注意缺陷多动障碍的神经机制及干预

注意缺陷多动障碍是一种常见的神经性、发展性障碍。大脑异常被认为是注意缺陷多动障碍的病因之一。随着脑成像技术的发展,当前对该障碍的脑解剖结构病变、脑神经发育迟缓和脑网络连接异常等方面都展开了深入研究。文章从以上三个方面介绍最新研究成果,并指出目前的不足和未来研究方向,在此基础上为提高诊断精确性和发展新型有效的治疗干预方法提供建议。     

Clinical and functional correlates of processing speed in pediatric Attention-Deficit/Hyperactivity Disorder: a systematic review and meta-analysis

It is well established that processing speed is negatively impacted in children and adolescents with Attention-Deficit/Hyperactivity Disorder (ADHD). Unfortunately, exactly how processing speed vulnerabilities manifest in daily functioning has not been well established. To support clinical care of youth with ADHD, it is important to better understand the functional consequences and relevant outcomes associated with processing speed deficits. This systematic review and meta-analysis sought to identify the association between processing speed and clinical or functional correlates among children or adolescents diagnosed with ADHD. A total of 409 abstracts were screened, of which, 60 full-text articles were identified as potentially relevant, and 8 of these studies met inclusion criteria. Domains evaluated across these studies included reading skills, mathematics skills, written expression, anxiety, self-appraisals of competence, and adaptive functioning. Six studies reported an association between processing speed and reading skills, allowing for meta-analysis. Processing speed difficulties among youth with ADHD appear strongly associated with several clinical and functional correlates including weaker academic skills, poorer adaptive skills, increased self-reported anxiety, and overestimates of social competence. Meta-analytic results for studies reporting the association between processing speed and reading skills indicate a medium overall weighted mean effect size (r = 0.33, 95% CI = 0.28 –0.39) with minimal heterogeneity (I² = 0.17). Clinical implications of these findings, limitations in the current knowledge base, and suggestions for future research are discussed.     

Parental involvement in children's learning: Comparing parents of children with and without Attention-Deficit/Hyperactivity Disorder (ADHD)

The present study examined involvement in children's learning among parents of 101 children between 8 and 12 years of age (53 parents of children with ADHD, 48 parents of children without ADHD). Compared to parents of children without ADHD, parents of children with ADHD reported lower self-efficacy in their ability to help their children, felt less welcome and supported by their children's schools and teachers, and perceived less time and energy for involvement in their children's academic lives. Mothers of children with and without ADHD reported similar types and levels of involvement behaviors in the home. Fathers of children with ADHD reported being more disengaged from their children's learning and using more coercive and punitive interactions regarding their children's achievement compared to fathers of children without ADHD. These findings underscore the difficulties in parent-supported learning practices and home-school collaboration initiatives faced by parents of children with ADHD and educators alike. Implications for school psychology practice are discussed.     

Performance and Private Speech of Children with Attention-Deficit/Hyperactivity Disorder While Taking the Tower of Hanoi Test: Effects of Depth of Search,Diagnostic Subtype,and Methylphenidate

We administered the Tower of Hanoi to demographically comparable samples of control participants (n = 34) and children with the Combined (n = 22) and Inattentive subtypes (n = 19) of Attention-Deficit/Hyperactivity Disorder (ADHD). Controls excelled over children with the Inattentive subtype, who outperformed patients with the Combined subtype. These results replicated findings of greater executive deficits in the Combined than in the Inattentive type of ADHD. Double-blind administration of methylphenidate improved task performance only for patients with the Inattentive subtype. In a drug-free Baseline session, children with both subtypes of ADHD made more private verbalizations than controls, particularly when failing puzzles. In later sessions, regardless of drug condition, the inattentive sample exhibited a smaller increase in self-regulatory utterances under failure. In contrast, the combined sample decreased self-regulatory verbalizations under failure only under methylphenidate. The results support some differences between the two subtypes of ADHD in executive functioning and in their response to stimulant therapy. Portions of these results were submitted as part of H. Theresa Chang's PhD dissertation (Chang, 2000) and Helena Kopecky's unpublished master's research, both conducted at the University of Rochester and supervised by Rafael Klorman.     

Etiologic Subtypes of Attention-Deficit/Hyperactivity Disorder: Brain Imaging, Molecular Genetic and Environmental Factors and the Dopamine Hypothesis

Multiple theories of Attention-Deficit/Hyper- activity Disorder (ADHD) have been proposed, but one that has stood the test of time is the dopamine deficit theory. We review the narrow literature from recent brain imaging and molecular genetic studies that has improved our understanding of the role of dopamine in manifestation of symptoms of ADHD, performance deficits on neuropsychological tasks, and response to stimulant medication that constitutes the most common treatment of this disorder. First, we consider evidence of the presence of dopamine deficits based on the recent literature that (1) confirms abnormalities in dopamine-modulated frontal-striatal circuits, reflected by size (smaller-than-average components) and function (hypoactivation); (2) clarifies the agonist effects of stimulant medication on dopaminergic mechanisms at the synaptic and circuit level of analysis; and (3) challenges the most-widely accepted ADHD-related neural abnormality in the dopamine system (higher-than-normal dopamine transporter [DAT] density). Second, we discuss possible genetic etiologies of dopamine deficits based on recent molecular genetic literature, including (1) multiple replications that confirm the association of ADHD with candidate genes related to the dopamine receptor D4 (DRD4) and the DAT; (2) replication of differences in performance of neuropsychological tasks as a function of the DRD4 genotype; and (3) multiple genome-wide linkage scans that demonstrate the limitations of this method when applied to complex disorders but implicate additional genes that may contribute to the genetic basis of ADHD. Third, we review possible environmental etiologies of dopamine deficits based on recent studies of (1) toxic substances that may affect the dopamine system in early development and contribute substantially to the etiology of ADHD; (2) fetal adaptations in dopamine systems in response to stress that may alter early development with lasting effects, as proposed by the developmental origins of health and disease hypothesis; and (3) gene-environment interactions that may moderate selective damage or adaptation of dopamine neurons. Based on these reviews, we identify critical issues about etiologic subtypes of ADHD that may involve dopamine, discuss methods that could be used to address these issues, and review old and new theories that may direct research in this area in the future.     

Parenting stress in parents of children with attention-deficit hyperactivity disorder and parents of children with learning disabilities

Parenting a child with ADHD can challenge parenting resources and coping. Increasingly, researchers are examining the relationship between the behavior of the child with ADHD and family functioning. While studies have shown inceased parenting stress in parents of children with ADHD, these studies have compared children with ADHD to non-disabled children. This study compares reports of parenting stress among mothers of children with ADHD, mothers of children with learning disabilities and mothers of non-referred children. Results showed that parenting stress was highest for mothers of children with ADHD. Increased parenting stress was associated with child characteristics and, in particular, with externalizing behavior problems.     

Comorbidity of attention Deficit Hyperactivity Disorder and Post-Traumatic Stress Disorder

Attention Deficit Hyperactivity Disorder (ADHD) and Post-Traumatic Stress Disorder (PTSD) show a high degree of comorbidity in traumatized children. Two hypotheses may help explain this relationship: children with ADHD are at higher risk for trauma due to their impulsivity, dangerous behaviors, and parents who may have a genetic predisposition for impairment of their own impulse control; and hyperarousal induced by severe trauma and manifested by hypervigilance and poor concentration may impair attention to create an ADHD-like syndrome. Four illustrative cases are presented, and implications for treatment are discussed.     

The Importance of Parental Attributions in Families of Children with Attention-Deficit/Hyperactivity and Disruptive Behavior Disorders

Presents a social-cognitive model outlining the role of parental attributions for child behavior in parent–child interactions. Examples of studies providing evidence for the basic model are presented, with particular reference to applications of the model in families of children with Attention-Deficit/Hyperactivity Disorder (ADHD) and/or oppositional defiant/conduct disordered behavior. Parent or child factors that may moderate the operation of links within the model are suggested, and evidence of such moderator effects is presented. The conceptualization and measurement of parental attributions also are discussed. The limitations of the model and existing evidence, as well as recommendations for future research in this area are presented throughout the paper. The paper concludes with a summary of the clinical implications of the model and research on parental attributions with regards to improving interventions for families of children with attentional and disruptive behavior problems.     

Suppression of Chronic High Frequency Spitting in a Multiply Handicapped and Mentally Retarded Adolescent

Excessive drooling and spitting are maladaptive behaviors often encountered among severely developmentally delayed children. In the present study a blind, deaf and retarded adolescent exhibited an extremely high rate of spitting which had resisted numerous classroom intervention efforts by teachers using punishment techniques. His recalcitrant spitting was eliminated with a behavioral intervention consisting of positive reinforcement for not spitting and facial screening for spitting. Experimental control was demonstrated using a multiple baseline across situations and within subject reversal design. The treatment package successfully eliminated the child's chronic spitting. Teacher reports one year later indicated the results maintained across time and spitting was no longer a problem. Social and academic implications of modifying such behaviors are discussed.     

Parent Ratings of Attention-Deficit/Hyperactivity Disorder Symptoms: Factor Structure and Normative Data

Changes in the diagnostic criteria for attention-deficit/hyperactivity disorder (ADHD) have necessitated the creation of new measures for clinical assessment. The factor structure of a parent rating scale containing the 18 symptoms of ADHD was examined in this study. Factor analyses and assessment of differences in ADHD ratings across sex, age, and ethnic group were conducted using a sample of 4666 participants ranging in age from 4 to 20 years old who attended kindergarten through 12th grade in 22 school districts across the United States. Two factors (Inattention and Hyperactivity–Impulsivity) were derived and normative data for a nationally representative sample are presented. A higher frequency of ADHD symptoms was found for boys, younger children, and African-American participants. Potential uses of this scale in clinical practice and research are discussed.     

A Comparison of Teacher and Parent Delivered Consequences: Improving Classroom Behavior in Low-Income Children with ADHD

Both teacher and parent delivered consequences have been shown to be effective in improving the classroom behavior of children with Attention Deficit Hyperactivity Disorder (ADHD). However, there is a delay between the behavior and delivery of parent provided consequences. The delay may make the consequences less salient and effective, for children with ADHD. The current study compared the effectiveness of parent delivered consequences (PC) to teacher delivered consequences (TC) for increasing academic performance and appropriate classroom behavior in African American, low income, elementary students with ADHD. Results indicate that the two interventions are equally effective in improving children's on-task behavior and classwork productivity.     

Empathy and Social Perspective Taking in Children with Attention-Deficit/Hyperactivity Disorder

This study explored empathy and social perspective taking in 8 to 12 year old children with and without Attention-Deficit/Hyperactivity Disorder (ADHD). The sample comprised 92 children, 50 with a diagnosis of ADHD and 42 typically developing comparison children. Although children with ADHD were rated by their parents as less empathic than children without ADHD, this difference was accounted for by co-occurring oppositional and conduct problems among children in the ADHD sample. Children with ADHD used lower levels of social perspective taking coordination in their definition of problems, identification of feelings, and evaluation of outcomes than children without ADHD, and these differences persisted after the role of language abilities, intelligence and oppositional and conduct problems were taken into account. Girls were more empathic and had higher overall social perspective taking scores than boys. Implications for research and practice are discussed. This research was funded by the Social Sciences and Humanities Research Council (SSHRC).     

Families of Children With Attention-Deficit/Hyperactivity Disorder: Review and Recommendations for Future Research

This review integrates and critically evaluates what is known about family characteristics associated with childhood Attention-Deficit/Hyperactivity Disorder (ADHD). Evidence suggests that the presence of ADHD in children is associated to varying degrees with disturbances in family and marital functioning, disrupted parent–child relationships, specific patterns of parental cognitions about child behavior and reduced parenting self-efficacy, and increased levels of parenting stress and parental psychopathology, particularly when ADHD is comorbid with conduct problems. However, the review reveals that little is known about the developmental mechanisms that underlie these associations, or the pathways through which child and family characteristics transact to exert their influences over time. In addition, the influence of factors such as gender, culture, and ADHD subtype on the association between ADHD and family factors remains largely unknown. We conclude with recommendations regarding the necessity for research that will inform a developmental psychopathology perspective of ADHD.     

Parent and Teacher Ratings of Attention-Deficit/Hyperactivity Disorder in Preschool: The ADHD Rating Scale-IV Preschool Version

Efforts for early identification and intervention for children with AD/HD have necessitated the development of rating scales of behavior for the preschool population. The standardization, reliability, and validity data were presented for the ADHD Rating Scale-IV Preschool Version. Parent and teacher ratings were collected on 902 and 977 children 3 to 5 years of age, respectively. Raw scores for the Inattention, Hyperactivity/Impulsivity and Total scores were converted to T-Scores and percentile ranks. Reliability coefficients ranged from 0.80 to 0.95 indicating good test–retest reliability. Concurrent validity with the Conners Teacher Rating Scales: Revised-Short and Conners Parent Rating Scale: Revised-Short ranged from 0.54 to 0.96. The ADHD-Rating Scale-IV appears to be a reliable, valid and user friendly measure for screening preschoolers with behavior problems. Future research is needed to validate its widespread use as a screening and diagnostic tool.     

Attention-Deficit/Hyperactivity Disorder symptoms in an adult sample: Associations with Cloninger’s temperament and character dimensions

Relationships between C.R. Cloninger’s temperament and character dimensions and the Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms of inattention (IA) and hyperactivity/impulsivity (HI) were examined in 231 adults from the general population. Regression analyses that predicated overall ADHD, IA and HI by the seven temperament/character dimensions revealed: IA was predicted positively by Harm Avoidance and negatively by Self-Directedness; HI was predicted positively by Persistence; and overall ADHD was predicted negatively by Self-Directedness. These findings are also interpreted in terms of current theories of ADHD, and the related original and revised versions of Gray’s reinforcement sensitivity theory (RST) of personality.     

Parenting and Family Stress Treatment Outcomes in Attention Deficit Hyperactivity Disorder (ADHD): An Empirical Analysis in the MTA Study

Parenting and family stress treatment outcomes in the MTA study were examined. Male and female (579), 7–9-year-old children with combined type Attention Deficit Hyperactivity Disorder (ADHD), were recruited at six sites around the United States and Canada, and randomly assigned to one of four groups: intensive, multi-faceted behavior therapy program alone (Beh); carefully titrated and monitored medication management strategy alone (MedMgt); a well-integrated combination of the two (Comb); or a community comparison group (CC). Treatment occurred over 14 months, and assessments were taken at baseline, 3, 9, and 14 months. Parenting behavior and family stress were assessed using parent-report and child-report inventories. Results showed that Beh alone, MedMgt alone, and Comb produced significantly greater decreases in a parent-rated measure of negative parenting, Negative/Ineffective Discipline, than did standard community treatment. The three MTA treatments did not differ significantly from each other on this domain. No differences were noted among the four groups on positive parenting or on family stress variables. Results are discussed in terms of the theoretical and empirically documented importance of negative parenting in the symptoms, comorbidities and long-term outcomes of ADHD.     

Components of Visual Search in Childhood-Onset Schizophrenia and Attention-Deficit/Hyperactivity Disorder

This study tested the hypotheses that visual search impairments in schizophrenia are due to a delay in initiation of search or a slow rate of serial search. We determined the specificity of these impairments by comparing children with schizophrenia to children with attention-deficit hyperactivity disorder (ADHD) and age-matched normal children. The hypotheses were tested within the framework of feature integration theory by administering children tasks tapping parallel and serial search. Search rate was estimated from the slope of the search functions, and duration of the initial stages of search from time to make the first saccade on each trial. As expected, manual response times were elevated in both clinical groups. Contrary to expectation, ADHD, but not schizophrenic, children were delayed in initiation of serial search. Finally, both groups showed a clear dissociation between intact parallel search rates and slowed serial search rates.     

Paired-Associate Learning in Attention-Deficit/Hyperactivity Disorder as a Function of Hyperactivity-Impulsivity and Oppositional Defiant Disorder

A paired-associate learning (PAL) test was administered to 22 community volunteers without disruptive disorders and 197 children (7.5–13.5 years-old) presenting with the inattentive and combined subtypes of attention-deficit/hyperactivity disorder (ADHD) either in combination with or without oppositional defiant disorder (ODD). Participants were screened for learning disorders. In comparison to non-ADHD participants, children with ADHD achieved worse PAL and made errors rated as more acoustically and less semantically similar to the correct paired associates. These deficits were not related to hyperactivity–impulsivity or comorbid ODD. These results suggest that ADHD children are less competent at PAL and use less efficient learning strategies than their non-ADHD peers.     

Response Style Differences in the Inattentive and Combined Subtypes of Attention-Deficit/Hyperactivity Disorder

This study examined potential differences between the inattentive and combined ADHD subtypes using laboratory tasks assessing behavioral inhibitory processes. Seventy-five children completed two tasks of behavioral inhibition believed to isolate different processes: the cued reaction time task (CRT), a basic inhibition task, and the go/no-go task (GNG), a complex inhibition task that incorporates motivational contingencies. Three groups of participants were identified, including ADHD/Inattentive (n = 17), ADHD/Combined (n = 37), and comparison (n = 21). Results indicated that rather than showing behavioral inhibition deficits, the ADHD/I children appeared overly inhibited, as evidenced by slower reaction times across the two tasks and significantly higher errors of omission in the GNG task. Additionally, the ADHD/I children did not demonstrate cue dependency effects on the CRT task, suggesting that they were failing to incorporate relevant information before making a response. The sluggish and inhibited performance of the ADHD/I group challenges the idea that it is a subtype of ADHD.