Theory of Mind, Language and Adaptive Functioning in ASD: A Neuroconstructivist Perspective.

INTRODUCTION: Neuroconstructivist theories of development highlight the potential effect one developmental domain may have on constraining or facilitating another. Empirical validation of this theory requires further testing in autism spectrum disorders (ASD), and may illuminate the complex interplay of developmental trajectories, particularly in the relationship between predictor and outcome variables. In ASD, language ability is an early predictor of important functional outcomes such as communication and socialization. We aimed to investigate whether theory of mind (ToM) mediates the relation between language ability and adaptive functioning in more cognitively able children with ASD (IQ > 70). METHODS: Thirty-nine children were followed prospectively every two years from 4-6 years to 12-14 years. Their language and theory of mind abilities and adaptive functioning were tested using the Test of Language Development-2 (the independent variable, at age 6-8 years), the "Eyes Test" (a measure of ToM, the mediator, at age 10-12) and the Vineland Adaptive Behaviour Scales (the outcome variable, at age 12-14). RESULTS: ToM mediated an association between language and adaptive functioning in the communication domain, but not in the social domain. CONCLUSION: These results challenge the usefulness of ToM as a unifying theory for ASD deficits and highlight the potential usefulness of a neuroconstructivist framework for prospective studies.

Résumé INTRODUCTION: Les théories neuroconstructivistes du développement soulignent l'effet potentiel de restriction ou de facilitation qu'un domaine développemental peut exercer sur un autre domaine. La confirmation empirique de cette théorie exige plus de vérifications dans les troubles du spectre de l'autisme (TSA), et peut faire la lumière sur l'interaction complexe des trajectoires développementales, en particulier sur la relation entre les variables de prédiction et celles des résultats. Dans le TSA, l'aptitude linguistique est un prédicteur précoce d'importants résultats fonctionnels comme la communication et la socialisation. Nous visions à rechercher si la théorie de l'esprit (TdE) aide la relation entre l'aptitude linguistique et le fonctionnement adaptatif chez les enfants cognitivement aptes souffrant d'un TSA (IQ > 70). MÉTHODES: Trente-neuf enfants ont été suivis prospectivement tous les deux ans, de 4 à 6 ans jusqu'à 12 à 14 ans. Leurs aptitudes de langage et à la théorie de l'esprit ainsi que leur fonctionnement adaptatif ont été vérifiés à l'aide du test du développement du langage-2 (la variable indépendante, à l'âge de 6 à 8 ans), du « Eyes Test ¼ (une mesure de la TdE, la médiatrice, à l'âge de 10 à 12 ans) et de l'Échelle de comportement adaptatif Vineland (la variable de résultat, à l'âge de 12 à 14 ans). RÉSULTATS: La TdE facilitait une association entre le langage et le fonctionnement adaptatif dans le domaine de la communication, mais pas dans le domaine social. CONCLUSION: Ces résultats remettent en question l'utilité de la TdE en tant que théorie unificatrice des déficits du TSA, et font valoir l'utilité potentielle d'un cadre neuroconstructiviste pour les études prospectives.

Similar developmental trajectories in autism and Asperger syndrome: from early childhood to adolescence.

OBJECTIVE: The objective of this study was to chart the developmental trajectories of high-functioning children with autism spectrum disorders (ASD) from early childhood to adolescence using the presence and absence of structural language impairment (StrLI) as a way of differentiating autism from Asperger syndrome (AS). METHOD: Sixty-four high-functioning children with ASD were ascertained at 4-6 years of age from several different regional diagnostic and treatment centers. At 6-8 years of age, the ADI-R and the Test of Oral Language Development were used to define an autism group (those with StrLI at 6-8 years of age) and an AS group (those without StrLI). Growth curve analysis was then used to chart the developmental trajectories of these children on measures of autistic symptoms, and adaptive skills in communication, daily living and socialization. RESULTS: Differentiating the ASD group in terms of the presence/absence of StrLI provided a better explanation of the variation in growth curves than not differentiating high-functioning ASD children. The two groups had similar developmental trajectories but the group without StrLI (the AS group) was functioning better and had fewer autistic symptoms than the group with StrLI (the autism group) on all measures across time. The differences in outcome could not be explained by non-verbal IQ or change in early language skills. CONCLUSION: Distinguishing between autism and Asperger syndrome based on the presence or absence of StrLI appears to be a clinically useful way of classifying ASD sub-types.

Differentiating autism and Asperger syndrome on the basis of language delay or impairment.

Asperger syndrome (AS) is differentiated from high-functioning autism (HFA) largely on a history of "language delay." This study examined "specific language impairment" as a predictor of outcome. Language skills of 19 children with AS and 45 with HFA were assessed at 4-6 years of age (Time 1) and 2 years later (Time 2). Children's symptoms and functional outcome scores were assessed every 2 years (Times 3, 4, and 5) until ages 15-17 years old. Regression analysis revealed that specific language impairment at time 2 more often accounted for the greatest variation in outcome scores in adolescence than the standard diagnosis of AS versus HFA based on history of language delay. Diagnostic implications are discussed.

Brief report: a scale for rating conversational impairment in autism spectrum disorder.

There are few well-standardized measures of conversational breakdown in Autism Spectrum Disorders (ASD). The study's objective was to develop a scale for measuring pragmatic impairments in conversations of individuals with ASD. We analyzed 46 semi-structured conversations of children and adolescents with high-functioning ASD using a functional linguistic paradigm. Five constructs were developed that assessed difficulties related to the pragmatics of conversation: atypical intonation; semantic drift; terseness; pedantic speech; perseveration. The scale shows good inter-rater reliability and variation in the scales is not simply a reflection of IQ or language competence. This tool represents a way of characterizing language use in ASD and is an initial step towards developing a tool to evaluate change in degree of social impairments in conversation.

The cholinergic system modulates kindling and kindling-induced mossy fiber sprouting.

In a previous study, our laboratory demonstrated that the intraventricular infusion of nerve growth factor (NGF) accelerated kindling rates and enhanced mossy fiber sprouting in the absence of noticeable kindling-associated neuronal loss. The purpose of the present study was to investigate whether these NGF effects were mediated via the cholinergic system. This study evaluated the effects of the cholinergic agonist pilocarpine and the cholinergic antagonist scopolamine on kindling rates and kindling-induced mossy fiber sprouting in adult rats. The results showed that pilocarpine accelerated kindling rates and enhanced kindling-induced mossy fiber sprouting in the CA3 region of the hippocampus, whereas scopolamine retarded kindling rates and blocked kindling-induced mossy fiber sprouting in the CA3 and IML regions. These findings suggest that the cholinergic system may contribute to the long-term structural and functional alterations that are characteristic of the kindled state. Moreover, these data provide support for the hypothesis that NGF infusions may mediate kindling and kindling-induced mossy fiber sprouting via regulation of the cholinergic system.