Pervasive Rightward Asymmetry Shifts of Functional Networks in Autism Spectrum Disorder

Abstract

utism spectrum disorder (ASD) is characterized by sociocommunicative impairments, repetitive behaviors, and restricted interests. 1 While viewed as a neurological disorder, its precise neural bases are not well understood. Growing evidence suggests that sociocommunicative, cognitive, and sensorimotor impairments are related to abnormalities of distributed networks, rather than of single brain loci. [2][3][4] Reports of atypical hemispheric asymmetries in ASD come from anatomical [5][6][7] and functional imaging studies. [8][9][10][11][12] Eyler and colleagues 13 observed atypical rightward asymmetry of receptive language activations during natural sleep in infants down to age 12.5 months, indicating that abnormal lateralization may predate language acquisition. However, all of the studies cited above focused on brain regions or stimuli specifically related to language. A recent study on gene expression in post mortem frontal cortex showed abnormalities in patterning pathways affecting lateralization in ASD, 14 possibly suggesting a broader impact on asymmetries even outside the language domain. While far from conclusive, these intriguing findings prompt the question whether atypical asymmetry could be a fundamental feature of brain organization in ASD. Indeed, theoretical considerations about possible left-hemisphere dysfunction 15,16 or, alternatively, predominant righthemisphere impairment 17,18 have a long history in autism research. However, these conjectures were largely based on limited behavioral findings, and conclusive imaging evidence beyond the language domain is lacking. Functional asymmetries related to nonverbal processing in ASD have received little attention, with only 2 studies reporting atypical left-hemisphere processing for motor tasks. 19,20 Moreover, functional studies have typically applied a priori models of task-driven activation effects. Since ASD is a pervasive developmental disorder whose neurofunctional bases are not well understood, hypothesis-driven approaches targeting single domains may, however, fail to provide comprehensive evidence because unexpected abnormalities may be missed.IMPORTANCE Autism spectrum disorder (ASD) is a brain-based pervasive developmental disorder, which-by growing consensus-is associated with abnormal organization of functional networks. Several previous studies of ASD have indicated atypical hemispheric asymmetries for language.OBJECTIVE To examine the asymmetry of functional networks using a data-driven approach for a comprehensive investigation of hemispheric asymmetry in ASD. DESIGN, SETTING, AND PARTICIPANTSThis cross-sectional study involved 24 children with ASD and 26 matched typically developing children at

Effects of therapeutic horse riding on gait cycle parameters and some aspects of behavior of children with autism

“…It exerts its multidisciplinary effects on the tone of the muscles by regulating malfunctions. Horse therapy is beneficial for improving sensation, motor functions, body scheme, balance, coordination, and the control of the head and trunk movement (5,6,7,9). Horse therapy may improve attention and cognition, broaden experience, grow self-confidence and improve selfexpression and independence (5,6,7,9).…”

“…Horse therapy is beneficial for improving sensation, motor functions, body scheme, balance, coordination, and the control of the head and trunk movement (5,6,7,9). Horse therapy may improve attention and cognition, broaden experience, grow self-confidence and improve selfexpression and independence (5,6,7,9). While in contact with the horse the patient gets motivated as a sign of emotional development and experiences being in the flow.…”

“…The complexity of the riding positions play important role in improving the condition of people with other types of disabilities than autism. Horse therapy reduces handicap resulting and compensates for disability; it improves psychological functions such as sensation, perception, memory, attention and thinking (5,6,7,9). The therapy is used to improve coordination of motor functions, to correct mal movements, establish adequate movements, reduce incorrect postures, improve balance and rhythm.…”

Understanding the Neuropsychology of Autism Spectrum Disorders in Men

“…Neuroimaging studies have demonstrated reduced or reversed hemispheric dominance of language perception among adults with ASD (Cardinale, Shih, Fishman, Ford, & Müller, 2013 ;Muller et al, 1999 ). Scott-Van Zeeland, Dapretto, Ghahremani, Poldrack, and Brookheimer ( 2010 ) demonstrated atypical frontal-temporal-parietal network activations during tapes of artifi cial languages in adults with ASD.…”

ASD: Psychopharmacologic Treatments and Neurophysiologic Underpinnings

“…Compromised interhemispheric WM connectivity is also revealed by modest reductions in overall corpus callosum size (e.g., Vidal et al 2006), a finding also associated with underconnectivity in the prefrontal cortex(Lo et al 2011). Callosal fiber reductions may further contribute to laterality differences seen in fMRI studies, which show that individuals with ASD tend to excessively utilize networks within the right hemisphere, including those underlying executive functioning (Cardinale et al 2013; Gilbert et al 2008). Even during sleep, rightward asymmetry is exhibited in 1-year-old infants affected by ASD, indicating abnormal lateralization is an early feature of neurodevelopment that predates language acquisition (Eyler et al 2012).…”