Learning as a possible sign of non-reflective consciousness in persons with a diagnosis of vegetative state and pervasive motor impairment.

A diagnosis of vegetative state represents a serious predicament, which basically precludes/minimizes rehabilitation perspectives. Reliability of the assessment approach in these situations is of paramount importance, but not easy to achieve. In recent studies, a learning assessment procedure has been suggested as a supplement in the diagnostic process and assessed with eight patients. The procedure involves an ABABCB sequence in which A represents baseline phases with no stimulation available, B intervention phases with stimuli delivered contingently on target responses, and C a control condition. This condition involves stimulation presented non-contingently. The patients' ability to associate responding with environmental stimuli and thus increase such responding during the B phases, and reduce it during the A and C phases, may be considered a sign of learning. Learning might be viewed as representative of forms of concrete knowledge and presumably basic levels of consciousness. Preliminary results indicate that (a) signs of learning may appear in patients with a previous diagnosis of vegetative state and (b) the presence of those signs may require a revision of their diagnostic label and a reappraisal of their rehabilitation perspectives.