Національно-демократичні об'єднання та політичні партії в Україні кінця XIX - початку XX століття

Deep brain stimulation (DBS) has become increasingly important for the treatment and relief of neurological disorders such as Parkinson's disease, tremor, dystonia and psychiatric illness. As DBS implantations and any other stereotactic and functional surgical procedure require accurate, precise and safe targeting of the brain structure, the technical aids for preoperative planning, intervention and postoperative follow-up have become increasingly important. The aim of this paper was to give and overview, from a biomedical engineering perspective, of a typical implantation procedure and current supporting techniques. Furthermore, emerging technical aids not yet clinically established are presented. This includes the state-of-the-art of neuroimaging and navigation, patient-specific simulation of DBS electric field, optical methods for intracerebral guidance, movement pattern analysis, intraoperative data visualisation and trends related to new stimulation devices. As DBS surgery already today is an important technology intensive domain, an "intuitive visualisation" interface for improving management of these data in relation to surgery is suggested

Design of a myo-seismic transducer for non-invasive transcutaneous vectorial recording of locally fast muscle-fibre micro-contractions

Mechanical recording usually concerns the analysis of movements in bio-mechanical research projects. Mechanical recording of locally fast muscle-fibre micro-contractions, however, is a little-developed and rarely-applied myographic technique. In the last decade, acoustic or myophonic measurements came increasingly into the picture when they were also applied to research on general muscle activity, such as in muscle fatigue studies. In this paper, a new micro-seismic recording technique is introduced. The technique registers extremely local activity in the velocity and force vector of skin movement as a function in time. The recording method is sensitive to micro excursions caused by muscle fibres under the skin. The resolution in time is at least 100 us, which is demonstrated in an experiment where a mechanical contraction is provoked by electrical stimulation of the median nerve. This indicates a seismic variant, referred to as seismic-myography (SMG), of surface EMG's, and offers complementary features. The most important features are: 1. Insensitivity to low frequent, large movement artefacts. 2. Sensitivity to fast mechanical micro-excursions and velocities. 3. Fast and precise discrimination of local mechanical events. 4. Vectorial reconstruction of superficial mechanic activity which can be used for the identification and functional behaviour of subcutaneous muscle fibres and, in addition, for the localisation of motor endplate zones. 5. The method is easy to use. The following, some clinical and physiological applications are discussed: a mechanical variant for the diagnosis of carpal tunnel syndrome (CTS) and measurements of nerve conduction velocities, precise timing of the process chain between electrical fibre membrane potential, and the first contraction of actine and myosine filaments. The function of the Ca++ depots is embedded in this chain. This might open new possibilities for research on muscle disease and muscle fatigue

Design of a myo-seismic transducer for non-invasive transcutaneous vectorial recording of locally fast muscle-fibre micro-contractions

Mechanical recording usually concerns the analysis of movements in bio-mechanical research projects. Mechanical recording of locally fast muscle-fibre micro-contractions, however, is a little-developed and rarely-applied myographic technique. In the last decade, acoustic or myophonic measurements came increasingly into the picture when they were also applied to research on general muscle activity, such as in muscle fatigue studies. In this paper, a new micro-seismic recording technique is introduced. The technique registers extremely local activity in the velocity and force vector of skin movement as a function in time. The recording method is sensitive to micro excursions caused by muscle fibres under the skin. The resolution in time is at least 100 us, which is demonstrated in an experiment where a mechanical contraction is provoked by electrical stimulation of the median nerve. This indicates a seismic variant, referred to as seismic-myography (SMG), of surface EMG's, and offers complementary features. The most important features are: 1. Insensitivity to low frequent, large movement artefacts. 2. Sensitivity to fast mechanical micro-excursions and velocities. 3. Fast and precise discrimination of local mechanical events. 4. Vectorial reconstruction of superficial mechanic activity which can be used for the identification and functional behaviour of subcutaneous muscle fibres and, in addition, for the localisation of motor endplate zones. 5. The method is easy to use. The following, some clinical and physiological applications are discussed: a mechanical variant for the diagnosis of carpal tunnel syndrome (CTS) and measurements of nerve conduction velocities, precise timing of the process chain between electrical fibre membrane potential, and the first contraction of actine and myosine filaments. The function of the Ca++ depots is embedded in this chain. This might open new possibilities for research on muscle disease and muscle fatigue

Intraoperative neurophysiological assessment of disabling symptoms in DBS surgery

Introduction. - Neurophysiological assessment can provide quantitative measures for the selected motor signs that have been targeted for surgery and may be helpful in predicting the therapeutic effects of deep brain stimulation (DBS) on pathological tremor, motor performance, and rigidity. Objective. - To present a survey and demonstrate the contribution of neurophysiological assessment of side effects and effects on disabling motor symptoms at various steps of DBS surgery, and to confirm its role for optimal target localization, as an adjuvant to anatomic imaging. Material and methods. - The data result from 192 nuclei in 118 procedures on patients with Parkinson's disease (84), essential tremor (24), Hallenvorder Spatz dystonia (4), multiple sclerosis (4), and Holmes tremor (2). The intra operative neurophysiological monitoring (IOM) protocol consists of semimicroelectrode recording (for subthalamic nuclei), whereas accelerotransducers and spectral analysis allow assessment of tremor, finger tapping (FT), diadochokinesis (DDK), and determination of the distance between DBS electrodes and internal capsule (IC). Rigidity is assessed by surface EMG recordings in combination with a goniometer. Results. - The determination of the functional distance between the DBS electrode and the IC is based on the activation functions of axons in the IC. We show the high sensitivity of accelerometers for tremor over a large part of the body, the relationship between clinical scores and spectral frequencies of FT and DDK. Parkinsonian rigidity can be assessed from surface EMG (sEMG) by means of a balance coefficient, which can detect negative rigidity, for tow unified Parkinson's disease rating scale (UPDRS) scores (0-2) and quantified EMG when negative rigidity is excluded. Conclusion. - Accelerometer and sEMG recording have shown their value for intraoperative assessment of disabling motor symptoms and side effects during surgery, to optimize the target position electrodes for DBS. The combination with contemporary signal analyzing techniques permit intraoperative monitoring without a significant delay. IONM improves sensitivity and adds objective neurophysiological data. (c) 2007 Elsevier Masson SAS. All rights reserved

The acoustic detection of intracranial aneurysms: A clinical study

A new recording method for the acoustical detection of intracranial aneurysms is presented. A study examining the capability of the method to discriminate between patients with an aneurysm and control patients by a simple, objective parameter is reported. Sound signals were recorded over the eyes, and a real-time spectral analysis was performed on these signals. For this study, recordings performed on 26 patients with an aneurysm were compared with recordings on 26 age- and sex-matched control patients without intracerebral abnormalities. As a result of measures taken to reduce artifacts and to improve the signal-to-noise ratio, the measurements were performed reliably, with little inconvenience for the patients; all measurements could be used for analysis. The power spectra measured in the control patients showed a typical, smoothly descending pattern; those measured in the aneurysm patients clearly differed from this pattern, showing peaks of varying width, height, and dominant frequency. For the objective judgment of the power spectra, the power median is introduced. The sensitivity and specificity of this parameter were determined. Possible methods to improve the results will be discussed

System for intra-operative monitoring of the cortical integrity of the pedicle during pedicle screw placement in low-back surgery: Design and clinical results

The placement of pedicle screws may involve a damage to the pedicle wall as well as to the adjacent nerve roots. This is visible as a lowering of the trans-screw stimulation current threshold of evoked compound action potentials (CAP) of the leg muscles and as a decrease of the electrical impedance of the screw. The objective was to design a system for intra-operative monitoring of the integrity of the pedicle wall and motor nerve and to test it in clinical practice. Spontaneous EMGs and CAPs, evoked by electrostimulation of the nerve and via the screw, of 8 muscle groups in the leg were recorded and furthermore, the screw impedance was measured. 102 pedicle screws were monitored. It is concluded that during pedicle screw fixation, the current thresholds for CAPs and impedance measurements are useful for monitoring nerve root integrity. Impedance measurements provide an early warning of the cortex of the pedicle by screw placement