence test scores varied depending on the use of visual or auditory stimuli.

Conclusion

The findings of this study contribute to clarifying our understanding of the cognitive characteristics of children and adolescents with ADHD and can be used in future research.

Sustained attention performance deficits in the three-choice serial reaction time task in male and female rats after experimental brain trauma

Impaired attention is central to the cognitive deficits associated with long-term sequelae for many traumatic brain injury (TBI) survivors. Assessing complex sustained attention post-TBI is clinically-relevant and may provide reliable avenues towards developing therapeutic and rehabilitation targets in both males and females. We hypothesized that rats subjected to a moderate TBI will exhibit attentional deficits seen as reduced accuracy and increased distractibility in an operant 3-choice serial reaction time task (3-CSRT), designed as an analogue of the clinical continuous performance test. Upon reaching baseline of 70% accuracy at the 300 ms cue, adult male and female Sprague-Dawley rats were subjected to a controlled cortical impact (2.8 mm deformation at 4 m/s) or sham injury over the right parietal cortex. After two weeks of recovery, they were retested on the 3-CSRT for ten days. Dependent measures include percent accuracy (overall and for each of the three cue ports), percent omissions, as well as latency to instrumental poke and retrieve reward. Results demonstrate that both males and females displayed reduced percent accuracy and increased omissions when re-tested post-TBI on 3-CSRT compared to Sham rats and to their own pre-insult baseline (p's < 0.05). Performance accuracy was impaired consistently throughout the ten days of post-surgery re-testing, suggesting pronounced and long-lasting dysfunction in sustained attention processes. Deficits were specifically more pronounced when the cue was pseudorandomly presented in the left-side cue port (p < 0.05), mirroring clinical hemispatial neglect. These data demonstrate significant and persistent complex attention impairments in both sexes after TBI, rendering identifying efficient therapies for cognitive recovery as pivotal.

Visual P3 abnormalities in patients with first-episode schizophrenia, unaffected siblings of schizophrenia patients and individuals at ultra-high risk for psychosis

Cued version of the continuous performance test (AX-CPT) assesses sustained attention, working memory and cognitive control processes, which have been reported as impaired in schizophrenia. This study investigated visual P3 event-related potential elicited during cued CPT in patients with schizophrenia and in individuals who were at clinical or genetic high risk for psychosis to determine whether any abnormality may provide a marker of vulnerability for psychosis. Visual P3 elicited during cued CPT have not been reported in individuals at high risk for psychosis. Visual Go and NoGo P3 potentials were assessed in 34 antipsychotic-naive patients with first-episode schizophrenia (FES), 25 clinically unaffected siblings of these patients (familial high-risk for psychosis, FHR), 49 antipsychotic-naive individuals at ultra-high risk for psychosis (UHR) and 37 healthy control (HC) participants. FES patients had overall smaller P3 amplitudes than all other groups. P3 amplitude of the UHR participants was in-between the HC participants and FES patients. The anteroposterior P3 topography differed between the groups, with FES patients and FHR participants showing a more frontally distributed P3 compared with the HC participants. These findings suggest that the reduction in visual P3 amplitude may provide a vulnerability marker for psychosis in individuals who are at clinical high risk for psychosis and that a more frontally distributed visual P3 may be a marker of genetic liability for psychosis.

Establishment of an objective index for the diagnosis of attention deficit/hyperactivity disorder by the continuous performance test "MOGRAZ"

OBJECTIVE

The diagnosis of attention deficit/hyperactivity disorder (AD/HD) in Japan is mainly based on information obtained from caregivers. There is therefore a need to establish an objectivity index that can be easily used in clinical practice. The purpose of the study was to create a predictive model for the diagnosis of AD/HD using the MOGRAZ, a visual continuous performance test developed in Japan.

METHODS

We collected data from an AD/HD group and a non-AD/HD group. The AD/HD group included 75 children with predominantly inattentive type AD/HD and 48 with combined type AD/HD who were aged 6 to 12 years and diagnosed at our department. The non-AD/HD group included 153 Japanese children aged 6 to 11 years enrolled in regular classes at a public elementary school. In both groups, multiple logistic regression analysis was performed using the results of MOGRAZ, age, and sex as parameters, and algorithms for a predictive diagnostic model of AD/HD were created.

RESULTS

The area under the receiver operating characteristic curve (ROC-AUC) between the predominantly inattentive type AD/HD subgroup and non-AD/HD group was 0.884 (95% confidence interval: 0.837-0.932), and the ROC-AUC between the combined type AD/HD subgroup and non-AD/HD group was 0.914 (95% CI: 0.869-0.959).

CONCLUSION

The prediction model using the MOGRAZ score allowed us to create an objectivity index to determine the diagnosis of AD/HD that can be easily used in clinical practice. We plan additional verification of this prediction model with additional participants.

How does malingered PTSD affects continuous performance task performance?

The purpose of this study was to determine how malingered PTSD behavior affects the performance of a continuous performance task (CPT). An analog trauma group, two malingering groups (with or without educational intervention), and a control group were organized according to simulation design. During the CPT, the numbers of errors and response time indicators along with post-error slowing (PES) and recovery (PER) process were measured. Results are as follows: First, the analog trauma group showed deficits of response inhibition and a higher level of PES compared to the control group. Second, malingered PTSD caused a significant number of errors, inconsistent performance, and no PES. Third, there was a significantly more impaired and inconsistent performance in the low level of knowledge of disability. Finally, a discriminant accuracy of more than 90% appeared in the discriminant analysis of all group comparison conditions. Taken together, the results of this study show that post-error behavior indicators are affected by malingered PTSD, and differences according to the degree of knowledge of PTSD can also be confirmed. These results are expected to be used as basic data for the development of tasks for the detection of malingerers in clinical scenes in the future.

Monitoring medication response in ADHD: what can continuous performance tests tell us?

Documenting effectiveness of ADHD medication is essential throughout the course of treatment. A rating scale and a continuous performance test (CPT) with motion tracking were used to study the effect of ADHD medication including compliance during one year. Children (N = 78, age 6-18 years) with ADHD were tested with the QbTest at baseline, visit 1 (1 month after baseline) and visit 5 (12 months after baseline). The ADHD-Rating scale was rated by investigator interview at the same visits. QbTest results and ADHD-RS ratings showed reductions in symptoms on all cardinal parameters of the QbTest and on all ADHD-RS subscales between baseline and 1 month and between baseline and 12 months. There was a weak but significant correlation between the total change scores on the two measures from baseline to 1 month. Eighteen participants dropped out of the study before visit 5; at baseline, these children showed significantly lower results on the inattention parameter of the QbTest, with faster reaction time and lower variation in reaction time, suggesting they suffered less problems with inattention. Both the QbTest and the ADHD-RS showed robust ADHD symptom improvements indicative of medication effect, and the QbTest results might also predict non-compliance of medication. Further research is warranted to increase knowledge about reliable monitoring of long-term medication and compliance.

The Effect of Long-Acting Methylphenidate and Modafinil on Attention and Impulsivity of Children with ADHD using a Continuous Performance Test: A Comparative Study

OBJECTIVES

Given the importance of having a continuous performance for the academic and social life of children with attention-deficit/hyperactivity disorder (ADHD), in this study, a Continuous Performance Test (CPT) was used to compare the effect of long-acting methylphenidate and modafinil on attention and impulsivity of these children.

MATERIALS & METHODS

A randomized clinical trial was conducted on 50 children with ADHD aged 6 to 12 years in the child and adolescent psychiatric departments of Imam Hossein and Mofid hospitals, Tehran, Iran. The children were selected by availability sampling and randomly assigned into two equal groups (n=25 in each). While the first group was treated with long-acting methylphenidate, the second was treated with modafinil for 14 days. The CPT was carried out before and after the treatment. The obtained data were analyzed by F and t tests.

RESULTS

Long-acting methylphenidate and modafinil were both effective in improving attention and impulsivity in children with ADHD. There was no significant difference between the two drugs in terms of effectiveness on attention and impulsivity.

CONCLUSION

The findings of this study showed that long-acting methylphenidate and modafinil are equally effective in improving attention and impulsivity in children with ADHD aged 6 to 12 years.

Clinical and neuropsychological characteristics of children with epilepsy and attention-deficit/hyperactivity disorder

OBJECTIVES

This study aimed to explore the clinical and neuropsychological characteristics-cognition, behavior, parenting-related stress, and sleep-of children with epilepsy, attention-deficit/hyperactivity disorder (ADHD), or both.

METHODS

We retrospectively reviewed the electronic medical records of 33 children with epilepsy and ADHD, 113 with epilepsy alone, and 294 with ADHD alone. The children were required to complete the Advanced Test of Attention (ATA), and their parents completed the ADHD Rating Scale (ARS), Child Behavior Checklist (CBCL), Children's Sleep Habits Questionnaire (CSHQ), Disruptive Behavior Disorder (DBD) Scale (DBD), Social Responsiveness Scale (SRS), and Parenting Stress Index-Short Form (PSI-SF).

RESULTS

Auditory Commission Errors made during the ATA were higher in children with epilepsy and ADHD than in those with epilepsy alone. On the SRS, all the subscales except Social Awareness were significantly higher in children with epilepsy and ADHD or ADHD alone than in those with epilepsy alone. The Oppositional Defiant and Conduct Disorder subscales on DBD, Attention Problems, and Aggressive Behaviors on CBCL were significantly higher in children with both epilepsy and ADHD than in those with epilepsy alone. The Parent-Child Dysfunctional Interaction subscales on the PSI-SF were significantly greater in children with both epilepsy and ADHD than in those with epilepsy alone. The subscales on the CSHQ did not significantly differ between children with both epilepsy and ADHD and those with epilepsy alone.

CONCLUSIONS

In children with epilepsy, comorbid ADHD was associated with negative effects on response inhibition, aggressive behavior, and parenting-related stress.

Sustained attention and vigilance deficits associated with HIV and a history of methamphetamine dependence

BACKGROUND

Human immunodeficiency virus (HIV)-associated neurocognitive disorders persist in the era of antiretroviral therapy. One factor that is elevated among persons with HIV (PWH) and independently associated with neurocognitive impairment is methamphetamine dependence (METH). Such dependence may further increase cognitive impairment among PWH, by delaying HIV diagnosis (and thus, antiretroviral therapy initiation), which has been posited to account for persistent cognitive impairment among PWH, despite subsequent treatment-related viral load suppression (VLS; <50 copies of the virus per milliliter in plasma or cerebrospinal fluid). This study examined the main and interactive (additive versus synergistic) effects of HIV and history of METH on the sustained attention and vigilance cognitive domain, while controlling for VLS.

METHODS

Participants included 205 (median age = 44 years; 77% males; HIV-/METH- n = 67; HIV+/METH - n = 49; HIV-/METH+ n = 36; HIV+/METH+ n = 53) individuals enrolled in the Translational Methamphetamine AIDS Research Center, who completed Conners' and the 5-Choice continuous performance tests (CPTs).

RESULTS

METH participants exhibited deficits in sustained attention and vigilance; however, these effects were not significant after excluding participants who had a positive urine toxicology screen for methamphetamine. Controlling for VLS, PWH did not have worse sustained attention and vigilance, but consistently displayed slower reaction times across blocks, relative to HIV- participants. There was no HIV x METH interaction on sustained attention and vigilance.

CONCLUSIONS

Recent methamphetamine use among METH people and detectable viral loads are detrimental to sustained attention and vigilance. These findings highlight the need for prompt diagnosis of HIV and initiation of antiretroviral therapy, and METH use interventions.

WISC-IV Intellectual Profiles in Korean Children and Adolescents with Attention Deficit/Hyperactivity Disorder

OBJECTIVE

This study aimed to compare the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV) profiles of children with attention deficit/hyperactivity disorder (ADHD) and typically-developing children (TC) in Korea.

METHODS

The Korean version of the WISC-IV and the Advanced Test of Attention (ATA) were administered to 377 children and adolescents: 224 with ADHD (age 8.2±2.1 years, 182 boys) and 153 TC (age 8.7±2.4 years, 68 boys). Partial correlation and an analysis of covariance were used to investigate the relationship between the scores of the WISC-IV and the ATA.

RESULTS

The mean score of the full-scale intelligence quotient was lower in ADHD children than in TC (p<0.001). In analyses controlling for gender and with the full-scale intelligence quotient as a covariate, the working memory index (WMI) (p<0.001) and values of the Digit span subtest (p=0.001) of the WISC-IV were lower in the ADHD group than in TC. The WMI (r=-0.26, p<0.001) and its subtest Arithmetic scores (r=-0.25, p<0.001) were negatively correlated with Commission errors on the auditory ATA.

CONCLUSION

Children with ADHD have significantly lower WMI scores, which were clinically correlated with Commission errors on the auditory task of the ATA. Thus, the WMI is an indicator of attention deficit in children with ADHD.

Differential Diagnosis in Patients with Substance Use Disorder and/or Attention-Deficit/Hyperactivity Disorder Using Continuous Performance Test

BACKGROUND

Although substance use disorders (SUD) and attention-deficit/hyperactivity disorder (ADHD) show significant symptomatic overlap, ADHD is often overlooked in SUD patients.

OBJECTIVE

The aim of the present study was to characterize aspects of attention and inhibition (as assessed by a continuous performance test [CPT]) in SUD patients with and without a comorbid diagnosis of ADHD and in healthy controls, expecting the most severe deficits in patients with a combined diagnosis.

METHODS

The MOXO-CPT version, which incorporates visual and auditory environmental distractors, was administered to 486 adults, including healthy controls (n = 172), ADHD (n = 56), SUD (n = 150), and combined SUD and ADHD (n = 108).

RESULTS

CPT performance of healthy controls was better than that of individuals in each of the 3 clinical groups. The only exception was that the healthy control group did not differ from the ADHD group on the Timing index. The 3 clinical groups differed from each other in 2 indices: (a) patients with ADHD (with or without SUD) showed increased hyperactivity compared to patients with SUD only and (b) patients with ADHD showed more responses on correct timing as compared with the SUD groups (with or without ADHD).

CONCLUSION

The CPT is sensitive to ADHD-related deficits, such as disinhibition, poor timing, and inattention, and is able to consistently differentiate healthy controls from patients with ADHD, SUD, or both. Our results are in line with previous research associating both ADHD and SUD with multiple disruptions across a broad set of cognitive domains such as planning, working memory, decision-making, inhibition control, and attention. The lack of consistent differences in cognitive performance between the 3 diagnostic groups might be attributed to various methodological aspects (e.g., heterogeneity in severity, type, and duration of substances use). Our results support the view that motor activity should be considered a significant marker of ADHD.

The Utility of the CPT in the Diagnosis of ADHD in Individuals with Substance Abuse: A Systematic Review

BACKGROUND

Early identification of attention-deficit/hyperactivity disorder (ADHD) in individuals with substance use disorders (SUD) is important because ADHD has an adverse effect on the development and course of SUD. Given the limited validity of self-report measures of ADHD in individuals with SUD, it is important to investigate the utility of the continuous performance test (CPT) in classifying ADHD in adults with SUD.

OBJECTIVE

This review aims to examine the quantitative similarities and differences in CPT performance of adults with ADHD, SUD, and their comorbidity to determine if a distinct neurocognitive profile exists for each.

METHOD

A systematic review of CPT studies that included patients with the comorbidity of ADHD and SUD and a comparison group of one of the disorders alone was conducted. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used.

RESULTS

Eight studies were identified with sample sizes ranging from n = 17 to n = 386. The comorbidity of ADHD and SUD was, mostly, not associated with higher rates of commission and omission errors than either disorder alone. However, the comorbidity of ADHD and SUD was more likely to be associated with increased deficits in response time variability compared with individuals with ADHD alone.

CONCLUSIONS

This review highlights the shortage of large-scale CPT research involving patients with ADHD and SUD. The CPT might be sensitive to attentional deficits, but it lacks specificity for the classification of adult ADHD, SUD, or their comorbidity, and the CPT is thus not useful in discriminating comorbid ADHD and SUD from either disorder alone. Future CPT research should explore whether specific attentional deficits account for the development and persistence of SUD. Such research should also reach beyond traditional CPT measures and include other cognitive and behavioral deficits that were associated with ADHD, such as distractibility and hyperactivity.

Investigation of the effects of transcranial direct current stimulation and neurofeedback by continuous performance test

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique based on weak direct current stimulation through the scalp. Neurofeedback (NFB) is a learning strategy that may help alter to brain wave parameters, by monitoring electroencephalography (EEG) feedback via special programs. We aimed to investigate the supportive effects of tDCS in addition to NFB training. 16 healthy volunteers were divided equally into two groups. One of the groups was trained by NFB with the sensorimotor rhythm (SMR) protocol; 2 days per week, 10 sessions of 30 min, the other group received 10 min of tDCS before each NFB sessions. Continuous Performance Test (CPT) was used to measure, response time and suppression and to determine selective attention condition. Also, Beck Depression and Anxiety Inventories were used to exclude people with depression and anxiety. Depression scores of NFB + tDCS group were decreased significantly. CPT scores were better at last sessions for both groups compared to the first sessions. Sessions were analyzed by comparing 1st, 2nd, 5th and 10th sessions. While the NFB + tDCS group had statistically significant changes at theta/beta ratios with SMR and alpha band amplitudes, NFB group statistics had changed at theta/SMR ratios. NFB training shows its effects at the end of 10 sessions. Despite an increase in the latencies of correct and commission responses on the task of CPT, additional use of tDCS improves cognitive performance. Also, tDCS has a supportive effect on the healthy participants who have mild anxiety and depression; also inhibition deficits of subjects were clear.

A Comparison of Virtual Reality Classroom Continuous Performance Tests to Traditional Continuous Performance Tests in Delineating ADHD: a Meta-Analysis

Computerized continuous performance tests (CPTs) are commonly used to characterize attention in attention deficit-hyperactivity disorder (ADHD). Virtual classroom CPTs, designed to enhance ecological validity, are increasingly being utilized. Lacking is a quantitative meta-analysis of clinical comparisons of attention performance in children with ADHD using virtual classroom CPTs. The objective of the present systematic PRISMA review was to address this empirical void and compare three-dimensional (3D) virtual classroom CPTs to traditional two-dimensional (2D) CPTs. The peer-reviewed literature on comparisons of virtual classroom performance between children with ADHD and typically developing children was explored in six databases (e.g., Medline). Published studies using a virtual classroom to compare attentional performance between children with ADHD and typically developing children were included. Given the high heterogeneity with modality comparisons (i.e., computerized CPTs vs. virtual classroom CPTs for ADHD), both main comparisons included only population comparisons (i.e., control vs. ADHD) using each CPT modality. Meta-analytic findings were generally consistent with previous meta-analyses of computerized CPTs regarding the commonly used omission, commission, and hit reaction time variables. Results suggest that the virtual classroom CPTs reliably differentiate attention performance in persons with ADHD. Ecological validity implications are discussed pertaining to subtle meta-analytic outcome differences compared to computerized 2D CPTs. Further, due to an inability to conduct moderator analyses, it remains unclear if modality differences are due to other factors. Suggestions for future research using the virtual classroom CPTs are provided.

Beneficial effects of acute high-intensity exercise on electrophysiological indices of attention processes in young adult men

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High-intensity exercise improved brain measures of attention processes.

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Fitness and physical activity level were not related to degree of improvement.

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We found no effects of exercise on subsequent Flanker and Reaction-time tasks.

Background

Emerging research suggests that a single bout of aerobic exercise can improve cognition, brain function and psychological health. Our aim was to examine the effects of high-intensity exercise on cognitive-performance and brain measures of attention, inhibition and performance-monitoring across a test-battery of three cognitive tasks.

Method

Using a randomised cross-over design, 29 young men completed three successive cognitive tasks (Cued Continuous Performance Task [CPT-OX]; Eriksen Flanker Task; four-choice reaction-time task [Fast Task]) with simultaneous electroencephalogram (EEG) recording before and after a 20-min high-intensity cycling exercise and resting control session. Cognitive-performance measures, EEG power and event-related potential measures, were obtained during the tasks. Random-intercept linear models were used to investigate the effects of exercise, compared to rest, on outcomes.

Results

A single bout of exercise significantly (p < 0.05) increased the amplitude of the event-related potential Go P3, but had no effect on the contingent negative variation (CNV), Cue P3 or NoGo P3, during the CPT-OX. Delta power, recorded during the CPT-OX, also significantly increased after exercise, whereas there was no effect on cognitive-performance in this task. Exercise did not influence any cognitive-performance or brain measures in the subsequent Flanker or Fast Tasks.

Conclusion

Acute high-intensity exercise improves brain-indices reflecting executive and sustained attention during task performance (Go P3 and delta activity), in the CPT-OX, but not anticipatory attention (Cue P3 and CNV) or response inhibition (NoGo P3) in young-adult men. Exercise had no effect on cognitive-performance or brain measures in the subsequent Flanker and Fast tasks, which may potentially be explained by the time delay after exercise.

Is experience in multi-genre video game playing accompanied by impulsivity?

Developing impulsivity has been one of the main concerns thought to arise from the increasing popularity of video gaming. Most of the relevant literature has treated gamers as pure-genre players (i.e. those who play only a specific genre of game). However, it is not clear how impulsivity is associated with different genres of games in multi-genre gamers, given that there is increasing diversity in the games played by individuals. In this study, we compared 33 gamers to 23 non-gamers in a go/no-go task: the Continuous Performance Test (CPT). To evaluate whether or not impulsivity occurs as a trade-off between speed and accuracy, we emphasised fast performance to all participants. Then, to examine the ability to predict impulsivity from game genre-hours, we fitted separate multiple regression models to several dependent variables. As an additional measure, we also compared groups in an antisaccade task. In the CPT, gamers showed a trend towards significantly faster reaction time (RT), accompanied by higher false alarm rate (FAR) and more risk-taking response bias (β), suggesting impulsive responses. Interestingly, there was a significant negative correlation between RT and FAR across all participants, suggesting an overall speed-accuracy trade-off strategy, perhaps driven by the emphasis on speed during task instruction. Moreover, time spent on role playing games (RPG) and real-time strategy (RTS) games better predicted FAR and β than did time spent on action and puzzle games. In the antisaccade task; however, gamers showed a shorter antisaccade latency but a comparable error rate in comparison with non-gamers. There was no specific game genre which could predict performance in the antisaccade task. Altogether, there was no evidence of oculomotor impulsivity in gamers; however, the CPT results suggested the presence of impulsive responses in gamers, which might be the result of a speed-accuracy trade-off. Furthermore, there was a difference in game genres, with time spent on RPG and RTS games being accompanied by greater probability of impulsive responses. Training studies are required to investigate the causality of different video game genres on the development of impulsivity.

Profiling attention and cognition enhancing drugs in a rat touchscreen-based continuous performance test

RATIONALE

A novel rodent continuous performance test (CPT) was developed as one of the goals of the NEWMEDS (Novel Methods leading to New Medications in Depression and Schizophrenia) consortium to improve its translatability to the CPT test used in human subjects.

OBJECTIVES

The objective of the study is to investigate the effects of attention and cognition enhancing drugs in rodent CPT.

METHODS

A single cohort of rats were trained to asymptotic performance in the test. Pharmacological test sessions were then performed twice per week in a full crossover design with the following drugs tested: methylphenidate (0.3, 1, and 3 mg/kg), the α4β2 nicotinic agonist ABT-594 (0.0023, 0.007 and 0.023 mg/kg), modafinil (8, 16, and 32 mg/kg), atomoxetine (0.3, 1, and 3 mg/kg), donepezil (0.1, 0.3, and 1 mg/kg), and memantine (1.25, 2.5, and 5 mg/kg).

RESULTS

The stimulant-like drugs methylphenidate, ABT-594, and modafinil were found to increase measures of impulsivity and overall responding with generally no positive effects on d', a putative measure of attention, with the exception of ABT-594 which improved d' at the highest dose tested. Atomoxetine and the memory-enhancing drugs donepezil and memantine, on the other hand, were found to reduce measures of impulsivity and responding and had either negligible or worsening effects on d'.

CONCLUSIONS

Our results suggest rodent CPT can detect changes in impulsivity resulting from drugs known to improve attention in rodents and humans. However, additional work is needed to assess the sensitivity and validity of this assay for assessing effects on attention.

Intrinsic, task-evoked and absolute gamma synchrony during cognitive processing in first onset schizophrenia

Cognitive deficits present from the first onset of schizophrenia are thought to arise from a core problem in neural synchrony. This is the first study to characterize the profile of gamma (30-100 Hz) synchrony (rather than power) and behavioral performance during higher-order cognitive processing in schizophrenia. Gamma synchrony was acquired from the EEG, and elicited by a Continuous Performance Test (CPT). We quantitated synchrony for regions associated with the fronto-parietal attention and visual networks for 59 young people with First Onset Schizophrenia (FOS) and 59 matched controls, facilitated by the BRAINnet.net data sharing initiative. We compared groups on gamma synchrony for intrinsic (pre-stimulus), task-evoked change (relative to baseline) and absolute (not relative to baseline) measures. Relationships between synchrony and CPT accuracy, symptoms and functioning were also assessed. FOS showed a reduced ability to modulate task-evoked changes in gamma synchrony, in the context of generally higher intrinsic and absolute synchrony, particularly in frontal regions. These gamma synchrony abnormalities in FOS were associated with performance on the CPT, but not with symptoms or functioning. Task-relevant changes in synchrony may be constrained by an overall excess of intrinsic background synchrony that is unrelated to specific task demands and this relates to cognitive performance. Results are in line with theoretical accounts of gamma synchrony as a core abnormality in schizophrenia, affecting functional connectivity in central executive circuits and causing cognitive symptoms. This study is the first to demonstrate that these gamma synchrony abnormalities are not limited to perceptual or lower-order cognitive processing.

Evaluation of artifact-corrected electroencephalographic (EEG) training: a pilot study

This double-blind study examined the effect of electromyographical (EMG) artifacts, which contaminate electroencephalographical (EEG) signals, by comparing artifact-corrected (AC) and non-artifact-corrected (NAC) neurofeedback (NF) training procedures. 14 unmedicated college students were randomly assigned to two groups: AC (n = 7) or NAC (n = 7). Both groups received 12 sessions of NF and were trained using identical NF treatment protocols to reduce their theta/beta power ratios (TBPR). Outcomes on a continuous performance test revealed that the AC group had statistically significant increases across measures of auditory and visual attention. The NAC group showed smaller gains that only reached statistical significance on measures of visual attention. Only the AC group reduced their TBPR, the NAC group did not. AC NF appears to play an important role during training that leads to improvements in both auditory and visual attention. Additional research is required to confirm the results of this study.

The Relationship between the SNAP-25 Polymorphism and Omission Errors in Korean Children with Attention Deficit Hyperactivity Disorder

Objective

This study aimed to investigate the association between the synaptosomal-associated protein 25 kDa (SNAP-25) genotype and performance on the continuous performance test (CPT) in Korean children with attention-deficit/hyperactivity disorder (ADHD).

Methods

Eighty-seven children with ADHD (mean age, 9.23±1.99 years) participated in this study. Omission errors, commission errors, reaction time, and reaction time variability on the CPT were analyzed. The single-nucleotide polymorphism (SNP) rs3746544 (1065 T>G) of SNAP-25 was genotyped to examine the association with CPT performance.

Results

We found significantly more omission errors on the CPT among children with the TT genotype of SNAP-25 (t=2.56, p=0.012) after correcting for multiple testing.

Conclusion

Our results suggest the possible involvement of the SNAP-25 1065 T>G polymorphism in the inattention phenotype in children with ADHD. Further studies with more refined neuropsychological measures and much larger sample sizes are needed to confirm our findings.

Deficits in Go and NoGo P3 potentials in patients with schizophrenia

Cognitive control processes elicited during a cued continuous performance test were evaluated using event-related potentials in 46 patients who were within the first 5 years of diagnosis of schizophrenia, and 29 healthy controls. Patients had longer reaction times, lower hit rates, and higher false alarm rates compared with controls. Patients had an overall P3 amplitude reduction that was more prominent on NoGo compared with Go trials. This greater P3 reduction on NoGo trials was present in central and parietal regions, but was absent in the frontal region, where the P3 reduction was comparable on NoGo and Go trials. Our findings suggest that the neural activity contributing to Go and NoGo P3s are both deteriorated in schizophrenia, but those contributing to central and parietal NoGo P3s are the most severely affected ones. We conclude that the cognitive control processes engaged during execution, and particularly during inhibition of a prepared motor response were disturbed in the early course of schizophrenia. Our findings might be related to our sample being in relatively early stages of schizophrenia and/or related to the use of atypical antipsychotics by most of our patients.

ADHD-related symptoms and attention profiles in the unaffected siblings of probands with autism spectrum disorder: focus on the subtypes of autism and Asperger's disorder

BACKGROUND

The presence of attention-deficit/hyperactive disorder (ADHD) symptoms and impaired attention performance are commonly noted in individuals with autism spectrum disorder (ASD). However, little is known about attention performance in their unaffected siblings. This study aimed to investigate the ADHD-related traits and attention performance in unaffected siblings of probands with autism and Asperger syndrome (AS), as well as the clinical correlates of ADHD-related traits.

METHODS

We assessed the intention, hyperactivity-impulsivity, and oppositional symptoms, and attention profiles of 199 probands with a diagnosis of ASD (122 autism, 77 AS), their unaffected siblings, and 196 typically developing controls (TD) by their parents' reports on the ADHD-related symptoms and the Connors' Continuous Performance Test (CCPT), respectively.

RESULTS

Compared to TD, unaffected siblings of ASD probands were more hyperactive/impulsive and oppositional, particularly unaffected siblings of AS probands. In CCPT, unaffected siblings of AS have intermediate levels of performance between probands with AS and TD on focused attention and sustained attention but were not statistically different from AS probands or TD in these attention profiles. In contrast, unaffected siblings of autism probands have significantly better CCPT performance when compared to autism probands but not to TD. In addition, stereotyped behaviors predicted ADHD-related traits in both sibling groups, but distinctive patterns of other correlates for ADHD-related traits were found between the two sibling groups.

CONCLUSIONS

This work suggested that unaffected siblings of AS, but not autism, have more hyperactive/impulsive traits and a trend of pervasive attention deficits assessed by CCPT which might serve as potential endophenotypes for genetic studies in AS.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01582256.

The effects of maternal and children phthalate exposure on the neurocognitive function of 6-year-old children

The primary purpose of this study was to investigate the effects of phthalate exposure on the intelligence and attentional performance of 6-year old children when adjusting each other as covariates. We also investigated the differential effects of phthalate exposure on the intelligence and attention according to exposure period (maternal or children). Urine concentrations of mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), mono-(2-ethyl-5-oxohexyl) phthalate (MEOHP), and mono-n-butyl phthalate (MBP) were analyzed. Multivariable linear regression models were used to investigate the relationship between exposure to various phthalates with IQ scores and continuous performance test (CPT) variables. There were robust associations between child MEHHP and MEOHP levels with full scale IQ (FSIQ) even after adjusting for demographic variables and CPT scores (MEHHP -9.27, 95% CI: -17.25, -1.29; MEOHP -9.83, 95% CI: -17.44, -2.21). Child MEHHP and MEHOP levels negatively affected omission errors (MEHHP -20.36, 95% CI: -34.17, -6.55; MEOHP -18.93, 95% CI: -32.58, -5.28) and the response time variability (MEHHP -21.07, 95% CI: -39.04, -3.10; MEOHP -20.41, 95% CI -38.14, -2.69) of the CPT after adjusting for demographic variables and IQ. Maternal phthalate exposure had no effects on IQ or CPT variables. These results suggest that children phthalate exposure, but not maternal exposure, has an adverse effect on IQ and attentional performance, and these associations were found to be independent of each other.

Linear and non-linear analyses of Conner's Continuous Performance Test-II discriminate adult patients with attention deficit hyperactivity disorder from patients with mood and anxiety disorders

BACKGROUND

Attention Deficit Hyperactivity Disorder (ADHD) is a heterogeneous disorder. Therefore it is important to look for factors that can contribute to better diagnosis and classification of these patients. The aims of the study were to characterize adult psychiatric out-patients with a mixture of mood, anxiety and attentional problems using an objective neuropsychological test of attention combined with an assessment of mood instability.

METHOD

Newly referred patients (n = 99; aged 18-65 years) requiring diagnostic evaluation of ADHD, mood or anxiety disorders were recruited, and were given a comprehensive diagnostic evaluation including the self-report form of the cyclothymic temperament scale and Conner's Continuous Performance Test II (CPT-II). In addition to the traditional measures from this test we have extracted raw data and analysed time series using linear and non-linear mathematical methods.

RESULTS

Fifty patients fulfilled criteria for ADHD, while 49 did not, and were given other psychiatric diagnoses (clinical controls). When compared to the clinical controls the ADHD patients had more omission and commission errors, and higher reaction time variability. Analyses of response times showed higher values for skewness in the ADHD patients, and lower values for sample entropy and symbolic dynamics. Among the ADHD patients 59 % fulfilled criteria for a cyclothymic temperament, and this group had higher reaction time variability and lower scores on complexity than the group without this temperament.

CONCLUSION

The CPT-II is a useful instrument in the assessment of ADHD in adult patients. Additional information from this test was obtained by analyzing response times using linear and non-linear methods, and this showed that ADHD patients with a cyclothymic temperament were different from those without this temperament.

The effect of a single dose of multivitamin and mineral combinations with and without guaraná on functional brain activity during a continuous performance task

OBJECTIVES

Relatively few studies have explored the possibility of acute cognitive effects of multivitamin ingestion. This report explores the acute brain electrophysiological changes associated with multivitamin and mineral supplementation, with and without guaraná, using the steady-state visually evoked potential (SSVEP).

METHODS

Based on the known SSVEP correlates of A-X continuous performance task (CPT) performance, and sensitivity to acute psychopharmacological manipulations, the A-X CPT was adopted as a task paradigm to explore treatment-related neurophysiological changes in attentional processing. Twenty healthy non-smoking adults aged 21-39 years (mean age = 28.35 years, SD = 5.52) took part in this double-blind, placebo-controlled, randomized, balanced crossover design study.

RESULTS

The study demonstrated both transient and tonic changes in the SSVEP response during completion of the A-X CPT following multivitamin and mineral treatment both with and without guaraná. Transient changes in SSVEP response in prefrontal regions were observed after a single dose of a multivitamin and mineral preparation indicative of enhanced activity within brain regions engaged by the attentional demands of the task. This pattern of change in frontal regions was correlated with improved behavioural performance after treatment with the multivitamin and mineral combination. Where tonic shifts in SSVEP response were investigated, multivitamin and mineral treatment was associated with a pattern of increased inhibition across posterior regions, with enhanced excitatory processing in prefrontal regions. In contrast, multivitamin and mineral treatment with additional guaraná showed a tonic shift towards greater excitatory processes after a single treatment, consistent with the caffeine content of this treatment.

DISCUSSION

While preliminary in nature, these findings suggest a single multivitamin/mineral dose is sufficient to impact on functional brain activity in task-related brain regions.

A four-year follow-up controlled study of stress response and symptom persistence in Brazilian children and adolescents with attention deficit disorder and hyperactivity (ADHD)

This study evaluated children and adolescents with Attention Deficit Disorder andHyperactivity Disorder (ADHD), reassessing them at a four-year follow-up. Their cortisol response to a stress stimulus was measured twice. ADHD symptom persistence, development of comorbidities, and psychostimulant usage were also reassessed. The initial sample consisted of 38 ADHD patients and 38 healthy controls, age ranging 6-14. At the follow-up, there were 37 ADHD patients and 22 healthy controls, age ranging 10-18. ADHD was classified as persistent if the patients fulfilled all DSM IV criteria for syndromic or subthreshold or had functional impairment. Salivary cortisol samples were collected prior to the application of a cognitive stressor (Continuous Performance Test - CPT), and at three time intervals afterwards at baseline and at the follow-up. Their reassessment showed that 75% had persistent symptoms, psychiatric comorbidities (oppositional defiant and behavioral disorders), functional and academic impairement. Only seven patients were on medication. The ADHD group's cortisol levels were lower than those measured four years earlier, but cortisol concentrations were similar for both ADHD and control groups at the four-year follow-up. The cortisol results suggest that HPA axis reactivity could be a marker differentiating ADHD from ADHD with comorbidities.

The continuous performance test (rCPT) for mice: a novel operant touchscreen test of attentional function

RATIONALE

Continuous performance tests (CPTs) are widely used to assess attentional processes in a variety of disorders including Alzheimer's disease and schizophrenia. Common human CPTs require discrimination of sequentially presented, visually patterned 'target' and 'non-target' stimuli at a single location.

OBJECTIVES

The aims of this study were to evaluate the performance of three popular mouse strains on a novel rodent touchscreen test (rCPT) designed to be analogous to common human CPT variants and to investigate the effects of donepezil, a cholinesterase inhibitor and putative cognitive enhancer.

METHODS

C57BL/6J, DBA/2J and CD1 mice (n = 15-16/strain) were trained to baseline performance using four rCPT training stages. Then, probe tests assessed the effects of parameter changes on task performance: stimulus size, duration, contrast, probability, inter-trial interval or inclusion of flanker distractors. rCPT performance was also evaluated following acute administration of donepezil (0-3 mg/kg, i.p.).

RESULTS

C57BL/6J and DBA/2J mice showed similar acquisition rates and final baseline performance following rCPT training. On probe tests, rCPT performance of both strains was sensitive to alteration of visual and/or attentional demands (stimulus size, duration, contrast, rate, flanker distraction). Relative to C57BL/6J, DBA/2J mice exhibited (1) decreasing sensitivity (d') across the 45-min session, (2) reduced performance on probes where the appearance of stimuli or adjacent areas were changed (size, contrast, flanking distractors) and (3) larger dose- and stimulus duration-dependent changes in performance following donepezil administration. In contrast, CD1 mice failed to acquire rCPT (stage 3) and pairwise visual discrimination tasks.

CONCLUSIONS

rCPT is a potentially useful translational tool for assessing attention in mice and for detecting the effects of nootropic drugs.

Effects of one night of induced night-wakings versus sleep restriction on sustained attention and mood: a pilot study

OBJECTIVE

Despite their high prevalence in daily life, repeated night-wakings and their cognitive and emotional consequences have received less research attention compared to other types of sleep disturbances. Our aim was to experimentally compare the effects of one night of induced infrequent night-wakings (of ∼15 min, each requiring a purposeful response) and sleep restriction on sustained attention and mood in young adults.

METHODS

In a within-between subjects counterbalanced design, 61 healthy adults (40 females; aged 20-29 years) underwent home assessments of sustained attention and self-reported mood at two times: after a normal (control) sleep night, and after a night of either sleep restriction (4h in bed) or induced night-wakings (four prolonged awakenings across 8h in bed). Sleep was monitored using actigraphy and sleep diaries. Sustained attention was assessed using an online continuous performance test (OCPT), and mood was reported online using the Profile of Mood States (POMS).

RESULTS

Actigraphic data revealed good compliance with experimental sleep requirements. Induced night-wakings and sleep restriction both resulted in more OCPT omission and commission errors, and in increased depression, fatigue and confusion levels and reduced vigor compared to the normal sleep night. Moreover, there were no significant differences between the consequences of induced awakenings and sleep restriction.

CONCLUSIONS

Our pilot study indicates that, similar to sleep restriction, one night of life-like repeated night-wakings negatively affects mood and sustained attention.

OROS-methylphenidate efficacy on specific executive functioning deficits in adults with ADHD: a randomized, placebo-controlled cross-over study

Attention-deficit/hyperactivity disorder (ADHD) is linked to impaired executive functioning (EF). This is the first study to objectively investigate the effects of a long-acting methylphenidate on neurocognitive test performance of adults with ADHD. Twenty-two adults with ADHD participated in a 6-weeks study examining the effect of osmotic-release oral system methylphenidate (OROS-mph) on continuous performance tests (CPTs; objective measures), and on the self-reported ADHD rating scale (subjective measure) using a randomized, double-blind, placebo-controlled cross-over design. OROS-mph significantly improved reaction time variability (RTV), commission errors (CE) and d-prime (DP) as compared to baseline (Cohen's d>.50), but did not affect hit reaction time (HRT) or omission errors (OE). Compared to placebo, OROS-mph only significantly influenced RTV on one of two CPTs (p<.050). Linear regression analyses showed predictive ability of more beneficial OROS-mph effects in ADHD patients with higher EF severity (RTV: β=.670, t=2.097, p=.042; omission errors (OE): β=-.098, t=-4.759, p<.001), and with more severe ADHD symptoms (RTV: F=6.363, p=.019; HRT: F=3.914, p=.061). Side effects rates were substantially but non-significantly greater for OROS-mph compared to placebo (77% vs. 46%, p=.063). OROS-mph effects indicated RTV as the most sensitive parameter for measuring both neuropsychological and behavioral deficits in adults with ADHD. These findings suggest RTV as an endophenotypic parameter for ADHD symptomatology, and propose CPTs as an objective method for monitoring methylphenidate titration.

A functional polymorphism of the GTP cyclohydrolase 1 gene predicts attention performance

Guanosine triphosphate cyclohydrolase 1 (GCH1) is the rate-limiting enzyme for the biosynthesis of tetrahydrobiopterin, a cofactor for aromatic amino acid hydroxylases and nitric oxide synthases. As monoamine neurotransmitters are synthesized by the reactions catalyzed by tyrosine hydroxylase and tryptophan hydroxylase, alterations in the content of tetrahydrobiopterin affect the monoamine levels in the brain. Here, we examined the possible association of a functional single-nucleotide polymorphism (SNP) of the GCH1 gene, rs841 (C+243T), with attentional function as assessed by the Continuous Performance Test-Identical Pairs version (CPT-IP) in healthy individuals. We found that homozygous T/T genotype carriers of rs841 scored lower performance on the CPT-IP test. Our data suggest that alterations in GCH1 activity affect attentional function, especially sustained attention and vigilance.

The relationship between sleep patterns and attention levels

Fifty-nine adults slept five nights with an Actigraph and answered two questionnaires related to sleeping quality and morningness/eveningness preferences. Next they performed a computerized attention task (the mathematics continuous performance test (MATH-CPT)) to assess various measures of attention. Results showed significant correlations between six attention variables and two measures of sleep assessed by the Actigraph. Linear regression with sleep variables as independent variables, and measures of the computerized test as dependent variables showed that sleep measures explained 30% of the variance of the score in the "final attention formula" of the test, and 27% of the "rate of response."

Effects of stimulus-driven and goal-directed attention on prepulse inhibition of the cortical responses to an auditory pulse

OBJECTIVE

Inhibition by a prepulse (prepulse inhibition, PPI) of the response to a startling acoustic pulse is modulated by attention. We sought to determine whether goal-directed and stimulus-driven attention differentially modulate (i) PPI of the N100 and P200 components of the auditory evoked potential (AEP) and (ii) the components' generators.

METHODS

128-channel electroencephalograms were recorded in 26 healthy controls performing an active acoustic PPI paradigm. Startling stimuli were presented alone or either 400 or 1000ms after a visual prepulse. Three types of prepulse were used: to-be-attended (goal-directed attention), unexpected (stimulus-driven attention) or to-be ignored (non focused attention). We calculated the percentage PPI for the N100 and P200 components of the AEP and determined cortical generators by standardized weighted low resolution tomography.

RESULTS

At 400ms, the PPI of the N100 was greater after an unexpected prepulse than after a to-be-attended prepulse, the PPI of the P200 was greater after a to-be-attended prepulse than after a to-be ignored prepulse. At 1000ms, to-be-attended and unexpected prepulses had similar effects. Cortical sources were modulated in areas involved in both types of attention.

CONCLUSIONS

Stimulus-driven attention and goal-directed attention each have specific effects on the attentional modulation of PPI.

SIGNIFICANCE

By using a new PPI paradigm that specifically controls attention, we demonstrated that the early stages of the gating process (as evidenced by N100) are influenced by stimulus-driven attention and that the late stages (as evidenced by P200) are influenced by goal-directed attention.

Executive functions in borderline personality disorder

Different domains of executive function such as working memory and response inhibition were investigated together with elementary cognitive processes in borderline personality disorder (BPD). Patients with BPD (N=28) were compared to nonpatient controls (NP, N=28) on eight tasks (e.g. n-back, Go/NoGo, CPT-AX). In order to separate impairments in different cognitive domains and to assess the influence of more elementary cognitive processes on executive functioning, tasks were embedded in a reaction-time-decomposition approach. BPD patients solved tasks with accuracies comparable to those of nonpatients. The only exception was the n-back task, for which working memory is required: here, error rates were higher and increased more prominently in BPD patients depending on working memory load. In most tasks, movement times were shorter for BPD patients than for nonpatients, while the quality of task-solving was comparable. The faster processing in the BPD group was observable starting with the simplest task, i.e. a simple reaction-time task. These findings suggest that domains of executive functioning are differentially affected in BPD. In contrast to load-dependent deficits in working memory, response inhibition processes were unimpaired. Faster action-related processes could be observed in BPD patients in a variety of tasks; however, these did not influence executive functioning.

Gender-specific association of the brain-derived neurotrophic factor gene with attention-deficit/hyperactivity disorder

OBJECTIVE

Attention-deficit/hyperactivity disorder (ADHD) is a complex neurodevelopmental disorder with a strong genetic component. Brain-derived neurotrophic factor (BDNF), which participates in the differentiation and survival of dopaminergic and noradrenergic neurons, could play a role in ADHD development. We aimed to explore the relationships between ADHD and BDNF gene polymorphism.

METHODS

We conducted a case-control analysis of 202 ADHD subjects and 159 controls, performed a transmission disequilibrium test on 151 trios, and compared the results of a continuous performance test (CPT) according to the genotype of the three single nucleotide polymorphisms (rs11030101, rs6265, rs16917204) in the BDNF gene.

RESULTS

In the case-control analysis, the AA genotype of the BDNF rs11030101 polymorphism was significantly associated with ADHD only in girls (p=0.024, odds ratio=3.00). The T-G-G haplotype was significantly less frequent (p=0.005) and A-G-G was more frequent (p=0.048) in girls with ADHD than in control girls (global p=0.027). A multivariate analysis of variance for commission errors on the CPT showed a significant main effect for the rs11030101 genotype (p=0.026) and an interaction effect of the rs11030101 genotype and gender (p=0.032) in ADHD probands.

CONCLUSION

These results provide preliminary evidence for a gender-specific association between BDNF and ADHD in the Korean population.

Association between Dopamine D4 Receptor Gene Polymorphism and Scores on a Continuous Performance Test in Korean Children with Attention Deficit Hyperactivity Disorder

OBJECTIVE

The aim of this study was to evaluate the association between a variable number of tandem repeats polymorphism at the dopamine D4 receptor gene (DRD4) and the performance of children with attention deficit hyperactivity disorder (ADHD) in a continuous performance test (CPT).

METHODS

This study included 72 ADHD children (mean age=9.39+/-2.05 years) who were recruited from one child psychiatric clinic. The omission errors, commission errors, reaction time and reaction standardization in the CPT were computed. The number of 48-base pairs tandem repeats in the exon III of DRD4 was analyzed in a blind manner.

RESULTS

The homozygosity of the 4-repeat allele at DRD4 was significantly associated with fewer commission errors (t=2.364, df=28.685, p=0.025) and standard deviation of reaction time (t=2.351, df=24.648, p=0.027) even after adjusting for age. The results of analyses of CPT measured values among three groups showed that the group with higher frequency of the 4-repeat allele showed a lower mean score of commission errors (F=4.268, df=2, p=0.018).

CONCLUSION

These results suggest a protective role of 4-repeat allele of the DRD4 polymorphisms on commission errors in the CPT in children with ADHD.