Physiological responses to affiliation during conversation: Comparing neurotypical males and males with Asperger syndrome.

We examined the emotional and psychophysiological underpinnings of social interaction in the context of autism spectrum disorder, more specifically, involving participants diagnosed with Asperger syndrome (AS). We recorded participants' autonomic nervous system (ANS) activation (electrodermal activity, heart rate, and heart rate variability) and facial muscle activation during conversations in two different types of male dyads: (1) ten dyads where one participant has been diagnosed with AS (AS/NT dyads) and (2) nine dyads where both participants are neurotypical (NT/NT dyads). Afterwards, three independent raters assessed continuously each participant's affiliative and dominant behaviors during the first and last 10 minutes of the conversations. The relationship between the assessed data and ANS responses was examined. We found that, in the NT/NT dyads, a high level of affiliation displayed by the conversational partner calms down the participant when they are actively dominating the interaction. In contrast, when the participants themselves expressed affiliation, their psychophysiological responses indicated increase in arousal, which suggests that the giving of affiliation is physiologically "hard work." The affiliation-related ANS responses were similar in those NT participants whose conversational partner had AS, while some differences in facial muscle activation did occur in comparison to NT/NT dyads. In the AS participants, in contrast, a high level of affiliation provided by the conversational partner was associated with increase in arousal, suggesting heightened alertness and stress. As for their own affiliative behavior, the AS participants exhibited similar indicators of alertness and stress as the NT participants, but only when their own level of dominance was low. Our results increase understanding of how individuals with AS experience social interaction at the physiological level, and how this experience differs from that in NT individuals. Moreover, our results confirm and further specify our earlier results, where we proposed that affiliation involves the type of "sharing of the burden" that also reverberates in the participants' bodies.

Reorganization of functionally connected brain subnetworks in high-functioning autism.

Previous functional connectivity studies have found both hypo- and hyper-connectivity in brains of individuals having autism spectrum disorder (ASD). Here we studied abnormalities in functional brain subnetworks in high-functioning individuals with ASD during free viewing of a movie containing social cues and interactions. Twenty-six subjects (13 with ASD) watched a 68-min movie during functional magnetic resonance imaging. For each subject, we computed Pearson's correlation between haemodynamic time-courses of each pair of 6-mm isotropic voxels. From the whole-brain functional networks, we derived individual and group-level subnetworks using graph theory. Scaled inclusivity was then calculated between all subject pairs to estimate intersubject similarity of connectivity structure of each subnetwork. Additional 54 individuals (27 with ASD) from the ABIDE resting-state database were included to test the reproducibility of the results. Between-group differences were observed in the composition of default-mode and ventro-temporal-limbic (VTL) subnetworks. The VTL subnetwork included amygdala, striatum, thalamus, parahippocampal, fusiform, and inferior temporal gyri. Further, VTL subnetwork similarity between subject pairs correlated significantly with similarity of symptom gravity measured with autism quotient. This correlation was observed also within the controls, and in the reproducibility dataset with ADI-R and ADOS scores. Our results highlight how the reorganization of functional subnetworks in individuals with ASD clarifies the mixture of hypo- and hyper-connectivity findings. Importantly, only the functional organization of the VTL subnetwork emerges as a marker of inter-individual similarities that co-vary with behavioral measures across all participants. These findings suggest a pivotal role of ventro-temporal and limbic systems in autism.

Abnormal wiring of the connectome in adults with high-functioning autism spectrum disorder.

BACKGROUND: Recent brain imaging findings suggest that there are widely distributed abnormalities affecting the brain connectivity in individuals with autism spectrum disorder (ASD). Using graph theoretical analysis, it is possible to investigate both global and local properties of brain's wiring diagram, i.e., the connectome. METHODS: We acquired diffusion-weighted magnetic resonance imaging data from 14 adult males with high-functioning ASD and 19 age-, gender-, and IQ-matched controls. As with diffusion tensor imaging-based tractography, it is not possible to detect complex (e.g., crossing) fiber configurations, present in 60-90 % of white matter voxels; we performed constrained spherical deconvolution-based whole brain tractography. Unweighted and weighted structural brain networks were then reconstructed from these tractography data and analyzed with graph theoretical measures. RESULTS: In subjects with ASD, global efficiency was significantly decreased both in the unweighted and the weighted networks, normalized characteristic path length was significantly increased in the unweighted networks, and strength was significantly decreased in the weighted networks. In the local analyses, betweenness centrality of the right caudate was significantly increased in the weighted networks, and the strength of the right superior temporal pole was significantly decreased in the unweighted networks in subjects with ASD. CONCLUSIONS: Our findings provide new insights into understanding ASD by showing that the integration of structural brain networks is decreased and that there are abnormalities in the connectivity of the right caudate and right superior temporal pole in subjects with ASD.

Increased coherence of white matter fiber tract organization in adults with Asperger syndrome: a diffusion tensor imaging study.

To investigate whether there are global white matter (WM) differences between autistic and healthy adults, we performed diffusion tensor imaging (DTI) in 14 male adults with Asperger syndrome (AS) and 19 gender-, age-, and intelligence quotient-matched controls. We focused on individuals with high-functioning autism spectrum disorder (ASD), AS, to decrease heterogeneity caused by large variation in the cognitive profile. Previous DTI studies of ASD have mainly focused on finding local changes in fractional anisotropy (FA) and mean diffusivity (MD), two indexes used to characterize microstructural properties of WM. Although the local or voxel-based approaches may be able to provide detailed information in terms of location of the observed differences, such results are known to be highly sensitive to partial volume effects, registration errors, or placement of the regions of interest. Therefore, we performed global histogram analyses of (a) whole-brain tractography results and (b) skeletonized WM masks. In addition to the FA and MD, the planar diffusion coefficient (CP) was computed as it can provide more specific information of the complexity of the neural structure. Our main finding indicated that adults with AS had higher mean FA values than controls. A less complex neural structure in adults with AS could have explained the results, but no significant difference in CP was found. Our results suggest that there are global abnormalities in the WM tissue of adults with AS.

Analysis of 9p24 and 11p12-13 regions in autism spectrum disorders: rs1340513 in the JMJD2C gene is associated with ASDs in Finnish sample.

OBJECTIVE: Autism spectrum disorders (ASD) often show obsessive repetitive symptoms that are characteristic to obsessive-compulsive disorder (OCD). Aberrant glutamate function has been suggested to a risk for both ASDs and OCD. Considering the common metabolic pathway and recent results from association studies both in OCD and ASDs, a question, whether there is common molecular background in ASDs and OCD, was raised. METHODS: Ten single nucleotide polymorphisms (SNPs) at 9p24 and 11p12-p13 containing glutamate transporter genes SLC1A1 and SLC1A2 and their neighboring regions in 175 patients with ASDs and 216 controls of Finnish origin were analyzed using real-time-PCR or direct sequencing. RESULTS: The strongest association was detected with rs1340513 in the JMJD2C gene at 9p24.1 (P=0.007; corrected P=0.011) that is the same SNP associated with infantile autism (P=0.0007) in the autism genome project consortium (2007). No association was detected at 11p12-p13 with ASD. Interestingly, the strongest association in OCD has been found at rs301443 (P=0.000067) residing between SLC1A1 and JMJD2C at 9p24. CONCLUSION: In summary, our results give evidence for a possible common locus for OCD and ASDs at 9p24. We speculate that the area may represent a special candidate region for obsessive repetitive symptoms in ASDs.

Language abilities of children with Asperger syndrome.

Current diagnostic taxonomies (ICD-10, DSM-IV) emphasize normal acquisition of language in Asperger syndrome (AS). Although many linguistic sub-skills may be fairly normal in AS there are also contradictory findings. There are only few studies examining language skills of children with AS in detail. The aim of this study was to study language performance in children with AS and their age, sex and IQ matched controls. Children with AS had significantly lower scores in the subtest of Comprehension of Instructions. Results showed that although many linguistic skills may develop normally, comprehension of language may be affected in children with AS. The results suggest that receptive language processes should be studied in detail in children with AS.

Comparison of diagnostic methods for asperger syndrome.

Several different diagnostic sets of criteria exist for Asperger syndrome (AS), but there is no agreement on a gold standard. The aim of this study was to compare four diagnostic sets of criteria for AS: the ICD-10, the DSM-IV, the Gillberg & Gillberg, and the Szatmari criteria. The series consists of 36 children who had been referred to two centers with a tentative diagnosis of AS. The best agreement was between the ICD-10 and the DSM-IV criteria (Kappa coefficient 0.48), and the lowest between the Gillberg & Gillberg and Szatmari criteria (Kappa coefficient -0.21). The poor agreement between these sets of diagnostic criteria compromises the comparability of studies on AS.

Sleep in children with Asperger syndrome.

The prevalence of sleep disturbances in 52 children with Asperger syndrome (AS) as compared with 61 healthy controls (all subjects aged 5-17 years) was investigated. Problems with sleep onset and maintenance, sleep-related fears, negative attitudes toward sleeping, and daytime somnolence were more frequent among children with AS than among controls. Short sleep duration (<9 h) was almost twofold (59% vs. 32%), and the risk for sleep onset problems more than fivefold (53% vs. 10%) more common in the AS group than in the control group. Child-reported sleeping problems were also more prevalent in the AS group than in controls (58% vs. 7%). The results suggest that sleep disturbances should be routinely evaluated in children with AS.

Auditory cortical change detection in adults with Asperger syndrome.

The present study investigated whether auditory deficits reported in children with Asperger syndrome (AS) are also present in adulthood. To this end, event-related potentials (ERPs) were recorded from adults with AS for duration, pitch, and phonetic changes in vowels, and for acoustically matched non-speech stimuli. These subjects had enhanced mismatch negativity (MMN) amplitudes particularly for pitch and duration deviants, indicating enhanced sound-discrimination abilities. Furthermore, as reflected by the P3a, their involuntary orienting was enhanced for changes in non-speech sounds, but tended to be deficient for changes in speech sounds. The results are consistent with those reported earlier in children with AS, except for the duration-MMN, which was diminished in children and enhanced in adults.

Clinical neurological abnormalities in young adults with Asperger syndrome.

Children with Asperger syndrome (AS), a neurodevelopmental disorder falling in the autism spectrum disorders, have an increased rate of neurological abnormalities, especially in motor coordination. While AS is a lifelong condition, little is known about the persistence of neurological abnormalities in adulthood. Twenty young adults with AS were compared with 10 healthy controls using a structured clinical neurological rating scale. The score for neurological abnormalities was higher in the AS group. In addition, a subscore for neurological soft signs indicating defective functioning of the central nervous system with a non-localizing value was significantly higher in the AS subjects. This preliminary study indicates that neurological abnormalities, soft signs in particular, represent a non-specific vulnerability factor for AS. Consistent with other features of AS, neurological abnormalities seem to persist into adulthood.

Childhood inattention and hyperactivity symptoms self-reported by adults with Asperger syndrome.

BACKGROUND: Increasing public awareness of the adult manifestations of developmental neuropsychiatric disorders, like Asperger syndrome and attention deficit hyperactivity disorder (ADHD), has provoked an increasing number of persons to seek assessment for the first time in adulthood. As these disorders have their origin in childhood, instruments for retrospective evaluation of childhood behavior are needed. SAMPLING AND METHODS: In this preliminary study, 20 adults with Asperger syndrome filled in the Wender-Utah Rating Scale for ADHD to describe retrospectively their childhood behavior. RESULTS: Fourteen out of 20 adults with Asperger syndrome self-rated above the cut-off limit for ADHD. The median total score was also higher than that reported in normal populations in previous studies. When compared with 10 controls, patients with Asperger syndrome scored higher in almost all individual items. CONCLUSIONS: A high score on the Wender-Utah rating Scale for ADHD in this patient group might be a sign of true comorbidity with ADHD, an indication of overlapping features typical of both disorders, or a result of other psychiatric comorbidity originating already in childhood. Moreover, there are no data about the proper cut-off limit for ADHD in these subjects. Therefore, one should be cautious when applying this scale beyond its original context of comparison between adults with ADHD, unipolar depression and healthy controls.

Analysis of four neuroligin genes as candidates for autism.

Neuroligins are cell-adhesion molecules located at the postsynaptic side of the synapse. Neuroligins interact with beta-neurexins and this interaction is involved in the formation of functional synapses. Mutations in two X-linked neuroligin genes, NLGN3 and NLGN4, have recently been implicated in pathogenesis of autism. The neuroligin gene family consists of five members (NLGN1 at 3q26, NLGN2 at 17p13, NLGN3 at Xq13, NLGN4 at Xp22, and NLGN4Y at Yq11), of which NLGN1 and NLGN3 are located within the best loci observed in our previous genome-wide scan for autism in the Finnish sample. Here, we report a detailed molecular genetic analysis of NLGN1, NLGN3, NLGN4, and NLNG4Y in the Finnish autism sample. Mutation analysis of 30 probands selected from families producing linkage evidence for Xq13 and/or 3q26 loci revealed several polymorphisms, but none of these seemed to be functional. Family-based association analysis in 100 families with autism spectrum disorders yielded only modest associations at NLGN1 (rs1488545, P=0.002), NLGN3 (DXS7132, P=0.014), and NLGN4 (DXS996, P=0.031). We conclude that neuroligin mutations most probably represent rare causes of autism and that it is unlikely that the allelic variants in these genes would be major risk factors for autism.

Higher plasma ACTH levels in adults with Asperger syndrome.

OBJECTIVE: The aim of this preliminary study was to characterize the levels of plasma adrenocorticotropic hormone (ACTH) and cortisol in adult patients with Asperger syndrome (AS). METHODS: Twenty medication-free individuals with high-functioning AS were recruited from a clinic specialized in autism spectrum disorders. Ten age-matched healthy persons (hospital staff or students) with no neuropsychiatric disorders served as controls. Blood samples for the assessment were collected at 8:00 a.m. RESULTS: The patients with AS had significantly higher plasma-ACTH values than did the healthy controls. Plasma-cortisol levels were similar in both groups. CONCLUSION: Increased plasma-ACTH levels are associated with AS. Future studies are needed to clarify whether this finding is a biological consequence of chronic anxiety and elevated stress, or a sign of facilitated response to an acute novel stressor.

Actigraphic assessment of sleep in young adults with Asperger syndrome.

A high prevalence of subjective insomnia in adults with Asperger syndrome has been reported. In the present study the sleep quality of these patients was studied using wrist actigraphy. Nineteen adults with Asperger syndrome and frequent feelings of insomnia were compared with 10 controls devoid of neuropsychiatric disorders and subjective sleep problems during six consecutive nights. The patients had similar actigraphic sleep profile to the controls. The subjective low sleep quality in patients was not reflected in actigraphic assessment of sleep. This finding suggests that pervasive anxiety inherent in persons with Asperger syndrome predisposes them to insomnia complaints.

Subjective face recognition difficulties, aberrant sensibility, sleeping disturbances and aberrant eating habits in families with Asperger syndrome.

BACKGROUND: The present study was undertaken in order to determine whether a set of clinical features, which are not included in the DSM-IV or ICD-10 for Asperger Syndrome (AS), are associated with AS in particular or whether they are merely a familial trait that is not related to the diagnosis. METHODS: Ten large families, a total of 138 persons, of whom 58 individuals fulfilled the diagnostic criteria for AS and another 56 did not to fulfill these criteria, were studied using a structured interview focusing on the possible presence of face recognition difficulties, aberrant sensibility and eating habits and sleeping disturbances. RESULTS: The prevalence for face recognition difficulties was 46.6% in individuals with AS compared with 10.7% in the control group. The corresponding figures for subjectively reported presence of aberrant sensibilities were 91.4% and 46.6%, for sleeping disturbances 48.3% and 23.2% and for aberrant eating habits 60.3% and 14.3%, respectively. CONCLUSION: An aberrant processing of sensory information appears to be a common feature in AS. The impact of these and other clinical features that are not incorporated in the ICD-10 and DSM-IV on our understanding of AS may hitherto have been underestimated. These associated clinical traits may well be reflected by the behavioural characteristics of these individuals.

Lower limb motor restlessness in Asperger's disorder, measured using actometry.

The movement disturbances and brain imaging findings in Asperger's disorder (AD) suggest a dopaminergic deficit in movement regulation. Movement disorders of different etiologies have been quantified and specified with actometry. We compared 10 AD patients with 10 healthy controls, measuring their rest-activities by actometry. The lower limb motor activity was significantly higher in the AD group. They also displayed a rhythmic, periodic movement pattern similar to akathisia. These findings suggest a hypothesis of idiopathic akathisia and a special sensitivity to adverse effects of neuroleptic drugs.

Sleep in young adults with Asperger syndrome.

Asperger syndrome (AS) is a neurodevelopmental disorder belonging to autism spectrum disorders. Both children and adults with AS have subjective impairment in the initiation and continuity of sleep, and studies using objective assessment are sparse. Twenty young AS adults with frequent complaints of low sleep quality were compared to 10 age-, gender- and education-matched controls without sleep complaints using polysomnography and spectral power analysis of slow-wave sleep. AS subjects displayed a similar polysomnographic profile as compared with controls. In spectral power analysis, a statistically nonsignificant trend towards decreased relative delta power and increased theta power in slow-wave sleep was found in the AS group. It seems that nonorganic insomnia, due to anxiety inherent in AS, is responsible for the low sleep quality in these subjects.

Increased presynaptic dopamine function in Asperger syndrome.

The etiology of Asperger syndrome is essentially unknown, but abnormality of the dopamine system has been shown in clinically overlapping disorders. The present study was designed to investigate the presynaptic dopamine function in Asperger syndrome. Eight healthy, drug-free males with Asperger syndrome and five healthy male controls were examined with positron emission tomography using 6-[18F]fluoro-L-DOPA ([18F]FDOPA) as a tracer. In the Asperger syndrome group, the [18F]FDOPA influx (Ki) values were increased in the striatum, i.e. in the putamen and caudate nucleus and in the frontal cortex. The results indicate that the dopamine system is affected in subjects with Asperger syndrome. Partially similar results have also been obtained in schizophrenia, suggesting an overlap not only of the clinical features but also of pathogenesis.