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Author Frenkel-Toledo, S.; Bentin, S.; Perry, A.; Liebermann, D.G.; Soroker, N. url  doi
openurl 
  Title Dynamics of the EEG Power in the Frequency and Spatial Domains During Observation and Execution of Manual Movements Type Journal Article
  Year 2013 Publication Brain Research Abbreviated Journal Brain Res  
  Volume (down) 1509 Issue Pages 43-57  
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  Abstract Mu suppression is the attenuation of EEG power in the alpha frequency range (8-12Hz) while executing or observing a motor action. Whereas typically observed at central scalp sites, there are diverging reports about the extent of the attenuation over the cortical mantle, its exact frequency range and the specificity of this phenomenon. We investigated the modulation of EEG oscillations in frequency-bands from 4 to 12Hz at frontal, central, parietal and occipital sites during the execution of manual movements and during observation of similar actions from allocentric (i.e., facing the actor) and egocentric (i.e., seeing the actor from behind) viewpoints. Suppression was determined relative to observation of a non-biological movement. Action observation elicited greater suppression in the lower (8-10Hz) compared to the higher mu range (10-12Hz), and greater suppression in the entire 4-12Hz range at frontal and central sites compared to parietal and occipital sites. In addition, suppression tended to be greater during observation of a motor action from allocentric compared to egocentric viewpoints. During execution of movement, suppression of the EEG occurred primarily in the higher alpha range and was absent at occipital sites. In the theta range (4-8Hz), the EEG amplitude was suppressed during action observation and execution. The results suggest a functional distinction between modulation of mu and alpha rhythms, and between the higher and lower ranges of the mu rhythms. The activity of the presumed human mirror neuron system seems primarily evident in the lower mu range and in the theta range.  
  Address Sackler Faculty of Medicine, Tel Aviv University, Israel; Department of Neurological Rehabilitation, Loewenstein Hospital, Raanana, Israel. Electronic address: silvi197@bezeqint.net  
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  Language English Summary Language Original Title  
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  Series Volume Series Issue Edition  
  ISSN 0006-8993 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23500633 Approved no  
  Call Number Serial 68  
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Author Frenkel-Toledoa, S.; Bentin, S.; Perry, A.; Liebermann, D. G.; Soroker, N. doi  openurl
  Title Mirror-neuron system recruitment by action observation: Effects of focal brain damage on mu suppression Type Journal Article
  Year 2014 Publication NeuroImage Abbreviated Journal  
  Volume (down) 87 Issue Pages 127-137  
  Keywords  
  Abstract Mu suppression is the attenuation of EEG power in the alpha frequency range (8-12 Hz), recorded over the sensorimotor cortex during execution and observation of motor actions. Based on this dual characteristic it is thought to signalize activation of a human analogue of the mirror neuron system (MNS) found in macaque monkeys, though much uncertainty remains concerning its specificity and full significance. To further explore the hypothesized relationship between mu suppression and MNS activation, we investigated how it is affected by damage to cortical regions, including areas where the MNS is thought to reside. EEG was recorded in 33 first-event stroke patients during observation of video-clips showing reaching and grasping hand movements. We examined the modulation of EEG oscillations at central and occipital sites, and analyzed separately the lower (8-10 Hz) and higher (10-12 Hz) segments of the alpha/mu range. Suppression was determined relative to observation of a non-biological movement. Normalized lesion data were used to investigate how damage to regions of the fronto-parietal cortex affects the pattern of suppression. The magnitude of mu suppression during action observation was significantly reduced in the affected hemisphere compared to the unaffected hemisphere. Differences between the hemispheres were significant at central (sensorimotor) sites but not at occipital (visual) sites. Total hemispheric volume loss did not correlate with mu suppression. Suppression in the lower mu range in the unaffected hemisphere (C3) correlated with lesion extent within the right inferior parietal cortex. Our lesion study supports the role of mu suppression as a marker of MNS activation, as suggested by findings gathered in previous studies in normal subjects.  
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  Notes Approved no  
  Call Number Serial 71  
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Author Davidowitz, I.; Parmet, Y.; Frenkel-Toledo, S.; Banina, M.C.; Soroker, N.; Solomon, J.M.; Liebermann, D.G.; Levin, M.F.; Berman, S. url  doi
openurl 
  Title Relationship Between Spasticity and Upper-Limb Movement Disorders in Individuals With Subacute Stroke Using Stochastic Spatiotemporal Modeling Type Journal Article
  Year 2019 Publication Neurorehabilitation and Neural Repair Abbreviated Journal Neurorehabil Neural Repair  
  Volume (down) 33 Issue 2 Pages 141-152  
  Keywords Gaussian mixture model; Kullback-Liebler divergence; spasticity; stroke; upper-limb kinematics  
  Abstract BACKGROUND: Spasticity is common in patients with stroke, yet current quantification methods are insufficient for determining the relationship between spasticity and voluntary movement deficits. This is partly a result of the effects of spasticity on spatiotemporal characteristics of movement and the variability of voluntary movement. These can be captured by Gaussian mixture models (GMMs). OBJECTIVES: To determine the influence of spasticity on upper-limb voluntary motion, as assessed by the bidirectional Kullback-Liebler divergence (BKLD) between motion GMMs. METHODS: A total of 16 individuals with subacute stroke and 13 healthy aged-equivalent controls reached to grasp 4 targets (near-center, contralateral, far-center, and ipsilateral). Two-dimensional GMMs (angle and time) were estimated for elbow extension motion. BKLD was computed for each individual and target, within the control group and between the control and stroke groups. Movement time, final elbow angle, average elbow velocity, and velocity smoothness were computed. RESULTS: Between-group BKLDs were much larger than within control-group BKLDs. Between-group BKLDs for the near-center target were lower than those for the far-center and contralateral targets, but similar to that for the ipsilateral target. For those with stroke, the final angle was lower for the near-center target, and the average velocity was higher. Velocity smoothness was lower for the near-center than for the ipsilateral target. Elbow flexor and extensor passive muscle resistance (Modified Ashworth Scale) strongly explained BKLD values. CONCLUSIONS: Results support the view that individuals with poststroke spasticity have a velocity-dependent reduction in active elbow joint range and that BKLD can be used as an objective measure of the effects of spasticity on reaching kinematics.  
  Address 1 Ben-Gurion University of the Negev, Beer-Sheva, Israel  
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  Language English Summary Language Original Title  
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  ISSN 1545-9683 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30744528 Approved no  
  Call Number Serial 93  
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Author Levin, M.F.; Banina, M.C.; Frenkel-Toledo, S.; Berman, S.; Soroker, N.; Solomon, J.M.; Liebermann, D.G. url  doi
openurl 
  Title Personalized upper limb training combined with anodal-tDCS for sensorimotor recovery in spastic hemiparesis: study protocol for a randomized controlled trial Type Journal Article
  Year 2018 Publication Trials Abbreviated Journal Trials  
  Volume (down) 19 Issue 1 Pages 7  
  Keywords Neurorehabilitation; Spasticity; Spatial threshold; Stroke; tDCS  
  Abstract BACKGROUND: Recovery of voluntary movement is a main rehabilitation goal. Efforts to identify effective upper limb (UL) interventions after stroke have been unsatisfactory. This study includes personalized impairment-based UL reaching training in virtual reality (VR) combined with non-invasive brain stimulation to enhance motor learning. The approach is guided by limiting reaching training to the angular zone in which active control is preserved (“active control zone”) after identification of a “spasticity zone”. Anodal transcranial direct current stimulation (a-tDCS) is used to facilitate activation of the affected hemisphere and enhance inter-hemispheric balance. The purpose of the study is to investigate the effectiveness of personalized reaching training, with and without a-tDCS, to increase the range of active elbow control and improve UL function. METHODS: This single-blind randomized controlled trial will take place at four academic rehabilitation centers in Canada, India and Israel. The intervention involves 10 days of personalized VR reaching training with both groups receiving the same intensity of treatment. Participants with sub-acute stroke aged 25 to 80 years with elbow spasticity will be randomized to one of three groups: personalized training (reaching within individually determined active control zones) with a-tDCS (group 1) or sham-tDCS (group 2), or non-personalized training (reaching regardless of active control zones) with a-tDCS (group 3). A baseline assessment will be performed at randomization and two follow-up assessments will occur at the end of the intervention and at 1 month post intervention. Main outcomes are elbow-flexor spatial threshold and ratio of spasticity zone to full elbow-extension range. Secondary outcomes include the Modified Ashworth Scale, Fugl-Meyer Assessment, Streamlined Wolf Motor Function Test and UL kinematics during a standardized reach-to-grasp task. DISCUSSION: This study will provide evidence on the effectiveness of personalized treatment on spasticity and UL motor ability and feasibility of using low-cost interventions in low-to-middle-income countries. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02725853 . Initially registered on 12 January 2016.  
  Address Department of Physical Therapy, Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel  
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  ISSN 1745-6215 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:29301545 Approved no  
  Call Number Serial 87  
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Author Lackritz, H.; Parmet, Y.; Frenkel-Toledo, S.; Banina, M.C.; Soroker, N.; Solomon, J.M.; Liebermann, D.G.; Levin, M.F.; Berman, S. url  doi
openurl 
  Title Effect of post-stroke spasticity on voluntary movement of the upper limb Type Journal Article
  Year 2021 Publication Journal of Neuroengineering and Rehabilitation Abbreviated Journal J Neuroeng Rehabil  
  Volume (down) 18 Issue 1 Pages 81  
  Keywords Gaussian mixture model; Hellinger's distance; Hemiparesis; Kinematics; Kullback-Liebler divergence; Spasticity; Stochastic model; Stroke  
  Abstract BACKGROUND: Hemiparesis following stroke is often accompanied by spasticity. Spasticity is one factor among the multiple components of the upper motor neuron syndrome that contributes to movement impairment. However, the specific contribution of spasticity is difficult to isolate and quantify. We propose a new method of quantification and evaluation of the impact of spasticity on the quality of movement following stroke. METHODS: Spasticity was assessed using the Tonic Stretch Reflex Threshold (TSRT). TSRT was analyzed in relation to stochastic models of motion to quantify the deviation of the hemiparetic upper limb motion from the normal motion patterns during a reaching task. Specifically, we assessed the impact of spasticity in the elbow flexors on reaching motion patterns using two distinct measures of the 'distance' between pathological and normal movement, (a) the bidirectional Kullback-Liebler divergence (BKLD) and (b) Hellinger's distance (HD). These measures differ in their sensitivity to different confounding variables. Motor impairment was assessed clinically by the Fugl-Meyer assessment scale for the upper extremity (FMA-UE). Forty-two first-event stroke patients in the subacute phase and 13 healthy controls of similar age participated in the study. Elbow motion was analyzed in the context of repeated reach-to-grasp movements towards four differently located targets. Log-BKLD and HD along with movement time, final elbow extension angle, mean elbow velocity, peak elbow velocity, and the number of velocity peaks of the elbow motion were computed. RESULTS: Upper limb kinematics in patients with lower FMA-UE scores (greater impairment) showed greater deviation from normality when the distance between impaired and normal elbow motion was analyzed either with the BKLD or HD measures. The severity of spasticity, reflected by the TSRT, was related to the distance between impaired and normal elbow motion analyzed with either distance measure. Mean elbow velocity differed between targets, however HD was not sensitive to target location. This may point at effects of spasticity on motion quality that go beyond effects on velocity. CONCLUSIONS: The two methods for analyzing pathological movement post-stroke provide new options for studying the relationship between spasticity and movement quality under different spatiotemporal constraints.  
  Address The Zlotowski Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel. sigalbe@bgu.ac.il  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1743-0003 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:33985543 Approved no  
  Call Number Serial 108  
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