The neuropathology of the vegetative state after an acute brain insult

The vegetative state is often described clinically as loss of function of t he cortex while the function of the brainstem is preserved, In all attempt to define the structural basis of the vegetative state we have undertaken a detailed neuropathological study of the brains of 39 patients who remained vegetative until death, 1 month to 8 Sears after an acute brain insult. Of these, 35 had sustained a blunt head injury and 14 some type of acute non- traumatic brain damage. In the traumatic cases the commonest structural abn ormalities identified mere grades 2 and 3 diffuse axonal injury (25 cases, 71%). The thalamus was abnormal in 28 cases (80 %), and in 96 % of the case s who survived fdr more than 3 months, Other abnormalities included ischaem ic damage in the neocortex (13 cases, 37%) and intracranial haematoma (nine cases, 26%). In the non-traumatic cases there was diffuse ischaemic damage in the neocortex in nine cases (64%) and focal damage in four (29%); the t halamus was abnormal in every case. There were cases in both groups where t he cerebral cortex, the cerebellum and the brainstem were of structurally n ormal appearance. In every case, however, there was profound damage to the subcortical white matter or to the major relay nuclei of the thalamus, or b oth, These lesions render any structurally intact cortex unable to function because connections between different cortical areas via the thalamic nucl ei are no longer functional, and there is also extensive damage to afferent and efferent cerebral connections.