Hypoxic encephalopathy during the late gestation and perinatal period occupies a large part as a cause of mentally and physically handicaps. An extensive study on the pathogenesis and pathophysiology of the hypoxic brain damage is, therefore, the matter of urgency to minimize the occurrence of handicapped children. The main factors and/or processes relating to hypoxic or hypoxic-ischemic brain damage are (1) structural and functional immaturity of the brain vascular system and (2) a metabolic cascade triggered by hypoxia. As the following metabolic cascade subsequent to hypoxia has been partly made clear;(a) disturbance of the energy metabolism, (b) excessive release of excitatory amino acids and subsequent activation of NMDA and K/Q receptors at the cell membrane, (c) collapse of the membrane ion pump, and (d) increase in turnover of membrane phospholipids.
Perinatal asphyxia is a well recognized cause of cerebaral palsy and related disabilities. However, uncertainties exist regarding the degree of asphyxia required to cause brain injury. Determination of degree of asphyxia is a simple matter of measuring blood gases and pH. However, the mechanism of asphyxia required to produce cellular damage in a particular individual varies widely, depending not only on depth and duration of the asphyxia but even more on other biochemical changes, especially glucose, excitatory amino acids, calcium activated protein, or the receptor side of ionic channels. The mechanism of delayed neuronal cell death or cell-to-cell connection is also mysterious. The immature brain is not a reduced version of the adult brain. Studies should develop to a wide variety of aproaches to clear the complex interactions between birth asphyxia and anoxic brain damage.
This symposium was forcused on habilitation for children with visual and hearing impairment, speech-language disorder, and hyperkinetic disorder. New and variable approaches were reported in topics of habilitation for these handicapped children by an ophthalmologist, an otorhinolaryngologist, a child neurologist, a speech therapist and an educational psychologist. Many points of these approaches were then discussed.