Methylphenidate-induced improvements of various measures of attention in adults with Attention Deficit Hyperactivity Disorder

Summary. The present study examined the effect of the stimulant medication methylphenidate (MPH) on attentional functioning of adults with ADHD. Sixteen adults with a diagnosed ADHD without comorbidity were assessed twice, at baseline off MPH and following MPH treatment. The assessment battery consisted of reaction time tasks of low complexity, including measures of alertness – subdivided into tonic and phasic alertness, vigilance, divided attention, flexibility and such aspects of selective attention as including focused attention, inhibition and integration of sensory information. In addition, 16 healthy participants who were matched to adults with ADHD according to sex, age, education level and intellectual functions were also assessed twice using the same test battery. The results of the present study suggest that adults with ADHD off stimulant medication are seriously impaired in various components of attention including vigilance, divided attention, selective attention and flexibility. These impairments of attention were observed primarily in regard to reaction time and its variability. Treatment of adults with ADHD using individually tailored doses of MPH has a positive effect on measures of alertness, vigilance, selective attention, divided attention and flexibility. However, even on MPH adults with ADHD displayed considerable deficits in vigilance and integration of sensory information. The present findings indicate that adults with ADHD are not differentially impaired in attentional processes but may suffer from a more global deficit of attention. Although MPH treatment has been found to be effective in the treatment of the attention deficit of adults with ADHD, additional treatment appears to be necessary.     

Attentional functioning in children with ADHD – predominantly hyperactive-impulsive type and children with ADHD – combined type

Summary. Although particular importance has been attributed to attention deficits in attention deficit hyperactivity disorder (ADHD), there is no consensus as to the exact nature of inattention in ADHD or which components of attention are affected. The present study was based on a neuropsychological model of attention and assessed various components of attention in 23 children with ADHD/predominantly hyperactive-impulsive type (ADHD-H), 32 children with ADHD/combined type (ADHD-C) and healthy children (N₁ = 23 and N₂ = 32). A computerized test battery consisting of reaction time tasks of low complexity was used for the assessment of attention (alertness task, vigilance task, divided attention task, visual scanning task, incompatibility task, test of crossmodal integration, flexibility task). In comparison to healthy participants, patient groups were impaired in measures of vigilance, divided attention, selective attention and flexibility but not in measures of alertness. Analysis of the test performance of patient groups revealed no differences between children with ADHD-H and children with ADHD-C. The results of the present study suggest that both children with ADHD-H and children with ADHD-C are seriously impaired in attentional functioning. Children with ADHD-H and children with ADHD-C produced comparable results in measures of attention.     

Sources of auditory selective attention and the effects of methylphenidate in children with attention-deficit/hyperactivity disorder.

BACKGROUND: The aim of this study was to determine 1) whether abnormal auditory selective attention in children with attention-deficit/hyperactivity disorder (ADHD), as reflected in the processing negativity (PN) of the event-related potential, is related to impaired frontal functioning; and 2) how methylphenidate (MPh) affects attentional functioning in ADHD. METHODS: Sources of electrical brain activity were estimated in healthy control children, in ADHD children without medication, and in children with ADHD during a placebo-controlled medication trial involving MPh. RESULTS: The source models showed that the PN is generated in the auditory cortex. Children with ADHD showed less activity related to selective attention in this brain region. Administration of MPh resulted in more frontally located sources. CONCLUSIONS: The results showed no evidence for an important role of the frontal cortex in abnormalities in selective attention in children with ADHD. Also, the data did not indicate that MPh normalizes brain activity in these children.     

The effects of methylphenidate on neural systems of attention in attention deficit hyperactivity disorder

OBJECTIVE: Recent studies have suggested that attention deficit hyperactivity disorder (ADHD) is associated with abnormalities in basal ganglia and prefrontal cortical functioning. However, these studies have primarily relied upon cognitive tasks that reflect impulse control rather than attentional mechanisms. METHOD: The authors used functional magnetic resonance imaging to investigate the neural correlates of selective and divided attention in a randomized, double-blind, placebo-controlled pharmacological challenge with methylphenidate in 15 adolescents with ADHD (ages 14-17), eight adolescents with reading disorder (ages 12-17), and four adolescents with both reading disorder and ADHD (ages 14-18) who were scanned during both a methylphenidate and a placebo session. Fourteen healthy comparison subjects (ages 12-20) who were not given methylphenidate served as the primary comparison group. RESULTS: During the divided attention task, unmedicated subjects with ADHD or reading disorder recruited the left ventral basal ganglia significantly less than the healthy comparison subjects. Methylphenidate led to an increase in activation in this region but had no effect on task performance. Subjects with ADHD also recruited the middle temporal gyrus significantly less than the comparison subjects, but methylphenidate did not have a direct effect on activation in this region. CONCLUSIONS: These results suggest that ADHD is associated with abnormal processing in attentional networks, with specific dysfunction in striatal circuitry. Methylphenidate may act to normalize activity within this network.     

Effect of osmotic-release oral system methylphenidate on different domains of attention and executive functioning in children with attention-deficit-hyperactivity disorder

Aim This study investigated whether components of attention and executive functioning improve when children with attention‐deficit–hyperactivity disorder (ADHD) are treated with osmotic‐release oral system (OROS) methylphenidate. Method Thirty children (24 males, six females; mean age 8y 6mo, SD 1y 11mo; range 6y 5mo –12y 6mo) with ADHD combined type participated in a double‐blind, placebo‐controlled crossover trial with the child’s clinically most effective dose as identified with a systematic open‐label titration procedure. After 1 week on each treatment (placebo and OROS methylphenidate), a neuropsychological battery that assessed sustained attention, selective attention, attentional control, response inhibition, and working memory was administered. This battery included the Gordon Diagnostic System, seven subtests of the Test of Everyday Attention for Children, and two tests of working memory. Results Performance on two of three tests of response inhibition improved on OROS methylphenidate compared with placebo (p<0.01). Performance on one of two tasks assessing attentional control and one of five measures assessing sustained attention demonstrated clear improvement. There was no improvement on the two tasks assessing selective attention or the two tasks assessing working memory. Interpretation When OROS methylphenidate was used to treat children with ADHD at the clinically most effective dose, general improvement was noted on tasks requiring response inhibition; response to treatment in other domains was either variable or not demonstrated.     

Neuropsychological assessment of attention in adults with different subtypes of attention-deficit/hyperactivity disorder

Summary There is only little information about varying attention functions of adults with different DSM-IV subtypes of attention-deficit/hyperactivity disorder (ADHD). In the present study groups of adult patients with ADHD – predominantly inattentive type, ADHD – predominantly hyperactive-impulsive type or ADHD – combined type and three healthy control groups were compared regarding multiple components of attention. Assessment of attention was performed using a computerized neuropsychological test battery for attentional functions. In comparison with healthy subjects, the three patient groups displayed impairments of vigilance, selective attention, divided attention, and flexibility. These impairments of attention of ADHD subgroups were primarily observed with regard to reaction time. With regard to tonic and phasic alertness no differences between patient and control groups could be found. Comparison between ADHD subgroups revealed that DSM-IV subtypes of ADHD differ in measures of divided attention, selective attention and flexibility. Differences between ADHD subgroups were primarily observed with regard to task accuracy. The results suggest that while distinct profiles of attentional functioning were observed between adult patients with ADHD and healthy adults indicating gross disturbances of various attention functions in patients with ADHD, differences between ADHD subgroups were only weak. Correspondence: Oliver Tucha, School of Psychology, University of Plymouth, Drake Circus, Plymouth, Devon PL4 8AA, UK     

Immediate effects of methylphenidate on cognitive attention skills of children with attention-deficit-hyperactivity disorder

This study investigated the immediate effects of stimulant medication (methylphenidate) on cognitive attention processes in children with attention-deficit-hyperactivity disorder (ADHD). Thirteen males and two females (mean age 9 y 5 mo, SD 18.3 mo) with a diagnosis of ADHD and who were to be prescribed methylphenidate were assessed twice on one day with the Test of Everyday Attention for Children, a neuropsychological battery designed to tap different aspects of cognitive attention. Between assessments, the children were administered methylphenidate (10 mg). Each child had at least average intelligence (IQ 80 or over, as measured by the Wechsler Intelligence Scale for Children-III UK) and was on no other medication. A group of 16 children, who were matched for age, sex, and intelligence, also performed the cognitive tests twice on the same day to control for practice effects of testing. At the first assessment, children with ADHD demonstrated significant impairments in several aspects of cognitive attention in comparison with the control group, particularly sustained attention. After administration of methylphenidate for the children with ADHD, they showed significant improvements in their performance on measures of cognitive attention compared to controls. The immediate effects of methylphenidate and the significance of measuring cognitive aspects of attention as well as behavioural measures are discussed.     

An examination of the effects of stimulant medication on response inhibition: a comparison between children with and without attention deficit hyperactivity disorder

This study investigated whether methylphenidate is effective in improving response inhibition in children with Attention Deficit Hyperactivity Disorder (ADHD). Children with ADHD were compared with normally developing children on measures of response inhibition. Participants with ADHD were compared across two conditions - medicated and unmedicated. There was no significant difference between the inhibitory control of children with and without ADHD. Children with ADHD showed significant improvements in inhibitory control following methylphenidate. The findings of the present study contrast with previous studies which document reduced inhibitory control in ADHD, compared with normally developing children. Reports of methylphenidate improving functioning in children with ADHD are supported. Limitation and implications of the study are discussed.     

A quantitative comparison of handwriting in children with high-functioning autism and attention deficit hyperactivity disorder

Children with high-functioning autism (HFA) and attention deficit hyperactivity disorder (ADHD) often experience significant handwriting difficulties, which can hamper their academic progress and ability to express themselves through symbols and words. Handwriting of children with HFA was compared to those with ADHD based on performance on the speed subtest of the Handwriting Performance Test. Differences in handwriting speed, size and alignment of words, and proportion of handwriting errors, such as corrections and substitutions, were assessed between groups. Results indicated distinct profiles of handwriting problems in HFA and ADHD: children with HFA demonstrated poorer spatial arrangement of words and reduced handwriting speed, and those with ADHD made more handwriting errors, such as corrections and transpositions. These findings have important implications in understanding the similarities and differences for children with HFA and ADHD and lay the groundwork for effective intervention strategies.     

Response to methylphenidate in children with attention deficit hyperactivity disorder and manic symptoms in the multimodal treatment study of children with attention deficit hyperactivity disorder titration trial

OBJECTIVE: Recent reports raise concern that children with attention deficit hyperactivity disorder (ADHD) and some manic symptoms may worsen with stimulant treatment. This study examines the response to methylphenidate in such children. METHODS: Data from children participating in the 1-month methylphenidate titration trial of the Multimodal Treatment Study of Children with ADHD were reanalyzed by dividing the sample into children with and without some manic symptoms. Two "mania proxies" were constructed using items from the Diagnostic Interview Schedule for Children (DISC) or the Child Behavior Checklist (CBCL). Treatment response and side effects are compared between participants with and without proxies. RESULTS: Thirty-two (11%) and 29 (10%) participants fulfilled criteria for the CBCL mania proxy and DISC mania proxy, respectively. Presence or absence of either proxy did not predict a greater or lesser response or side effects. CONCLUSION: Findings suggest that children with ADHD and manic symptoms respond robustly to methylphenidate during the first month of treatment and that these children are not more likely to have an adverse response to methylphenidate. Further research is needed to explore how such children will respond during long-term treatment. Clinicians should not a priori avoid stimulants in children with ADHD and some manic symptoms.     

Differential stimulant response on attention in children with comorbid anxiety and oppositional defiant disorder

Attention-deficit hyperactivity disorder (ADHD) affects 3% to 7% of school-age children. Approximately 30% of the children with ADHD also have comorbid anxiety or oppositional defiant disorder. Methylphenidate is the drug of choice for the medical treatment of such cases. When compared with children with ADHD alone, children with comorbid anxiety or oppositional defiant disorder may show worsening of the global attention score in response to methylphenidate and not only a "reduced response," as reported in previous studies. This study included 1122 children diagnosed as ADHD, of which 174 were diagnosed with comorbid anxiety and 141 with comorbid oppositional defiant disorder. All patients performed the Test of Variables of Attention before and after methylphenidate administration. A normal distribution (Gaussian distribution) of reaction to methylphenidate, as measured by the global ADHD score in children diagnosed as pure ADHD, was found. These findings were in contrast to children with ADHD and comorbid anxiety or oppositional defiant disorder who showed a bimodal distribution and hence represent a distinct population. In both groups with comorbid disorders, there was a larger subgroup in which significant worsening of global ADHD score occurred after methylphenidate administration (P < .05). Children with ADHD and comorbid anxiety or oppositional defiant disorder might represent clinically distinct populations in which inattention is secondary to those disorders; therefore, methylphenidate may be an inappropriate treatment for such children.     

Cognitive effects of immediate-release methylphenidate in children with attention-deficit/hyperactivity disorder

A growing body of literature has examined the cognitive effects of immediate-release methylphenidate in children with attention-deficit/hyperactivity disorder (ADHD). However, a clear understanding of the types and magnitude of such effects are difficult to discern from such a large and varied collection of published reports. This review evaluated a total of 40 relevant placebo-controlled studies published since Rapport and Kelly's [1993. Psychostimulant effects on learning and cognitive function. In: Matson, J.L. (Ed.), Handbook of Hyperactivity in Children. Allyn & Bacon, Boston, pp. 97–136] original review of cognitive effects of methylphenidate in children with ADHD. Of these published studies, 63.5% identified some improvement in cognitive function following methylphenidate treatment. Methylphenidate improved performance on saccadic eye movement, planning/cognitive flexibility, attention/vigilance, and inhibitory control tasks in 83.3%, 71.4%, 70.6%, and 69.7% of studies, respectively. A total 58.3% and 50% of studies that evaluated the effect of methylphenidate on tasks of memory and working memory/divided attention, respectively, noted improvement. Variability of findings across studies may be explained by differential effects of methylphenidate on brain function, intra- and inter-individual variability in medication response, methodological limitations, and problems associated with repeated neuropsychological assessment and metric properties of commonly utilised neuropsychological instruments.     

Effects of stimulants and atomoxetine on cortisol levels in children with ADHD

Children with attention deficit hyperactivity disorder (ADHD) have lower diurnal cortisol levels than non-ADHD comparison subjects. Aiming at elucidating the effects of medications used to treat ADHD, we investigated saliva cortisol in children with ADHD: 20 without medication, 147 on methylphenidate, and 21 on atomoxetine. The only significant finding was that children on atomoxetine had higher cortisol levels at bedtime than unmedicated children.     

Effects of stimulant medication on the lateralisation of line bisection judgements of children with attention deficit hyperactivity disorder

OBJECTIVES—Deficits inthe maintenance of attention may underlie problems in attention deficithyperactivity disorder (ADHD). Children with ADHD also show asymmetricattention deficits in traditional lateralisation and visuospatialorienting tasks, suggesting right hemispheric (and left hemispace)attentional disturbance. This study aimed to examine the lateralisationof selective attention in ADHD; specifically, the effect of a moving,random dot background, and stimulant medication in the line bisection task.
METHODS—Theperformance of children with ADHD, on and off methylphenidate, wasexamined using a computerised horizontal line bisection task withmoving and blank backgrounds. Twenty children with a DSM-IV diagnosisof ADHD participated with 20 controls, individually matched for age,sex, grade at school, and IQ. Twelve of the 20children with ADHD wereon stimulant medication at the time of testing. Horizontal lines ofvarying length were presented in the centre of a computer screen, witheither a blank background, or a moving, random dot field. The randomdots moved either leftward or rightward across the screen at either 40 mm/s or 80 mm/s.
RESULTS—The childrenwith ADHD off medication bisected lines significantly further to theright compared with controls, who showed a small leftward error.Methylphenidate normalised the performance of the children with ADHDfor the task with the moving dots.
CONCLUSIONS—Theseresults support previous evidence for a right hemispheric hypoarousaltheory of attentional dysfunction, and are consistent with the emergingpicture of a lateralised dysfunction of frontostriatal circuitry in ADHD.

     

Development of self-regulation and inhibition in children exhibiting attention deficit disorder with or without hyperactivity (ADHD)

INTRODUCTION: Self-regulation shares several affinities with executive functions. However, the specificity of self-regulation deficits in attention deficit/hyperactivity disorder (ADHD) remains unclear. The typical child starts around the age of four to develop a self-control mechanism along with an internal language that allows the child to modulate impulsively. Conversely, a child with ADHD seems to have greater difficulties delaying or retaining an action or response. OBJECTIVE: In this study we aim to evaluate self-regulation of comprehension in ADHD. RESULTS: Our results show that children with ADHD fail to recognize inconsistencies in presented stories at a rate ranging between 72 (eight years) and 54% (ten years). We also found a positive correlation between a better control of self-regulation and our behavioral inhibition measurement. The attentional deficits exhibited through markedly longer reaction times to continuous performance test (CPT) could be responsible for a poor ability to self-regulate. Fast reaction times were found to be associated with increased vigilance/attention that in turn would permit better self-regulation. Furthermore, our findings show that older subjects with ADHD have shorter reaction times to CPT approaching this group to the typical children. DISCUSSION: This suggests that improvement overtime in self-regulation processes may be attributed to the associated development of vigilance/attention in children with ADHD. Improved vigilance/attention would result in optimal reaction times during tasks that require self-regulation. In addition, our findings suggest that subjects with ADHD have developmental trajectories similar to those observed in healthy subjects. CONCLUSION: In the present study, the lack of a comparison group does not allow us to conclude if such trajectory is delayed compared to typical subjects. Finally, there was no significant relation between the degree of intelligence and the rate of self-regulation, which makes it possible to distinguish the two functions. However, in ADHD self-regulation is favourably influenced by age as observed in developmental studies on typical children. Thus, maturation independent of intelligence, influences self-regulation processes.     

Assessment of attention following pre-school traumatic brain injury: a behavioural attention measure

This study investigated attentional impairments and recovery in pre-school children following traumatic brain injury (TBI). Children aged between 3-8 years were assigned to two groups on the basis of severity of injury: (i) mild TBI and (ii) severe TBI. Children were evaluated at the acute stage postinjury (0-3 months) and again at 6 months on a range of standardized intellectual and attention measures. In addition, a specifically developed behavioural attention measure was employed. Results revealed a tendency for children with severe injuries to exhibit greater attentional impairments in the acute phase post-injury. In addition, children who sustained a severe TBI demonstrated significant recovery in attentional functioning over time. Results indicated differential recovery rates for separate components of attention. Both groups demonstrated a trend towards recovery of arousal and motivation over time, while focused attention, impulsivity and hyperactivity remained stable.     

Components of Attention in Children with Complex Partial Seizures With and Without ADHD

Summary: Purpose: To evaluate attentional difficulties in children with complex partial seizures, we reviewed the records of 12 children with complex partial seizures with attention deficient hyperactivity disorder (CPS/ADHD); 21 children with CPS without ADHD (CPS); 22 children with ADHD; and 15 control children.
Methods: Each child completed a computerized performance test (CPT), which evaluated sustained attention, inhibition of response, response time, and consistency of response. The ADHD groups also completed the CPT after a dose of methylphenidate.
Results: The results found poorest performance on the CPT by the CPS/ADHD group. Particular difficulty in attention was found for children with epilepsy regardless of the ADHD diagnosis. When methylphenidate was administered to the ADHD groups, both groups improved in performance on the CPT.
Conclusions: Epilepsy may predispose children to attention problems that can significantly interfere with learning. Similar improvement for children with CPS/ADHD was found with methylphenidate compared with baseline as for children with ADHD but without CPS.     

Influence of methylphenidate on motor performance and attention in children with developmental coordination disorder and attention deficit hyperactive disorder

Individuals with attention deficit hyperactive disorder (ADHD) often have coexisting developmental coordination disorder (DCD). The positive therapeutic effect of methylphenidate on ADHD symptoms is well documented, but its effects on motor coordination are less studied. We assessed the influence of methylphenidate on motor performance in children with comorbid DCD and ADHD. Participants were 30 children (24 boys) aged 5.10–12.7 years diagnosed with both DCD and ADHD. Conners’ Parent Rating Scale was used to reaffirm ADHD diagnosis and the Developmental Coordination Disorder Questionnaire was used to diagnose DCD. The Movement Assessment Battery for Children-2 and the online continuous performance test were administrated to all participants twice, with and without methylphenidate. The tests were administered on two separate days in a blind design. Motor performance and attention scores were significantly better with methylphenidate than without it (p < 0.001 for improvement in the Movement Assessment Battery for Children-2 and p < 0.006 for the online continuous performance test scores).The findings suggest that methylphenidate improves both attention and motor coordination in children with coexisting DCD and ADHD. More research is needed to disentangle the causality of the improvement effect and whether improvement in motor coordination is directly affected by methylphenidate or mediated by improvement in attention.     

Adaptive, emotional, and family functioning of children with obsessive-compulsive disorder and comorbid attention deficit hyperactivity disorder

OBJECTIVE: The purpose of the study was to examine adaptive, emotional, and family functioning in a well-characterized group of children and adolescents with obsessive-compulsive disorder (OCD) and to evaluate the influence of comorbid attention deficit hyperactivity disorder (ADHD) on the levels of impairment in various functional domains. METHOD: The study group included 287 children and adolescents (191 boys, 96 girls) ages 7-18 years. Fifty-six subjects had a diagnosis of OCD only, 43 had both OCD and ADHD, 95 had ADHD, and 93 were unaffected comparison children. Best estimate DSM-IV diagnoses were assigned on the basis of structured interviews and clinical ratings. The children's functioning was evaluated with a comprehensive battery of well-established, standardized measures, including the Vineland Adaptive Behavior Scales, parents' ratings of social and family functioning, and children's self-reports of emotional adjustment. RESULTS: The children with OCD only were more impaired than were unaffected comparison subjects in most areas of adaptive functioning and emotional adjustment. Children with OCD plus ADHD had additional difficulties in social functioning, school problems, and self-reported depression. Impairment in daily living skills, reduced number of activities, and self-reported anxiety were uniquely associated with the diagnosis of OCD. Family dysfunction was associated with ADHD but not with OCD. CONCLUSIONS: Children and adolescents with OCD are impaired in multiple domains of adaptive and emotional functioning. When comorbid ADHD is present, there is an additional burden on social, school, and family functioning.     

Symptomatic improvement in children with ADHD treated with long-term methylphenidate and multimodal psychosocial treatment

OBJECTIVE: To test the hypotheses that in children with attention-deficit/hyperactivity disorder (ADHD) (1) symptoms of ADHD, oppositional defiant disorder, and overall functioning are significantly improved by methylphenidate combined with intensive multimodal psychosocial treatment compared with methylphenidate alone and with methylphenidate plus attention control and (2) more children receiving combined treatment can be taken off methylphenidate. METHOD: One hundred three children with ADHD (ages 7-9), free of conduct and learning disorders, who responded to short-term methylphenidate were randomized for 2 years to (1) methylphenidate alone; (2) methylphenidate plus psychosocial treatment that included parent training and counseling, social skills training, psychotherapy, and academic assistance, or (3) methylphenidate plus attention psychosocial control treatment. Assessments included parent, teacher, and psychiatrist ratings, and observations in academic and gym classes. RESULTS: Combination treatment did not lead to superior functioning and did not facilitate methylphenidate discontinuation. Significant improvement occurred across all treatments and continued over 2 years. CONCLUSIONS: In stimulant-responsive children with ADHD, there is no support for adding ambitious long-term psychosocial intervention to improve ADHD and oppositional defiant disorder symptoms. Significant benefits from methylphenidate were stable over 2 years.