Novel kinematic indices for quantifying upper limb ability and dexterity after cervical spinal cord injury.

Loss of motor function is a consequence after cervical spinal cord injury. Three-dimensional kinematic analysis equipments are used for quantifying human movements in clinical laboratories. These systems may provide objectivity to the patient assessments. Nowadays, the kinematic variables found in the literature have some deficiencies, and the efficient management of these data sets is a demand and a challenge in the clinical setting. The aim of the present paper is to propose a set of novel kinematic indices, as a combination of kinematic variables, for quantifying upper limb motor disorders in terms of characteristics in relation to ability and dexterity such as accuracy, efficiency, and coordination. These indices are defined for measuring patients' motor performance during the activity of daily living of drinking from a glass. This task is included within the upper limb rehabilitative process that patients receive. The main contribution of this research, with the aim of detecting upper limb impairments in patients, consists of the proposal of three kinematic indices from experimental data, whose results are dimensionless and relative to a pattern of healthy subjects. We hope that kinematic indices proposed are a step toward the standardization of the quantitative assessment of movement characteristics and functional impairments.

Novel kinematic indices for quantifying movement agility and smoothness after cervical Spinal Cord Injury.

BACKGROUND: After cervical Spinal Cord Injury (SCI), upper limb movements made by patients have a lack of smoothness and a hand velocity profile characterized by a high number of velocity peaks. OBJECTIVE: The aim of the present paper is to propose three novel kinematic indices for quantifying movement agility and smoothness, and to analyze their discriminative capability between healthy and pathological people. METHODS: 18 people, healthy and two groups of patients with cervical SCI, participated in the study. Kinematic indices in relation to movement agility and smoothness were computed from hand trajectories and velocity profiles during the performance of the ADL of drinking from a glass. RESULTS: The proposed indices discriminated between healthy and SCI people. The results are greater in healthy than SCI people. Both smoothness indices detected significant differences between healthy and both SCI groups. Moreover, the Agility index showed capacity for discriminating between both patients groups. CONCLUSIONS: The main contribution of this research consists on the proposal of kinematic indices from experimental data, whose results are dimensionless and relative to a pattern of healthy subjects. We hope that kinematic indices proposed are a step toward the standardization of the quantitative assessment of movement characteristics and functional impairments.

Variable threshold algorithm for division of labor analyzed as a dynamical system.

Division of labor is a widely studied aspect of colony behavior of social insects. Division of labor models indicate how individuals distribute themselves in order to perform different tasks simultaneously. However, models that study division of labor from a dynamical system point of view cannot be found in the literature. In this paper, we define a division of labor model as a discrete-time dynamical system, in order to study the equilibrium points and their properties related to convergence and stability. By making use of this analytical model, an adaptive algorithm based on division of labor can be designed to satisfy dynamic criteria. In this way, we have designed and tested an algorithm that varies the response thresholds in order to modify the dynamic behavior of the system. This behavior modification allows the system to adapt to specific environmental and collective situations, making the algorithm a good candidate for distributed control applications. The variable threshold algorithm is based on specialization mechanisms. It is able to achieve an asymptotically stable behavior of the system in different environments and independently of the number of individuals. The algorithm has been successfully tested under several initial conditions and number of individuals.

Quantitative assessment based on kinematic measures of functional impairments during upper extremity movements: A review.

BACKGROUND: Quantitative measures of human movement quality are important for discriminating healthy and pathological conditions and for expressing the outcomes and clinically important changes in subjects' functional state. However the most frequently used instruments for the upper extremity functional assessment are clinical scales, that previously have been standardized and validated, but have a high subjective component depending on the observer who scores the test. But they are not enough to assess motor strategies used during movements, and their use in combination with other more objective measures is necessary. The objective of the present review is to provide an overview on objective metrics found in literature with the aim of quantifying the upper extremity performance during functional tasks, regardless of the equipment or system used for registering kinematic data. METHODS: A search in Medline, Google Scholar and IEEE Xplore databases was performed following a combination of a series of keywords. The full scientific papers that fulfilled the inclusion criteria were included in the review. FINDINGS: A set of kinematic metrics was found in literature in relation to joint displacements, analysis of hand trajectories and velocity profiles. These metrics were classified into different categories according to the movement characteristic that was being measured. INTERPRETATION: These kinematic metrics provide the starting point for a proposed objective metrics for the functional assessment of the upper extremity in people with movement disorders as a consequence of neurological injuries. Potential areas of future and further research are presented in the Discussion section.

Heterogeneous collaborative sensor network for electrical management of an automated house with PV energy.

In this paper we present a heterogeneous collaborative sensor network for electrical management in the residential sector. Improving demand-side management is very important in distributed energy generation applications. Sensing and control are the foundations of the "Smart Grid" which is the future of large-scale energy management. The system presented in this paper has been developed on a self-sufficient solar house called "MagicBox" equipped with grid connection, PV generation, lead-acid batteries, controllable appliances and smart metering. Therefore, there is a large number of energy variables to be monitored that allow us to precisely manage the energy performance of the house by means of collaborative sensors. The experimental results, performed on a real house, demonstrate the feasibility of the proposed collaborative system to reduce the consumption of electrical power and to increase energy efficiency.

An Open Localization and Local Communication Embodied Sensor.

In this paper we describe a localization and local communication system which allows situated agents to communicate locally, obtaining at the same time both the range and the bearing of the emitter without the need of any centralized control or any external reference. The system relies on infrared communications with frequency modulation and is composed of two interconnected modules for data and power measurement. Thanks to the open hardware license under which it is released, the research community can easily replicate the system at a low cost and/or adapt it for applications in sensor networks and in robotics.