Background Impaired postural control in Parkinson’s disease (PD) seriously compromises life quality. Although balance training improves mobility and postural stability, lack of quantitative studies on the neurophysiological mechanisms of balance training in PD impedes the development of patient-specific therapies. We evaluated the effects of a balance-training program using functional balance and mobility tests, posturography, and a postural control model. Methods Center-of-pressure (COP) data of 40 PD patients before and after a 12-session balance-training program, and 20 healthy control subjects were recorded in four conditions with two tasks on a rigid surface (R-tasks) and two on foam. A postural control model was fitted to describe the posturography data. The model comprises a neuromuscular controller, a time delay, and a gain scaling the internal disturbance torque. Results Patients’ axial rigidity before training resulted in slower COP velocity in R-tasks; which was reflected as lower internal torque gain. Furthermore, patients exhibited poor stability on foam, remarked by abnormal higher sway amplitude. Lower control parameters as well as higher time delay were responsible for patients’ abnormal high sway amplitude. Balance training improved all clinical scores on functional balance and mobility. Consistently, improved ‘flexibility’ appeared as enhanced sway velocity (increased internal torque gain). Balance training also helped patients to develop the ‘stability degree’ (increase control parameters), and to respond more quickly in unstable condition of stance on foam. Conclusions Projection of the common posturography measures on a postural control model provided a quantitative framework for unraveling the neurophysiological factors and different recovery mechanisms in impaired postural control in PD. Electronic supplementary material The online version of this article (10.1186/s12984-019-0574-0) contains supplementary material, which is available to authorized users.

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Context: Ellagic acid (EA) is a natural phenol antioxidant with various therapeutic activities. However, the efficacy of EA has not been examined in neuropathologic conditions.Objective:In vivo neuroprotective effects of EA on cuprizone (cup)-induced demyelination were evaluated.Material and methods: C57BL/6 J mice were fed with chow containing 0.2% cup for 4 weeks to induce oligodendrocytes (OLGs) depletion predominantly in the corpus callosum (CC). EA was administered at different doses (40 or 80 mg/kg body weight/day/i.p.) from the first day of cup diet. Oligodendrocytes apoptosis [TUNEL assay and myelin oligodendrocyte glycoprotein (MOG+)/caspase-3+ cells), gliosis (H&E staining, glial fibrillary acidic protein (GFAP+) and macrophage-3 (Mac-3+) cells) and inflammatory markers (interleukin 17 (IL-17), interleukin 11 (IL-11) and stromal cell-derived factor 1 α (SDF-1α) or CXCL12] during cup intoxication were examined.Results: High dose of EA (EA-80) increased mature oligodendrocytes population (MOG+ cells, p < 0.001), and decreased apoptosis (p < 0.05) compared with the cup mice. Treatment with both EA doses did not show any considerable effects on the expression of CXCL12, but significantly down-regulated the expression of IL-17 and up-regulated the expression of IL-11 in mRNA levels compared with the cup mice. Only treatment with EA-80 significantly decreased the population of active macrophage (MAC-3+ cells, p < 0.001) but not reactive astrocytes (GFAP+ cells) compared with the cup mice.Discussion and conclusion: In this model, EA-80 effectively reduces lesions via reduction of neuroinflammation and toxic effects of cup on mature OLGs. EA is a suitable therapeutic agent for moderate brain damage in neurodegenerative diseases such as multiple sclerosis.

Background: Katz Index is a well-known index for assessing basic activities of daily living. The aim was to determine validity and reliability of the Katz Index in Iranian patients with acute stroke. Methods: Eighty-seven patients (56 male, 31 female) with acute stroke (1-30 days post-stroke) participated in this psychometric properties study. Interval time for retest was 14 days. All participants were Iranian with Persian as native language, had no other major diseases (e.g. cancer, Alzheimer) and no psychiatric disorder. Cognitive mental score of all participants was above 18 (according to Mini-Mental State Examination). If they had another stroke during the following-up period, they were excluded from the study. Intraclass Correlation Coefficient (ICC), Standard Error of Measurement (SEM) and Minimum Detectable Change (MDC) were calculated to investigate the reliability of the KI. Criterion validity of the KI was assessed by Spearman’s Correlation Coefficient (ρ). Moreover, Confirmatory Factor Analysis (CFA) and Exploratory Factor Analysis (EFA) were performed to investigate the construct validity of the KI. Results: Inter-rater and intra-rater reliability of Persian Katz Index were reasonable (ICC2,1=0.93, ICC2,1=0.83; respectively). Internal consistency of this index was high (cronbach’s alpha=0.79). The high to excellent correlation was found between Katz Index and the motion (ρ=0.88), self-care (ρ=0.98), and total scores (ρ=0.92) of Barthel Index. Factor analysis of the Persian Katz Index indicated two factors including motion (bathing, toileting, and transferring) and self-care (dressing, bowel & bladder control, and feeding). Conclusion: The results of this study suggest that Persian version of Katz Index in patients with acute stroke can be considered as an acceptable clinical instrument in practice and research.

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