Considerations for the future development of virtual technology as a rehabilitation tool

BACKGROUND: Virtual environments (VE) are a powerful tool for various forms of rehabilitation. Coupling VE with high-speed networking [Tele-Immersion] that approaches speeds of 100 Gb/sec can greatly expand its influence in rehabilitation. Accordingly, these new networks will permit various peripherals attached to computers on this network to be connected and to act as fast as if connected to a local PC. This innovation may soon allow the development of previously unheard of networked rehabilitation systems. Rapid advances in this technology need to be coupled with an understanding of how human behavior is affected when immersed in the VE. METHODS: This paper will discuss various forms of VE that are currently available for rehabilitation. The characteristic of these new networks and examine how such networks might be used for extending the rehabilitation clinic to remote areas will be explained. In addition, we will present data from an immersive dynamic virtual environment united with motion of a posture platform to record biomechanical and physiological responses to combined visual, vestibular, and proprioceptive inputs. A 6 degree-of-freedom force plate provides measurements of moments exerted on the base of support. Kinematic data from the head, trunk, and lower limb was collected using 3-D video motion analysis. RESULTS: Our data suggest that when there is a confluence of meaningful inputs, neither vision, vestibular, or proprioceptive inputs are suppressed in healthy adults; the postural response is modulated by all existing sensory signals in a non-additive fashion. Individual perception of the sensory structure appears to be a significant component of the response to these protocols and underlies much of the observed response variability. CONCLUSION: The ability to provide new technology for rehabilitation services is emerging as an important option for clinicians and patients. The use of data mining software would help analyze the incoming data to provide both the patient and the therapist with evaluation of the current treatment and modifications needed for future therapies. Quantification of individual perceptual styles in the VE will support development of individualized treatment programs. The virtual environment can be a valuable tool for therapeutic interventions that require adaptation to complex, multimodal environments

Reaching within a dynamic virtual environment

This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens

Pairing virtual reality with dynamic posturography serves to differentiate between patients experiencing visual vertigo

<p>Abstract</p> <p>Background</p> <p>To determine if increased visual dependence can be quantified through its impact on automatic postural responses, we have measured the combined effect on the latencies and magnitudes of postural response kinematics of transient optic flow in the pitch plane with platform rotations and translations.</p> <p>Methods</p> <p>Six healthy (29–31 yrs) and 4 visually sensitive (27–57 yrs) subjects stood on a platform rotated (6 deg of dorsiflexion at 30 deg/sec) or translated (5 cm at 5 deg/sec) for 200 msec. Subjects either had eyes closed or viewed an immersive, stereo, wide field of view virtual environment (scene) moved in upward pitch for a 200 msec period for three 30 sec trials at 5 velocities. RMS values and peak velocities of head, trunk, and head with respect to trunk were calculated. EMG responses of 6 trunk and lower limb muscles were collected and latencies and magnitudes of responses determined.</p> <p>Results</p> <p>No effect of visual velocity was observed in EMG response latencies and magnitudes. Healthy subjects exhibited significant effects (<it>p </it>< 0.05) of visual field velocity on peak angular velocities of the head. Head and trunk velocities and RMS values of visually sensitive subjects were significantly larger than healthy subjects (<it>p </it>< 0.05), but their responses were not modulated by visual field velocity. When examined individually, patients with no history of vestibular disorder demonstrated exceedingly large head velocities; patients with a history of vestibular disorder exhibited head velocities that fell within the bandwidth of healthy subjects.</p> <p>Conclusion</p> <p>Differentiation of postural kinematics in visually sensitive subjects when exposed to the combined perturbations suggests that virtual reality technology could be useful for differential diagnosis and specifically designed interventions for individuals whose chief complaint is sensitivity to visual motion.</p

Self versus Environment Motion in Postural Control

To stabilize our position in space we use visual information as well as non-visual physical motion cues. However, visual cues can be ambiguous: visually perceived motion may be caused by self-movement, movement of the environment, or both. The nervous system must combine the ambiguous visual cues with noisy physical motion cues to resolve this ambiguity and control our body posture. Here we have developed a Bayesian model that formalizes how the nervous system could solve this problem. In this model, the nervous system combines the sensory cues to estimate the movement of the body. We analytically demonstrate that, as long as visual stimulation is fast in comparison to the uncertainty in our perception of body movement, the optimal strategy is to weight visually perceived movement velocities proportional to a power law. We find that this model accounts for the nonlinear influence of experimentally induced visual motion on human postural behavior both in our data and in previously published results

Posturography using the Wii Balance Board. A feasibility study with healthy adults and adults post-stroke

[EN] Background: Posturography systems that incorporate force platforms are considered to assess balance and postural control with greater sensitivity and objectivity than conventional clinical tests. The Wii Balance Board (WBB) system has been shown to have similar performance characteristics as other force platforms, but with lower cost and size. Objectives: To determine the validity and reliability of a freely available WBB-based posturography system that combined the WBB with several traditional balance assessments, and to assess the performance of a cohort of stroke individuals with respect to healthy individuals. Methods: Healthy subjects and individuals with stroke were recruited. Both groups were assessed using the WBB-based posturography system. Individuals with stroke were also assessed using a laboratory grade posturography system and a battery of clinical tests to determine the concurrent validity of the system. A group of subjects were assessed twice with the WBB-based system to determine its reliability. Results: A total of 144 healthy individuals and 53 individuals with stroke participated in the study. Concurrent validity with another posturography system was moderate to high. Correlations with clinical scales were consistent with previous research. The reliability of the system was excellent in almost all measures. In addition, the system successfully characterized individuals with stroke with respect to the healthy population. Conclusions: The WBB-based posturography system exhibited excellent psychometric properties and sensitivity for identifying balance performance of individuals with stroke in comparison with healthy subjects, which supports feasibility of the system as a clinical tool. (C) 2015 Elsevier B.V. All rights reserved.This study was funded by project NeuroVR (TIN2013-44741-R) of the Ministerio de Economia y Competitividad (Madrid, Spain).Llorens Rodríguez, R.; Grau Latorre, J.; Noe, E.; Keshner, EA. (2015). Posturography using the Wii Balance Board. A feasibility study with healthy adults and adults post-stroke. Gait and Posture. 43:228-232. https://doi.org/10.1016/j.gaitpost.2015.10.002S2282324

Open Access

Visual conflict and cognitive load modify postural responses to vibrotactile nois

Re-evaluating the theoretical model underlying the neurodevelopmental therapy: a literature review. Phys Ther.

The purpose of this paper is to evaluate the foundations of a prevalent physical therapy technique based on the current research on motor control. The conceptual framework of the neurodevelopmental theory, as described in the writings of the Bobaths, is presented. Their explanations of central nervous system disorders and recommendations for intervention are based upon a unidirectional model of the nervous system in which postural and voluntary motion become two separate and distinct entities. Systems theory is an alternative model of nervous system structure. In systems theory, the organism is a circular network of interacting yet autonomous subsystems, rather than a vertical structure of descending controls. Relevant research that supports the systems viewpoint is discussed and applied to the theories in the neurodevelopmental approach. Thus, another model is offered for understanding the functioning of the central nervous system when it is intact and when it is in a pathological state. Key Words: Neural transmission, Motor control, Neurodevelopmental theory. Validation and acceptance of a clinical treatment require that the practice stem from an acknowledged theoretical model of the functioning organism and be supported by replicable research designs. One physical therapy technique that has popular acceptance through its empirical appropriateness is based on the neurodevelopmental theory (NDT) as devised by the Bobaths. 1-3 Their doctrine of early intervention 4,5 has been followed by clinical practitioners and has received several reports of positive results in the patient population. 6-8 Generalized support of the doctrine by the medical field would require that the clinical observations on which this treatment is based be validated by the relevant research. The Bobaths originally substantiated the conceptual model of NDT through the theoretical approach of Jackson. 3 Jackson described the CNS as a hierarchically functioning structure in which the normal, more complex patterns of behavior (for example, righting and equilibrium reactions) are, at a higher level of organization, combinations of the same movements that make up the abnormal, phylogenetically simpler behaviors (for example, tonic neck and tonic labyrinthine reflexes). 3,9,10 Current literature on motor control and the recovery of function after brain damage suggests that the CNS does not function as a strictly descending hierarchy, but as a network of independent systems that support desired movement results through their interaction. 11,12 Application of the approach based on NDT to the distributed control model of the CNS creates questions about the underlying assumptions of the technique. This paper is directed toward clarifying the concepts upon which NDT is based and evaluates them through an extensive review and presentation of the relevant literature. The following questions are answered: 1) How does the systems approac