A chart review study of the inattentive and combined types of ADHD

Studies of the clinical correlates of the subtypes of Attention-Deficit/Hyperactivity Disorder (ADHD) have identified differences in the representation of age, gender, prevalence, comorbidity, and treatment. We report retrospective chart review data detailing the clinical characteristics of the Inattentive (IA) and Combined (C) subtypes of ADHD in 143 cases of ADHD-IA and 133 cases of ADHD-C. The children with ADHD-IA were older, more likely to be female, and had more comorbid internalizing disorders and learning disabilities. Individuals in the ADHD-IA group were two to five times as likely to have a referral for speech and language problems. The children with ADHD-IA were rated as having less overall functional impairment, but did have difficulty with academic achievement. Children with ADHD-IA were less likely to be treated with stimulants. One eighth of the children with ADHD-IA still had significant symptoms of hyperactivity/impulsivity, but did not meet the DSM-IV threshold for diagnosis of ADHD-Combined Type. The ADHD-IA subtype includes children with no hyperactivity and children who still manifest clinically significant hyperactive symptomatology but do not meet DSM-IV criteria for Combined Type. ADHD-IA children are often seen as having speech and language problems, and are less likely to receive medication treatment, but respond to medical treatment with improvement both in attention and residual hyperactive/impulsive symptoms.     

Behavioral Characteristics of DSM-IV ADHD Subtypes in a School-Based Population

From an ethnically diverse sample of 2,744 school children, 221 attention deficit hyperactivity disorder (ADHD) [123 (4.5%) predominantly inattentive (IA), 47 (1.7%) predominantly hyperactive/impulsive (HI), and 51 (1.9%) combined type (C)] were identified using teacher ratings on a Diagnostic and Statistical Manual of Mental Disorders (4th ed.) (DSM-IV) symptom checklist. Subjects were compared to 221 controls on teacher ratings of behavioral, academic, and social functioning. The results revealed relatively independent areas of impairment for each diagnostic group. The IA children were impaired in all areas, but were rated as displaying more appropriate behavior and fewer externalizing problems than HI or C children. The HI group displayed externalizing and social problems, but was rated as no different than controls in learning or internalizing problems. The C group demonstrated severe and pervasive difficulties across domains. These findings support the validity of the DSM-IV ADHD subtypes; all ADHD groups demonstrated impairment relative to controls, but show different patterns of behavioral characteristics.     

Attention Problems and Executive Functions in Children With Spina Bifida and Hydrocephalus

This study addressed the incidence of Attention-Deficit/Hyperactivity Disorder (ADHD) subtypes in children with spina bifida meningomyelocele and shunted hydrocephalus (SBH) as well as differences in executive functions among these subtypes. Parent rating scales revealed that 31% of the group with SBH could be identified with AD/HD, mostly the Inattentive type (23%). The group with SBH differed from normal controls on cognitive measures of executive functions, but subtype differences were not significant. Multivariate tests showed that children with SBH were rated with greater difficulties on the Behavior Rating Inventory of Executive Function (BRIEF) compared to controls; those with SBH and any subtype of ADHD differed from those with SBH and no ADHD; and those with ADHD (Combined Type) differed significantly from those with ADHD (Predominantly Inattentive Type). Subtype differences on univariate tests in the latter comparison were significant on the BRIEF Inhibit scale, showing more disinhibition in those with SBH and ADHD (Combined Type), but no significant differences were apparent on the BRIEF Sustain, Shift, and Initiate scales. The results show that the incidence of ADHD in children with SBH exceeds the population rate, is represented by problems with inattention rather than with impulsivity and hyperactivity; and that as with non-brain injured individuals, subtype differences in cognitive function remain to more clearly delineated.     

Attention problems and executive functions in children with spina bifida and hydrocephalus.

This study addressed the incidence of Attention-Deficit/Hyperactivity Disorder (ADHD) subtypes in children with spina bifida meningomyelocele and shunted hydrocephalus (SBH) as well as differences in executive functions among these subtypes. Parent rating scales revealed that 31% of the group with SBH could be identified with AD/HD, mostly the Inattentive type (23%). The group with SBH differed from normal controls on cognitive measures of executive functions, but subtype differences were not significant. Multivariate tests showed that children with SBH were rated with greater difficulties on the Behavior Rating Inventory of Executive Function (BRIEF) compared to controls; those with SBH and any subtype of ADHD differed from those with SBH and no ADHD; and those with ADHD (Combined Type) differed significantly from those with ADHD (Predominantly Inattentive Type). Subtype differences on univariate tests in the latter comparison were significant on the BRIEF Inhibit scale, showing more disinhibition in those with SBH and ADHD (Combined Type), but no significant differences were apparent on the BRIEF Sustain, Shift, and Initiate scales. The results show that the incidence of ADHD in children with SBH exceeds the population rate, is represented by problems with inattention rather than with impulsivity and hyperactivity; and that as with non-brain injured individuals, subtype differences in cognitive function remain to more clearly delineated.     

Symptom Properties as a Function of ADHD Type: An Argument for Continued Study of Sluggish Cognitive Tempo

Inconsistent alertness and orientation (sluggishness, drowsiness, daydreaming) were reported to accompany Attention Deficit Disorder (ADD) without Hyperactivity in DSM-III. Such Sluggish Cognitive Tempo items were tested in the DSM-IV Field Trial for ADHD, but were discarded from the Inattention symptom list because of poor negative predictive power. Using 692 children referred to a pediatric subspecialty clinic for ADHD, Sluggish Tempo items were re-evaluated. When Hyperactivity–Impulsivity was absent (i.e., using only cases of Inattentive Type plus clinic controls), Sluggish Tempo items showed substantially improved utility as symptoms of Inattention. Factor analyses distinguished a Sluggish Tempo factor from an Inattention factor. When DSM-IV ADHD types were compared, Inattentive Type was uniquely elevated on Sluggish Tempo. These findings suggest that (a) Sluggish Tempo items are adequate symptoms for Inattentive Type, or (b) Sluggish Tempo may distinguish two subtypes of Inattentive Type. Either conclusion is incompatible with ADHD nosology in DSM-IV.     

Variations in Anxiety and Depression as a Function of ADHD Subtypes Defined by DSM-IV: Do Subtype Differences Exist or Not?

Concerns have been raised about the ability of diagnostic criteria for attention-deficit/hyperactivity disorder (ADHD) to distinguish subtypes that are clearly distinct from each other with regard to clinical correlates. One area of concern is that research regarding differences in anxiety and depression as a function of ADHD subtype has produced discrepant findings. This study was designed to systematically evaluate whether the ADHD subtypes differ with regard to level of internalizing symptoms. From a large pool of children referred to an ADHD center based in a pediatric hospital, children were differentiated into three groups: ADHD, Combined Type (ADHD/COM); ADHD, Inattentive Type (ADHD/I); and a non-ADHD, comparison group (COMP). Parent- and child-report measures using both dimensional and categorical methods were used to assess internalizing symptoms. The results indicated that children with ADHD/COM and ADHD/I had similar levels of anxiety and depression. Subtype differences related to parent-reported depression were accounted for by group differences in level of externalizing problems. The results were discussed with regard to their implications for refining the criteria used to differentiate children with ADHD into subtypes.     

两亚型注意缺陷多动障碍(ADHD)儿童的内隐注意定向

研究探讨注意缺陷障碍儿童与正常儿童之间,混合型与注意缺陷型ADHD儿童之间在内源与外源注意定向功能的差异。ADHD儿童及与之匹配的正常儿童对照组分别参与了两个实验,实验一采用了内源性内隐注意定向任务,实验二采用了外源性内隐注意定向任务。研究表明：（1）ADHD儿童与正常儿童相比,在注意定向过程（注意解除、转移与施加）上有一定缺陷。（2）ADHD儿童注意定向网络功能有缺陷,与反应水平上动作准备有关的注意功能可能受损。（3）两种亚类型儿童注意定向功能缺陷模式不同。在内原定向上,混合型与注意缺陷型相比较,混合型ADHD儿童表现为有较强的反应冲动性;注意缺陷型儿童,主要表现为注意加工过程比较缓慢,注意更易涣散。在外源定向上,混合型儿童在反应的运动准备及运动控制方面的缺陷要大于注意缺陷型儿童     

Criterion-related validity of self-report measures of female heterosocial functioning

Common measures of female heterosocial functioning, the Survey of Heterosocial Interactions for Females (SHI-F) and dating frequency questions, were validated against the criterion of male liking, i. e., how well men like a woman. The SHI-F was unrelated to the criterion and to the other measures of heterosocial activity. The dating frequency and satisfaction questions were moderately related to the criterion. It was concluded the self-reported ability to initiate contact with men (as measured by the SHI-F) may not be related to female heterosocial functioning. Self-reported dating frequency and satisfaction appear to be a valid measure of female heterosocial functioning.The data were collected while the first author was at Louisiana State University.     

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.     

Parent Ratings of ADHD Symptoms: Differential Symptom Functioning Across Malaysian Malay and Chinese Children

This study examined differential symptom functioning (DSF) in ADHD symptoms across Malay and Chinese children in Malaysia. Malay (N=571) and Chinese (N=254) parents completed the Disruptive Behavior Rating Scale, which lists the DSM-IV ADHD symptoms. DSF was examined using the multiple indicators multiple causes (MIMIC) structural equation modeling procedure. Although DSF was found for a single inattention (IA) symptom and three hyperactivity-impulsivity (HI) symptoms, all these differences had low effect sizes. Controlling for these DSF, Chinese children had higher IA and HI latent factor scores. However the effect sizes were small. Together, these findings suggest adequate support for invariance of the ADHD symptoms across these ethno-cultural groups. The implications of the findings for cross-cultural invariance of the ADHD symptoms are discussed.     

Timing and force control in boys with attention deficit hyperactivity disorder: subtype differences and the effect of comorbid developmental coordination disorder

This study examined the motor and performance outcomes of boys with subtypes of attention deficit hyperactivity disorder (ADHD) (DSM-IV, [American Psychiatric Association, Diagnostic and statistical manual of mental disorders, 4th ed., Washington, DC, 1994]). It also examined the differences between boys with a single diagnosis of ADHD versus those who have the dual categorisation of ADHD and developmental coordination disorder (DCD). The participants were 157 boys, aged 7.70-12.98 years recruited from a community sample. Parent report was used to classify 143 boys into either a comparison group or one of the three DSM-IV ADHD subtypes. Participants were given a battery of tests that included the Movement Assessment Battery for Children [Movement Assessment Battery for Children, Psychological Corporation/Harcourt Brace-Jovanovich, New York, 1992], the Wechsler Intelligence Scales for Children--Third Edition [Manual for the Wechsler Intelligence Scale for Children, Psychological Corporation, New York, 1992] and a finger tapping task targeting motor processing, preparation, and execution. Boys with subtypes that included inattentive symptomatology had significant difficulties with timing, force output and showed greater variability in motor outcomes. Boys with the comorbid condition (i.e., ADHD and DCD) had particular difficulty with force control. These outcomes identify a need for increased recognition of the clinical and research implications of the relationship between ADHD and motor dysfunction. This potentially impacts on assessment, intervention, theoretical modelling and the general interpretation of cognitive abilities research with children with ADHD.     

The Shifting Subtypes of ADHD: Classification Depends on How Symptom Reports are Combined

Research on the correlates of ADHD subtypes has yielded inconsistent findings, perhaps because the procedures used to define subtypes vary across studies. We examined this possibility by investigating whether the ADHD subtype distribution in a community sample was sensitive to different methods for combining informant data. We conducted a study to screen all children in grades 1-5 (N = 7847) in a North Carolina County for ADHD. Teachers completed a DSM-IV behavior rating scale and parents completed a structured telephone interview. We found substantial differences in the distribution of ADHD subtypes depending on whether one or both sources were used to define the subtypes. When parent and teacher data were combined, the procedures used substantially influenced subtype distribution. We conclude the ADHD subtype distribution is sensitive to how symptom information is combined and that standardization of the subtyping process is required to advance our understanding of the correlates of different ADHD subtypes.     

Processing Speed in Children With Attention Deficit/Hyperactivity Disorder,Inattentive Type

Attention Deficit/Hyperactivity Disorder (ADHD) is among the most common and most often reconceptualized neurobehavioral disorders of childhood. In the most recent DSM-IV, a primarily inattentive subtype of ADHD (AD) has again been identified. This study explores the neuropsychological profile of this group of children. Eighty-two children referred for school-related problems participated. Twenty-five met criteria for AD; 52 met criteria for reading disability (RD); 9 were comorbid for RD and AD. AD children performed poorly on measures of information processing speed. Children with comorbid AD/RD were distinguishable from those with RD on speed of processing measures only. Vulnerability to information processing load may be at the root of many of the behavioral manifestations of AD.     

Processing speed in children with attention deficit/hyperactivity disorder, inattentive type.

Attention Deficit/Hyperactivity Disorder (ADHD) is among the most common and most often reconceptualized neurobehavioral disorders of childhood. In the most recent DSM-IV, a primarily inattentive subtype of ADHD (AD) has again been identified. This study explores the neuropsychological profile of this group of children. Eighty-two children referred for school-related problems participated. Twenty-five met criteria for AD; 52 met criteria for reading disability (RD); 9 were comorbid for RD and AD. AD children performed poorly on measures of information processing speed. Children with comorbid AD/RD were distinguishable from those with RD on speed of processing measures only. Vulnerability to information processing load may be at the root of many of the behavioral manifestations of AD.     

Attention-Deficit/Hyperactivity Disorder: A Neuropsychological Perspective Towards DSM-V

Neuropsychological methods and techniques have much to offer in the evaluation of the individual suspected as having Attention-Deficit/Hyperactivity Disorder (ADHD). After a review of the historical evolution of the ADHD concept, incidence and prevalence, and DSM-IV criteria for diagnosis, especially as regards omission related to gender differences, and other associated cultural, familial, socioenvironmental, and subject influences, this paper describes a number of dilemmas and obstacles encountered in clinical practice. Included are the confounds associated with the wide range of possible comorbidities, the insufficiency of current DSM-IV criteria, the emergence of subtype differentiation and its impact on diagnosis and treatment. The complex relationship between neuropsychological constructs and ADHD, and obstacles to valid assessment are also addressed. The complexities associated with a thorough ADHD evaluation are viewed within an impressive and expansive existing scientific framework and recommendations are made for future directions.     

Which components of processing speed are affected in ADHD subtypes?

The term “processing speed” (PS) encompasses many components including perceptual, cognitive and output speed. Despite evidence for reduced PS in Attention-Deficit/Hyperactivity Disorder (ADHD), little is known about which component(s) is most impacted in ADHD, or how it may vary by subtypes. Participants included 151 children, ages 8–12 years, with ADHD Predominantly Inattentive Type, ADHD Combined Type and typically developing controls using DSM-IV criteria. All children completed four measures of processing speed: Symbol Search, Coding, Decision Speed, and simple reaction time. We found children with ADHD-PI and ADHD-C had slower perceptual and psychomotor/incidental learning speed than controls and that ADHD-PI had slower decision speed than controls. The subtypes did not differ on any of these measures. Mean reaction time was intact in ADHD. Hence, at a very basic output level, children with ADHD do not have impaired speed overall, but as task demands increase their processing speed becomes less efficient than controls’. Further, perceptual and psychomotor speed were related to inattention, and psychomotor speed/incidental learning was related to hyperactivity/impulsivity. Thus, inattention may contribute to less efficient performance and worse attention to detail on tasks with a higher perceptual and/or psychomotor load; whereas hyperactivity/impulsivity may affect psychomotor speed/incidental learning, possibly via greater inaccuracy and/or reduced learning efficiency. Decision speed was not related to either dimension. Results suggest that PS deficits are primarily linked to the inattention dimension of ADHD but not exclusively. Findings also suggest PS is not a singular process but rather a multifaceted system that is differentially impacted in ADHD.     

Activation of brain attention systems in individuals with symptoms of ADHD

Previous research investigating attention and impulse control in individuals with Attention-Deficit/Hyperactivity Disorder (ADHD) has largely ignored the symptomatic differences among the three subtypes of ADHD: ADHD-Inattentive Type, ADHD-Hyperactive/Impulsive Type, and ADHD-Combined Type. The present study examined attention and impulse control by focusing on these subtypes. Based on their self-reported symptoms of ADHD, participants belonged to one of four groups: ADHD-Inattentive, ADHD-Hyperactive/Impulsive, ADHD-Combined, and control. Cortical activity was recorded from participants during performance of a Go/NoGo task. The event-related potentials (ERP) measured at frontal and posterior sites discriminated between the control group and participants with symptoms of ADHD. The control group consistently exhibited a higher P3 amplitude than all the ADHD groups. The main difference occurred at the frontal site, indicating that individuals with ADHD symptoms have deficits in the anterior attentional system, which mediates signal detection. Behavioral measures of signal sensitivity revealed that the ADHD-Inattentive and the ADHD-Hyperactive/Impulsive groups had more difficulty with the attention-demanding Go/NoGo respond-to-target task, while behavioral measures of response bias indicated that the ADHD-Hyperactive/Impulsive and the ADHD-Combined groups responded more liberally in the inhibition-demanding Go/NoGo suppress-to-target task.     

Institutional care and iron deficiency increase ADHD symptomology and lower IQ 2.5–5 years post‐adoption

Increased ADHD symptomology and lower IQ have been reported in internationally adopted (IA) children compared to non‐adopted peers (Hostinar, Stellern, Schaefer, Carlson & Gunnar, 2012; Kreppner, O'Connor & Rutter, 2001). However, it is unclear whether these outcomes are due to institutional deprivation specifically or to co‐occurring micronutrient deficiencies that disrupt brain development (Fuglestad, Rao & Georgieff, 2008b). In this study, IA children were compared to children raised in their biological families to examine differences in ADHD symptomology and IQ 2.5–5 years post‐adoption and to assess the contributions of iron deficiency (ID) and duration of deprivation to these cognitive outcomes. ADHD symptoms (parent‐ and experimenter‐reported) and IQ were evaluated in 88 IA (M = 62.1 months, SD = 2.4) and 35 non‐adopted children (M = 61.4 months, SD = 1.6). IA children were assessed 29–64 months post‐adoption (M = 41.9 months, SD = 10.2). ID was assessed during the initial post‐adoption medical visit in 69 children, and children were classified into four groups by iron status, ranging from normal to ID anemia (most severe). IA children had greater ADHD symptomology, p < .01, and lower IQ, p = .001, than non‐adopted children. Within the IA group, children with more severe ID at adoption had greater ADHD symptomology, r(69) = 0.40, p = .001, and lower IQ, r(68) = −0.28, p < .05. Duration of institutional care was positively correlated with ADHD symptoms, r(86) = .28, p < .01, but not IQ, r(85) = −.08, p = .52. Longitudinal results indicate improvement in IQ from 12 months post‐adoption to age 5 for children with greater ID severity at adoption and longer duration of institutional care but no improvement in ADHD symptoms. These results signify continuing effects of early deprivation and ID on ADHD symptoms and IQ years after adoption. A video abstract of this article can be viewed at http://www.youtube.com/watch?v=vUFDAS3DD1c     

Assessing ADHD across settings: contributions of behavioral assessment to categorical decision making

Adapted methods of behavioral assessment to assess home and school functioning in a way that maps directly to the Diagnostic and Statistical Manual of Mental Disorders (4th ed., [DSM-IV]; American Psychiatric Association, 1994). The study was conducted in a school-based sample with 5- to 12-year-old children referred to a school intervention team. A multigate set of procedures was used to assign children to one of 3 groups: attention deficit hyperactivity disorder (ADHD), inattentive group; ADHD, combined group; and a non-ADHD control group. The ADHD Rating Scale-IV was used to assess parent and teacher ratings of ADHD symptoms as delineated in DSM-IV. The findings suggest that the use of a fixed cutoff point (i.e., 6 or more symptoms), which is employed in the DSM-IV, is often not the best strategy for making diagnostic decisions. The optimal approach depends on whether diagnostic information is being provided by the parent or teacher and whether the purpose of assessment is to conduct a screening or a diagnostic evaluation. Also, the results indicate that a strategy that aggregates symptoms in the order in which they are accurate in predicting a diagnosis of ADHD is a more effective strategy than the approach used in DSM-IV, which aggregates any combination of a specific number of items. Implications for using methods of behavioral assessment to make diagnostic decisions using DSM-IV criteria are discussed.