title: Childhood autism in India: A case-control study using tract-based spatial statistics analysis.
abstract: BACKGROUND
  Autism is a serious behavioral disorder among young children that now occurs at epidemic rates in developing countries like India. We have used tract-based spatial statistics (TBSS) of diffusion tensor imaging (DTI) measures to investigate the microstructure of primary neurocircuitry involved in autistic spectral disorders as compared to the typically developed children.
  
  
  OBJECTIVE
  To evaluate the various white matter tracts in Indian autistic children as compared to the controls using TBSS.
  
  
  METHODS
  Prospective, case-control, voxel-based, whole-brain DTI analysis using TBSS was performed. The study included 19 autistic children (mean age 8.7 years ± 3.84, 16 males and 3 females) and 34 controls (mean age 12.38 ± 3.76, all males). Fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) values were used as outcome variables.
  
  
  RESULTS
  Compared to the control group, TBSS demonstrated multiple areas of markedly reduced FA involving multiple long white matter tracts, entire corpus callosum, bilateral posterior thalami, and bilateral optic tracts (OTs). Notably, there were no voxels where FA was significantly increased in the autism group. Increased RD was also noted in these regions, suggesting underlying myelination defect. The MD was elevated in many of the projections and association fibers and notably in the OTs. There were no significant changes in the AD in these regions, indicating no significant axonal injury. There was no significant correlation between the FA values and Childhood Autism Rating Scale.
  
  
  CONCLUSIONS
  This is a first of a kind study evaluating DTI findings in autistic children in India. In our study, DTI has shown a significant fault with the underlying intricate brain wiring system in autism. OT abnormality is a novel finding and needs further research.
authors.affiliation: Department of NIIR, NIMHANS, Bengaluru, Karnataka, India.
authors.forename: Zarina Abdul
authors.initials: ZA
authors.lastname: Assis
authors.affiliation: Department of Neurosciences, NIMHANS, Bengaluru, Karnataka, India.
authors.forename: Bhavani Shankara
authors.initials: BS
authors.lastname: Bagepally
authors.affiliation: Department of NIIR, NIMHANS, Bengaluru, Karnataka, India.
authors.forename: Jitender
authors.initials: J
authors.lastname: Saini
authors.affiliation: Department of Child and Adolescent Psychiatry, NIMHANS, Bengaluru, Karnataka, India.
authors.forename: Shoba
authors.initials: S
authors.lastname: Srinath
authors.affiliation: Department of NIIR, NIMHANS, Bengaluru, Karnataka, India.
authors.forename: Rose Dawn
authors.initials: RD
authors.lastname: Bharath
authors.affiliation: Senior Medical Advisor, Biocon Ltd, Bengaluru, Karnataka, India.
authors.forename: Purushotham R
authors.initials: PR
authors.lastname: Naidu
authors.affiliation: Department of NIIR, NIMHANS, Bengaluru, Karnataka, India.
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Gupta
keywords: Autism; India; diffusion tensor imaging; tract-based spatial statistics