2.2 fMRI demonstrates covert consciousness despite
fluctuations in responsiveness
In the following period (weeks 9-10-11) the patient continued to show
significant variations in behavioral responsiveness (CRS-R total score
ranging from 5 to 9) corresponding to transitions between a VS/UWS and a
MCS- diagnosis. However, the clinical evolution and the consistently
high values of brain complexity, suggested the possibility of an
underlying state of covert consciousness amidst large fluctuations in
behavioral responsiveness. To test this hypothesis, we evaluated the
patient during a period of unresponsiveness (week 6, CRS-R=6; diagnosis
VS/UWS) employing a fMRI paradigm whereby covert consciousness can be
demonstrated with high specificity based on the patient’s ability to
modulate brain activity in response to verbal commands (Owen et
al. , 2006; Monti et al. , 2010; Owen, 2013). In particular, the
fMRI paradigm (ABAB block design) consisted of a simple
command-following task (Bekinschtein et al. , 2011; Curleyet al. , 2018) that prompted the patient to actually perform the
motoric action of opening and closing the left or the right hand, even
if incapable of doing so. The fMRI EPI* sequence was acquired on the
same 3T Siemens Prisma scanner (resolution:3x3x3mm3; matrix:80x80;
TR/TE: 2000ms/30ms). As shown in Figure 5, when comparing right-hand
commands vs rest, a consistent blood-oxygen-level-dependent (BOLD)
activation of left superior temporal and premotor cortices was revealed.