Sudden Infant Death Syndrome & Arousal Deficiency Theory

Abstract

To reduce infant mortality in present-day Japan, a country that boasts of a very wholesome environment for infants and children but faces a trend of extreme aging of the population and a marked reduction in birth rate, it is mandatory that efforts be made to prevent sudden infant death syndrome (SIDS), which makes up a large portion of infants mortality. The etiological investigation on SIDS has been conducted independently in the areas of epidemiology, physiology and pathology but the cause of this syndrome has remained unknown. Thus an attempt was made to conduct a comprehensive study by combining these disciplines. For a physiopathological hypothesis on SIDS, a theory of incomplete arousal has emerged from the apnea hypothesis (which had been proposed) and through its re-evaluation. As a consequence of the comprehensive study cited above, it was proven that the tendency toward arousal is reduced when an epidemiological risk factors for SIDS are loaded to otherwise normal infants and that the phenomenon of incomplete wakefulness exists in SIDS infants. A human being does not succumb because of incomplete arousal alone. The results of a comprehensive study, in which physiological and pathological data are linked in a single individual, suggested that a failure in neuronal plasticity exists in the arousal pathway of the brain stem and the basis for recognition and memory for a hypoxic state is altered, thus triggering death in infants.