About this Research Topic
Content reportability has often been considered as the principal access to phenomenal consciousness. However, in severe conditions such as aphasia and persistent vegetative state that preclude conventional reporting strategies, it is not possible to exclude some forms of conscious processing. The question invests both the antecedent problem of the assessment of consciousness and the consequent applicative task of rehabilitation possibilities. Researchers and clinicians are called to provide: 1) unambiguous definitions of consciousness (and of its minimal levels) also in relation to the different neuro-cognitive models; 2) proofs and indicators of phenomenal consciousness, from the neurological, to the behavioural, up to the neuroscience level; 3) modalities and types of stimulation programs to foster learning and responsiveness in the rehabilitation process.
1) Confusion on the definition of consciousness arises from the multiplicity of disciplines interested in this topic, concerning both living and artificial systems, and ranging from Philosophy, Psychology, Neurosciences, up to Artificial Intelligence, Cognitive Robotics and Artificial Life. But agreement is lacking also with regard to which answer may be considered as a expression of consciousness, since different answers are connected to different levels of consciousness also in relation to different neurocognitive models. It is also possible that levels of consciousness are not distinct but arranged on a continuum (from vegetative state or minimal consciousness to full consciousness) along which many patients may be slowly moving, while clinicians are often required to categorize them according to a presence/absence dichotomy. Moreover the links among conscious experience and its neural correlates at the different levels of consciousness are not accounted for in current models of brain and behaviour.
2) As regards the second question about proofs and indicators of consciousness, behavioral, electrophysiological and neuroimaging assessment strategies have been developed, mostly based on cognitive accessibility and awareness, which replace the notion of reportability. Awareness is generally viewed as the ability to recognize/revisit a link between events previously experienced. Awareness may also be considered as the ability to acquire new links between events experienced in the context. In the former sense, neurological strategies may be invoked to check signs of these links. In the latter sense, neurological practices may be combined with the monitoring of behavioral signs of learning. The combination of the techniques or even the simple possibility to rely on behavioral signs and learning paradigms would allow new and challenging ways of checking the reliability of the persons’ behaviors as expressions of consciousness.
3) At present, three main behavioral, intervention strategies are available: (a) the use of music, in order to establish human contact, re-enact musical experiences and re-create emotions and related responsiveness; (b) the general sensory stimulation, at the scope of reducing the risk of sensory deprivation while promoting alertness; and (c) the use of learning programs in order to promote the acquisition and consolidation of simple responses and eventually ascertain choice behavior. Extended responding and choice could also be viewed as important rehabilitation objectives. Meanwhile today research is increasingly trying to develop rehabilitation techniques on a neurological basis, taking advantage of progresses in computer science, robotics and neuroscience.
To substantiate the interdisciplinary debate, together with a Cognitive Scientist (Marta Olivetti Belardinelli), a Philosopher (Thomas Huenefeldt), a Psychologist expert in behavioral rehabilitation (Giulio Lancioni) and a Neurologist (Steven Laureys) act as co-editors for this Frontiers Research Topic.
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