Responsiveness and the Autonomic Control–CNS Two-Way Interaction in Disorders of Consciousness

Functional neuroimaging has documented stimulus- or condition-related regional brain activation in subjects in VS/UWS or minimally conscious state and suggested retained connectivity in segregated cortical networks. It also provided indications of direct/indirect functional links between the autonomic control and higher brain activities. An integrated model (the central autonomic network) has been contrived to describe the interaction among neuronal structures involved in cognitive, sensory, or affective processes and autonomic regulation. The measures of heart rate variability (HRV) are thought to indirectly reflect these activities and interaction; integrative models equate HRV to autonomic nervous system outputs, with HRV reflecting affective, physiological, “cognitive,” and behavioral elements and homeostatic responses. HRV provides tools for the evaluation of responsiveness in DoC and has proved reliable in physiological research in the absence of conscious behavior