The conduction velocity of the ulnar, median and peroneal nerves was studied from birth to adult age in normal infants, children and adolescents. The method allowed measurements of the conduction velocity of the thickest and fastest conducting motor nerve fibres. In newborns the conduction velocity of all 3 nerves was roughly half of that of adults. The value for the ulnar nerve increased rapidly during the first 3 years. After that age it rose only slightly and between adolescence and adult age there was a significant reduction. The value for the median nerve increased
A low white blood cell count usually is caused by: 1  Viral infections that temporarily disrupt the work of bone marrow. 2  Certain disorders present at birth (congenital) that involve diminished bone marrow function. 3  Cancer (or other diseases that damage bone marrow)  Autoimmune disorders that destroy white blood cells or bone marrow cells.
With all that in mind, if you and your doctor determine that your white blood cell count is lower than it should be, that is cause for concern. Because a low white blood cell count cannot, in and of itself, be used to diagnose a specific disease or disorder, you'll likely need more testing to further assess your condition. Underlying causes for a low white blood cell count can range from benign disorders, such as vitamin deficiencies, to more serious blood diseases, such as leukemia or lymphoma.