Patrick van Bogaert | Search PubMed

PubMed2003

Agenesis of corpus callosum: prenatal diagnosis and prognosis.

INTRODUCTION: Agenesis of corpus callosum (ACC) is commonly diagnosed prenatally. When isolated, it appears to carry a good prognosis but studies are often retrospective and follow-up short. We report a prospective study of 17 children (11 boys, 6 girls) with prenatally diagnosed isolated ACC. METHODS: Neuropsychological evaluation was performed each year and results at the ages of 2, 4, and 6 years were compared. RESULTS: Febrile seizures occurred in 3 patients. Median intellectual quotient (IQ) was within the normal range (80-109) and nonrelated to partial or complete ACC, sex, or febrile seizures. Lower median IQ was significantly related to low cultural status. With age, the number of children with IQ in the lower range (80-89) increased and slowness, attentional troubles, and instability appeared. CONCLUSION: This study demonstrates that if outcome of isolated ACC is favorable, a long follow-up is necessary: with age, IQ in the lower range and behavioral troubles are linked to difficulties in school.

Age Factors↗

PubMed2002

Brain function in the vegetative state.

Positron emission tomography (PET) techniques represent a useful tool to better understand the residual brain function in vegetative state patients. It has been shown that overall cerebral metabolic rates for glucose are massively reduced in this condition. However, the recovery of consciousness from vegetative state is not always associated with substantial changes in global metabolism. This finding led us to hypothesize that some vegetative patients are unconscious not just because of a global loss of neuronal function, but rather due to an altered activity in some critical brain regions and to the abolished functional connections between them. We used voxel-based Statistical Parametric Mapping (SPM) approaches to characterize the functional neuroanatomy of the vegetative state. The most dysfunctional brain regions were bilateral frontal and parieto-temporal associative cortices. Despite the metabolic impairment, external stimulation still induced a significant neuronal activation (i.e., change in blood flow) in vegetative patients as shown by both auditory click stimuli and noxious somatosensory stimuli. However, this activation was limited to primary cortices and dissociated from higher-order associative cortices, thought to be necessary for conscious perception. Finally, we demonstrated that vegetative patients have impaired functional connections between distant cortical areas and between the thalami and the cortex and, more importantly, that recovery of consciousness is paralleled by a restoration of this cortico-thalamo-cortical interaction.

Cerebral Cortex↗