Lateralization of Brain Networks and Clinical Severity in Toddlers with Autism Spectrum Disorder: A HARDI Diffusion MRI Study.
Recent diffusion tensor imaging studies in adolescents and children with Autism Spectrum Disorder (ASD) have reported a loss or an inversion of the typical left-right lateralization in fronto-temporal regions crucial for sociocommunicative skills. No studies explored atypical lateralization in toddlers and its correlation with clinical severity of ASD. We recruited a cohort of 20 subjects aged 36 months or younger receiving a first clinical diagnosis of ASD (15 males; age range 20-36 months). Patients underwent diffusion MRI (High-Angular-Resolution Diffusion Imaging protocol). Data from cortical parcellation were combined with tractography to obtain a connection matrix and diffusion indexes (DI ) including mean fractional anisotropy (DFA ), number of tracts (DNUM ), and total tract length (DTTL ). A laterality index was generated for each measure, and then correlated with the Autism Diagnostic Observation Schedule-Generic (ADOS-G) total score. Laterality indexes of DFA were significantly correlated with ADOS-G total scores only in two intrafrontal connected areas (correlation was positive in one case and negative in the other). Laterality indexes of DTTL and DNUM showed significant negative correlations (P < 0.05) in six connected areas, mainly fronto-temporal. This study provides first evidence of a significant correlation between brain lateralization of diffusion indexes and clinical severity in toddlers with a first diagnosis of ASD. Significant correlations mainly involved regions within the fronto-temporal circuits, known to be crucial for sociocommunicative skills. It is of interest that all correlations but one were negative, suggesting an inversion of the typical left-right asymmetry in subjects with most severe clinical impairment.
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.|Department of Clinical and Experimental Medicine, University of Pisa, Italy.
Eugenia
E
Conti
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.
Sara
S
Calderoni
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.
Anna
A
Gaglianese
The Australian eHealth Research Centre, CSIRO, Brisbane, Queensland, Australia.
Kerstin
K
Pannek
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.
Sara
S
Mazzotti
The Australian eHealth Research Centre, CSIRO, Brisbane, Queensland, Australia.
Stephen
S
Rose
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.
Danilo
D
Scelfo
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.
Michela
M
Tosetti
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.|Department of Clinical and Experimental Medicine, University of Pisa, Italy.
Filippo
F
Muratori
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.|Department of Clinical and Experimental Medicine, University of Pisa, Italy.
Giovanni
G
Cioni
Department of Developmental Neuroscience, Stella Maris Scientific Institute, Pisa, Italy.|Department of Clinical and Experimental Medicine, University of Pisa, Italy.
Andrea
A
Guzzetta
D000067877:Autism Spectrum Disorder / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods*; D002675:Child, Preschool; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D007223:Infant; D008297:Male; D009434:Neural Pathways / Q000503:physiopathology; D011446:Prospective Studies; D012720:Severity of Illness Index
autism; autism spectrum disorder; brain lateralization; cerebral lateralization; diffusion imaging; high-angular-resolution diffusion imaging; toddlers; whole brain tractography