Clinical neurological examination of infants and children.

A thorough but focused history and neurological examination remain the most important initial elements of neurological diagnosis at all ages. Advances over the past two decades in clinical neurophysiology, neuroimaging, genetics, and neuropathological examination of tissue have at times appeared to predominate over traditional history and physical exam, but no laboratory studies can provide the focus and clues to diagnosis that clinical findings offer. History taking and the techniques of neurological examination are skills to be learned by the student, refined by the resident, and practiced and perfected throughout the career of a pediatric neurologist. Examination must be specifically modified to correspond to age and with the expectation of developmental skills achieved at various ages, in addition to the localizing value of particular signs that may apply at all ages. Hypotonia, extensor plantar responses, and lack of visual fixation may be normal in a preterm infant but abnormal at several months of age. "Primitive" reflexes disappear at a certain age, but really are only suppressed or inhibited and may become re-expressed with disinhibition many decades later. Finally, the pediatric neurologist needs to have a firm foundation in normal development, neuroembryology, and changes in the expression of diseases at various stages of maturation of the nervous system.