BACKGROUND TO THE STUDY

In the past, little has been known about the effects of a severe and acute neurological illness during infancy on the later health, abilities and behaviour of growing children. In this report we present new data derived from a follow-up of children recruited into the National Childhood Encephalopathy study (NCES) some 10 years previously. The study included about a thousand children who had had an early neurological illness, as well as two control children for each case child, matched according to age, sex and geographical location. The NCES was carried out between 1976 and 1979. All children aged under three years old who had been admitted to hospitals in England, Scotland and Wales with serious acute neurological illnesses were studied for up to 18 months after the onset of illness. Clinical details of cases, as well as medical, social and immunisation histories for both cases and controls were collected, and standardised neurological and developmental assessments were carried out on children who had continuing neurological problems. While this information provided a good picture of the early outcomes of illness, the follow-up period was too short to draw firm conclusions about the nature and permanence of any damage suffered. The present follow-up was carried out between 1986 and 1989. By this time the NCES children were aged from eight to 14 years (most were between 10 and 12) and old enough for conclusions to be drawn on whether or not they had sustained lasting physical or mental disabilities. These conclusions were likely to be reasonably secure and to have general applicability, given the substantial database provided by the original investigation, with its large population, its matched controls and the long time-period over which the children had been followed. Most earlier work, which is referred to in later chapters, has concentrated on specific diagnoses such as infantile spasms or febrile convulsions. In this study we were able to examine a broader spectrum, and therefore we can directly compare the development of children with various types of early illness. The prognosis for children with specific diagnoses is an important question. We show that the outcome for children with infantile spasms is almost invariably poor, whereas it is more mixed for those with encephalopathies or idiopathic convulsions. Prognosis, moreover, depends on how a condition is defined. The significance of febrile convulsions is a good example. Brief uncomplicated convulsions are usually benign and hence not important so far as the child’s later development is concerned. Complicated and/or prolonged seizures of this type, however, may have greater significance. In the present study we include only children with prolonged febrile convulsions, so we are able to document outcomes in these cases. We also consider whether children react similarly to neurological insult or whether the reactions depend on the type of illness or even the individual child. Some have suggested that typical behaviour patterns occur after cerebral damage, whatever its aetiology (e.g. Bakwin and Bakwin 1967), while others have suggested that generally no typical syndrome is found (e.g. Rutter 1984). Our follow-up data illuminate this controversy. In order to try to identify risk factors which predict long-term outcome, we