Intellectual outcome following childhood severe traumatic brain injury: Results of a prospective longitudinal study: The seven-year follow-up of the TGE cohort

Abstract

Childhood traumatic brain injury (TBI) is a leading cause of death and lifelong acquired disability. The aim of this study was to prospectively study intellectual ability following childhood severe TBI over 7–8 years post-injury, and factors influencing outcome and change over time. Children (0–15 years) consecutively admitted in a single trauma center for severe non-inflicted TBI over a 3-year period were included in a prospective longitudinal study. Assessment was conducted at 3, 12 and 24 months, and at 7–8 years using age appropriate Wechsler Intelligence Scales. For the 7–8-year follow-up, one third of the group was aged 18 years or more, and a group of matched controls was included. SES was assessed by parents’ education. Sixty-five of the 81 included children survived (66% boys). After a mean delay post-injury of 7.6 years (SD = 1.5), 39 patients (60%) participated in the study [mean age at injury 7.6 years (SD = 4.72; < 6 years, n = 15; ≥ 6 years, n = 23); median initial Glasgow Coma Scale (GCS) score: 6; mean coma duration: 6 days (SD = 4.8)]. Participants and non-participants did not differ in terms of demographic and severity factors, or initial full scale IQ (FSIQ). For 36% of the sample, at least one parent had graduated from high school. At the 7–8 year follow-up, mean FSIQ in the TBI group was significantly lower than in the control group (86.4; SD = 18 versus 97.2; SD = 11.2; P = 0.016), with no significant change over time when compared with initial FSIQ (3 months post-injury; 85.2; SD = 18). In multivariate analysis, FSIQ was predicted mainly by parental SES ( P = 0.031), with a marginal effect of length of coma ( P = 0.079) and no effect of age at injury, initial GCS or intracranial hypertension. Severe childhood TBI leads to severe and long-standing cognitive impairments, without significant improvement over time. Parental education appears to be the main predictor of cognitive outcome several years post-injury, consistent with previous studies in the literature.