Complex Balance Task Research Articles

Effect of a hippotherapy intervention program on static balance and strength in adolescents with intellectual disabilities

The aim of this study was to assess the effects of a hippotherapy program on static balance and strength in adolescents with intellectual disability (ID). Nineteen adolescents with moderate ID were assigned either an experimental group (n=10) or a control group (n=9). The experimental group attended a 10-week hippotherapy program. To assess static balance, three tasks of increasing difficulty (Double-Leg Stance with opened or closed eyes, and One-Leg Stance with opened eyes) were performed while standing on an EPS pressure platform (Loran Engineering S.r.I., Bologna, Italy). The strength measurements consisted of three maximal isometric half-squats from the seating position (knee joint at 90°). The hippotherapy intervention program resulted in significant improvements in strength parameters, and on the more complex balance task (i.e. standing on one leg). In conclusion, this study provides evidence that hippotherapy can be used as an effective intervention for improving balance and strength in individuals with ID, and could thus influence functional activities and quality of life.

Medication improves balance and complex gait performance in Parkinson disease

Gait and balance impairments in people with Parkinson disease (PD) may lead to falls and serious injuries. Therefore, it is critical to improve our understanding of the nature of these impairments, including how they respond to prescribed anti-Parkinson medication. This is particularly important for complex balance and gait tasks that may be associated with falls. We evaluated motor function, functional balance, and gait performance during various gait tasks in 22 people with PD OFF and ON medication (PD OFF, PD ON) and 20 healthy older adults. Although MDS-UPDRS-III score, Berg Balance Scale, Mini-Balance Evaluations Systems test, and Timed-Up-and-Go improved in PD with medication, impairments persisted in all measures on medication, compared to controls. Dual task Timed-Up-and-Go did not improve with medication, and PD ON required more time than controls. Gait velocity and stride length improved similarly with medication in PD across forward, fast, backward, dual task forward, and dual task backward gait tasks. Cadence did not change with medication, nor did it differ between PD ON and controls. Velocity and stride length were reduced in PD ON compared to controls. Velocity reductions in PD ON during fast gait were cadence-mediated, while velocity reductions in backward gait were stride length-mediated. Our results suggest functional balance improves with medication in PD and gait performance improves with medication, regardless of task complexity. Remaining impairments on medication highlight the need to examine additional therapeutic options for individuals with PD to reduce the risk of falls.

Effect of Modified Visual Information on Postural Balance of Unilateral Transfemoral Amputees during Quiet Standing

INTRODUCTION: In the absence of visual information, postural balance is ensured through the integration of sensory inputs from the somatosensory and vestibular systems. Due to the loss of a lower limb, unilateral lower limb amputees cannot effectively use somatosensory inputs from their prosthetic side to control their postural balance. This prosthetic somatosensory state causes them to adopt a different sensory-motor strategy for the maintenance of upright posture. PURPOSE: To assess the effect of modified visual information on the postural balance of unilateral transfemoral amputees (UTFA) during quiet standing. METHODS: A total of 23 UTFA subjects (63.2 ± 7.5 yrs) and 10 healthy subjects (57.4 ± 8.8 yrs) participated in the experiment. Subjects were instructed to stand on dual force plates (Kistler) while center of pressure (COP) displacements from each foot were measured for 30 seconds. They wore display-device eye gear (Olympus Eye-Trek FMD-700), to which a modified image signal, consisting of the tilting of real visual surroundings in the 10th and 20th second, was applied via a personal computer. RESULTS: When the image signal was applied to UTFA, COP increased in the anteroposterior direction under the non-affected limb (0.95 vs. 1.42 cm, p <.01). The overall COP decreased in the anteroposterior direction (1.45 vs. 0.95 cm, p <.05), and the velocity of the overall COP decreased (2.80 vs. 2.32 cm/s, p <.01) during the interval (0-30s) image application. In contrast, the application of the image signal to the healthy subjects induced increased the overall COP in the mediolateral direction (0.31 vs. 0.51 cm, p <.01), increased velocity of the overall COP in the mediolateral (1.06 vs. 1.66 cm/s, p <.01) and anteroposterior (1.28 vs. 2.12 cm/s, p <.05) directions, and increased velocity of the COP (1.85 vs. 3.0 cm/s, p <.05) under the dominant limb. CONCLUSION: The visual signal application had a different effect on the observed sensory-motor strategies of UTFA as compared to healthy subjects. The findings suggest that rehabilitating UTFA using complex balance tasks in challenging environments could help UTFA manage a variety of balance disturbances safely.

Multi-segmental postural coordination in professional ballet dancers

Ballet dancers have heightened balance skills, but previous studies that compared dancers to non-dancers have not quantified patterns of multi-joint postural coordination. This study utilized a visual tracking task that required professional ballet dancers and untrained control participants to sway with the fore–aft motion of a target while standing on one leg, at target frequencies of 0.2 and 0.6Hz. The mean and variability of relative phase between the ankle and hip, and measures from cross-recurrence quantification analysis (i.e., percent cross-recurrence, percent cross-determinism, and cross-maxline), indexed the coordination patterns and their stability. Dancers exhibited less variable ankle–hip coordination and a less deterministic ankle–hip coupling, compared to controls. The results indicate that ballet dancers have increased coordination stability, potentially achieved through enhanced neuromuscular control and/or perceptual sensitivity, and indicate proficiency at optimizing the constraints that enable dancers to perform complex balance tasks.

Dynamic Properties of Human Brain Structure: Learning-Related Changes in Cortical Areas and Associated Fiber Connections

Recent findings in neuroscience suggest that adult brain structure changes in response to environmental alterations and skill learning. Whereas much is known about structural changes after intensive practice for several months, little is known about the effects of single practice sessions on macroscopic brain structure and about progressive (dynamic) morphological alterations relative to improved task proficiency during learning for several weeks. Using T1-weighted and diffusion tensor imaging in humans, we demonstrate significant gray matter volume increases in frontal and parietal brain areas following only two sessions of practice in a complex whole-body balancing task. Gray matter volume increase in the prefrontal cortex correlated positively with subject's performance improvements during a 6 week learning period. Furthermore, we found that microstructural changes of fractional anisotropy in corresponding white matter regions followed the same temporal dynamic in relation to task performance. The results make clear how marginal alterations in our ever changing environment affect adult brain structure and elucidate the interrelated reorganization in cortical areas and associated fiber connections in correlation with improvements in task performance.

O061 The energy cost for balance control in healthy people

To study balance control on a moving platform in lower limb amputees.Observational cohort study.Unilateral transfemoral and transtibial amputees and able-bodied control subjects.Balance control on a platform that moved in the anteroposterior direction was tested with eyes open, blindfolded and while performing a dual task.Weight bearing symmetry, anteroposterior ground reaction force and centre of pressure shift.Compared to able-bodied subjects, in amputees the anteroposterior ground reaction force was larger in the prosthetic and non-affected limb, and the centre of pressure displacement was increased in the non-affected limb and decreased in the prosthetic limb. In amputees body weight was loaded more on the non-affected limb. Blindfolding or adding a dual task did not influence the outcome measures importantly.The results of this study indicate that experienced unilateral amputees with a high activity level compensate for the loss of ankle strategy by increasing movements and loading in the non-affected limb. The ability to cope with balance perturbations is limited in the prosthetic limb. To enable amputees to manage all possible balance disturbances in real life in a safe manner, we recommend to improve muscle strength and control in the non-affected limb and to train complex balance tasks in challenging environments during rehabilitation.

Balance control on a moving platform in unilateral lower limb amputees

Objective To study balance control on a moving platform in lower limb amputees. Design Observational cohort study. Participants Unilateral transfemoral and transtibial amputees and able-bodied control subjects. Interventions Balance control on a platform that moved in the anteroposterior direction was tested with eyes open, blindfolded and while performing a dual task. Main outcome measures Weight bearing symmetry, anteroposterior ground reaction force and centre of pressure shift. Results Compared to able-bodied subjects, in amputees the anteroposterior ground reaction force was larger in the prosthetic and non-affected limb, and the centre of pressure displacement was increased in the non-affected limb and decreased in the prosthetic limb. In amputees body weight was loaded more on the non-affected limb. Blindfolding or adding a dual task did not influence the outcome measures importantly. Conclusion The results of this study indicate that experienced unilateral amputees with a high activity level compensate for the loss of ankle strategy by increasing movements and loading in the non-affected limb. The ability to cope with balance perturbations is limited in the prosthetic limb. To enable amputees to manage all possible balance disturbances in real life in a safe manner, we recommend to improve muscle strength and control in the non-affected limb and to train complex balance tasks in challenging environments during rehabilitation.

Overcoming spontaneous patterns of coordination during the acquisition of a complex balancing task.

Learning in complex tasks is usually conceived as the problem of mastering the multiple and redundant degrees of freedom of the system. To reduce control requirements, two different strategies are conceivable. The first one consists of a "freezing-freeing" process for most articular joints to reduce the number of active biomechanical degrees of freedom to be managed. The second strategy consists of introducing rigid couplings between the oscillators building the system. In this case, learning implies the dissolution of initial couplings and the emergence of new, more task-specific couplings. The goal of our study was to analyze the spontaneous coordination of beginners and its development in a complex balancing task on a stabilometer, and to examine the emergence of these two strategies. Our results showed that beginners were characterized by strong couplings between the joints of the lower limbs. During learning, new and more task-specific couplings emerged that reflected a new organization of the trunk and a decoupling of some joints of the lower limbs that were initially coupled during the first few trials.