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50. Detection of the “will to move” for an ambulatory system for tremor suppression based on functional electrical stimulation
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Abstracts / Clinical Neurophysiology 121 (2010) e5–e18
47. Anxiety and epilepsy—P. Simonovic´ 1, M. Milovanovic´ 1, N. ˇ . Martinovic´ 1,2 (1 Institute of Buder 1, M. Jovanovic´ 1, R. Dokic´ 1, Z Mental Health, Belgrade, Serbia, 2 Belgrade University Medical School, Belgrade, Serbia) Purpose: Quantitative analysis of anxiety level in patient groups with generalized and focal, temporal or extratemporal epilepsy. Material and method: Ninety patients (30 with generalized epilepsy, 30 with temporal and 30 with extratemporal epilepsy), and agematched healthy control subjects were investigated. Anxiety level in all subjects was assessed with Beck Anxiety Inventory. Sheehan Disability Scale was used to determine the functional disability level. Patients with comorbid major depression, schizophrenia or bipolar disorder, progressive neurological disease, alcoholism, and epilepsy associated with mental retardation were excluded. Results: The investigation demonstrated a significantly higher anxiety level and significantly more varied anxiety symptoms in epilepsy patients in relation to the anxiety level in control group. Anxiety level in the group of patients with focal epilepsy was higher than in the group of patients with generalized epilepsy. Also, anxiety level in temporal lobe epilepsy was higher than in epilepsy of extratemporal location. Patients with epilepsy associated with very high anxiety level also demonstrated a significantly higher functional disability level. Conclusion: Anxiety is an emotion significantly associated with epilepsy. Pronounced anxiety in epilepsy patients lead to a worse quality of life in professional, social and family milieu. doi:10.1016/j.clinph.2009.11.064
49. Paroxysmal dystonia and epilepsy – one differential diagnostic aspect—D. Momcˇilovic´-Kostadinovic´ (Clinic for Child Neurology and Psychiatry, Belgrade, Serbia) Paroxysmal nocturnal dystonia (PND) and autosomal – dominant nocturnal frontal lobe epilepsy (ADNFLE) are rare and similar childhood – onset diseases, characterized by brief nocturnal attacks that arise abruptly, several times per night in NREM stage of sleep. Clinical characteristics of PND closely resemble partial seizures, with dystonic postures and actions, but without loss of consciousness and with normal EEG, even during an attack. There are opposite opinions in the literature from the attitude that these are the same diseases to the opinion that PND is an entity per se. Inspite of similarities, special electrophysiological characteristics and different gene loci suggest separate disease entities. We present 19 year-old boy who has been suffering from paroxysmal nocturnal attacks of painful dystonic postures involving one hand, neck and eyes, for several years. The consciousness is always preserved, standard day-time EEG examinations are normal. Initial therapeutical response to carbamazepine was effective. During the clinical course, and disease aggravation, ictal sleep EEG suggested epileptic frontal lobe discharges. Although PND and ADNFLE are very similar diseases, their electrophysiological differences suggest the most important role of EEG in establishing the final, correct diagnosis of some neurological diseases.
doi:10.1016/j.clinph.2009.11.066
48. Freezing of gait (FOG) in Parkinson’s disease patients: Time analysis—Mirjana B. Popovic 1,2, Milica Djuric 1, Igor Petrovic 3, Saša Radovanovic 4, Vladimir Kostic 3 (1 Belgrade University, Belgrade, Serbia, 2 Department of Health Science and Technology, Aalborg University, Denmark, 3 Clinical Center of Serbia, Belgrade, Serbia, 4 Institute for Medical Research, Belgrade, Serbia)
50. Detection of the will to move for an ambulatory system for tremor suppression based on functional electrical stimulation— A. Savic 1, M.B. Popovic 1,2,3, D.B. Popovic 1,3 (1 School of Electrical Engineering, Belgrade University, Belgrade, Serbia, 2 Institute for Multidisciplinary Research, Belgrade, Serbia, 3 Center for Sensory Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Denmark)
Purpose: We present a simple method in the time domain for evaluating episodes of freezing of gait (FOG) in Parkinson’s disease (PD) patients by using ground reaction forces. Methods: Three sources were applied to study gait: video, force sensitive resistors (FSR) attached to one foot, and accelerometers in pairs attached to the foot, shank and thigh. Task included walking through the corridor, doorway pass, U-turn and approaching the destination. We analyzed 24 FOG episodes from 9 PD patients in on state. In addition to common methods for time analysis based on video, ground reaction forces and accelerations, we computed Pearson’s correlation coefficient (Pcc) between a regular/normal step and the complete record from FSR. Results show that Pcc oscillates between ±1 for normal locomotion, while during freezing episodes Pcc peaks are reduced to narrower range. Timing of FOG episodes from Pcc analysis is in agreement with times estimated from video and accelerations. Here we propose that Pcc may be used alone for the detection of FOG. Further, we suggest graphical presentation of FOG episodes as the area between Pcc peaks and ±1. Conclusion: This simple instrument, if added to other ambulatory methods, may provide a tool for better understanding of freezing. Acknowledgment: Research supported by the Ministry of Science, Serbia (#145041 and #145057) and the Danish National Research Foundation, Denmark.
Purpose: An ambulatory system that applies functional electrical stimulation (FES) for tremor attenuation relies on the information when the movement will start. Brain computer interface (BCI) is at disposal to drive the system. We propose the computing method for the evaluation of various arm movements in order to detect intention to move prior to the movement. Method relies on the fact that Bereitschaftspotential (BP) is a measure of activity in the brain that is related to the planning of movement. The database was created for the Tremor project (FP7) and contains signals from standard EEG recordings. Method: We developed the method for tracking changes of power spectral densities in various frequency bands that correspond to different EEG rhythms. Algorithm uses fast Fourier transform (FFT) and autoregressive (AR) model based spectral estimation methods. Results: Signals from 5 patients with tremor (PD-Parkinson disease and ET-essential tremor) were analyzed. We successfully detected the changes in frequency content of the data prior to the movement. Algorithm is sensitive to all movements tested. Conclusion: Proposed method is suitable for the detection of movement initiation. If applied on-line, this algorithm may be used to drive an ambulatory system for the suppression of tremor by FES. Acknowledgment: Research supported by FP7 project TREMOR (#224051) and the Ministry of Science, Serbia (#145041).
doi:10.1016/j.clinph.2009.11.065
doi:10.1016/j.clinph.2009.11.067
Abstracts / Clinical Neurophysiology 121 (2010) e5–e18
47. Anxiety and epilepsy—P. Simonovic´ 1, M. Milovanovic´ 1, N. ˇ . Martinovic´ 1,2 (1 Institute of Buder 1, M. Jovanovic´ 1, R. Dokic´ 1, Z Mental Health, Belgrade, Serbia, 2 Belgrade University Medical School, Belgrade, Serbia) Purpose: Quantitative analysis of anxiety level in patient groups with generalized and focal, temporal or extratemporal epilepsy. Material and method: Ninety patients (30 with generalized epilepsy, 30 with temporal and 30 with extratemporal epilepsy), and agematched healthy control subjects were investigated. Anxiety level in all subjects was assessed with Beck Anxiety Inventory. Sheehan Disability Scale was used to determine the functional disability level. Patients with comorbid major depression, schizophrenia or bipolar disorder, progressive neurological disease, alcoholism, and epilepsy associated with mental retardation were excluded. Results: The investigation demonstrated a significantly higher anxiety level and significantly more varied anxiety symptoms in epilepsy patients in relation to the anxiety level in control group. Anxiety level in the group of patients with focal epilepsy was higher than in the group of patients with generalized epilepsy. Also, anxiety level in temporal lobe epilepsy was higher than in epilepsy of extratemporal location. Patients with epilepsy associated with very high anxiety level also demonstrated a significantly higher functional disability level. Conclusion: Anxiety is an emotion significantly associated with epilepsy. Pronounced anxiety in epilepsy patients lead to a worse quality of life in professional, social and family milieu. doi:10.1016/j.clinph.2009.11.064
49. Paroxysmal dystonia and epilepsy – one differential diagnostic aspect—D. Momcˇilovic´-Kostadinovic´ (Clinic for Child Neurology and Psychiatry, Belgrade, Serbia) Paroxysmal nocturnal dystonia (PND) and autosomal – dominant nocturnal frontal lobe epilepsy (ADNFLE) are rare and similar childhood – onset diseases, characterized by brief nocturnal attacks that arise abruptly, several times per night in NREM stage of sleep. Clinical characteristics of PND closely resemble partial seizures, with dystonic postures and actions, but without loss of consciousness and with normal EEG, even during an attack. There are opposite opinions in the literature from the attitude that these are the same diseases to the opinion that PND is an entity per se. Inspite of similarities, special electrophysiological characteristics and different gene loci suggest separate disease entities. We present 19 year-old boy who has been suffering from paroxysmal nocturnal attacks of painful dystonic postures involving one hand, neck and eyes, for several years. The consciousness is always preserved, standard day-time EEG examinations are normal. Initial therapeutical response to carbamazepine was effective. During the clinical course, and disease aggravation, ictal sleep EEG suggested epileptic frontal lobe discharges. Although PND and ADNFLE are very similar diseases, their electrophysiological differences suggest the most important role of EEG in establishing the final, correct diagnosis of some neurological diseases.
doi:10.1016/j.clinph.2009.11.066
48. Freezing of gait (FOG) in Parkinson’s disease patients: Time analysis—Mirjana B. Popovic 1,2, Milica Djuric 1, Igor Petrovic 3, Saša Radovanovic 4, Vladimir Kostic 3 (1 Belgrade University, Belgrade, Serbia, 2 Department of Health Science and Technology, Aalborg University, Denmark, 3 Clinical Center of Serbia, Belgrade, Serbia, 4 Institute for Medical Research, Belgrade, Serbia)
50. Detection of the will to move for an ambulatory system for tremor suppression based on functional electrical stimulation— A. Savic 1, M.B. Popovic 1,2,3, D.B. Popovic 1,3 (1 School of Electrical Engineering, Belgrade University, Belgrade, Serbia, 2 Institute for Multidisciplinary Research, Belgrade, Serbia, 3 Center for Sensory Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Denmark)
Purpose: We present a simple method in the time domain for evaluating episodes of freezing of gait (FOG) in Parkinson’s disease (PD) patients by using ground reaction forces. Methods: Three sources were applied to study gait: video, force sensitive resistors (FSR) attached to one foot, and accelerometers in pairs attached to the foot, shank and thigh. Task included walking through the corridor, doorway pass, U-turn and approaching the destination. We analyzed 24 FOG episodes from 9 PD patients in on state. In addition to common methods for time analysis based on video, ground reaction forces and accelerations, we computed Pearson’s correlation coefficient (Pcc) between a regular/normal step and the complete record from FSR. Results show that Pcc oscillates between ±1 for normal locomotion, while during freezing episodes Pcc peaks are reduced to narrower range. Timing of FOG episodes from Pcc analysis is in agreement with times estimated from video and accelerations. Here we propose that Pcc may be used alone for the detection of FOG. Further, we suggest graphical presentation of FOG episodes as the area between Pcc peaks and ±1. Conclusion: This simple instrument, if added to other ambulatory methods, may provide a tool for better understanding of freezing. Acknowledgment: Research supported by the Ministry of Science, Serbia (#145041 and #145057) and the Danish National Research Foundation, Denmark.
Purpose: An ambulatory system that applies functional electrical stimulation (FES) for tremor attenuation relies on the information when the movement will start. Brain computer interface (BCI) is at disposal to drive the system. We propose the computing method for the evaluation of various arm movements in order to detect intention to move prior to the movement. Method relies on the fact that Bereitschaftspotential (BP) is a measure of activity in the brain that is related to the planning of movement. The database was created for the Tremor project (FP7) and contains signals from standard EEG recordings. Method: We developed the method for tracking changes of power spectral densities in various frequency bands that correspond to different EEG rhythms. Algorithm uses fast Fourier transform (FFT) and autoregressive (AR) model based spectral estimation methods. Results: Signals from 5 patients with tremor (PD-Parkinson disease and ET-essential tremor) were analyzed. We successfully detected the changes in frequency content of the data prior to the movement. Algorithm is sensitive to all movements tested. Conclusion: Proposed method is suitable for the detection of movement initiation. If applied on-line, this algorithm may be used to drive an ambulatory system for the suppression of tremor by FES. Acknowledgment: Research supported by FP7 project TREMOR (#224051) and the Ministry of Science, Serbia (#145041).
doi:10.1016/j.clinph.2009.11.065
doi:10.1016/j.clinph.2009.11.067