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1.1 1 xml info:srw/schema/1/mods-v3.2 Lackritz H author Parmet Y author Frenkel-Toledo S author Banina M C author Soroker N author Solomon J M author Liebermann D G author Levin M F author Berman S author 2021 English 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. Gaussian mixture model Hellinger's distance Hemiparesis Kinematics Kullback-Liebler divergence Spasticity Stochastic model Stroke PMID:33985543 exported from refbase (https://refbase.nfshost.com/show.php?record=108), last updated on Tue, 18 May 2021 19:45:02 +0000 text http://www.ncbi.nlm.nih.gov/pubmed/33985543 http://www.ncbi.nlm.nih.gov/pubmed/33985543 10.1186/s12984-021-00876-6 33985543 Lackritz_etal2021 2021 continuing periodical academic journal 18 1 81 1743-0003 1