Frontal lobe metabolic alterations in autism spectrum disorder: a 1H-magnetic resonance spectroscopy study.

PURPOSE: Recently, neuroimaging studies were performed using 1H-magnetic resonance spectroscopy (1H-MRS), revealing a quantitative alteration of neurochemicals (such as neurotransmitters and metabolites) in several brain regions of patients with autism spectrum disorder (ASD). The involvement of the frontal lobe in the neurobiology of ASD has long been documented in the literature. Therefore, the aim of this study was to analyze the alterations of N-acetylaspartate/creatine (NAA/Cr) and choline/Cr (Cho/Cr) ratios in the frontal lobe subcortical white matter (WM) in ASD patients, in order to reveal any alteration of metabolites that might be the expression of specific clinical features of the disorder. PATIENTS AND METHODS: An 1H-MRS study of the frontal lobe subcortical WM was performed in 75 children with ASD and in 50 age-matched controls to evaluate the functional activity of this brain region. RESULTS: NAA/Cr and Cho/Cr ratios were significantly altered in ASD, compared to control subjects. Moreover, in the ASD group, NAA/Cr was significantly lower in patients with a cognitive impairment. CONCLUSION: Results from this study confirm the existence of brain metabolites' alterations in frontal lobe WM in children with ASD, supporting the relevance of this brain region in the clinical expressions of this disorder, including its role in the cognitive impairment. Further 1H-MRS investigations will allow to comprehensively explain the relationship between metabolic alteration in a specific brain region and specific clinical features of ASD.

Cerebrovascular disorders in the prenatal period.

Fetal stroke can occur between the 14th week of pregnancy and the beginning of labor. The incidence is approximately 17-35 of 100,000 live births. Risk factors are correlated to the mother, the pregnancy, or the factors associated with the fetus itself. Computerized tomography and magnetic resonance imaging are the most commonly used imaging techniques. The authors studied 3 cases with neurological symptoms by magnetic resonance imaging and magnetic resonance-angiography. In these cases, the authors found massive involvement of the left hemisphere that was presumptively correlated with the persistence of the oval foramen. Magnetic resonance-angiography showed a flow reduction in the left cerebral vessels, and in 1 case, there was also persistence of the fetal primitive trigeminal artery. The discrepancy between the extent of the cerebral lesions and the neurological symptoms is associated with cerebral plasticity, which is greater in damage occurring early in fetal life.

Description of six cases of child cauda equina leptomeningitis: an emerging disease.

Child cauda equina leptomeningitis (CCEL) is a typical clinical example of aseptic meningitis with patterns of an emerging disease, and it affects children aged 2-9. Here we will describe six cases of CCEL. After the prodromes, all children underwent an acute phase with hypoasthenia of the lower limbs, hyporeflexia, staggering and ataxia with steppage. Only in one case there were generalized fits and coma of grade 1-2 too. All children underwent a spinal magnetic resonance imaging (MRI), proving pathologic enhancement of cauda equina and conus medullaris leptomeningitis. At the same time, MRI made possible the differential diagnosis between cauda equina leptomeningitis and isolated minor forms of Guillain-Barre syndrome involving the lower limbs. Three hypotheses will be formulated for understanding the pathogen mechanism(s) of CCEL. The first one is based on the presence of an immediate viral damage on the meninges, the second one, the more likely, contemplates the occurrence of an immunomediated mechanism in a host genetically prone to react in an abnormal way from an immune viewpoint. The third hyphotesis consists in a two-time damage: an early immediate damage from the virus, and a later immunomediated reaction.