Individuals with autism spectrum disorders (ASD) spend the majority of their lives as adults, and psychosocial interventions show promise for improving outcomes in this population. This research conducted a systematic review of all peer-review studies evaluating psychosocial interventions for adults with ASD. A total of 1217 studies were reviewed, only 13 met inclusion criteria. The majority of studies were single case studies or non-randomized controlled trials, and most focused on applied behavior analysis or social cognition training. Effects of psychosocial treatment in adult ASD were largely positive ranging from d = .14 to 3.59, although the quantity and quality of studies is limited. There is substantial need for the rigorous development and evaluation of psychosocial treatments for adults with ASD.
Asperger’s; Pervasive Developmental Disorder; Treatment; Therapy
Current theories concerning the cause of autism spectrum disorders (ASDs) have converged on the concept of abnormal development of brain connectivity. This concept is supported by accumulating evidence from functional imaging, diffusion tensor imaging, and high definition fiber tracking studies which suggest altered microstructure in the axonal tracts connecting cortical areas may underly many of the cognitive manifestations of ASD. Additionally, large-scale genomic studies implicate numerous gene candidates known or suspected to mediate neuritic outgrowth and axonal guidance in fetal and perinatal life. Neuropathological observations in postmortem ASD brain samples further support this model and include subtle disturbances of cortical lamination and subcortical axonal morphology. Of note is the relatively common finding of poor differentiation of the gray–white junction associated with an excess superficial white matter or “interstitial” neurons (INs). INs are thought to be remnants of the fetal subplate, a transient structure which plays a key role in the guidance and morphogenesis of thalamocortical and cortico-cortical connections and the organization of cortical columnar architecture. While not discounting the importance of synaptic dysfunction in the etiology of ASD, this paper will briefly review the cortical abnormalities and genetic evidence supporting a model of dysregulated axonal growth and guidance as key developmental processes underlying the clinical manifestations of ASD.
autism spectrum disorders; connectivity; neuritic outgrowth; axonal guidance; subplate
Prior studies have indicated brain abnormalities underlying social processing in autism, but no fMRI study has specifically addressed the differential processing of direct and averted gaze, a critical social cue. Fifteen adolescents and adults with autism and 14 typically developing comparison participants viewed dynamic virtual-reality videos depicting a simple but realistic social scenario, in which an approaching male figure maintained either direct or averted gaze. Significant group by condition interactions reflecting differential responses to direct versus averted gaze in people with autism relative to typically developing individuals were identified in the right temporoparietal junction, right anterior insula, left lateral occipital cortex, and left dorsolateral prefrontal cortex. Our results provide initial evidence regarding brain mechanisms underlying the processing of gaze direction during simple social encounters, providing new insight into the social deficits in individuals with autism.
Autism; direct gaze; averted gaze; gaze processing; functional magnetic resonance imaging
Adults with autism experience significant impairments in social and non-social information processing for which few treatments have been developed. This study conducted an 18-month uncontrolled trial of Cognitive Enhancement Therapy (CET), a comprehensive cognitive rehabilitation intervention, in 14 verbal adults with autism spectrum disorder to investigate its feasibility, acceptability, and initial efficacy in treating these impairments. Results indicated that CET was satisfying to participants, with high treatment attendance and retention. Effects on cognitive deficits and social behavior were also large (d = 1.40 to 2.29) and statistically significant (all p < .001). These findings suggest that CET is a feasible, acceptable, and potentially effective intervention for remediating the social and non-social cognitive impairments in verbal adults with autism.
Cognitive Enhancement Therapy; cognitive rehabilitation; cognitive remediation; psychosocial treatment; cognitive therapy; adult treatment; autism; autism spectrum disorder
Behavioral studies have documented a relative advantage in some aspects of visuospatial cognition in autism although it is not consistently found in higher functioning individuals with autism. The purpose of this functional neuroimaging study was to examine the neural activity in high functioning individuals with autism while they performed a block design task that systematically varied with regard to whether a global pattern was present. Participants were 14 adults with high-functioning autism and 14 age and IQ matched typical controls. The task was to identify a missing block in target figures which had either an obvious global shape or was an arbitrary array of blocks. Behavioral results showed intact, but not superior, performance in our participants with autism. A key group difference was that the participants with autism showed reliably greater activation in occipital and parietal regions in both tasks suggesting an increased reliance of the autism group on posterior brain areas to mediate visuospatial tasks. Thus, increased reliance on relatively posterior brain regions in itself may not guarantee superior performance as seen in the present study.
Autism; fMRI; global-local processing; block design task
Despite extensive reports of sensory symptoms in autism, there is little empirical support for their neurological basis. Sixty individuals with high-functioning autism and 61 matched typical comparison participants were administered a sensory questionnaire and standardized neuropsychological tests of elementary and higher cortical sensory perception. Thirty-two per cent of participants with autism endorsed more sensory sensitivity items than any of the participants in the comparison group. On the sensory perceptual exam, both groups made few errors on elementary sensory perception items. Controls made few errors on higher cortical sensory perception items, but 30% of the participants with autism made high numbers of errors, though there was no evidence of the neglect syndrome. There was little correlation between the sensory sensitivities and the sensory perceptual deficits, likely due to the low correspondence between the measures. These results support the common occurrence of disturbances in sensory experiences in high functioning individuals with autism based on first person report, and the presence of neurological abnormalities in higher cortical sensory perception.
autism; sensory sensitivities; sensory perception; sensory neglect
To investigate the functional integrity of cerebellar and frontal system in autism using oculomotor paradigms.
Cerebellar and neocortical systems models of autism have been proposed. Courchesne and colleagues have argued that cognitive deficits such as shifting attention disturbances result from dysfunction of vermal lobules VI and VII. Such a vermal deficit should be associated with dysmetric saccadic eye movements because of the major role these areas play in guiding the motor precision of saccades. In contrast, neocortical models of autism predict intact saccade metrics, but impairments on tasks requiring the higher cognitive control of saccades.
A total of 26 rigorously diagnosed nonmentally retarded autistic subjects and 26 matched healthy control subjects were assessed with a visually guided saccade task and two volitional saccade tasks, the oculomotor delayed-response task and the antisaccade task.
Metrics and dynamic of the visually guided saccades were normal in autistic subjects, documenting the absence of disturbances in cerebellar vermal lobules VI and VII and in automatic shifts of visual attention. Deficits were demonstrated on both volitional saccade tasks, indicating dysfunction in the circuitry of prefrontal cortex and its connections with the parietal cortex, and associated cognitive impairments in spatial working memory and in the ability to voluntarily suppress context-inappropriate responses.
These findings demonstrate intrinsic neocortical, not cerebellar, dysfunction in autism, and parallel deficits in higher order cognitive mechanisms and not in elementary attentional and sensorimotor systems in autism.
We examined motor and tactile-perceptual skills in individuals with high-functioning autism (IHFA) and matched typically developing individuals (TDI) ages 5 – 21 years. Grip strength, motor speed and coordination were impaired in IHFA compared to matched TDI, and the differences between groups varied with age. Although tactile-perceptual skills of IHFA were impaired compared to TDI on several measures, impairments were statistically and clinically significant only for stereognosis. Motor and tactile-perceptual skills should be assessed in children with IHFA and intervention should begin early because these skills are essential to school performance. Impairments in coordination and stereognosis suggest a broad though selective under-development of the circuitry for higher order abilities regardless of domain that is important in the search for the underlying disturbances in neurological development.
autism; motor skills; coordination; strength; tactile-perceptual skills; stereognosis
Cognitive rehabilitation is an emerging set of potentially effective interventions for the treatment of autism spectrum disorder, yet the applicability of these approaches for “high functioning” adults who have normative levels of intelligence remains unexplored. This study examined the initial cognitive performance characteristics of 40 verbal adults with autism enrolled in a pilot trial of Cognitive Enhancement Therapy to investigate the need for cognitive rehabilitation in this population. Results revealed marked and broad deficits across neurocognitive and social-cognitive domains, despite above-average IQ. Areas of greatest impairment included processing speed, cognitive flexibility, and emotion perception and management. These findings indicate the need for comprehensive interventions designed to enhance cognition among verbal adults with autism who have intact intellectual functioning.
Cognition; Social cognition; Neurocognition; Cognitive rehabilitation; Adults
Autism spectrum disorder (ASD) is often associated with poor emotional control and psychopathology, such as anxiety and depression; however, little is known about the underlying mechanisms. Emotion regulation (ER) is a potential contributing factor, but there has been limited research on ER and its role in comorbid psychopathology in ASD. In this study, we compared self-reported ER with self- and parent reports of psychopathology in 25 high-functioning adolescents with ASD and 23 age- and Intelligence Quotient (IQ)-matched typically developing controls. Contrary to expectations, both groups reported similar levels of adaptive, voluntary forms of ER (problem solving, acceptance, etc.). However, the ASD group reported significantly greater use of involuntary forms of ER that are typically maladaptive, including remaining focused on the stressor (e.g. rumination and emotional arousal) and shutting down (e.g. emotional numbing and being unable to think or act). Associations between ER and psychopathology were generally more robust using self-report rather than parent report. For both groups, greater endorsement of involuntary ER strategies was associated with higher ratings of psychopathology, whereas voluntary ER strategies focused on changing or adapting to the situation were significantly associated with lower levels of psychopathology. The magnitude and direction of association between ER types and psychopathology were similar for measures of depression and anxiety. These findings can help guide the development of psychosocial treatments targeting dysfunctional ER in adolescents with ASD. Interventions focused on ER as a transdiagnostic process may be a more robust method to improve emotional control and decrease emotional distress in ASD than disorder-specific interventions.
emotion regulation; psychiatric comorbidity; depression; anxiety; coping
Research has demonstrated the potential role of the brainstem in the pathobiology of autism. Previous studies have suggested reductions in brainstem volume and a relationship between this structure and sensory abnormalities. However, little is known regarding the developmental aspects of the brainstem across childhood and adolescence. The goal of this pilot study was to examine brainstem development via MRI volumetry using a longitudinal research design. Participants included 23 boys with autism and 23 matched controls (age range = 7–17 years), all without intellectual disability. Participants underwent structural MRI scans once at baseline and again at two-year follow-up. Brainstem volumetric measurements were performed using the BRAINS2 software package. There were no significant group differences in age, gender, handedness, and total brain volume; however, full-scale IQ was higher in controls. Autism and control groups showed different patterns of growth in brainstem volume. While whole brainstem volume remained stable in controls over the two-year period, the autism group showed increases with age reaching volumes comparable to controls by age 15 years. This increase of whole brainstem volume was primarily driven by bilateral increases in gray matter volume. Findings from this preliminary study are suggestive of developmental brainstem abnormalities in autism primarily involving gray matter structures. These findings are consistent with autism being conceptualized as a neurodevelopmental disorder with alterations in brain-growth trajectories. More longitudinal MRI studies are needed integrating longitudinal cognitive/behavioral data to confirm and elucidate the clinical significance of these atypical growth patterns.
Autism; brainstem; development; gray matter; longitudinal; MRI
Autism spectrum disorder (ASD) and schizophrenia are both conditions that are characterized by impairments in social and non-social cognition, yet commonalities in the magnitude and domains of cognitive deficits across these two conditions remains unclear. This study examined neurocognitive and social-cognitive functioning in 47 outpatients with schizophrenia, 43 verbal adults with ASD, and 24 healthy volunteers. A comprehensive neuropsychological battery assessing processing speed, attention, memory, and problem-solving domains was administered along with a social-cognitive battery of emotion processing. Results demonstrated large and significant impairments in emotion processing and neurocognition relative to healthy individuals in participants with autism (d = -.97 and -1.71, respectively) and schizophrenia (d = -.65 and -1.48, respectively). No significant differences were observed between those with ASD and schizophrenia on any cognitive domain assessed, and the areas of greatest impairment were identical across both disorders and included slowness in speed of processing and an inability to understand emotions. These findings indicate a high degree of similarity in the cognitive challenges experienced by verbal adults with autism and schizophrenia, and the potential need for trans-diagnostic remediation approaches to enhance cognition in these conditions.
This review covers a fraction of the new research developments in autism but establishes the basic elements of the new neurobiologic understanding of autism. Autism is a polygenetic developmental neurobiologic disorder with multiorgan system involvement, though it predominantly involves central nervous system dysfunction. The evidence supports autism as a disorder of the association cortex, both its neurons and their projections. In particular, it is a disorder of connectivity, which appears, from current evidence, to primarily involve intrahemispheric connectivity. The focus of connectivity studies thus far has been on white matter, but alterations in functional magnetic resonance imaging activation suggest that intracortical connectivity is also likely to be disturbed. Furthermore, the disorder has a broad impact on cognitive and neurologic functioning. Deficits in high-functioning individuals occur in processing that places high demands on integration of information and coordination of multiple neural systems. Intact or enhanced abilities share a dependence on low information-processing demands and local neural connections. This multidomain model with shared characteristics predicts an underlying pathophysiologic mechanism that impacts the brain broadly, according to a common neurobiologic principle. The multiorgan system involvement and diversity of central nervous system findings suggest an epigenetic mechanism.
A clinical memory test was administered to 38 high-functioning children with autism and 38 individually matched normal controls, 8–16 years of age. The resulting profile of memory abilities in the children with autism was characterized by relatively poor memory for complex visual and verbal information and spatial working memory with relatively intact associative learning ability, verbal working memory, and recognition memory. A stepwise discriminant function analysis of the subtests found that the Finger Windows subtest, a measure of spatial working memory, discriminated most accurately between the autism and normal control groups. A principal components analysis indicated that the factor structure of the subtests differed substantially between the children with autism and controls, suggesting differing organizations of memory ability.
autism; memory assessment; discriminant analysis; principal components analysis
A wide range of abilities was assessed in 56 high-functioning children with autism and 56 age- and IQ-matched controls. Stepwise discriminant analyses produced good group discrimination for sensory-perceptual, motor, complex language, and complex memory domains but lower agreement for the reasoning domain than previously obtained for adults. Group discrimination did not occur for attention, simple language, simple memory, and visuospatial domains. Findings provide additional support for a complex information-processing model for autism, previously based on adult data, demonstrating a pattern across domains of selective impairments on measures with high demands for integration of information and sparing when demands were low. Children as compared to adults with autism exhibited more prominent sensory-perceptual symptoms and less pronounced reasoning deficits reflecting brain maturation.
Autism is a neurodevelopmental disorder involving dysmaturation of widely distributed brain systems. Accordingly, behaviors that depend on distributed systems, such as higher level cognition and sensorimotor control, are compromised in the disorder. The current study investigated alterations in neural systems underlying sensorimotor disturbances in autism. An fMRI investigation was conducted using saccadic and pursuit eye movement paradigms with 13 high-functioning individuals with autism and 14 age- and IQ- matched typically developing individuals. Individuals with autism had reduced activation in cortical eye fields and cerebellar hemispheres during both eye movement tasks. When executing visually guided saccades, individuals with autism had greater activation bilaterally in a frontostriatal circuit including dorsolateral prefrontal cortex, caudate nucleus, medial thalamus, anterior and posterior cingulate cortex, and right dentate nucleus. The increased activation in prefrontal-striatal-thalamocortical circuitry during visually guided saccades indicates that systems typically dedicated to cognitive control may need to compensate for disturbances in lower-level sensorimotor systems. Reduced activation throughout visual sensorimotor systems may contribute to saccadic and pursuit disturbances that have been reported in autism. These findings document that neurodevelopmental disturbances in autism affect widely distributed brain systems beyond those mediating language and social cognition.
Autism; Neuroimaging; Eye Movement; Attention; Frontostriatal Systems
This study used the modality shift experiment, a relatively simple reaction time measure to visual and auditory stimuli, to examine attentional shifting within and across modalities in 33 children and 42 adults with high-functioning autism as compared to matched numbers of age- and ability-matched typical controls. An exaggerated “modality shift effect” relative to the TD children occurred for the children with autism in conditions involving the reaction time when shifting from sound to light but not from light to sound. No exaggerated MSE was found for the adults with autism; rather, their responses were characterized by a generalized slowness relative to the adults with TD. These results suggest a lag in maturational development in autism in basic information processing mechanisms.
autism; attentional shifting; speed of processing; perceptual development
Attention allows us to selectively process the vast amount of information with which we are confronted. Focusing on a certain location of the visual scene (visual spatial attention) enables the prioritization of some aspects of information while ignoring others. Rapid manipulation of the attention field (i.e., the location and spread of visual spatial attention) is a critical aspect of human cognition, and previous research on spatial attention in individuals with autism spectrum disorders (ASD) has produced inconsistent results. In a series of three experiments, we evaluated claims in the literature that individuals with ASD exhibit a deficit in voluntarily controlling the deployment and size of the spatial attention field. We measured how well participants perform a visual discrimination task (accuracy) and how quickly they do so (reaction time), with and without spatial uncertainty (i.e., the lack of predictability concerning the spatial position of the upcoming stimulus). We found that high–functioning adults with autism exhibited slower reactions times overall with spatial uncertainty, but the effects of attention on performance accuracies and reaction times were indistinguishable between individuals with autism and typically developing individuals, in all three experiments. These results provide evidence of intact endogenous spatial attention function in high–functioning adults with ASD, suggesting that atypical endogenous spatial attention cannot be a latent characteristic of autism in general.
Rapid manipulation of the attention field (i.e., the location and spread of visual spatial attention) is a critical aspect of human cognition, and previous research on spatial attention in individuals with autism spectrum disorders (ASD) has produced inconsistent results. In a series of three psychophysical experiments, we evaluated claims in the literature that individuals with ASD exhibit a deficit in voluntarily controlling the deployment and size of the spatial attention field. We measured the spatial distribution of performance accuracies and reaction times to quantify the sizes and locations of the attention field, with and without spatial uncertainty (i.e., the lack of predictability concerning the spatial position of the upcoming stimulus). We found that high–functioning adults with autism exhibited slower reactions times overall with spatial uncertainty, but the effects of attention on performance accuracies and reaction times were indistinguishable between individuals with autism and typically developing individuals, in all three experiments. These results provide evidence of intact endogenous spatial attention function in high–functioning adults with ASD, suggesting that atypical endogenous attention cannot be a latent characteristic of autism in general.
Attention; spatial attention; endogenous attention; psychophysics; adults; autism; autism spectrum disorders; ASD
Autism is characterized by disruption in multiple dimensions of perception, emotion, language and cognition. Many hypotheses for the underlying neurophysiological basis have been proposed. Among these is the excitation/inhibition (E/I) imbalance hypothesis, which states that levels of cortical excitation and inhibition are disrupted in autism. We tested this theory in the visual system, because vision is one of the better understood systems in neuroscience, and because the E/I imbalance theory has been proposed to explain hypersensitivity to sensory stimuli in autism. We conducted two experiments on binocular rivalry, a well-studied psychophysical phenomenon that depends critically on excitation and inhibition levels in cortex. Using a computational model, we made specific predictions about how imbalances in excitation and inhibition levels would affect perception of two aspects of binocular rivalry: mixed perception (Experiment 1) and traveling waves (Experiment 2). We found no significant differences in either of these phenomena between high-functioning adults with autism and controls, and no evidence for a relationship between these measurements and the severity of autism. These results do not conclusively rule out an excitation/inhibition imbalance in visual system of those with autism, but they suggest that such an imbalance, if it exists, is likely to be small in magnitude.
binocular rivalry; psychophysics; computational model; autism
Deficits or atypicalities in attention have been reported in individuals with autism spectrum disorder (ASD), yet no consensus on the nature of these deficits has emerged. We conducted three experiments that paired a peripheral precue with a covert discrimination task, using protocols for which the effects of covert exogenous spatial attention on early vision have been well established in typically developing populations. Experiment 1 assessed changes in contrast sensitivity, using orientation discrimination of a contrast-defined grating; Experiment 2 evaluated the reduction of crowding in the visual periphery, using discrimination of a letter-like figure with flanking stimuli at variable distances; and Experiment 3 assessed improvements in visual search, using discrimination of the same letter-like figure with a variable number of distractor elements. In all three experiments, we found that exogenous attention modulated visual discriminability in a group of high-functioning adults with ASD and that it did so in the same way and to the same extent as in a matched control group. We found no evidence to support the hypothesis that deficits in exogenous spatial attention underlie the emergence of core ASD symptomatology.
covert attention; exogenous attention; crowding; visual search; contrast sensitivity; adults; autism; ASD
Autism has been described as a disorder of general neural processing, but the particular processing characteristics that might be abnormal in autism have mostly remained obscure. Here, we present evidence of one such characteristic: poor evoked response reliability. We compared cortical response amplitude and reliability (consistency across trials) in visual, auditory, and somatosensory cortices of high-functioning individuals with autism and controls. Mean response amplitudes were statistically indistinguishable across groups, yet trial-by-trial response reliability was significantly weaker in autism, yielding smaller signal-to-noise ratios in all sensory systems. Response reliability differences were evident only in evoked cortical responses and not in ongoing resting-state activity. These findings reveal that abnormally unreliable cortical responses, even to elementary non-social sensory stimuli, may represent a fundamental physiological alteration of neural processing in autism. The results motivate a critical expansion of autism research to determine whether (and how) basic neural processing properties such as reliability, plasticity, and adaptation/habituation are altered in autism.
Autism; Autism spectrum disorders; fMRI; response variability; response reliability; sensory systems; visual; auditory; somatosensory; noise; neural reliability; neural noise
Autism spectrum disorders are defined behaviorally by the Diagnostic and Statistical Manual (DSM) IV-TR based on abnormal development in social interaction and communication and restricted, repetitive, and stereotyped patterns of behaviors and interests that are evident before the age of 3. After decades of debate, research has demonstrated that the distinctions among autism, Asperger disorder, and pervasive developmental disorder not otherwise specified are neither clinically reliable nor based on valid neurobiological or genetic differences. The fifth edition of the DSM therefore proposes to collapse all of the clinical syndromes under the single diagnosis of autism spectrum disorder (ASD).
There is a growing amount of evidence suggesting that individuals with autism have difficulty with categorization. One basic cognitive ability that may underlie this difficulty is the ability to abstract a prototype. The current study examined prototype and category formation with dot patterns in high-functioning adults with autism and matched controls. Individuals with autism were found to have difficulty forming prototypes and categories of dot patterns. The eye-tracking data did not reveal any between group differences in attention to the dot patterns. However, relationships between performance and intelligence in the autism group suggest possible processing differences between the groups. Results are consistent with previous studies that have found deficits in prototype formation and extend these deficits to dot patterns.
categorization; prototype; autism; cognition; eye-tracking; implicit
It has been established that typically developing individuals have a bias to attend to facial information in the left visual field (LVF) more than in the right visual field (RVF). This bias is thought to arise from the right hemisphere’s advantage for processing facial information, with evidence suggesting it to be driven by the configural demands of face processing. Considering research showing that individuals with autism have impaired face processing abilities, with marked deficits in configural processing, it was hypothesized that they would not demonstrate a LVF bias for faces. Eye-tracking technology was used to show that, individuals with autism were not spontaneously biased to facial information in the LVF, in contrast to a control group, while discriminating facial gender.
Autism; face processing; left visual field (LVF) bias
Varied presentations of emotion dysregulation in autism complicate diagnostic decision making and may lead to inaccurate psychiatric diagnoses or delayed autism diagnosis for high-functioning children. This pilot study aimed to determine the concordance between prior psychiatric diagnoses and the results of an autism-specific psychiatric interview in adolescents with high-functioning autism.
Participants included 35, predominantly Caucasian and male, verbal 10 – 17 year olds with a confirmed autism spectrum disorder and without intellectual disability. The average age of autism spectrum diagnosis was 11-years-old. Lifetime psychiatric diagnoses were established via the Autism Comorbidity Interview, developed to identify co-morbid conditions within the context of autism. Autism Comorbidity Interview results were compared to parent report of prior community psychiatric diagnoses.
Approximately 60% of prior psychiatric diagnoses were not supported on the Autism Comorbidity Interview; the lowest diagnostic concordance was for prior bipolar disorder and obsessive-compulsive disorder diagnoses. While 51% of children met Autism Comorbidity Interview criteria for at least one psychiatric disorder, rates of prior diagnoses were much higher, with 77% having at least one prior psychiatric diagnosis and 60% having two or more.
Although many participants met criteria for comorbid psychiatric disorders, the majority of previous psychiatric diagnoses were not supported when autism-related manifestations were systematically taken into account. These findings require replication and may not generalize to lower-functioning and earlier diagnosed children with ASD. Results emphasize the importance of increasing awareness of the manifestations of high-functioning autism in order to improve accuracy of diagnosis and appropriateness of interventions.
Autism; Asperger’s Disorder; Psychiatric Comorbidity; Diagnosis