Publications by authors named "Christopher Chatham"

Many individuals with autism spectrum disorder (ASD) experience various degrees of impairment in social interaction and communication, restricted, repetitive behaviours, interests/activities. These impairments make a significant contribution to poorer everyday adaptive functioning. Yet, there are no pharmacological therapies to effectively treat the core symptoms of ASD.

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  • Autism is a common condition influenced by both single gene issues and multiple genes, and many autistic people need better healthcare that genomics can help provide.
  • The European Autism GEnomics Registry (EAGER) aims to collect info about autistic people who have had their entire DNA sequenced to help with future research and trials.
  • EAGER will involve 1,500 participants from 13 places in 8 countries who will share genetic samples and fill out surveys to help researchers understand the link between genetics and health.
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  • The study investigates repetitive and restricted behaviors and interests (RRBI) in autism, classifying them into 'motor-driven' and 'cognitively driven' categories while considering the roles of clinical contexts and neuroanatomy.
  • Researchers analyzed data from 792 participants, including autistic individuals, their relatives, and typically developing individuals, using standardized scales and MRI to assess RRBI patterns and brain volumes.
  • The analysis revealed three main RRBI factors, with 'motor-driven' symptoms linked to lower putamen volumes, while 'cognitively driven' symptoms showed different associations with brain structure, highlighting the complexity of RRBI in autism.
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A paradigm shift in research culture is required to ease perceived tensions between autistic people and the biomedical research community. As a group of autistic and non-autistic scientists and stakeholders, we contend that through participatory research, we can reject a deficit-based conceptualization of autism while building a shared vision for a neurodiversity-affirmative biomedical research paradigm.

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Challenges in social communication is one of the core symptom domains in autism spectrum disorder (ASD). Novel therapies are under development to help individuals with these challenges, however the ability to show a benefit is dependent on a sensitive and reliable measure of treatment effect. Currently, measuring these deficits requires the use of time-consuming and subjective techniques.

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  • The study investigates sensory processing issues in autistic individuals, focusing on hypo and hyper-sensory sensitivities potentially linked to genetic factors affecting GABA-ergic and glutamatergic pathways.
  • Researchers analyzed the sensory profiles of 1136 participants (including autistic individuals, relatives, and controls) and found significant differences in sensory processing between these groups, with variability being a key factor.
  • While the new differential Short Sensory Profile (dSSP) provided useful insights, it struggled to distinguish between individuals with similar sensory symptom levels, suggesting a need for combining this score with genetic and other sensory assessments for better understanding of sensory processing in autism.
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  • - Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition marked by challenges in social communication and varying individual characteristics, making targeted treatments essential.
  • - A study involving 436 individuals analyzed neural responses to faces and found that children and adults with ASD had slower early brain activity (N170 latency) compared to those without ASD, which correlated with social functioning and prognosis.
  • - Findings suggest that measuring N170 latency can effectively stratify different subgroups within ASD, offering potential for improved personalized treatment approaches based on biological and social outcome predictions.
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Background: Autism spectrum disorder (ASD) is a common and heterogeneous neurodevelopmental condition that is characterized by the core symptoms of social communication difficulties and restricted and repetitive behaviors. At present, there is an unmet medical need for therapies to ameliorate these core symptoms in order to improve quality of life of autistic individuals. However, several challenges are currently faced by the ASD community relating to the development of pharmacotherapies, namely in the conduct of clinical trials.

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Background: Understanding the development of the neuronal circuitry underlying autism spectrum disorder (ASD) is critical to shed light into its etiology and for the development of treatment options. Resting state EEG provides a window into spontaneous local and long-range neuronal synchronization and has been investigated in many ASD studies, but results are inconsistent. Unbiased investigation in large and comprehensive samples focusing on replicability is needed.

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Background: Inhibitory control and attention processing atypicalities are implicated in various diseases, including autism spectrum disorders (ASD). These cognitive functions can be tested by using visually guided saccade-based paradigms in children, adolescents and adults to determine the time course of such disorders.

Methods: In this study, using Gap, Step, Overlap and Antisaccade tasks, we analyzed the oculomotor behavior of 82 children, teenagers and adults with high functioning ASD and their peer typically developing (TD) controls in a two-year follow-up study under the auspices of the InFoR-Autism project.

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In this work, we propose a Bluetooth low energy (BLE) beacon-based algorithm to enable remote measurement of the social behavior of the participants of an observational Autism Spectrum Disorder (ASD) clinical trial (NCT03611075). We have developed a mobile application for a smartphone and a smartwatch to collect beacon signals from BLE beacon sensors as well as to store information about the participants' household rooms. Our goal is to collect beacon information about the time the participants spent in different rooms of their household to infer sociability information.

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Repetitive behaviors (RB) represent a wide spectrum of symptoms ranging from sensory-motor stereotypies to complex cognitive rituals, frequently dichotomized as low- and high-order sub-groups of symptoms. Even though these subgroups are considered as phenomenologically distinct in autism spectrum disorder (ASD) and obsessive-compulsive disorder (OCD), brain imaging and genetic studies suggest that they have common mechanisms and pathways. This discrepancy may be explained by the frequent intellectual disability reported in ASD, which blurs the RB expressivity.

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Background: Reduced activation of dopamine D receptor signaling may be implicated in reward functioning as a potential driver of negative symptoms in schizophrenia. Phosphodiesterase 10A (PDE10A), an enzyme that is highly expressed in the striatum, modulates both dopamine D- and D-dependent signaling.

Methods: We assessed whether augmentation of D signaling by the PDE10 inhibitor RG7203 enhances imaging and behavioral markers of reward functions in patients with schizophrenia and negative symptoms.

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Flexible behavior is critical for everyday decision-making and has been implicated in restricted, repetitive behaviors (RRB) in autism spectrum disorder (ASD). However, how flexible behavior changes developmentally in ASD remains largely unknown. Here, we used a developmental approach and examined flexible behavior on a probabilistic reversal learning task in 572 children, adolescents, and adults (ASD N = 321; typical development [TD] N = 251).

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The contents of working memory must be maintained in the face of distraction, but updated when appropriate. To manage these competing demands of stability and flexibility, maintained representations in working memory are complemented by distinct gating mechanisms that selectively transmit information into and out of memory stores. The operations of such dopamine-dependent gating systems in the midbrain and striatum and their complementary dopamine-dependent memory maintenance operations in the cortex may therefore be dissociable.

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Heart rate variability (HRV) measures the regularity between consecutive heartbeats driven by the balance between the sympathetic and parasympathetic branches of the autonomous nervous system. Wearable devices embedding photoplethysmogram (PPG) technology can be used to derive HRV, creating many opportunities for remote monitoring of this physiological parameter. However, uncontrolled conditions met in daily life pose several challenges related to disturbances that can deteriorate the PPG signal, making the calculation of HRV metrics untrustworthy and not reliable.

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Autism spectrum disorders (ASD) are heterogeneous and complex neurodevelopmental conditions that urgently need reliable and sensitive measures to inform diagnosis properly. The Reading the Mind in the Eyes Task (or Eyes Test from now on) is widely used for this purpose. A recent study showed that subcategories of items of the children version of the Eyes Test could be especially discriminative to distinguish ASD and control children.

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  • Recognition of social anxiety symptoms in individuals with Autism Spectrum Disorders (ASD) is challenging due to overlapping symptoms, prompting a study to investigate this association.
  • The study involved 79 children and adolescents with ASD and 28 matched control participants, utilizing various standard assessment tools to evaluate anxiety, depression, and social skills.
  • Results indicated that higher levels of social anxiety correlate significantly with impairments in social communication and motivation in ASD individuals, highlighting the importance of considering comorbid anxiety disorders in diagnostic assessments.
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Background: Dopamine D1 receptor signaling plays key roles in core domains of neural function, including cognition and reward processing; however, many questions remain about the functions of circuits modulated by dopamine D1 receptor, largely because clinically viable, selective agonists have yet to be tested in humans.

Methods: Using a novel, exploratory neurofunctional domains study design, we assessed the safety, tolerability, pharmacodynamics, and pharmacokinetics of PF-06412562, a selective D1/D5R partial agonist, in healthy male volunteers who met prespecified criteria for low working memory capacity. Functional magnetic resonance imaging, electrophysiologic endpoints, and behavioral paradigms were used to assess working memory, executive function, and motivation/reward processing following multiple-dose administration of PF-06412562.

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: Gallery Game, deployed within the Mezurio smartphone app, targets the processes of episodic memory hypothesized to be first vulnerable to neurofibrillary tau-related degeneration in Alzheimer's Disease, prioritizing both perirhinal and entorhinal cortex/hippocampal demands.: Thirty-five healthy adults (aged 40-59 years), biased toward those at elevated familial risk of dementia, completed daily Gallery Game tasks for a month. Assessments consisted of cross-modal paired-associate learning, with subsequent tests of recognition and free recall following delays ranging from one to 13 days.

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  • - Recent studies using resting-state fMRI have uncovered unusual patterns of brain connectivity in individuals with autism spectrum disorder (ASD), although there's no solid agreement on what these changes mean clinically.
  • - An analysis of four large ASD groups showed consistent patterns of both increased (hyperconnectivity) and decreased (hypoconnectivity) brain activity, particularly in sensory-motor areas and regions involved in higher cognitive functions.
  • - While these brain connectivity patterns might link to ASD symptoms related to communication and daily skills, their overlap with typical brain patterns limits their potential use in diagnosis and treatment efficacy evaluations.
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Application of metabolic magnetic resonance imaging measures such as cerebral blood flow in translational medicine is limited by the unknown link of observed alterations to specific neurophysiological processes. In particular, the sensitivity of cerebral blood flow to activity changes in specific neurotransmitter systems remains unclear. We address this question by probing cerebral blood flow in healthy volunteers using seven established drugs with known dopaminergic, serotonergic, glutamatergic and GABAergic mechanisms of action.

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