1. Left middle frontal cortex, caudate nuclei
A multiple case study investigating the sub-categorization of the minimally conscious state state
Aubinet C¹, Rajanikant P¹, Cassol H¹, Larroque S¹, Laureys S¹ & Thibaut A¹
¹ GIGA-Consciousness, Coma Science Group & Neurology Department, Liège University & University Hospital of Liège, Liège, Belgium
Methods
Introduction
The minimally conscious state (MCS) has two subcategories, namely, MCS- and MCS+, based on the absence or presence of language-related signs of consciousness (e.g., command-following)¹. Using positron emission tomography (PET) and functional magnetic resonance imaging (MRI), patients in MCS+ have been shown to present a higher brain metabolism and connectivity in language-related areas²¯³.
We here describe the longitudinal recovery of command-following using neuroimaging measurements in a case-series.
Three chronic MCS patients were assessed at two time points by means of repeated Coma Recovery Scale-Revised, PET and MRI (voxel-based morphometry). At time 1 (T1), they were diagnosed as MCS-. They later recovered command-following (i.e., MCS+) when they were reassessed at time 2 (T2). We thus compared the neuroimaging differences between both diagnoses in each patient. Results were considered significant at FDR-corrected p<0.05.
Results
PET1 ≠ PET2
VBM1 ≠ VBM2
Case 1:
Female, 30 years old, 20 months post-TBI, 27 months between T1 and T2, left-handed
Left angular and middle frontal cortex, precuneus
No significant recovery of grey matter volume
Case 2:
Male, 23 years old, 10 months post-TBI, 31 months between T1 and T2, right-handed
Left temporal cortex, right thalamus, orbitofrontal cortex
Caudate nuclei, left temporal and angular cortex
Case 3:
Male, 37 years old, 5 years post-hemorrhage, 26 months between T1 and T2, right-handed
Right thalamus, bilateral temporal cortex, frontal cortex, left caudate
Left middle frontal cortex, caudate nuclei
Contact :
References: ¹Bruno MA et al. From unresponsive wakefulness to minimally conscious PLUS and functional locked-in syndromes: Recent advances in our understanding of disorders of consciousness. J Neurol. 2011;258(7): ²Bruno MA et al. Functional neuroanatomy underlying the clinical subcategorization of minimally conscious state patients. J Neurol. 2012;259(6): ³Aubinet C et al. Clinical sub-categorization of minimally conscious state according to resting functional connectivity. Under review.
Conclusion
The reappearance of command-following in these three chronic patients was concomitant with the recovery of regional brain metabolism and grey matter in neural regions that have been associated with self-consciousness, language processing or other cognitive functions. We therefore suggest that both consciousness and language could be involved in the transition from MCS- to MCS+.