Project description:Background: Postural instability is a debilitating and largely treatment-resistant symptom of Parkinson's disease (PD). A better understanding of the neural substrates contributing to postural instability could lead to new targets for improved pharmacological and neurosurgical interventions. However, investigating these neural substrates necessitates the use of functional MRI scanners, which are almost exclusively horizontally-based. Objective: We aimed to develop, and validate the use of, an MRI compatible balance simulator to study static and dynamic balance control in PD patients and elderly controls. Methods: Our MRI compatible balance simulator allowed participants to actively balance an inverted pendulum by activating postural muscles around the ankle joint while supine. Two studies were performed to compare static and dynamic balance performance between upright stance and simulated stance in PD patients and controls. Study 1 (14 PD; 20 controls) required participants to maintain static balance during upright and simulated stance for 120 s with eyes open and closed. In study 2 (20 PD; 22 controls) participants repeated the static balance task (80 s, eyes closed only), and also completed a dynamic balance task which required maintaining balance while experiencing random anterior-posterior perturbations applied to the trunk/pendulum. Postural sway of the body/pendulum was measured using an angular velocity sensor (SwayStarTM, study 1) and Optotrak motion capture (study 2). Outcome measures were amplitude and frequency of center of mass sway for static balance, and peak and time-to-peak of center of mass displacement and velocity for dynamic balance. Results: PD patients had larger sway amplitude during both upright and simulated static balance compared to controls. PD patients had larger peak and time-to-peak sway, and larger time-to-peak sway velocity, during simulated, but not upright, dynamic balance compared to controls. Conclusions: Deficits in static and dynamic balance control can be detected in PD patients using a novel MRI compatible balance simulator. This technique allows for functional neuroimaging to be combined with balance-relevant tasks, and provides a new means to create insights into the neural substrates contributing to postural instability in PD.

Project description:BackgroundBalance challenges are associated with not only the aging process but also a wide variety of psychiatric and neurological disorders. However, relatively little is known regarding the neural basis of balance and the effects of balance interventions on the brain.Research questionThis review synthesizes the existing literature to answer the question: What are the key brain structures associated with balance?MethodsThis review examined 37 studies that assessed brain structures in relation to balance assessment or intervention. These studies provided 234 findings implicating 71 brain structures. The frequency of implication for each structure was examined based upon specific methodological parameters, including study design (assessment/intervention), type of balance measured (static/dynamic), population (clinical/non-clinical), and imaging analysis technique (region of interest [ROI]/voxel-based morphometry [VBM]).ResultsAlthough a number of structures were associated with balance across the brain, the most frequently implicated structures included the cerebellum, basal ganglia, thalamus, hippocampus, inferior parietal cortex, and frontal lobe regions. Findings in the cerebellum and brainstem were most common in studies with clinical populations, studies that used an ROI approach, and studies that measured dynamic balance. Findings in the frontal, occipital, and parietal regions were also more common in studies that measured dynamic compared to static balance.SignificanceWhile balance appears to be a whole-brain phenomenon, a subset of structures appear to play a key role in balance and are likely implicated in balance disorders. Some of these structures (i.e., the cerebellum, basal ganglia and thalamus) have a well-appreciated role in balance, whereas other regions (i.e., hippocampus and inferior parietal cortex) are not commonly thought to be associated with balance and therefore may provide alternative explanations for the neural basis of balance. Key avenues for future research include understanding the roles of all regions involved in balance across the lifespan and in different clinical populations.

Project description:BACKGROUND:Postural balance is an important rehabilitation outcome, and screening stroke patients for confidence in postural balance during rehabilitation and before hospital discharge is recommended. Early supported discharge could improve postural balance self-confidence. This study aimed to investigate associations between patient self-confidence in postural balance and observer-assessed postural balance and anxiety during the first year after stroke. Whether very early supported discharge (VESD) affects self-confidence in postural balance compared with standard discharge was also evaluated. METHODS:A longitudinal trial for with data extracted from a randomized controlled study of 140 adults with confirmed stroke was conducted. The experimental group received VESD. The control group was discharged according to the standard routine. Postural balance was assessed with Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and Falls Efficacy Scale. Anxiety was assessed with the Hospital Anxiety and Depression Scale. Spearman's rank correlation coefficient (rho) was used to test associations between independent variables. The Wilcoxon signed-rank test was used to examine differences over time. A single test, according to Eid, Gollwitzer, and Schmidt, was used to test temporal differences in correlation. RESULTS:The correlation between self-confidence in postural balance and observer-assessed postural balance was 0.62-0.78 in the first year after stroke. The correlation between self-confidence and anxiety was 0.22-0.41 in the first year after stroke. Correlations did not differ by group affiliation at any time point when the postural balance was assessed with BBS. The intervention group had a significantly higher correlation (r?=?-?0.709) than the control group (r?=?-?0.416) when postural balance was assessed with the TUG test 1 month after discharge. There were no significant differences in correlations between confidence in postural balance and anxiety between the two groups at any time point. CONCLUSIONS:Patients with mild stroke can accurately assess their confidence in performing daily activities without falling. VESD does not substantially affect the correlation between self-confidence in postural balance and observer assessed postural balance and is safe to use as an alternative to standard discharge. Assessment of self-confidence can provide important information for rehabilitation planning and supporting the physical activity of patients after discharge. TRIAL REGISTRATION:Clinical Trials.gov: NCT01622205 . Registered 19 June 2012 (retrospectively registered).

Project description:Reduced muscle strength is an independent risk factor for falls and related to postural instability in individuals with Parkinson's disease. The ability of resistance training to improve postural control still remains unclear.To compare resistance training with balance training to improve postural control in people with Parkinson's disease.40 patients with idiopathic Parkinson's disease (Hoehn&Yahr: 2.5-3.0) were randomly assigned into resistance or balance training (2x/week for 7 weeks). Assessments were performed at baseline, 8- and 12-weeks follow-up: primary outcome: Fullerton Advanced Balance (FAB) scale; secondary outcomes: center of mass analysis during surface perturbations, Timed-up-and-go-test, Unified Parkinson's Disease Rating Scale, Clinical Global Impression, gait analysis, maximal isometric leg strength, PDQ-39, Beck Depression Inventory. Clinical tests were videotaped and analysed by a second rater, blind to group allocation and assessment time.32 participants (resistance training: n = 17, balance training: n = 15; 8 drop-outs) were analyzed at 8-weeks follow-up. No significant difference was found in the FAB scale when comparing the effects of the two training types (p = 0.14; effect size (Cohen's d) = -0.59). Participants from the resistance training group, but not from the balance training group significantly improved on the FAB scale (resistance training: +2.4 points, Cohen's d = -0.46; balance training: +0.3 points, Cohen's d = -0.08). Within the resistance training group, improvements of the FAB scale were significantly correlated with improvements of rate of force development and stride time variability. No significant differences were found in the secondary outcome measures when comparing the training effects of both training types.The difference between resistance and balance training to improve postural control in people with Parkinson's disease was small and not significant with this sample size. There was weak evidence that freely coordinated resistance training might be more effective than balance training. Our results indicate a relationship between the enhancement of rate of force development and the improvement of postural control.ClinicalTrials.gov ID: NCT02253563.

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Quantitative postural models as biomarkers of balance in Parkinson’s disease.

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