Brain function assessment in different conscious states

Background: The study of brain functioning is a major challenge in neuroscience fields as human brain has a dynamic and ever changing information processing. Case is worsened with conditions where brain undergoes major changes in so-called different conscious states. Even though the exact definition of consciousness is a hard one, there are certain conditions where the descriptions have reached a consensus. The sleep and the anesthesia are different conditions which are separable from each other and also from wakefulness. The aim of our group has been to tackle the issue of brain functioning with setting up similar research conditions for these three conscious states.Methods: In order to achieve this goal we have designed an auditory stimulation battery with changing conditions to be recorded during a 40 channel EEG polygraph (Nuamps) session. The stimuli (modified mismatch, auditory evoked etc.) have been administered both in the operation room and the sleep lab via Embedded Interactive Stimulus Unit which was developed in our lab. The overall study has provided some results for three domains of consciousness. In order to be able to monitor the changes we have incorporated Bispectral Index Monitoring to both sleep and anesthesia conditions.Results: The first stage results have provided a basic understanding in these altered states such that auditory stimuli have been successfully processed in both light and deep sleep stages. The anesthesia provides a sudden change in brain responsiveness; therefore a dosage dependent anesthetic administration has proved to be useful. The auditory processing was exemplified targeting N1 wave, with a thorough analysis from spectrogram to sLORETA. The frequency components were observed to be shifting throughout the stages. The propofol administration and the deeper sleep stages both resulted in the decreasing of N1 component. The sLORETA revealed similar activity at BA7 in sleep (BIS 70) and target propofol concentration of 1.2 μg/mL.Conclusions: The current study utilized similar stimulation and recording system and incorporated BIS dependent values to validate a common approach to sleep and anesthesia. Accordingly the brain has a complex behavior pattern, dynamically changing its responsiveness in accordance with stimulations and states. © 2010 Ozgoren et al; licensee BioMed Central Ltd

The changes in cyclic alternating pattern parameters of epilepsy patients [Epilepsi hastalarında sıklık alternan pattern parametrelerinde ortaya çıkan değişiklikler]

Aim: The aim of this study is to determine the changes in the polysomnographic parameters and the cyclic alternating pattern (CAP) in generalized and partial epilepsy patients (with and without epileptiform discharges in EEG) using video-EEG-PSG recording. Materials and Methods: 73 patients diagnosed with epilepsy and 19 healthy controls within the same age group (control group) underwent an 8 hour long sleep video-EEG-PSG recording. After the first evaluation, CAP parameters were scored in 57 patients (31 generalized and 26 partial epilepsy) and 16 healty subjects who have no sleep diseases and the results were compared within groups. Results: Total sleep time and NREM I phase were found to be longest in the partial epilepsy group, shortest in the control group while REM phase was just the opposite to this. Mean CAP ratios were found to be statistically higher in the generalized epilepsy group when compared to other two groups. This difference was found to be continued when the control group and the generalized epileptic patients who had no abnormality in EEG. No difference was found between the partial epilepsy and control group regarding CAP ratios. Conclusion: Patients with generalized epilepsy have differences compared to healthy individuals regarding the macro and microstructure of sleep and it seems that these differences are independent of the epileptiform discharges. In partial epilepsy patients, no microstructural differences were detected while macrostructural changes were evident

Childhood and juvenile onset multiple sclerosis: clinical and paraclinical features

It is well known that multiple sclerosis (MS) is a demyelinating disease of the central nervous system that mostly starts in the second to third decade. In the present study, we reviewed our own observations of the clinical and paraclinical features in the 36 of 890 (4.04%) MS patients whose symptoms started before 16 years of age. The average age at onset of the disease in these 36 patients was 12.9 years. In 18 patients, the disease onset was monosymptomatic. Diplopia and sensory disturbances were the most common initial manifestations and occurred in 27.7% of cases. Twenty-one patients (59%) had a relapsing and 11 patients (30.5%) had a secondary progressive course. On the last evaluation, the EDSS score was above 5 in 11 patients and it was below 5 in 21 patients. As a result of this study, we concluded that childhood onset MS does not significantly differ from that it has been typically seen in adults in terms of major clinical manifestations and course of disease. (C) 2003 Elsevier Science B.V. All rights reserved