Abnormal regional cerebral blood flow in childhood autism

Neuroimaging studies of autism have shown abnormalities in the limbic syste m and cerebellar circuits and additional sites. These findings are not, how ever, specific or consistent enough to build up a coherent theory of the or igin and nature of the brain abnormality in autistic patients. Twenty-three children,vith infantile autism and 26 nonautistic controls matched for IQ and age were examined using brain-perfusion single photon emission computed tomography with technetium-99m ethyl cysteinate dimer, In autistic subject s, we assessed the relationship between regional cerebral blood flow (rCBF) and symptom profiles. Images were anatomically normalized, and voxel-by-vo xel analyses were performed. Decreases in rCBF in autistic patients compare d with the control group were identified in the bilateral insula, superior temporal gyri and left prefrontal cortices, Analysis of the correlations be tween syndrome scores and rCBF revealed that each syndrome was associated w ith a specific pattern of perfusion in the limbic system and the medial pre frontal cortex, The results confirmed the associations of (i) impairments i n communication and social interaction that are thought to be related to de ficits in the theory of mind (ToM) with altered perfusion in the medial pre frontal cortex and anterior cingulate gyrus, and (ii) the obsessive desire for sameness with altered perfusion in the right medial temporal lobe, The perfusion abnormalities seem to be related to the cognitive dysfunction obs erved in autism, such as deficits in ToM, abnormal responses to sensory sti muli, and the obsessive desire for sameness. The perfusion patterns suggest possible locations of abnormalities of brain function underlying abnormal behaviour patterns in autistic individuals.