Neurology
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Functional neuroimaging has shown that the absence of externally observable signs of consciousness and cognition in severely brain-injured patients does not necessarily indicate the true absence of such abilities. However, relative to traumatic brain injury, nontraumatic injury is known to be associated with a reduced likelihood of regaining overtly measurable levels of consciousness. We investigated the relationships between etiology and both overt and covert cognitive abilities in a group of patients in the minimally conscious state (MCS). ⋯ The overt behavioral signs of awareness (measured with the Coma Recovery Scale-Revised) exhibited by nontraumatic MCS patients appear to be an accurate reflection of their covert cognitive abilities. In contrast, one-third of a group of traumatically injured patients in the MCS possess a range of high-level cognitive faculties that are not evident from their overt behavior.
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Deep brain stimulation (DBS) of the ventral intermediate nucleus of thalamus (VIM) is a treatment option in medically intractable tremor, such as essential tremor or tremor-dominant Parkinson disease (PD). Although functional studies demonstrated modulation of remote regions, the structural network supporting this is as yet unknown. In this observational study, we analyzed the network mediating clinical tremor modulation. ⋯ Patients undergoing DBS provide a unique opportunity to assess an electrophysiologically defined seed region in human thalamus, a technique that is usually restricted to animal research. In the future, preoperative tractography could aid with stereotactic planning of individual subcortical target points for stimulation in tremor and in other disease entities.
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The determinants of subarachnoid hemorrhage (SAH) volume and an atypical pattern of blood are not clear. Our objective was to determine if reduced platelet activity on admission and abnormal venous drainage are associated with greater SAH volume. ⋯ Discontinuous venous drainage and reduced platelet activity were associated with increased SAH volume and hydrocephalus. These factors may explain thick SAH and reduce the need for repeated invasive imaging in such patients.
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Brain arteriovenous malformations (AVMs) often present with epileptic seizures, but prospective data on the risk of seizures with respect to morphologic AVM characteristics are scarce. ⋯ Our study suggests that seizures mainly occur in AVMs with superficial drainage. Other predisposing factors include male sex, increasing AVM size, and frontal lobe and arterial borderzone location. Whether or not interventional treatment has an effect on the long-term risk of epilepsy remains to be determined.