Minimal Consciousness Research Articles

Stimulus complexity enhances auditory discrimination in patients with extremely severe brain injuries

There is controversy as to what extent the processing of spectrally rich sounds in the human auditory cortex is related to the processing of singular frequencies. An informative index of the function of the auditory cortex, particularly important in neurological patients, is the mismatch negativity (MMN), a component of auditory event-related potentials. In the present study the MMN was recorded in 79 patients with extremely severe diffuse brain injuries, most of them in persistent vegetative state or minimal consciousness state. Both sinusoidal (‘pure’) and complex musical tones were used. Different statistical approaches converged in that musical tones elicited an MMN significantly more frequently, and of a larger amplitude, than simple sine tones. This implies that using simple stimuli in clinical populations may lead to a severe underestimation of the functional state of a patient's auditory system. The findings are also in line with behavioral and physiological data indicating independent processing of complex sounds in the auditory cortex.

Health Attitudes, Preventive Behavior, and Playing-related Health Problems among Music Students

The goal of the present study was to survey music students regarding their health attitudes, their use of body-oriented training as a measure of preventive behavior, and their playing-related symptoms and consultation for these symptoms with health professionals. In the framework of a cross-sectional study, the music students at the Freiburg Conservatory were investigated by means of questionnaires. One hundred ninety-seven students participated and were evaluated. It was shown that more students believe that health can be actively influenced by one’s own behavior than have a fatalistic, passive attitude toward their health. One third of the music students use body-oriented training--increasingly during their studies. The close connection of this phenomenon with the presence of playing-related problems, and the fact that only a very small number of music students indicating no physical problems use a body-oriented training method, suggests that body-oriented training was not practiced for preventive reasons, but was motivated by a need for therapy. Two thirds of the music students stated that they had suffered at least once from playing-related problems; half of the music students felt psychologically affected by such difficulties. Half of the musicians had sought professional help due to playing-related health problems. All in all, it must be concluded that there is minimal consciousness regarding questions of health problems, so that few music students have taken preventive measures up to the present time. Therefore, preventive courses should be offered in order to inculcate health consciousness that would enhance the music students’ motivation for proactive health-promoting behavior.

The vegetative and minimally conscious states in children: spasticity, muscle contracture and issues for physiotherapy treatment

The neuropathology of the vegetative (VS) and minimally conscious (MCS) states and the pathophysiology of spasticity are reviewed. Current treatment options available in the physical management of children in a low-level state and factors influencing the physiotherapy treatment of children in a low-level state will be discussed. The complex neuropathology of VS and MCS helps to explain the varied clinical presentations of children in VS and MCS. Spasticity and muscle contracture are common motor sequelae of VS and MCS. Loss of inhibition by descending motor pathways is thought to result in increased muscle tone or spasticity. However, secondary changes in muscle fibre structure and periarticular connective tissue may be an additional component to increased muscle tone. A multimodal approach combining physical, pharmacological and surgical interventions is likely to be the most effective. Knowledge of the likelihood of recovery from VS and MCS can be helpful in determining the frequency and intensity of physiotherapy. Ethical issues in the management of children in a low-level state include a consideration of the benefits to the child and the child's family and the costs to the health care team and the medical institution.

Critical review of passive muscle stretch: implications for the treatment of children in vegetative and minimally conscious states

The efficacy of passive muscle stretch in the treatment of children in vegetative (VS) and minimally conscious (MCS) states is reviewed. Seventeen studies are critically reviewed. Study quality was evaluated using a quality filter adapted from Guyatt. Levels of evidence were assigned to each study using criteria based on Sackett's guidelines and a recent adaptation of those guidelines. Based on these levels of evidence, specific recommendations were made. These recommendations were classified as grade A, B, C or D depending on the levels of evidence used to generate them. There is limited evidence to support the efficacy of passive muscle stretch to improve range of motion and reduce spasticity in children in VS and MCS. Caution must be used when interpreting these recommendations because of the limited number of studies available and the extrapolation of study results from a different population. Further research is needed to strengthen these recommendations and establish the efficacy of passive muscle stretch in the treatment of children in VS and MCS.

The mind/brain inequality

A unified consciousness may be resolved into multiple perceptual and conceptual components. This suggests that it might be useful to represent experience as a vector in a multi-dimensional space (the ‘mental state vector’). If it is supposed that a single neuron alone supports minimal consciousness, that vector would exist in a space of minimal dimension. The direction of the vector might then describe both the content of consciousness and the probability of neuronal depolarisation (the ‘bridging principle’). I will outline a mathematical formalism that generalises this description to multiple neurons (and multiple dimensions), while preserving unity. This formalism implies that objective access to subjective information is limited, expressed as the ‘mind/brain inequality’. The formalism also predicts a correlation of neural activity between remote anatomic sites that is inconsistent with a purely local model of neuronal signalling (Physics 1 (1964) 195). This prediction allows experimental test of the scheme and suggests a role for consciousness in the ‘binding’ (Curr. Opin. Neurobiol. 5 (1995) 520) of perception.

Towards a characterization of minimal consciousness

Intentionalistic explanations of infant behavior are underdetermined and their legitimacy depends upon whether there is independent motivation for the characterizations of consciousness that they entail. I survey several aspects of adult consciousness and consider whether these aspects might be attributed to infants. It is suggested that infants experience minimal consciousness, which is likened to the experience that underlies implicit information processing in a variety of domains. A characterization of minimal consciousness is the first step towards an account of the development of consciousness and intentional action.

Toward a theory of perception: participation as a function of body-flexibility.

Summary The main purpose of this study was to present a tentative statement of a theory of perception in which the role of the body was emphasized. The relationship of the body to the perceived world was conceptualized in terms of a dynamic body-schema, the extent and flexibility of which was termed body-flexibility. This hypothetical construct—i.e., body-flexibility—was seen as emerging in ontogenesis along a developmental continuum from immature to mature. The immature perceiver was conceptualized as embedded in a world, with minimal polarization of his body and his world, with minimal consciousness of his body-as-subject and body-as-object of experience. The mature perceiver was conceptualized as having the ability to distantiate: i.e., as conscious of his subjective and objective poles of being in relation to the phenomena of experience. The ability to distantiate was conceptualized in terms of degree of body-flexibility. The language and constructs of this statement were mostly distilled from the wor...