Cathriona Cantio

Increased Prepulse Inhibition and Sensitization of the Startle Reflex in Autistic Children

The relation between autism spectrum disorders (ASD) and schizophrenia is a subject of intense debate and research due to evidence of common neurobiological pathways in the two disorders. The objective of this study was to explore whether deficits in prepulse inhibition (PPI) of the startle reflex, as usually seen in schizophrenic patients, can be replicated in a group of children with ASD in comparison with a group of matched neuro‐typically developed (NTD) controls. An additional aim was to explore possible psychophysiological subgroups within our ASD sample. In a case‐control design, 35 ASD patients and 40 matched NTD controls were tested in a psychophysiological test battery. The PPI of the acoustic startle reflex was analyzed in 18 ASD subjects and 34 NTD controls. Habituation and sensitization were analyzed in 23 ASD subjects and 39 NTD controls. In trials with less intense prestimuli (76 dB), patients with ASD did not display the drop in percentage PPI normally found in healthy controls. In addition, ASD patients showed significantly increased sensitization compared with NTD controls. Combined, our results may reflect the hypersensitivity to sensory information in children with ASD. The relation to PPI deficits observed in schizophrenia is not apparent. Future research should study the developmental course of PPI deficits in ASD patients in a longitudinal design. Autism Res 2014, 7: 94–103.

Exploring 'The autisms' at a cognitive level

The autism spectrum is characterized by genetic and behavioral heterogeneity. However, it is still unknown whether there is a universal pattern of cognitive impairment in autism spectrum disorder (ASD) and whether multiple cognitive impairments are needed to explain the full range of behavioral symptoms. This study aimed to determine whether three widely acknowledged cognitive abnormalities (Theory of Mind (ToM) impairment, Executive Function (EF) impairment, and the presence of a Local Processing Bias (LB)) are universal and fractionable in autism, and whether the relationship between cognition and behavior is dependent on the method of behavioral assessment. Thirty‐one high‐functioning children with ASD and thirty‐seven children with neurotypical development (NTD), comparable in age, gender and Intelligence Quotient (IQ), completed several tasks tapping into ToM, EF, and LB, and autistic symptomatology was assessed through parental and teacher questionnaires, parental interview and direct observation. We found that ToM and EF deficits differentiated the groups and some ToM and EF tasks were related to each other. ToM and EF were together able to correctly classify more than three‐quarters of the children into cases and controls, despite relating to none of the specific behavioral measures. Only a small subgroup of individuals displayed a LB, which was unrelated to ToM and EF, and did not aid diagnostic classification, most likely contributing to non‐diagnostic symptoms in a subgroup. Despite the characteristic heterogeneity of the autism spectrum, it remains a possibility therefore that a single cognitive cause may underlie the range of diagnostic symptoms in all individuals with autism. Autism Res 2016, 9: 1328–1339.

Normal P50 Gating in Children with Autism, Yet Attenuated P50 Amplitude in the Asperger Subcategory.

Autism spectrum disorders (ASD) and schizophrenia are separate disorders, but there is evidence of conversion or comorbid overlap. The objective of this paper was to explore whether deficits in sensory gating, as seen in some schizophrenia patients, can also be found in a group of ASD children compared to neurotypically developed children. An additional aim was to investigate the possibility of subdividing our ASD sample based on these gating deficits. In a case–control design, we assessed gating of the P50 and N100 amplitude in 31 ASD children and 39 healthy matched controls (8–12 years) and screened for differences between groups and within the ASD group. We did not find disturbances in auditory P50 and N100 filtering in the group of ASD children as a whole, nor did we find abnormal P50 and N100 amplitudes. However, the P50 amplitude to the conditioning stimulus was significantly reduced in the Asperger subgroup compared to healthy controls. In contrast to what is usually reported for patients with schizophrenia, we found no evidence for sensory gating deficits in our group of ASD children taken as a whole. However, reduced P50 amplitude to conditioning stimuli was found in the Asperger group, which is similar to what has been described in some studies in schizophrenia patients. There was a positive correlation between the P50 amplitude of the conditioning stimuli and anxiety score in the pervasive developmental disorder not otherwise specified group, which indicates a relation between anxiety and sensory registration in this group. Autism Res 2015, 8: 371–378.

Auditory processing in autism spectrum disorder : Mismatch negativity deficits

Children with autism spectrum disorders (ASD) often show changes in (automatic) auditory processing. Electrophysiology provides a method to study auditory processing, by investigating event‐related potentials such as mismatch negativity (MMN) and P3a‐amplitude. However, findings on MMN in autism are highly inconsistent, partly due to small sample sizes in the studies and differences in MMN paradigms. Therefore, in the current study, MMN and P3a amplitude were assessed in a relatively large sample of children with ASD, using a more extensive MMN paradigm and compared with that of typically developing children (TDC). Thirty‐five children (aged 8–12 years) with ASD and 38 age and gender matched TDC were assessed with a MMN paradigm with three types of deviants, i.e., frequency, duration and a combination of these two. MMN elicited by duration and frequency‐duration deviants was significantly reduced in the ASD group. P3a‐amplitude elicited by duration deviants was significantly increased in the ASD group. Reduced MMN in children with ASD suggests that children with ASD may be less responsive to environmentally deviant stimuli at an early (sensory) level. P3a‐amplitude was increased in ASD, implying a hyper‐responsivity at the attentional level. In addition, as similar MMN deficits are found in schizophrenia, these MMN results may explain some of the frequently reported increased risk of children with ASD to develop schizophrenia later in life. Autism Res 2017, 10: 1857–1865.

Do cognitive deficits persist into adolescence in autism?: The Development of Cognitive Skills in Autism

The three cognitive domains (ToM, EF, and LB) were examined in a group of high‐functioning children (age: 8–12, mean 10.85; IQ: 78–139, mean 105.48) with ASD and a matched group of children with neurotypical development (NTD) (IQ: 75–145, mean: 109.47), and several tasks were used within each domain to ensure the validity of the cognitive measures. Approximately 3 years later (mean age: 14.34), all children and their families were invited to participate in the follow‐up (ASD, N = 21; NTD, N = 30). While the understanding of others minds does improve from childhood to adolescence, ToM impairment persists in adolescents with ASD relative to their peers. Likewise, a development in EF was observed in the ASD group, while no significant improvement was seen in the NTD group, leading the ASD group to catch up in this domain. We did not detect any group differences at any time point regarding local bias processing (LB). Individual patterns of development were seen, but remarkably, ToM deficits were present in every child with ASD in whom we could detect any cognitive impairment at baseline, and a similar pattern was found at follow‐up. These findings indicate that ToM is a persistent cognitive deficit in ASD. Autism Res 2018, 11: 1229–1238.