Search

Autonomic functions were studied in three patients with hydrencephalus and five with hydrocephalus. Autonomic failure of central origin was found in the patients with hydrencephalus; whereas, those suffering from hydrocephalus had essentially normal autonomic function. In two patients with hydrencephalus, the hypothalamus was markedly abnormal but the rest of the autonomic nervous system was histologically normal. From this it is concluded that in some patients with mental and motor retardation, autonomic failure may be of cerebral origin but that this is not a feature of patients with hydrocephalus.

Myelinated fibres in the human sympathetic paravertebral chain were examined histologically and in single teased fibre preparations in various age groups in subjects dying from disorders not affecting primarily the autonomic nervous system. An increase in fibre density predominantly due to an increase in the number of small fibres was found in older subjects. A correlation between internodal length and fibre diameter was found but the internodes of sympathetic myelinated fibres are shorter for any given diameter than those found on fibres of comparable size in the sural nerve. A reduction in internodal lengths with advancing years was demonstrated. These observations are interpreted to show that Wallerian degeneration and segmental demyelination occur with increasing frequency in old age and that regeneration does not keep pace with successive degenerative events. The deterioration in function of the autonomic nervous system with advancing years may be attributed in part to the changes found in myelinated fibres in the paravertebral sympathetic chain.