Age and recovery from brain injury: clinical opinions and experimental evidence

Abstract

For many years the notion that brain damage causes less impairment in children than in adults (sometimes known as the 'Kennard Principle') has enjoyed widespread support among scientists and clinicians. More recently neuroscientists have questioned the Principle, most now taking an opposing view that damage to the rapidly developing brain can be more harmful than equivalent damage in adulthood. Many clinicians, however, appear reluctant to reject the Kennard Principle. This study investigates the extent to which the Kennard Principle still guides the judgement of different groups of health-care professionals (neurosurgeons, neurologists, neuropsychologists, general practitioners, nurses, physiotherapists, occupational therapists, and speech therapists). Subjects were asked to estimate the extent of recovery in clinically based but fictitious case studies which differed only in the reported age of the patient. The professions differed in their levels of optimism regarding the extent of recovery to be expected, but all predicted better recovery in younger patients (under 10) than in adults with otherwise similar brain injuries. The results are discussed in terms of their implications for the treatment of brain injuries in the young.

Predicting outcome after childhood brain injury: Figure 1:

“…72 What is clear, however, is that widespread views that young brains make better recoveries are naive. 73 Early injury alters the entire developmental trajectory (the challenge of making "a year's progress every year" with an injured brain), and effects can compound through childhood. This is particularly clear in the literature surrounding pediatric traumatic brain injury, 74 where sometimes impressive early motor recoveries obscure the characteristic emergence of cognitive and psychological morbidity in subsequent years.…”

Cognitive dysfunction in young men following head injury in childhood and adolescence: a population study

“…1 There remains, however, uncertainty over possible differential effects of age at injury, and earlier perceptions that recovery is better at young ages [2][3][4] are now questioned. [5][6][7] There have also hitherto been comparatively few studies that have examined the continuing consequences of pre-adult head injury on cognitive functioning in adulthood, and here too results have been conflicting.…”

Le traumatisme crânien de l’enfant

“…Dans ce cas, non seulement l'enfant ne rattrapera pas la perte constatée au moment de l'atteinte cérébrale, mais le décalage par rapport à la norme ira en s'accentuant. Malgré les données mettant à mal le principe de Kennard lorsque les lésions sont diffuses, les professionnels dans leur ensemble, qu'ils appartiennent au monde des soins ou au monde juridique [12,13], continuent à tort à croire en ce principe. Webb et al ont rappelé la prudence dont il convient de s'entourer lorsqu'on évoque l'avenir après une lésion cérébrale de l'enfant et préconisent d'attendre l'âge adulte pour en apprécier complètement les conséquences.…”