Visual filtering in time and space among persons with Down syndrome

BACKGROUND

Individuals with Down syndrome (DS) appear to perform at a level that is commensurate with developmental expectations on simple tasks of selective attention. In this study, we examine how their selective attention is impacted by target changes that unfold over both time and space. This increased complexity reflects an attempt at greater ecological validity in an experimental task, as a steppingstone for better understanding attention among persons with DS in real-world environments.

METHODS

A modified flanker task was used to assess visual temporal and spatial filtering among persons with DS (n = 14) and typically developing individuals (n = 14) matched on non-verbal mental age (mental age = 8.5 years). Experimental conditions included varying the stimulus onset asynchronies between the onset of the target and flankers, the distances between the target and flankers, and the similarity of the target and flankers.

RESULTS

Both the participants with DS and the typically developing participants showed slower reaction times and lower accuracy rates when the flankers appeared closer in time and/or space to the target.

CONCLUSION

No group differences were found on a broad level, but the findings suggest that dynamic stimuli may be processed differently by those with DS. Implications of the findings are discussed in relation to the developmental approach to intellectual disability originally articulated by Ed Zigler.

Re-visiting the 'mysterious myth of attention deficit': A systematic review of the recent evidence

Based on the inclusive and methodologically rigorous framework provided by Ed Zigler's developmental approach, we previously challenged what we called, 'the mysterious myth of attention deficit', the fallacy of attention as a universal deficit among persons with intellectual disability (ID). In this latest update, we conducted a systematic review of studies of essential components of attention among persons with ID published in the interim since the last iteration of the mysterious myth narrative was submitted for publication approximately a decade ago. We searched the databases PubMed and PsycINFO for English-language peer-reviewed studies published from 1 January 2011 through 5 February 2021. In keeping with the developmental approach, the two essential methodological criteria were that the groups of persons with ID were aetiologically homogeneous and that the comparisons with persons with average IQs (or with available norms) were based on an appropriate index of developmental level, or mental age. Stringent use of these criteria for inclusion served to control for bias in article selection. Articles were then categorised based on aetiological group studied and component of visual attention. Based on these criteria, 18 articles were selected for inclusion out of the 2837 that were identified. The included studies involved 547 participants: 201 participants with Down syndrome, 214 participants with Williams syndrome and 132 participants with fragile X syndrome. The findings from these articles call attention to the complexities and nuances in understanding attentional functioning across homogeneous aetiological groups and highlight that functioning must be considered in relation to aetiology; factors associated with the individual, such as developmental level, motivation, styles and biases; and factors associated with both the task, such as context, focus, social and emotional implications, and levels of environmental complexity.

Trauma-informed Approaches to Substance Use Interventions with Indigenous Peoples: A Scoping Review

Indigenous Peoples experience disproportionately higher rates of problematic substance use. These problems are situated in a context of individual and intergenerational trauma from colonization, residential schools, and racist and discriminatory practices, policies, and services. Therefore, substance use interventions need to adopt a trauma-informed approach. We aimed to synthesize and report the current literature exploring the intersection of trauma and substance use interventions for Indigenous Peoples. Fourteen databases were searched using keywords for Indigenous Peoples, trauma, and substance use. Of the 1373 sources identified, 117 met inclusion criteria. Literature on trauma and substance use with Indigenous Peoples has increased in the last 5 years (2012-2016, n = 29; 2017-2021, n = 48), with most literature coming from the United States and Canada and focusing on historical or intergenerational trauma. Few articles focused on intersectional identities such as 2SLGBTQIA+ (n = 4), and none focused on veterans. There were limited sources (n = 25) that reported specific interventions at the intersection of trauma and substance use. These sources advocate for multi-faceted, trauma-informed, and culturally safe interventions for use with Indigenous Peoples. This scoping review illuminates gaps in the literature and highlights a need for research reporting on trauma-informed interventions for substance use with Indigenous Peoples.

Choices, challenges, and constraints: a pragmatic examination of the limits of mental age matching in empirical research

The work of Ed Zigler spans decades of research all singularly dedicated to using science to improve the lives of children facing different challenges. The focus of this article is on one of Zigler's numerous lines of work: advocating for the practice of mental age (MA) matching in empirical research, wherein groups of individuals are matched on the basis of developmental level, rather than chronological age. While MA matching practices represented a paradigm shift that provided the seeds from which the developmental approach to developmental disability sprouted, it is not without its own limits. Here, we examine and test the underlying assumption of linearity inherent in MA matching using three commonly used IQ measures. Results provide practical constraints of using MA matching, a solution which we hope refines future clinical and empirical practices, furthering Zigler's legacy of continued commitment to compassionate, meaningful, and rigorous science in the service of children.

Learning from facial expressions in individuals with Williams syndrome

BACKGROUND

Despite high levels of social engagement, the social competence of individuals with Williams syndrome (WS) is frequently compromised. This descriptive study explores the ability of young people with WS to learn from facial expressions when provided as a source of feedback for their actions.

METHOD

Using a novel task, the ability to interpret facial expressions and adapt behaviour after receiving feedback in the form of happy or angry faces was assessed in 12 participants with WS aged between 10 and 28 years and with a mean nonverbal mental age of 6.5 years, and in typically developing (TD) children aged between 4 and 7 years.

RESULTS

Individuals with WS were able to use facial expressions as feedback in a manner commensurate with their mental age, only when other cognitive demands were low. Their performance profile differed from that of the TD children matched for mental age and from the performance profile of 4 year olds.

CONCLUSIONS

Possible explanations for the unique performance profile observed in the participants with WS are discussed. The results highlight the need to examine social competencies in the context of the cognitive demands characteristic of social environments.

Parameters of semantic multisensory integration depend on timing and modality order among people on the autism spectrum: evidence from event-related potentials

Individuals with autism spectrum disorders (ASD) report difficulty integrating simultaneously presented visual and auditory stimuli (Iarocci & McDonald, 2006), albeit showing enhanced perceptual processing of unisensory stimuli, as well as an enhanced role of perception in higher-order cognitive tasks (Enhanced Perceptual Functioning (EPF) model; Mottron, Dawson, Soulières, Hubert, & Burack, 2006). Individuals with an ASD also integrate auditory-visual inputs over longer periods of time than matched typically developing (TD) peers (Kwakye, Foss-Feig, Cascio, Stone & Wallace, 2011). To tease apart the dichotomy of both extended multisensory processing and enhanced perceptual processing, we used behavioral and electrophysiological measurements of audio-visual integration among persons with ASD. 13 TD and 14 autistics matched on IQ completed a forced choice multisensory semantic congruence task requiring speeded responses regarding the congruence or incongruence of animal sounds and pictures. Stimuli were presented simultaneously or sequentially at various stimulus onset asynchronies in both auditory first and visual first presentations. No group differences were noted in reaction time (RT) or accuracy. The latency at which congruent and incongruent waveforms diverged was the component of interest. In simultaneous presentations, congruent and incongruent waveforms diverged earlier (circa 150 ms) among persons with ASD than among TD individuals (around 350 ms). In sequential presentations, asymmetries in the timing of neuronal processing were noted in ASD which depended on stimulus order, but these were consistent with the nature of specific perceptual strengths in this group. These findings extend the Enhanced Perceptual Functioning Model to the multisensory domain, and provide a more nuanced context for interpreting ERP findings of impaired semantic processing in ASD.

Frontal electroencephalogram asymmetry during affective processing in children with Down syndrome: a pilot study

BACKGROUND

Although the pattern of frontal electroencephalogram (EEG) asymmetry during the processing of emotion has been examined in many studies of healthy adults and typically developing infants and children, no published work has used these theoretical and methodological approaches to study emotion processing in children with Down syndrome. The purpose of this pilot study was to examine the feasibility of using brain-based measures of emotion (i.e. regional EEG asymmetry measures) with children with Down syndrome, and whether children with Down syndrome exhibit patterns of frontal brain activity during the processing of affective stimuli that are not different from typically developing children, but of lesser magnitude.

METHODS

Regional brain electrical activity (EEG) was measured in response to the presentation of popular children's video clips that varied in affective content in three children with Down syndrome and three typically developing children who were matched on reading level.

RESULTS

The children with Down syndrome appeared to show a similar pattern of frontal EEG asymmetry as the typically developing children for the video clips depicting happiness, sadness and fear. However, the magnitude of the frontal asymmetry scores for the children with Down syndrome was large across the affective stimuli, and they appeared to process the video clip depicting anger differently from the typically developing children.

CONCLUSION

This preliminary evidence suggests that brain-based measures of affective processing can be used to study the differentiation of emotion on an electrocortical level among children with Down syndrome.

Theory of mind deficits in children with fragile X syndrome

BACKGROUND

Given the consistent findings of theory of mind deficits in children with autism, it would be extremely beneficial to examine the profile of theory of mind abilities in other clinical groups such as fragile X syndrome (FXS) and Down syndrome (DS). Aim The aim of the present study was to assess whether boys with FXS are impaired in simple social situations that require them to understand their own and others' mental states - in essence: do they have a 'theory of mind'?

METHOD

Well-standardized tasks of theory of mind, the location change false belief task and the appearance-reality tasks were employed to examine whether any impairment might be specific to the FXS or part of a more generalized developmental deficit.

RESULTS

The results suggest that children with FXS do have impairment in theory of mind that is comparable to the deficit reported in other groups with learning disabilities such as DS. However, closer inspection of the impairment between these groups revealed qualitative differences in error types (realist vs. phenomenist), suggestive of atypical development that goes beyond general cognitive delay.

CONCLUSION

The findings are discussed in terms of the teasing apart of different components of social cognition in order to identify syndrome-specific deficiencies and proficiencies.

Age differences in visual search for compound patterns: long- versus short-range grouping

Visual search for compound patterns was examined in observers aged 6, 8, 10, and 22 years. The main question was whether age-related improvement in search rate (response time slope over number of items) was different for patterns defined by short- versus long-range spatial relations. Perceptual access to each type of relation was varied by using elements of same contrast (easy to access) or mixed contrast (hard to access). The results showed large improvements with age in search rate for long-range targets; search rate for short-range targets was fairly constant across age. This pattern held regardless of whether perceptual access to a target was easy or hard, supporting the hypothesis that different processes are involved in perceptual grouping at these two levels. The results also point to important links between ontogenic and microgenic change in perception (H. Werner, 1948, 1957).

Theory of mind and rule use in individuals with Down's syndrome: a test of the uniqueness and specificity claims

The relationship between Theory of Mind (ToM) and rule use was explored in adults with Down's Syndrome (DS) and in non-handicapped pre-schoolers. Twelve low-functioning individuals with DS (mean mental age = 5.1 years, mean chronological age = 22.7) performed worse than 12 MA-matched non-handicapped children (mean MA = 5.1 years) on several standard ToM tasks and on a color-shape card-sorting task in which subjects were required to switch between two incompatible sets of rules. On the ToM tasks, people with DS tended to focus on a single state of affairs (e.g. the present situation). Likewise, on the card sort, these subjects tended to use a single set of rules on all trials. Performance in the two types of task was positively correlated when MA was partialed out. The results are inconsistent with the slaim that ToM reflects a domain-specific psychological function and the notion that deficits in ToM are unique to individuals with autism.

Selective attention deficits in persons with autism: preliminary evidence of an inefficient attentional lens

A forced-choice reaction time (RT) task was used to assess the filtering component of selective attention in mental-age (MA) matched groups of persons with autism (n = 12), organic mental retardation (n = 32), familial mental retardation (n = 30), and no handicap (n = 34). Conditions varied with regard to the presence or absence of a window and number (zero, two or four) and location of distractors. The RTs of the persons with autism improved relative to the other groups in the presence of the window without distractors, but this effect was negated when distractors were also presented. The performance of the persons with autism was the most impaired in the presence of distractors. These findings represent preliminary behavioral evidence of an inefficient attentional lens among persons with autism.

Selective attention deficits in persons with autism: preliminary evidence of an inefficient attentional lens

A forced-choice reaction time (RT) task was used to assess the filtering component of selective attention in mental-age (MA) matched groups of persons with autism (n = 12), organic mental retardation (n = 32), familial mental retardation (n = 30), and no handicap (n = 34). Conditions varied with regard to the presence or absence of a window and number (zero, two or four) and location of distractors. The RTs of the persons with autism improved relative to the other groups in the presence of the window without distractors, but this effect was negated when distractors were also presented. The performance of the persons with autism was the most impaired in the presence of distractors. These findings represent preliminary behavioral evidence of an inefficient attentional lens among persons with autism.

Development of low- and high-functioning autistic children

Aspects of developmental sequences and structures were assessed in low- and high-functioning autistic and non-autistic developmentally disabled children. Specific developmental issues examined included sequences, regressions and profiles. Classification into the high- or low-functioning groups was based on a full scale IQ cutoff of 50. In general, there were few differences in the sequences of development among the groups. However, the autistic children were more likely than non-autistic children to display developmental regressions and unevenness across developmental domains. These developmental peculiarities were more pronounced in the low- as compared to high-functioning autistic children. These findings are discussed with regard to issues of developmental processes, classification and autism.

Intentional and incidental memory in organically mentally retarded, familial retarded, and nonretarded individuals

Groups of organically mentally retarded, familial retarded, and nonretarded subjects were compared on two tasks of intentional memory and one of incidental memory. With mental age being covaried, the familial group did better than the organic group on both tasks of intentional memory. However, the performance of both retarded groups was inferior to that of the nonretarded children. The three groups did not differ on incidental learning. The finding of differences between organically retarded and familial retarded persons supports the view that etiology needs to be considered when studying cognitive functioning in mentally retarded persons. The differences between the familial retarded and nonretarded groups appear to be in contradiction to the similar structure hypothesis of mental retardation.

Issues in the classification of mental retardation: differentiating among organic etiologies

Many researchers of mental retardation fail to take etiological differences into account, although the value of distinguishing between organic and familial mental retardation has long been discussed. The argument is made that even the two-group approach needs to be extended so that groups with different organic etiologies are studied separately. Taking etiological distinctions into account will allow for more precise research and a better understanding of mental retardation. Evidence for the utility of differentiating retarded persons by etiology is provided by a research review showing examples of behavioral differences between organically retarded groups. It is concluded that such differentiation also has clear implications for intervention.