No-report Paradigmatic Ascription of the Minimally Conscious State: Neural Signals as a Communicative Means for Operational Diagnostic Criteria
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The minimally conscious state (MCS) is usually ascribed when a patient with brain damage exhibits observable volitional behaviors that predict recovery of cognitive functions. Nevertheless, a patient with brain damage who lacks motor capacity might nonetheless be in MCS. For this reason, some clinicians use neural signals as a communicative means for MCS ascription. For instance, a vegetative state patient is diagnosed with MCS if activity in the motor area is observed when the instruction to imagine wiggling toes is given. The validity of using neural signals in ascribing MCS requires a special sort of inference. That is, no-report paradigmatic assessments must have inductively strong ways of inferring a purported informational content from the observed neural signal that grounds the fact that the patient has top-down cognitive control (or residual volition). Shannon’s mathematical theory of communication and Bayes’ theorem reveals the formal structure of neural communication. On the basis of relevant data from the neuroscience literature, I conclude that the formal structure combined with the data shows that neural signals can be used as a communicative means for operational diagnostic criteria for MCS ascription.
KeywordsMinimally conscious state Mental motor action Neural signal Informational content Shannon information Bayes’ theorem Residual volition No-report paradigm
I am indebted to Carrie Figdor for many fruitful discussions and her invaluable comments made on earlier drafts. I am also grateful to Gregory Landini, Richard Fumerton, as well as two anonymous reviewers of this journal for their well-placed suggestions on previous versions. Many thanks to Seung Wook Kim, David Redmond, and members of the University of Iowa Graduate Philosophical Society for helpful discussions.
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