1/84. Impaired effective cortical connectivity in vegetative state: preliminary investigation using PET. Vegetative state (VS) is a condition of abolished awareness with persistence of arousal. awareness is part of consciousness, which itself is thought to represent an emergent property of cerebral neural networks. Our hypothesis was that part of the neural correlate underlying VS is an altered connectivity, especially between the associative cortices. We assessed regional cerebral glucose metabolism (rCMRGlu) and effective cortical connectivity in four patients in VS by means of statistical parametric mapping and [18F]fluorodeoxyglucose-positron emission tomography. Our data showed a common pattern of impaired rCMRGlu in the prefrontal, premotor, and parietotemporal association areas and posterior cingulate cortex/precuneus in VS. In a next step, we demonstrated that in VS patients various prefrontal and premotor areas have in common that they are less tightly connected with the posterior cingulate cortex than in normal controls. These results provide a strong argument for an alteration of cortical connectivity in VS patients. ( info) |
2/84. Assessment of command-following in minimally conscious brain injured patients. OBJECTIVE: To develop a method for establishing the presence of command-following in individuals with traumatic brain injury, based on the principles of single-subject experimental design. DESIGN: A series of single-subject experiments, individualized to the particular command-following question about a particular patient. SETTING: An inpatient rehabilitation hospital with a specialized program for vegetative and minimally conscious brain injured patients. patients: Eight individuals with serious brain injury of traumatic or nontraumatic origin, presenting in vegetative or minimally conscious states. INTERVENTIONS: The frequency of performance of the behavior in question was assessed in response to commands and in relation to appropriate control conditions. Data were analyzed with chi2 or Fisher's exact test, as well as measures derived from signal detection theory. MAIN OUTCOME MEASURES: The frequency of performance of a specific behavior in the presence of a command and in relevant contrasting conditions. RESULTS: This method identified whether a specific behavior was being performed in response to command and whether the reliability of this behavior was changing over time either spontaneously or in response to treatment. CONCLUSIONS: Quantitative assessment of command-following based on principles of single-subject experimental design can determine whether patients are capable of following commands and whether this ability changes over time or in response to treatment. ( info) |
3/84. consciousness in congenitally decorticate children: developmental vegetative state as self-fulfilling prophecy. According to traditional neurophysiological theory, consciousness requires neocortical functioning, and children born without cerebral hemispheres necessarily remain indefinitely in a developmental vegetative state. Four children between 5 and 17 years old are reported with congenital brain malformations involving total or near-total absence of cerebral cortex but who, nevertheless, possessed discriminative awareness: for example, distinguishing familiar from unfamiliar people and environments, social interaction, functional vision, orienting, musical preferences, appropriate affective responses, and associative learning. These abilities may reflect 'vertical' plasticity of brainstem and diencephalic structures. The relative rarity of manifest consciousness in congenitally decorticate children could be due largely to an inherent tendency of the label 'developmental vegetative state' to become a self-fulfilling prophecy. ( info) |
4/84. Cerebral arteriovenous malformation in pregnancy: presentation and neurologic, obstetric, and ethical significance. Cerebral arteriovenous malformations infrequently complicate pregnancy. We sought to determine the neurologic, obstetric, and ethical significance of such malformations. We present the clinical course of 2 pregnant women with arteriovenous malformations who experienced cerebral hemorrhage and a loss of capacity for decision making. We also review the neurologic and obstetric significance of arteriovenous malformations in pregnancy. Various treatment options with concern for pregnancy and the prognosis for arteriovenous malformations are outlined. The ethical issues involved for pregnant patients whose decisional capacity is compromised as a result of cerebral injury are explored. A review of persistent vegetative state and brain death (death by neurologic criteria) occurring in pregnancy allows us to explore many issues that are applicable to decisionally incapacitated but physiologically functioning pregnant women. We outline a document, the purpose of which is to obtain advance directives from pregnant women regarding end-of-life decisions and to appoint a surrogate decision maker. We believe that evaluation and treatment of the arteriovenous malformation may be undertaken without regard for the pregnancy and that the pregnancy should progress without concern for the arteriovenous malformation. ( info) |
5/84. A 4-year-old with pica, progressive incoordination, and decreased responsiveness. This article reports a typical case of subacute sclerosing panencephalitis (SSPE). The patient contracted measles as an infant during the 1989 to 1991 united states measles epidemic. At 4 1/2 years of age, he developed behavioral changes and quickly progressed through the typical clinical stages of SSPE. His EEG was characteristic. serum and CSF measles immunoglobulin g were markedly elevated. He remains alive but is vegetative. To our knowledge, this is the first case of SSPE stemming from the 1989 to 1991 measles epidemic. Because infants--the group at highest risk to develop SSPE--were most severely affected by this measles outbreak, other cases of SSPE stemming from this epidemic may occur. ( info) |
6/84. Subacute encephalopathy in a 5-year-old boy. A 5-year-old boy presented with an acute ataxia and altered mental status. Although he initially recovered from these symptoms, he presented a second time with myoclonus and seizures and rapidly became vegetative. cerebrospinal fluid studies, magnetic resonance imaging, and brain biopsy all confirmed the presence of subacute sclerosing panencephalitis. Despite courses of therapy with cimetidine, amantadine, ribavirin, and inosine, no clinical improvement has been seen. Clinicians need to be alert to the possibility of subacute sclerosing panencephalitis even in the vaccinated child in the appropriate clinical setting. ( info) |
7/84. Assessment of minimally responsive patients: clinical difficulties of single-case design. Improved management of very severely central nervous system (CNS) injured individuals has given rise to an increasing number of patients in a minimally responsive state. There is a growing literature stressing the importance of accurately determining these patients' level of cognitive functioning and its role in appropriate rehabilitation and long term management. The single case design model appears to be the intervention of choice, with its great flexibility and tailored approach to each individual case. The recent literature has focused on the technical aspects of the assessment, offering clear procedural guidelines. Unfortunately, there is a dearth of information about clinical factors such as clinical setting and family involvement, which may interfere with or prevent a planned intervention. The case of MT is presented, who was the subject of a single case intervention 9 months following an extremely severe traumatic brain injury. The planned intervention was to examine the effects of a psychostimulant on MT's level of arousal, in order to improve his participation in the rehabilitation programme. Beyond the results (which were equivocal), the clinical difficulties in conducting single case study designs in rehabilitation are discussed. Ways to minimize these difficulties are proposed. ( info) |
8/84. Words without mind. A woman (LR), unconscious for 20 years, spontaneously produces infrequent, isolated words unrelated to any environmental context. Fluorodeoxy-glucose-positron emission tomography (FDG-PET) imaging coregistered with magnetic resonance imaging (MRI) revealed a mean brain metabolism equivalent to deep anesthesia. Nevertheless, PET imaging demonstrated islands of modestly higher metabolism that included Broca's and Wernicke's areas. Functional brain imaging with magnetoencephalographic (MEG) imaging, a technique providing a temporal resolution of better than 1 msec, identified preserved dynamic patterns of spontaneous and evoked brain activity in response to sensory stimulation. Specifically, we examined spontaneous gamma-band activity (near 40 Hz) and its reset or modification during early auditory processing, a measure that correlated with human perception of sensory stimuli (Joliot, Ribary, & Llinas, 1994). Evidence of abnormal and incomplete gamma-band responses appeared in the left hemisphere only in response to auditory or somatosensory stimulation. MEG single-dipole reconstructions localized to the auditory cortex in the left hemisphere and overlapped with metabolically active regions identified by FDG-PET. The observation demonstrates that isolated neuronal groups may express well-defined fragments of activity in a severely damaged, unconscious brain. The motor fixed-action pattern character of her expressed words supports the notion of brain modularity in word generation. ( info) |
9/84. Neuropsychological assessment of a potential "euthanasia" case: a 5 year follow up. McMillan reported a neuropsychological assessment procedure which was used to determine whether or not there was evidence for sentience in a young woman who had been rendered tetraplegic and anarthric as a result of a road traffic accident. An application to court had been made to withdraw feeding and this was supported by medical evidence which gave the view that the individual was functioning little beyond vegetative state, had a poor quality of life and had little prospect of further recovery. Evidence for an ability to communicate reliably was found including for a wish to continue living, and as a consequence the application to court was withdrawn. This paper describes further recovery 2-4 years after the original assessment (i.e. 4-6 years post-injury). At follow-up, she remained dependent for all care, but was now feeding orally and was talking. She could learn new information, some of which she retained for at least 12 months and had greater insight into her condition. She now reported low mood and some pain. As before, she consistently reported a wish to live. The implications of the follow-up are discussed in the context of assumptions made about quality of life and decision making about euthanasia in brain injured people who are severely disabled, but are not in a vegetative state. ( info) |
| A 5-year-old with spastic quadraparetic cerebral palsy suffered multiple strokes after extensive orthopedic surgery. Coagulation testing was undertaken to determine whether a familial thrombophilia was present. The patient was found to be heterozygous for factor v Leiden. factor v Leiden may be a risk factor for central nervous system events in special-needs children, particularly when common medical conditions create additional procoagulant risks. ( info) |