A prospective study of children with head injuries: II. Cognitive sequelae

Abstract

SYNOPSIS: A 2¼-year prospective study of children suffering head injury is described. Three groups of children were studied: (a) 31 children with ‘severe’ head injuries resulting in a post-traumatic amnesia (PTA) of at least 7 days; (b) an individually matched control group of 28 children with hospital treated orthopaedic injuries; and (c) 29 children with ‘mild’ head injuries resulting in a PTA exceeding 1 hour but less than 1 week. Individual psychological testing was carried out as soon as the child recovered from PTA, and then again 4 months, 1 year, and 2¼ years after the injury. A shortened version of the Wechsler Intelligence Scale for Children (WISC), the Neale Analysis of Reading Ability and a battery of tests of specific cognitive functions were employed. The mild head injury group had a mean level of cognitive functioning below the control group, but the lack of any recovery during the follow-up period indicated that the intellectual impairment was not a consequence of the injury. In the severe head injury group, the presence of cognitive recovery and a ‘dose—response’ relationship with the degree of brain injury showed that the intellectual deficits were caused by brain damage. Some degree of cognitive impairment was common following head injuries giving rise to a PTA of at least 2 weeks. Conversely no cognitive sequelae, transient or persistent, could be detected when the PTA was less than 24 hours. The results were less consistent in the 1-day to 2-week PTA range, but the evidence suggested that a broadly defined threshold for impairment operated at about that level of severity of injury. Timed measures of visuo-spatial and visuo-motor skills tended to show more impairment than verbal skills but otherwise there was no suggestion of a specific pattern of cognitive deficit. Recovery was most rapid in the early months after injury, but substantial recovery continued for 1 year with some improvement continuing in the second year in some children, especially those with the most severe injuries. Age, sex and social class showed no significant effects on the course of recovery.