Authors:

Menon, D.K., OWEN, A. M., Williams, E.J., Kendall, I. V., Downey, S.P.M.J., Minhas, P.S., Allen, C.M.C., Boniface, S., Antoun, N., Pickard, J.D.,

Reference:

Year of publication:

1999

CBU number:

3840

Abstract:

Despite converging agreement about the definition of persistent vegetative state (PVS), recent reports have raised concerns regarding accuracy of this diagnosis in some patients, and the extent to which, in some cases, residual cognitive functions may remain undetected. While the investigation of such patients using resting blood flow and glucose metabolism as markers of neural capacity or potential is important, establishing that such activation is related to the presence of residual cognitive function is of greater significance. Objective assessment of residual cognitive function can be extremely difficult since motor responses may be minimal, inconsistent, and difficult to document in many patients, or may be undetectable in others because no cognitive output is possible. We have recently used 15-Oxygen PET activation studies to study covert cognitive processing in two patients with a probable clinical diagnosis of PVS. Here, the results of these studies are discussed in the context of alternative imaging methods and how they have been utilised in the assessment of patients with PVS.