Persistent Vegetative and Minimally Conscious States

Machado, Calixto; Korein, Julius

doi:10.1515/revneuro.2009.20.3-4.203

Cited by 13 publications

(10 citation statements)

References 189 publications

(90 reference statements)

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“…They showed no evidence of gestural or verbal communication, no ability to follow commands, and no visual pursuit, or purposeful motor behavior, fulfilling PVS diagnostic criteria. [2][3][4][5][6][7][8][9][10] Auditory, visual, motor, oromotor, communication, and arousal processes were assessed in all cases by the JFK scale, 22 ranging from 3 and 6 points.…”

Section: Methodsmentioning

confidence: 99%

TCD Diastolic Velocity Decay and Pulsatility Index Increment in PVS Cases

Pérez-Nellar

Machado

Scherle

et al. 2010

Can. j. neurol. sci.

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Patients in a persistent vegetative state (PVS) are awake but are apparently unaware of themselves or their environment. 1 The diagnosis of PVS has been made more difficult by recognition of the minimally conscious state as a transitional phase in the partial recovery of self-awareness or environmental awareness as a patient emerges from PVS, leading to a relative high proportion of diagnostic errors. 2-10Functional neuroimaging has provided new insights for assessing cerebral function in these patients. Compared to controls, positron emission tomography and single photon emission tomography have shown a substantial reduction of global brain cerebral glucose metabolism and perfusion in PVS. 11-15On the other hand, transcranial Doppler ultrasonography (TCD) assesses local blood flow velocity and direction in the ABSTRACT: Background: Functional neuroimaging has provided new insights for assessing cerebral function in persistent vegetative state patients (PVS). Compared to controls, positron emission tomography and single photon emission tomography have shown a substantial reduction of global brain cerebral glucose metabolism and perfusion in PVS. Doppler ultrasonography (TCD) assesses local blood flow velocity and direction in the proximal portions of large intracranial arteries; it is a noninvasive technique, and it can be carried out at the bedside. To date, few studies have applied TCD to study PVS. Methods: We assessed intracranial circulation by TCD in five PVS patients. The cause of brain insult was hypoxic encephalopathy in four cases, and the other suffered an embolic cerebral infarct causing a top of the basilar artery syndrome. The sample volume was set at 12 mm; power output and gain settings were maximized as needed. The temporal bone acoustic window was not suitable for intracranial vessel insonation in all patients. As an alternative, the internal carotid artery siphon was assessed by orbital insonation between 55-70 mm. Results: Systolic velocity was within a normal range, between 44 and 62 cm/second in all cases. However, the diastolic amplitude was reduced, as well as the end diastolic velocity, and the pulsatility index was increased in all patients. Conclusions: We conclude that TCD diastolic velocity decrement and PI augmentation in our cases might be related to uncoupling of cerebral blood flow and cerebral metabolic rate, arising from reduced cerebral glucose consumption and oxygen uptake, after extensive brain injury.RÉSUMÉ: Déclin de la vélocité diastolique à l'échographie Doppler et accroissement de l'index de pulsatilité chez les patients en état végétatif persistant. Contexte : La neuroimagerie fonctionnelle a fourni de nouvelles avenues pour l'évaluation de la fonction cérébrale chez les patients en état végétatif persistant (EVP). La tomographie par émission de positons et la tomographie par émission d'un seul photon ont démontré une diminution substantielle du métabolisme et de la perfusion cérébrale du glucose dans tout le cerveau chez les patients en EVP par rapport aux sujets témo...

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Section: Methodsmentioning

confidence: 99%

TCD Diastolic Velocity Decay and Pulsatility Index Increment in PVS Cases

Pérez-Nellar

Machado

Scherle

et al. 2010

Can. j. neurol. sci.

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“…Does this, once again, put the other animals into the category of unconscious zombies? Another emerging dilemma among the nonspeaking is that brain imaging is revealing individuals with so-called persistent vegetative states (PVS) who may still have certain types of experiences in their uncommunicative minds (Machado & Korein, 2009;Marino & Bramanti, 2009;Nachev & Hacker, 2010;. Neither the consciousness of animals nor humans beset by PVS can provide linguistic self-reports, but it may be accessible using other procedures (e.g., eye movement, EEG responses, as well as in animals self-stimulation of and escape from certain types of brain circuit arousals).…”

Section: Levels Of Organizations Of the Experienced Mindbrainmentioning

confidence: 99%

The Neural Basis of the Dynamic Unconscious

Berlin

2011

Neuropsychoanalysis

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A great deal of complex cognitive processing occurs at the unconscious level and affects how humans behave, think, and feel. Scientists are only now beginning to understand how this occurs on the neural level. Understanding the neural basis of consciousness requires an account of the neural mechanisms that underlie both conscious and unconscious thought, and their dynamic interaction. For example, how do conscious impulses, thoughts, or desires become unconscious (e.g., repression) or, conversely, how do unconscious impulses, desires, or motives become conscious (e.g., Freudian slips)? Research taking advantage of advances in technologies, like functional magnetic resonance imaging, has led to a revival and re-conceptualization of some of the key concepts of psychoanalytic theory, but steps toward understanding their neural basis have only just commenced. According to psychoanalytic theory, unconscious dynamic processes defensively remove anxiety-provoking thoughts and impulses from consciousness in response to one's conflicting attitudes. The processes that keep unwanted thoughts from entering consciousness include repression, suppression, and dissociation. In this literature review, studies from psychology and cognitive neuroscience in both healthy and patient populations that are beginning to elucidate the neural basis of these phenomena are discussed and organized within a conceptual framework. Further studies in this emerging field at the intersection of psychoanalytic theory and neuroscience are needed.Keywords: unconscious; psychodynamic; repression; suppression; dissociation; neural "Nothing is so difficult as not deceiving oneself."Ludwig Wittgenstein Cognitive unconscious processingThe intricate relationship between conscious and unconscious processes is one of the many mysteries that continue to perplex our understanding of ourselves.

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“…The second (operant learning) procedure might have the relevant advantage of being suitable for rehabilitation intervention also (Machado and Korein, 2009; Lancioni et al, 2010a, 2012b). In fact, it might help the persons become more active (i.e., increase the frequency of the responses selected for them) to access their environment, enhance their level of sensory input, and show their preference for different stimuli and caregivers (Lancioni et al, 2010a, 2012b; Bagnato et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Assessing learning as a possible sign of consciousness in post-coma persons with minimal responsiveness

Lancioni

Bosco

Belardinelli

et al. 2014

Front. Hum. Neurosci.

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A learning test procedure based on operant principles may be useful in the diagnosis (and eventually rehabilitation) of post-coma persons with minimal responsiveness. This study was aimed at extending the evaluation of such a procedure with seven participants who presented with very limited behavior and apparently severe disorders of consciousness. The procedure was evaluated through an ABACB design, in which A represented baseline phases without stimulation, B intervention phases with brief stimulation periods contingent on specific responses of the participants, and C a control phase in which stimulation was available all the time. Increased responding during the B phases, as opposed to the A and C phases, was taken to indicate learning and possibly a non-reflective expression of phenomenal consciousness. All participants were also evaluated with the coma recovery scale-revised (CRS-R) prior to the start of the learning test procedure and at the end of it. The results of the learning test showed that all participants had significantly higher responding levels during the B phases. The CRS-R scores suggested minimally conscious state for four of them prior to the learning test and for five of them after the completion of the learning test. The implications of the findings are discussed in terms of potential and time cost of the learning test.

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Persistent Vegetative and Minimally Conscious States

Cited by 13 publications

References 189 publications

TCD Diastolic Velocity Decay and Pulsatility Index Increment in PVS Cases

TCD Diastolic Velocity Decay and Pulsatility Index Increment in PVS Cases

The Neural Basis of the Dynamic Unconscious

Assessing learning as a possible sign of consciousness in post-coma persons with minimal responsiveness

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