Neurological research
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Neurological research · Jan 2012
Cerebrovascular time constant: dependence on cerebral perfusion pressure and end-tidal carbon dioxide concentration.
The cerebrovascular time constant (τ) describes the time to establish a change in cerebral blood volume after a step transient in arterial blood pressure (ABP). We studied the relationship between τ, ABP, intracranial pressure (ICP), and end-tidal carbon dioxide concentration (EtCO2). ⋯ Cerebrovascular time constant τ is modulated by ABP, ICP, and EtCO2.
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Neurological research · Jan 2012
Isoflurane-induced spatial memory impairment by a mechanism independent of amyloid-beta levels and tau protein phosphorylation changes in aged rats.
The molecular mechanism of postoperative cognitive dysfunction is largely unknown. Isoflurane has been shown to promote Alzheimer's disease neuropathogenesis. We set out to determine whether the effect of isoflurane on spatial memory is associated with amyloid-beta (A-beta) levels and tau phosphorylation in aged rats. ⋯ Isoflurane may induce spatial memory impairment through non-A-beta or tau neuropathogenesis mechanisms in aged rats.
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Neurological research · Nov 2011
Randomized Controlled TrialLong-term antalgic effects of repetitive transcranial magnetic stimulation of motor cortex and serum beta-endorphin in patients with phantom pain.
To assess the long-term analgesic effect of repetitive transcranial stimulation (rTMS) on chronic phantom pain using high frequency stimulation and to measure the serum beta-endorphin level pre- and post-rTMS. ⋯ These results confirm that five daily sessions of rTMS over motor cortex can produce long lasting pain relief in patients with phantom pain and it might be related to an elevation of serum beta-endorphin concentration.
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Neurological research · Nov 2011
Cerebrospinal fluid leak after microsurgical surgery in vestibular schwannomas via retrosigmoidal craniotomy.
Cerebrospinal fluid (CSF) leak is still a common complication in surgery of vestibular schwannoma, increasing morbidity and prolonging hospital stay. Our single center study was performed to determine the incidences of CSF leaks after microsurgical removal of vestibular schwannoma via a retrosigmoidal approach with two different surgical closure techniques. ⋯ Suture and occlusion of the dura is an important step to prevent CSF leak and postoperative infection. By comparing sandwich technique and single-layer dural sealing, no significant difference could be shown.
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Neurological research · Nov 2011
EEG non-linear feature extraction using correlation dimension and Hurst exponent.
In this work, we evaluated the differences between epileptic electroencephalogram (EEG) and interictal EEG by computing some non-linear features. Correlation dimension (CD) and Hurst exponent (H) were calculated for 100 segments of epileptic EEG and 100 segments of interictal EEG. A comparison was made between epileptic EEG and interictal EEG in those non-linear parameters. ⋯ This indicates that both epileptic and interictal EEGs show long-range anticorrelation. The value of Hurst exponent of epileptic EEG signals is lower than that of interictal EEG signals, showing that the degree of anticorrelation of epileptic EEG signals is larger than that of interictal EEG. Hence, the non-linear parameters such as CD and Hurst exponent can help interpret epileptic and interictal EEGs and their neurodynamics.