[Electroencephalograpic Parameters of Healthy Persons with Different Successfulness of Dual-Task Performance (Postural Control and Calculation)].

Complex electroencephalographic (EEG), stabilographic and psychological study was executed during the number dual tasks performance--postural control and calculation in 25 healthy volunteers (age 25 ± 0.7). Successful performances of dual tasks required a high usage of cognitive resources, such as memory and attention as well as good motor command and low level of anxiety. Two EEG-markers of successful dual tasks performance were revealed. An increase of EEG coherence for long diagonal pairs of leads between frontal and parieto-occipital areas was observed. Additionally a decrease of EEG coherence for short pairs of leads was revealed. The poor performance of dual tasks was accompanied by an increase of EEG coherence between local pairs of leads for different spectral bands.

[EEG markers of spontaneous recovery of vertical posture in patients with consequences of severe traumatic brain injury].

9 patients (mean age 23.6 +/- 3.15 y.o.) with severe traumatic brain injury (TBI) and impairment of vertical posture were included in complex clinical and EEG study during spontaneous recovery of vertical posture (VP). Patients were included in three different groups according to severity of deficit according to MPAI, FIM and MMSE scales. EEG data have been compared to those of 10 healthy volunteers (mean age 22.8 +/- 0.67 yo.). In patients with moderate brain impairment and fast recovery of VP (over 2 weeks) change of posture from sitting to standup has been accompanied by EEG-signs similar to those of healthy people. These included predominant increase of coherence in right hemisphere for majority of frequency bands, although in more complex conditions EEG of these patients showed pathological signs. In patients with more severe deficit spontaneous recovery of VP has been accompanied by "hyper-reactive" change of EEG for all frequency bands without local specificity. This finding didn't depend on side ofbrain impairment and could be considered as marker of positive dynamics of VP restoration. In patients with most severe brain impairment and deficit of functions VP didn't recover after 3 month of observation. EEG-investigation has revealed absence of reactive change of EEG during passive verticalisation. This finding can be used as marker of negative prognosis.

[Features of dual--postural and calculation--task performance in patients with consequences of traumatic brain injury].

Dual tasks with voluntary postural control and calculation have been done by 14 patients (25.7 +/- 4.7 yo.) after traumatic brain injury and 40 healthy volunteers (29.8 +/- 2.5 y.o.). Complex clinical (MMSE, FIM, MPAI-3 and Berg scales) and stabilographic evaluation has been performed. According to clinical evaluation 8 patients were included into group 1 with less severe functional deficit and 6 patients formed group 2 with more severe deficit. Parameters of motor and especially cognitive sub-tasks in patients were lower than in healthy subjects in both separate and dual tasks. In group 2 these parameters were lower than in group 1. Certain types of dual task where the quality of sub-tasks, especially of the motor-one increased in healthy subjects and patients of the first group were revealed. The complex of stabilographic parameters which could be used for estimation of quality of sub-tasks performance has been revealed. Dual tasks could be an additional method of evaluation of patients' adaptive possibilities and certain type of dual task could become a promising approach to recovery at late period of rehabilitation.

[EEG-markers of vertical postural organization in healthy persons].

In 10 healthy persons (22.8 +/- 0.67 years) spectral-coherence parameters of EEG were analyzed in different steps of verticalizations--from gorizontal position to seat and stand one. Maximal changes of all EEG parameters were observed in state with absence of visual control. We observed an increase of power for fast spectral bands of EEG (beta- and gamma-bands) in all conditions and additional increase of these EEG parameters was observed at situation of complication of conditions of vertical pose supporting. Results of EEG coherent analysis in conditions of human verticalization showed specific increase of coherence for the majority of rhythm ranges in the right hemisphere especially in the central-frontal and in occipital-parietal areas and for interhemispheric pairs for these leads. This fact can reflect participation of cortical as well as subcortical structures in these processes. In conditions of complicate conditions of vertical pose supporting the additional increase of EEG coherence in fast bands (beta-rhythm) was observed at the frontal areas. This fact can testify about increasing of executive functions in this conditions.

[Integrating role of voluntary postural control recovery during rehabilitation of patients with traumatic brain injury].

Results of complex clinical, stabilographic and electroencephalographic (EEG) examination of 20 patients (28 +/- 6.9 years) suffered a severe traumatic brain injury (STBI) are presented. The examination was carried out in early terms after the STBI before and after a course of stabilographic training (ST) with a visual feedback as compared to a group of 18 healthy volunteers (26 +/- 5.8 years). The 4- to 6-week course of ST consisted of 8-15 sessions. Before the course, the patients experienced problems in different kinds of activity, maximum in the motor sphere. The EEG study revealed a decrease in the power and coherence of the alpha rhythm and an increase in the power of the slow spectral bands (delta). The ST restored not only the postural control of patients, but also reduced the defects in other spheres. The EEG study showed an increase in the alpha-rhythm power maximum in the occipital-parietal areas and a tendency to normalization of its regional specificity. In all examined patients, the interhemispheric coherence increased for different EEG-rhythms, especially of the alpha-band, in the central and parietal brain areas. The described EEG changes can be a marker of the integrating role of postural control and an important stage in restoration of integrative brain activity in early terms after the STBI accompanied by improvement of damaged functions.

[Peculiarities of changes of EEG reactivity during performance of dual tasks in healthy subjects (voluntary postural control and calculation)].

Complex EEG and stabilography investigation with separate and simultaneous performance of motor (voluntary postural control) and cognitive (calculation) tasks has been performed in 20 healthy subjects (22 +/- 0.7 yo.). Specific spatial and frequency reactive changes have been revealed during motor task performance. These included increase of coherence in alpha-band for long pair of channels in right hemisphere as well as in symmetric parietal-occipital regions in both hemispheres. Cognitive task performance has been accompanied by coherence increase for low bands (delta- and theta-) with higher activation in left hemisphere and frontal regions. In dual tasks where both components were performed worse comparing to control, performance led to reactive spatial and frequency changes of both--motor and cognitive--tasks, though these changes were less than during separate task performance. Decrease of coherence in alphal-band in frontal areas appeared as a zone of "conflict of interest - interferention". In dual tasks with better performance of each component comparing to control EEG coherence increased in each specific area as well as in areas of "conflict of interest".

[The use of stabilo-training with feedback in the rehabilitation of patients with posttraumatic Korsakov's syndrome].

The complex research, including clinical scales (FIM, Mayo-Portland) and data on stabilography and electroencephalography (EEG) studies, was conducted in 10 patients with posttraumatic Korsakov's syndrome (KS) before and after the rehabilitation course using stabilo-training (ST) with feedback (7-12 sessions). A control group consisted of 18 healthy people. In patients with KS, more severe cognitive (memory) disorders were noted before ST that was correlated with the maximal reduction of coherence in all frequency bands in frontal and parietal-occipital areas as well as in the long diagonal pairs between the left frontal and the right parietal-occipital areas which was most distinct for the alpha-band. A trend to the normalization of stabilography parameters and step-by step increasing of EEG coherence parameters, especially the alpha-band, was found after the rehabilitation ST course, which was accompanied with the KS regress. It increased initially in parietal-occipital-central areas of the right hemisphere with the following increase in central-frontal areas and then in frontal areas, mostly in the left hemisphere, that was in compliance with the tendency to the normalization of spatial-temporary EEG organization.

[Miniature thin layer biosensors which are sensitive to glutamate and glutamine]. / Miniatiurnye tonkoplenochnye biosensory, chuvstvitel'nye k glutaminovoi kislote i glutaminu.

Integrated thin film biosensors for simultaneous measurement of L-glutamine and L-glutamate in a micro-flow cell were developed. Due to a novel glutaminase with an activity optimum in the neutral pH range a direct monitoring of glutamine in mammalian cell culture medium could be performed. The glutamine bienzyme sensor was prepared by coimmobilization of glutaminase with glutamate oxidase within a photo patterned poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel membrane. The sensor response is linear in the concentration range of 55 mmol to 10 mmol glutamine/l. Additionally a glutamate biosensor is integrated on the sensor chip for difference measurement of possible glutamate interferences. The sensor chip can be used for at least 300 measurements without any alteration in the performance of its sensors. A new sensor chip with an integrated flow cell provides the possibility of simultaneous measurement of four different parameters at a cell volumina of 1 ml. Completing the microsystem a battery operated surface mounted device (SMD) potentiostat was developed to get a "lab on chip".

Miniaturized thin film glutamate and glutamine biosensors.

Integrated thin film biosensors were developed for the simultaneous measurement of L-glutamine and L-glutamate in a mu-flow cell. Due to a novel glutaminase with an activity optimum in the neutral pH range, direct monitoring of glutamine in a mammalian cell culture medium could be performed. The glutamine bienzyme sensor was prepared by co-immobilization of glutaminase with glutamate oxidase within a photopatterned poly(2-hydroxyethyl methacrylate) (pHEMA) hydrogel membrane. The sensor response was linear in the concentration range of 50 mumol to 10 mmol glutamine/l. Additionally, a glutamate biosensor was integrated on the sensor chip for difference measurement of possible glutamate interferences. The sensor-chip could be used for at least 300 measurements without any alteration in the performance of its sensors. A new sensor-chip with an integrated flow cell provided the possibility of simultaneous measurement of four different parameters at a cell volume of 1 microliter. In order to complete the microsystem, and in order to obtain a "lab on chip", a battery operated surface mounted device (SMD) potentiostat was developed.