Is attention impaired in ADHD?

Explanations of Attention Deficit Hyperactivity Disorder (ADHD) in terms of a weakness in Executive Function (EF) or related concepts, such as inhibition, are briefly reviewed. Some alternative views are considered, in particular a proposal by Manly and others that ADHD is a weakness primarily of sustained attention (plus control of attention), but not of selective attention, as measured by the Test of Everyday Attention in Children (TEA-Ch; Manly et al., 2001). The underlying structure of the TEA-Ch is analysed and it is concluded that the distinction between selective attention, sustained attention, and control of attention in this battery is not well-founded. Furthermore, evidence from studies by Wilding and others, from visual search tasks similar to those employed by Manly et al. to measure selective attention, demonstrates that, while unimpaired- and impaired-attention groups do not differ in speed of performance on such tasks (the measure employed in the TEA-Ch), they do differ reliably in accuracy. Available evidence from other visual search tasks comparing such groups is reviewed and found to be inconsistent. An attempt is made to resolve the inconsistencies and it is suggested that search tasks including demands that engage EF processes are more likely to demonstrate differences between these groups. It is concluded therefore that the most plausible explanation at present of impaired attention is in terms of weaknesses in EF. Suggestions for improving the precision and detail of this type of explanation are offered.     

Is grasping impaired in hemispatial neglect?

Patients with right unilateral cerebral stroke, four of which showed acute hemispatial neglect, and healthy aged-matched controls were tested for their ability to grasp objects located in either right or left space at near or far distances. Reaches were performed either in free vision or without visual feedback from the hand or target object. It was found that the patient group showed normal grasp kinematics with respect to maximum grip aperture, grip orientation, and the time taken to reach the maximum grip aperture. Analysis of hand path curvature showed that control subjects produced straighter right hand reaches when vision was available compared to when it was not. The right hemisphere lesioned patients, however, showed similar levels of curvature in each of these conditions. No behavioural differences, though, could be found between right hemisphere lesioned patients with or without hemispatial neglect on either grasp parameters, path deviation or temporal kinematics.     

Is implicit sequence learning impaired in schizophrenia? A meta-analysis

Cognition in schizophrenia seems to be characterized by impaired performance on most tests of explicit or declarative learning contrasting with relatively intact performance on most tests of implicit or procedural learning. At the same time there have been conflicting results for studies that have used the Serial Reaction Time (SRT) task to examine implicit learning in people with schizophrenia. In the present research, we used meta-analysis to clarify whether or not people with schizophrenia show impaired performance on the SRT task. A systematic review found nine studies published in peer review journals that had each compared the performance of a group of people with schizophrenia with healthy controls on the standard SRT task or a variant of it. The resulting meta-analysis represented the responses of 205 participants with schizophrenia and 159 healthy controls on the SRT task. The analysis found that participants with schizophrenia perform less well than controls reflected by a pooled effect size of 0.51. A secondary analysis of all nine studies found that they all reported a point estimate of the change in reaction time between sequence and random trials that was greater for the controls. We conclude that there is a moderate impairment in implicit sequence learning among people with schizophrenia and speculate on the implications of this for understanding this disorder. Suggestions for improving the methodological quality and statistical reporting of studies of this topic are made.     

Is ADHD a disinhibitory disorder?

Attention deficit hyperactivity disorder (ADHD) is widely theorized to stem from dysfunctional inhibitory processes. However, the definition of inhibition is imprecisely distinguished across theories. To clarify the evidence for this conception, the author relies on a heuristic distinction between inhibition that is under executive control and inhibition that is under motivational control (anxiety or fear). It is argued that ADHD is unlikely to be due to a motivational inhibitory control deficit, although suggestions are made for additional studies that could overturn that conclusion. Evidence for a deficit in an executive motor inhibition process for the ADHD combined type is more compelling but is not equally strong for all forms of executive inhibitory control. Remaining issues include specificity to ADHD, whether inhibitory problems are primary or secondary in causing ADHD, role of comorbid anxiety and conduct disorder, and functional deficits in the inattentive ADHD subtype.     

Is associative recognition more impaired than item recognition memory in Schizophrenia? A meta-analysis

Item recognition memory judgment can be based on two processes: item familiarity and/or the conscious recollection of the initial event. On the other hand, associative recognition relies preferably on conscious recollection. Since evidence points to a specific deficit of conscious recollection in schizophrenia, these patients could show greater impairment during associative recognition tasks relative to item recognition tasks. A meta-analysis of 23 studies of recognition memory in schizophrenia was conducted to test this hypothesis. The impairment is indeed 20% greater (p=0.04) for associative recognition relative to item recognition. This study supports the hypothesis of a specific conscious recollection deficit underlying episodic memory impairment in schizophrenia.     

Is recognition accuracy really impaired when the target is repeated in the display?

Bjork and Murray (1977) have presented a feature-specific interactive channels model that predicts perceptual interference between letters presented simultaneously in visual displays. Maximum interference is predicted when a target letter is presented with an identical letter. In their experiment, Bjork and Murray found support for their model, but their results could have occurred artifactually from response biases of their subjects. Santee and Egeth (1980) used a different paradigm that eliminated the possibility of this particular response bias and reported that their data supported the feature-specific model. However, the present paper shows that analysis of their data by Santee and Egeth was incomplete and the comparisons inappropriate. In two experiments that used the Santee and Egeth paradigm, we failed to find support for the feature-specific model when more detailed analyses of the data were undertaken. In a third experiment, one that used the Bjork and Murray paradigm, but with control of response bias, no significant or suggestive evidence was found that feature similarity between noise and target letters affected recognition of the latter.     

Social Problems in ADHD: Is it a Skills Acquisition or Performance Problem?

Recent models suggest that social skills training’s inefficacy for children with ADHD may be due to target misspecification, such that their social problems reflect inconsistent performance rather than knowledge/skill gaps. No study to date, however, has disentangled social skills acquisition from performance deficits in children with ADHD. Children ages 8–12 with ADHD (n?=?47) and without ADHD (n?=?23) were assessed using the well-validated social behavioral analysis framework to quantify cross-informant social skills acquisition deficits, performance deficits, and strengths. Results provided support for the construct and predictive validities of this Social Skills Improvement System (SSIS) alternate scoring method, including expected magnitude and valence relations with BASC-2 social skills and ADHD symptoms based on both parent and teacher report. Acquisition deficits were relatively rare and idiosyncratic for both the ADHD and Non-ADHD groups, whereas children with ADHD demonstrated cross-informant social performance deficits (d?= 0.82–0.99) on several specific behaviors involving attention to peer directives, emotion regulation, and social reciprocity. Relative to themselves, children with ADHD were perceived by parents and teachers as exhibiting more social strengths than social acquisition deficits; however, they demonstrated significantly fewer social strengths than the Non-ADHD group (d?=??0.71 to ?0.89). These findings are consistent with recent conceptualizations suggesting that social problems in ADHD primarily reflect inconsistent performance rather than a lack of social knowledge/skills. Implications for refining social skills interventions for ADHD are discussed.     

Is inhibition of return a reflexive effect?

The inhibition of return (IOR) phenomenon is routinely considered an effect of reflexive attention because the paradigm used to generate IOR employs peripheral cues that are uninformative as to where a target will appear. Because the cues are spatially unreliable it is thought that there is no reason for attention to be committed volitionally to them, and hence, the IOR effect is considered reflexive. What has been generally overlooked, however, is that the cues provide reliable temporal information as to when a target will occur. This predictive information is used by participants to prepare volitionally for when a target is likely to appear. We investigated whether the IOR effect is a product of the volitional application of attention to peripheral cues for the use of their temporal information. To test this idea we rendered the temporal information provided by peripheral cues unreliable. While this eliminated participants using the cues volitionally, it did not abolish the IOR phenomenon. These data demonstrate two new findings. First, the IOR effect is fundamentally a reflexive phenomenon. Second, when peripheral cues are not used volitionally, the IOR effect is attenuated. Together, the present findings indicate that the IOR effect can be modulated by volitional (top-down) processes but it is not the product of them. We argue that an intimate link between fronto-parietal regions and the superior colliculus provide a functional neural mechanism for this volitional effect to impact IOR.     

Is verbal–spatial binding in working memory impaired by a concurrent memory load?

Binding processes play a critical role in memory. We investigated whether the binding of (visually presented) verbal and spatial (locations) information involves general attentional resources, as stipulated in the revised working memory model, by comparing measures of binding in the presence and absence of a concurrent memory load. Using an adaptation of a probe recognition task contrasting performance between intact and recombined conditions, we found that the concurrent retention of a sequence of three pure tones eliminated verbal–spatial binding. The present study constitutes the first to directly measure the impact of a concurrent memory load on verbal–spatial binding and suggests that such binding may indeed recruit attentional resources, consistent with some recent findings in the visual–spatial binding literature.     

Is It ADHD,LD, Depression or Allergies?

Abstract

This article presents a model for understanding the complexity of diagnosing Attention Deficit Hyperactivity Disorder (ADHD). The model uses a continuum of attentional skills to help the reader understand why accurate diagnosis is so important. Issues related to differential determination of attentional problems that may be attributed to learning disabilities, allergies and childhood depression are explored. Specific guidelines to help teachers understand how to judge the appropriateness and comprehensiveness of the diagnostic process are provided.     

Psychology impaired?

This article comments on M.J. Layman and J.R. McNamara's (1997) article about remediation for ethics violations. The author addresses the practice of regarding ethical violation, and its subset, boundary violation, and its subset, sexual misconduct, as synonymous. When professional impairment (disability) is seen as equivalent to sexual misconduct, the resulting generalized confusion impedes much needed progress in critical areas. The profession awaits structured assistance from the American Psychological Association to clarify and provide leadership in policy development.     

Is the Positive Illusory Bias Illusory? Examining Discrepant Self-Perceptions of Competence in Girls with ADHD

It has been claimed that excessively positive self-perceptions of competence are a key risk factor for concurrent and subsequent impairments in youth with attention-deficit/ hyperactivity disorder (ADHD). We examined whether girls with ADHD demonstrate positive illusory self-perceptions in scholastic competence, social acceptance, and behavioral conduct domains. We then tested, across a five-year longitudinal span, whether (a) such self-perceptions versus (b) the constituent informant ratings or test scores were more strongly predictive of adolescent impairment and positive adjustment. Participants included an ethnically diverse sample of 140 girls with ADHD and 88 comparison girls, aged 6-12 at baseline (M?=?9.0, SD?=?1.7). Girls with ADHD rated themselves as more positive than indicated by external ratings, but these self-reports were still in a negative direction (comparison girls rated themselves as less positive than these indicators). ADHD subtypes were not related to discrepancy scores. Higher rates of depression symptoms were associated with attenuated discrepancy scores. Crucially, measures of actual competence were more strongly associated with adolescent impairment and positive adjustment than were "illusory" self-perceptions for girls with ADHD. Our findings challenge the view that, at least in girls with ADHD, overly positive and "illusory" appraisals of competence are strongly associated with future impairment and adjustment. The key psychometric point is that, in difference or discrepancy scores, the individual components of such scores should be separately examined.     

Is a Mild Deficit in Executive Functions in Boys Related to Childhood ADHD or to Parental Multigenerational Alcoholism?

A mild deficit in executive functions has been hypothesized to be associated with attention deficit hyperactivity disorder (ADHD), with externalizing problem behaviors such as conduct disorder (CD) and with the vulnerability to alcoholism in sons of multi-generational alcoholics (SOMGAs). These three categories overlap, which raises concerns about the specificity of the hypothesized associations. In the present study, measures of executive functions (EFs) were tested in seventy-six 7- to 11-year-old boys: boys with ADHD but without a family history of addiction, SOMGAs, and controls. Specific deficits in EFs were found for boys with ADHD but not for SOMGAs. The association between a deficit in EFs and attention problems remained after controlling for externalizing problem behaviors, but not for the reverse. These results suggest that a mild deficit in EFs is specifically related to ADHD and that the deficits reported in boys with CD and in SOMGAs are due to relatively high attentional problems in these groups or due to other factors such as motivation.     

Whither causal models in the neuroscience of ADHD?

In this paper we examine the current status of the science of ADHD from a theoretical point of view. While the field has reached the point at which a number of causal models have been proposed, it remains some distance away from demonstrating the viability of such models empirically. We identify a number of existing barriers and make proposals as to the best way for these to be overcome in future studies. These include the need to work across multiple levels of analysis in multidisciplinary teams; the need to recognize the existence of, and then model, causal heterogeneity; the need to integrate environmental and social processes into models of genetic and neurobiological influence; and the need to model developmental processes in a dynamic fashion. Such a model of science, although difficult to achieve, has the potential to provide the sort of framework for programmatic model-based research required if the power and sophistication of new neuroscience technologies are to be effectively exploited.     

Is social inhibition of return due to action co-representation?

When two individuals alternate reaching responses to visual targets presented on a shared workspace, one individual is slower to respond to targets occupying the same position as their partner’s previous response. This phenomenon is thought to be due to processes that inhibit the initiation of a movement to a location recently acted upon. However, two distinct forms of the inhibition account have been posited, one based on inhibition of an action, the other based on inhibition of an action and location. Furthermore, an additional recent explanation suggests the phenomenon is due to mechanisms that give rise to action congruency effects. Thus the three different theories differ in the degree to which action co-representation plays a role in the effect. The aim of the present work was to examine these competing accounts. Three experiments demonstrated that when identical actions are made, the effect is modulated by the configuration of the visual stimuli acted upon and the perceptual demands of the task. In addition, when the co-actors perform different actions to the same target, the effect is still observed. These findings support the hypothesis that this particular joint action phenomenon is generated via social cues that induce location-based inhibition of return rather than being due to shared motor co-representations.     

Is the Association of ADHD with Socio-Economic Disadvantage Explained by Child Comorbid Externalizing Problems or Parent ADHD?

It has been unclear whether an associations of child ADHD with socio-economic disadvantage (SES) could be accounted for by (a) parental ADHD explaining both low SES and child ADHD, and/or (b) the joint overlap of ODD or CD with low SES and ADHD. Study 1 used a community-recruited case-control sample with detailed evaluation of SES indicators, child ADHD, child externalizing, and parent ADHD symptoms (n = 931 children, 521 ADHD, 577 boys, 354 girls) in a path modeling analysis with latent variables. Study 2 evaluated ADHD and externalizing behavior in a regression model using a poverty index for SES, in 70,927 children (48.2% female) aged 5–17 years from the US 2011–2012 National Survey of Children’s Health (NSCH). In Study 1, lower SES was related to the ADHD latent variable, β = ?.18, p < .001; 95%CI [?.25,-.12]. This effect held when parent ADHD and child ODD and CD were in the model, β = ?.11, p < .01, 95% CI [?.09,-.03], equivalent to OR = 1.50, 95% CI[1.12–2.04]). In Study 2, these results replicated. Adjusting only for age and sex, children from families who were below 200% of the federal poverty line were more likely to have moderate or severe ADHD than no ADHD, versus children above that line, OR = 2.13, 95% CI[1.79,2.54], p < .001. The effect held after adjusting for disruptive/externalizing problems, OR = 1.61, p < .01, 95%CI [1.32,1.96]. The effect size for comparable models was similar across both studies, lending higher confidence to the results. It is concluded that the SES association with child ADHD is not explained by artifact and requires a mechanistic explanation.     

Diagnosis of ADHD in Adults: What Is the Appropriate DSM-5 Symptom Threshold for Hyperactivity-Impulsivity?

Objective: To empirically identify the appropriate symptom threshold for hyperactivity-impulsivity for diagnosis of ADHD in adults. Method: Participants were 88 adults (M [SD] age = 41.69 [11.78] years, 66% female, 16% minority) meeting formal DSM-IV criteria for ADHD combined or predominantly inattentive subtypes based on a structured diagnostic interview keyed to DSM-IV (Conners' Adult ADHD Diagnostic Interview for DSM-IV [CAADID]). All participants also completed the Conners' Adult ADHD Rating Scale (CAARS), which was normed on the general adult population and includes subscales for DSM-IV inattentive and DSM-IV hyperactive-impulsive symptoms. A T-score threshold of 65 (at least 1.5 SD above population mean) on the CAARS DSM-IV hyperactive-impulsive dimension was used to identify participants with empirically elevated symptom severity. Results: Of 88 participating adults, 48 (55%) had a T-score of at least 65 (1.5 SD) on the CAARS DSM-IV Hyperactive-Impulsive scale. Of these, only 25 (52%) met the DSM-IV cutoff of six hyperactive-impulsive symptoms on the CAADID. Thus, approximately half of those who reported empirically elevated hyperactive-impulsive complaints on the CAARS did not concurrently meet the six-symptom DSM-IV cutoff on the CAADID. An alternative cutoff of four hyperactive-impulsive symptoms on the CAADID captured 39 (81%) cases identified by the CAARS. Conclusion: In adults, mandating at least six hyperactive-impulsive symptoms excludes a significant percentage (almost half) of adults who are at least 1.5 SD above the population mean on a dimensional measure of hyperactivity-impulsivity. These data provide a compelling basis for lowering the symptom threshold of hyperactivity-impulsivity for adults in the DSM-5.     

Latent inhibition in the honey bee, Apis mellifera: Is it a unitary phenomenon?

Latent inhibition refers to learning that some stimuli are not signals of important events. It has been widely studied in vertebrates, but it has been substantially less well studied in invertebrates. We present an investigation into latent inhibition in the honey bee (Apis mellifera) using a proboscis extension response conditioning procedure that involved ‘preexposure’ of an odor without reinforcement prior to appetitive conditioning. A significant latent inhibition effect, measured in terms of a reduction in acquisition performance to the preexposed odor, was observed after 8 unreinforced presentations, and the effect continued to increase in strength up to 30 presentations. We also observed that memories formed for the preexposed odor lasted at least 24 h. Further manipulation of interstimulus interval and the visual conditioning context partially attenuated the effect. The latter results indicate that latent inhibition in honey bees may not be a unitary phenomenon. Two different mechanisms may be required, in which one mechanism is dependent on the visual context and the second is not.     

PDD Symptoms in ADHD,an Independent Familial Trait?

The aims of this study were to investigate whether subtle PDD symptoms in the context of ADHD are transmitted in families independent of ADHD, and whether PDD symptom familiality is influenced by gender and age. The sample consisted of 256 sibling pairs with at least one child with ADHD and 147 healthy controls, aged 5–19 years. Children who fulfilled criteria for autistic disorder were excluded. The Children’s Social Behavior Questionnaire (CSBQ) was used to assess PDD symptoms. Probands, siblings, and controls were compared using analyses of variance. Sibling correlations were calculated for CSBQ scores after controlling for IQ, ADHD, and comorbid anxiety. In addition, we calculated cross-sibling cross-trait correlations. Both children with ADHD and their siblings had higher PDD levels than healthy controls. The sibling correlation was 0.28 for the CSBQ total scale, with the CSBQ stereotyped behavior subscale showing the strongest sibling correlation (r = 0.35). Sibling correlations remained similar in strength after controlling for IQ and ADHD, and were not confounded by comorbid anxiety. Sibling correlations were higher in female than in male probands. The social subscale showed stronger sibling correlations in elder than in younger sibling pairs. Cross-sibling cross-trait correlations for PDD and ADHD were weak and not-significant. The results confirm that children with ADHD have high levels of PDD symptoms, and further suggest that the familiality of subtle PDD symptoms in the context of ADHD is largely independent from ADHD familiality.