Visuomotor tracking related to attention-deficit hyperactivity disorder (ADHD)

Deficient visuomotor tracking in children with attention-deficit hyperactivity disorder (ADHD) has been described, but the specific influence of attention on this deficit has not yet been elucidated. The present study compares visuomotor tracking under different conditions of attentional loading in children with ADHD with that of age-matched controls. A computerized visuomotor attentional tracking test that incorporated several levels of distraction was administered to 13 typical children. The same test, as well as a standard Matching Familiar Figures Test and the Proteus Maze test, was administered to 32 children with ADHD and 21 control children. Significant differences between children with ADHD and controls in visuomotor attentional tracking indices that relate to pacing and the accuracy of the tracking movements were observed under all levels of distraction. In parallel, a significant performance decrement was observed in all subjects once distraction was introduced. Discriminant analysis, based on the visuomotor attentional tracking test findings, resulted in correct classification of 92.3% of the typical children and 46% of the children with ADHD. Significant correlations between Matching Familiar Figures Test latency, as well as errors and visuomotor attentional tracking indices, were noted among children with ADHD when the visuomotor attentional tracking did not involve distraction. Under distraction, these correlations extended to the control group as well. In conclusion, visuomotor tracking appears to reflect the availability of attentional resources in general and is significantly affected by the presence of ADHD in particular. These results have potential implications related to the evaluation of children with ADHD on and off drugs.     

Down syndrome and attention-deficit/hyperactivity disorder (ADHD)

Clinicians might minimize the prevalence of behavioral disorders among mentally retarded people. Decreased attention, hyperactivity, and impulsivity are frequently reported in children with Down syndrome, yet the exact prevalence of attention-deficit/hyperactivity disorder (ADHD) has not been clearly estimated in this population. The objective of this study was to estimate the prevalence of ADHD in children with Down syndrome and to emphasize the possible relationship between ADHD symptoms and the level of mental retardation and common medical comorbidity. In this study, the prevalence of ADHD among Down syndrome children was very high, reaching 43.9%. No significant correlation was found between ADHD symptoms and the level of mental retardation, but significant correlation was found with ophthalmologic problems. We conclude that children with Down syndrome are at increased risk for ADHD. When evaluating children with Down syndrome for attention deficits, psychiatric comorbidity as well as medical problems should be carefully taken into consideration.     

Treatment of comorbidity in conduct disorder with attention-deficit hyperactivity disorder (ADHD)

Conduct disorder (CD) is one of the most common psychiatric disorders in childhood and adolescence. It is characterized by a variety of chronic antisocial behaviors, a repetitive and persistent pattern of behavior that violates the basic rights of others, major age-appropriate societal norms, or both. Aggressive behavior, lying, stealing, fire-setting, and running away from home and school are the most frequent manifestations of CD and are often accompanied by hyperactivity, impulsive behavior, explosiveness, cognitive and learning problems, and poor social skills. The rate of comorbidity is high, with attention-deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD) being the most common; comorbid anxiety and depressive disorders are also seen, especially in adolescents. The diagnostic process should include the use of structured interviews, and scores from reliable and valid rating scales that cover all psychiatric disorders must be considered in the differential diagnosis, because CD alone is an extreme rarity and multiple disorders are almost always the rule rather than exception. Treatment should include parenting skills training combined with training of the child to improve his or her relationships with peers, academic performance, and compliance with legitimate demands of authority figures. The appropriate use of medications and integration of patient/parent education and support, as well as individual, group, family, residential, and inpatient treatment may be beneficial for patients with CD and ADHD. The article describes a number of psychopharmacological agents that are used in patients with CD with ADHD and other comorbid disorders. Drugs that may be useful include psychostimulants; atomoxetine (Strattera); antidepressants (imipramine [Tofranil], desipramine [Norpramin]); Selective Serotonin Reuptake Inhibitors (SSRIs); atypical antipsychotics such as risperidone (Risperdal); or mood regulators including lithium (Eskalith).     

Age dependent electroencephalographic changes in attention-deficit/hyperactivity disorder (ADHD)

ObjectiveObjective biomarkers for attention-deficit/hyperactivity disorder (ADHD) could improve diagnostics or treatment monitoring of this psychiatric disorder. The resting electroencephalogram (EEG) provides non-invasive spectral markers of brain function and development. Their accuracy as ADHD markers is increasingly questioned but may improve with pattern classification.MethodsThis study provides an integrated analysis of ADHD and developmental effects in children and adults using regression analysis and support vector machine classification of spectral resting (eyes-closed) EEG biomarkers in order to clarify their diagnostic value.ResultsADHD effects on EEG strongly depend on age and frequency. We observed typical non-linear developmental decreases in delta and theta power for both ADHD and control groups. However, for ADHD adults we found a slowing in alpha frequency combined with a higher power in alpha-1 (8–10 Hz) and beta (13–30 Hz). Support vector machine classification of ADHD adults versus controls yielded a notable cross validated sensitivity of 67% and specificity of 83% using power and central frequency from all frequency bands. ADHD children were not classified convincingly with these markers.ConclusionsResting state electrophysiology is altered in ADHD, and these electrophysiological impairments persist into adulthood.SignificanceSpectral biomarkers may have both diagnostic and prognostic value.     

Psychiatric comorbidity in adults with attention-deficit/hyperactivity disorder (ADHD)

Attention-deficit/hyperactivity disorder (ADHD) is a chronic, lifelong disorder with childhood-onset, which seriously impairs the affected adults in a variety of daily living functions like educational and occupational functioning, partnership and parenting. ADHD is associated with a high percentage of comorbid psychiatric disorders in every lifespan. In adulthood between 65-89% of all patients with ADHD suffer from one or more additional psychiatric disorders, above all mood and anxiety disorders, substance use disorders and personality disorders, which complicates the clinical picture in terms of diagnostics, treatment and outcome issues. The present overview provides information of comorbid psychiatric disorders in adults with ADHD, underlying associations and clinical implications.     

Psychiatric comorbidity in adults with attention-deficit/hyperactivity disorder (ADHD)

European Archives of Psychiatry and Clinical Neuroscience - Attention-deficit/hyperactivity disorder (ADHD) is a chronic, lifelong disorder with childhood-onset, which seriously impairs the...     

Attitudes toward attention-deficit hyperactivity disorder (ADHD) treatment: parents' and children's perspectives

Attitudes toward pharmacological treatment may be a major factor contributing to adherence to such treatment. In the current study, attitudes toward methylphenidate treatment among 50 children diagnosed with attention-deficit hyperactivity disorder (ADHD) and their parents were assessed. Authors of this study have found that the study population is concerned and suspicious toward methylphenidate treatment. Most participants were exposed to negative information even before treatment initiation, which caused many participants to consult other sources and postpone the treatment initiation. Although experiencing methylphenidate as safe and effective (after 23.5 months of treatment), the leading cause of negative attitudes is the concern regarding long-term effects. The single most effective factor regarding the attitude toward methylphenidate treatment is the neurologist's explanation. It is concluded that the pediatric neurologist has a crucial role in affecting attitudes of children and parents toward methylphenidate treatment.     

Nonstimulant therapies for attention-deficit hyperactivity disorder (ADHD) in children and adults

While stimulant medications are the primary pharmacological treatment for ADHD across the lifespan, a subset of patients with ADHD do not experience significant symptom relief from stimulants or can not tolerate effective stimulant doses. Psychosocial therapies, particularly behavioral modification techniques, should be considered for children with ADHD and oppositional behaviors, while Cognitive Behavioral Therapy (CBT) may be a helpful adjunct for adolescents and adults with ADHD. Among the nonstimulant medications, atomoxetine (Strattera) is the only the FDA approved option. It has been found to be efficacious for the entire spectrum of ADHD symptoms in both children and adults. However, daily compliance is essential, and it may take several weeks to achieve full therapeutic effect. Other nonstimulants that have been used to treat ADHD include bupropion (Wellbutrin), the alpha-2 agonists guanfacine (Tenex) and clonidine (Catapres) as well as the tricylic antidepressants. Modafinil (Provigil) is actively being studied for the treatment of pediatric ADHD, and there has been some preliminary studies assessing the efficacy of cholinergic agents for ADHD. Recently, there has been increasing interest in combining nonstimulant therapies with stimulants to further enhance treatment effects. However, more controlled data on the safety and efficacy of combining pharmacological therapies are needed.     

Meta-analysis of fMRI studies of timing in attention-deficit hyperactivity disorder (ADHD)

Attention-deficit hyperactivity disorder (ADHD) is associated with deficits in timing functions with, however, inconclusive findings on the underlying neurofunctional deficits. We therefore conducted a meta-analysis of 11 functional magnetic resonance imaging (fMRI) studies of timing in ADHD, comprising 150 patients and 145 healthy controls. Peak coordinates were extracted from significant case–control activation differences as well as demographic, clinical, and methodological variables. In addition, meta-regression analyses were used to explore medication effects.The most consistent deficits in ADHD patients relative to controls were reduced activation in typical areas of timing such as left inferior prefrontal cortex (IFC)/insula, cerebellum, and left inferior parietal lobe. The findings of left fronto-parieto-cerebellar deficits during timing functions contrast with well documented right fronto-striatal dysfunctions for inhibitory and attention functions, suggesting cognitive domain-specific neurofunctional deficits in ADHD. The meta-regression analysis showed that right dorsolateral prefrontal cortex (DLPFC) activation was reduced in medication-naïve patients but normal in long-term stimulant medicated patients relative to controls, suggesting potential normalization effects on the function of this prefrontal region with long-term psychostimulant treatment.     

Oculomotor inhibition in children with and without attention-deficit hyperactivity disorder (ADHD)

Summary. The aim of the present study was to distinguish between a general deficit in oculomotor control and a deficit restricted to inhibitory functions in children with attention deficit hyperactivity disorder (ADHD). In addition, we were interested in differentiating between a general inhibition deficit and deficient subfunctions of inhibition. We used a prosaccade task to measure general oculomotor abilities in 22 children with ADHD and in age- and gender-matched healthy controls. A fixation, an antisaccade and a countermanding saccade task were used to measure specific aspects of oculomotor inhibition. Two major results were obtained: First, our prosaccade task suggests similar saccadic response preparation and saccadic accuracy in the ADHD compared to the control children. Secondly, the fixation and the countermanding saccade task indicate deficits on measures of oculomotor inhibition in the ADHD group. While patients were specifically impaired in stopping an already initiated response or in suppressing exploratory saccades in a novel situation, inhibition of a prepotent response was not deficient. Our data thus indicate an underlying impairment in cognitive inhibition in ADHD that has been associated with prefrontal lobe functions. More specifically, as the anterior cingulate gyrus has been associated with the countermanding saccade task and group differences were most pronounced in this paradigm our data are in line with imaging data stressing the importance of this cortical structure in the pathophysiology of ADHD.     

Increased regional fractional anisotropy in highly screened attention-deficit hyperactivity disorder (ADHD)

Diffusion tensor imaging data were collected at 3.0 Tesla from 16 children with attention-deficit hyperactivity disorder (ADHD) and 16 typically developing controls, ages 9 to 14 years. Fractional anisotropy images were calculated and normalized by linear transformation. Voxel-wise and atlas-based region-of-interest analyses were performed. Using voxel-wise analysis, fractional anisotropy was found to be significantly increased in the attention-deficit hyperactivity disorder group in the right superior frontal gyrus and posterior thalamic radiation, and left dorsal posterior cingulate gyrus, lingual gyrus, and parahippocampal gyrus. No regions showed significantly decreased fractional anisotropy in attention-deficit hyperactivity disorder. Region-of-interest analysis revealed increased fractional anisotropy in the left sagittal stratum, that is, white matter that connects the temporal lobe to distant cortical regions. Only fractional anisotropy in the left sagittal stratum was significantly associated with attention-deficit hyperactivity disorder symptom severity. Several recent studies have reported pathological increases in fractional anisotropy in other conditions, highlighting the relevance of diffusion tensor imaging in identifying atypical white matter structure associated with neurodevelopmental processes.     

Sensory and sensorimotor gating in adult attention-deficit/hyperactivity disorder (ADHD)

Even though there is an impaired perceptual capacity in attention-deficit/hyperactivity disorder (ADHD) patients, psychophysiological alterations, such as impaired gating as indexed by prepulse inhibition (PPI) or suppression of P50 auditory event-related potentials, have not been found in patients with ADHD. Hence, potential relationships of psychophysiological measures of gating to psychopathology and cognitive performance remain unclear. The present study investigates two distinct operational measures of gating as well as cognitive performance within adult ADHD patients in order to assess the relationship of these measures to psychopathology. PPI, P50 suppression, cognitive performance, and psychopathologic symptoms were assessed in 26 ADHD patients and 26 healthy control subjects. ADHD patients compared to healthy control subjects exhibited impaired P50 suppression, performed worse in cognitive tasks, and reported more psychopathological symptoms, but were normal in the test of PPI. Thus, P50 gating deficits are not specific to schizophrenia-spectrum disorders. These findings highlight the differences between P50 gating and PPI as measures of the gating construct. In keeping with the lack of correlations between these two putative operational measures of gating seen in both humans and animals, adult ADHD patients exhibit deficient P50 suppression and poor cognitive performance, despite exhibiting normal levels of PPI.     

Attention-deficit hyperactivity disorder (ADHD)

Approaches to the diagnosis and treatment of attention-deficit hyperactivity disorder (ADHD) are undergoing a major change as a result of information from studies on the genetics of ADHD and the use of new neuroimaging technologies. Moreover, pharmacogenomics, although still in its infancy, will provide a basis for much more sophisticated treatment strategies for ADHD, particularly once more information is available about the genetics of ADHD. Even at this point in time, there is some pertinent information available that, although not ready for application in clinical settings, nonetheless provides a broader perspective for the clinician. In terms of etiology, ADHD is a neuropsychiatric disorder. There is a genetic basis in about 80% of the cases, involving a number of different genes, and in about 20% of the cases, ADHD is the result of an acquired insult to the brain. Some individuals likely have both genetic and acquired forms. Although medication works well in many cases of ADHD, optimal treatment of ADHD requires integrated medical and behavioral treatment. The family plays a crucial role in the management of children with ADHD. Because there is often a very high degree of comorbidity between ADHD and learning disabilities, teachers also have a great deal to contribute in the day-to-day management of these children. Early recognition and treatment prevent the development of more serious psychopathology in adolescence and adulthood.     

The neural correlates of deficient error awareness in attention-deficit hyperactivity disorder (ADHD)

The ability to detect and correct errors is critical to adaptive control of behaviour and represents a discrete neuropsychological function. A number of studies have highlighted that attention-deficit hyperactivity disorder (ADHD) is associated with abnormalities in behavioural and neural responsiveness to performance errors. One limitation of previous work has been a failure to determine the extent to which these differences are attributable to failures of conscious error awareness, a process that is dependent on the integrity of the frontal lobes. Recent advances in electrophysiological research make it possible to distinguish unconscious and conscious aspects of error processing. This study constitutes an extensive electrophysiological investigation of error awareness and error processing in ADHD. A Go/No-Go response inhibition task specifically designed to assess error awareness was administered to a group of adults diagnosed with ADHD and a group of matched control participants. The ADHD group made significantly more errors than the control group but was less likely to consciously detect these errors. An analysis of event-related potentials elicited by errors indicated that an early performance monitoring component (early positivity) was significantly attenuated in the ADHD group as was a later component that specifically reflects conscious error processing (Pe). Dipole source modelling suggested that abnormal Pe amplitudes were attributable to decreased activation of the anterior cingulate cortex. Decreased electrodermal activity in the ADHD group also suggested a motivational insensitivity to performance errors. Our data provide evidence that neuropsychological deficits associated with ADHD can be exacerbated by error processing abnormalities. Error awareness may represent an important cognitive and physiological phenotype for ADHD.     

Caudate nucleus volume asymmetry predicts attention-deficit hyperactivity disorder (ADHD) symptomatology in children

Clinical diagnosis of attention-deficit hyperactivity disorder (ADHD) is based on evaluation of behavioral functioning in three domains: inattentiveness, hyperactivity, and impulsivity. Caudate and frontal lobe function figures prominently in several neuroanatomic models of attentional functioning. Studies comparing children with and without ADHD have found differences in the size and symmetry of the caudate nuclei. Using multiple regression, we tested the hypothesis that caudate volume symmetry (log left minus log right caudate volume) measured from serial sagittal magnetic resonance images in a sample of nonreferred children (12 girls/15 boys, 7.0 to 16.6 years, 81 to 129 IQ) would predict the cumulative severity of parent-reported ADHD diagnostic behaviors beyond variance predicted by age, sex, and level of internalizing problems as measured by the Child Behavior Checklist. No child had been previously diagnosed with ADHD, although one child was found to meet diagnostic criteria based on the rating scale used for the study. The degree of caudate asymmetry significantly predicted cumulative severity ratings of inattentive behaviors (P = .015), uniquely accounting for 17.1% of the variance in inattention symptomatology over demographic variables and internalizing problems, which collectively predicted 28.9% of the variance. Caudate asymmetry uniquely accounted for only 4.3% of the variance in cumulative severity ratings of hyperactive/impulsive symptomatology over demographic variables and internalizing problems that collectively predicted 21.2% of the variance. A greater degree of right to left caudate volume asymmetry predicted subclinical inattentive behaviors in a sample of nonreferred children. This finding is congruent with neuroanatomic models of attention emphasizing lateralized alteration in prefrontal/striatal systems. The results support the view that clinical ADHD is the extreme of a behavioral continuum that extends into the normal population.