Autism and Cerebellar Mutism: A Review of the Neuroanatomical Findings

Abstract

Autistic Spectrum Disorder (ASD) is behaviorally defined syndrome characterized by atypical social interaction, disordered verbal and non-verbal communication, restricted areas of interest and limited imaginative play. The prevalence of ASD is considered to be approximately 4 to 5 per 1000, but numbers differ according to criteria used for diagnosis [1].Individuals with ASD have three core features; 1. Impairments of reciprocal social interactions, 2. Abnormal development and use of language and 3. Repetitive and ritualized behaviors and a narrow range of interests. In addition to the core features of autism, there are common co-morbid neurological disorders. The prevalence of mental retardation in the autism spectrum is approximately 30%. Epilepsy prevalence associated with autism varies from 5% to 44%. Anxiety and mood disorders are also very common in autism.There is heterogeneity in the onset of autism. Although some children have signs of development delays between 0-18 months of life, up to 40% of children with ASD initially demonstrate the near-normal development until 18-24 months.As Brunelle et al. says: All the results are converging toward the description of anatomical and functional anomalies in the regions of the so-called "social brain" [2]. Several brain regions such as frontal lobe, the superior temporal cortex, the parietal cortex, and amygdala have been implicated in social behavior. But the recent developments make us think more about the role of cerebellum in ASD. This review presents an overview of the neuroanatomical abnormalities that occur within ASD. We discuss the findings that have advanced our understanding of cerebellar organization in ASD.