Locomotion is a fundamental function in the active life of a human individual at different levels - personal, professional, social, and for a full participation in today’s society in fulfillment of one’s citizenship. Unfortunately, several neuromuscular or muscle-skeletal disorders can significantly impair human locomotion or produce gait abnormalities. Among them, cerebral palsy, Parkinson disease, hemiplegia, or diabetic neuropathy, just to name a few. The analysis of normal or pathological gait is applied in the diagnosis of these disorders and as a way of pre and post assessing treatment programs, either surgical, orthotic, prosthetic, by medication or physiotherapy.

Current instruments and methods for gait analysis are still expensive and complex, difficult to apply by healthcare staff, difficult to use and uncomfortable for the patient (figures 1 - a, b, c, in annex), and require a very high level of expertise for data gathering, analysis and interpretation. Gait analysis laboratories and instruments include video or infra-red cameras, force plates, rotary mats or insoles, goniometry and electromyography acquisition equipments, treadmills, for indoor in-the-lab use only (figures 1, 2, in annex).

One has witnessed this decade a significant development of new technological features in medical appliances, which are enabled by highly complex systems and highly integrated technologies. In fact, in 2008, the medical segment was estimated in about 7% of the 24500 million Euro global industrial semiconductor market. Medical electronics has been the fastest growing segment in this market, with a growth rate of 15% per year in average, and is expected to exceed 4800 million Euro in revenue by 2013. Europe was responsible for about 30% of this market in 2007. In this project, a new electronic instrument will be conceived and developed that can measure human locomotion parameters in the most practical and non-invasive way possible, even for those persons that have strong impairments or disabilities. This instrument will not only include the measurement of typical kinematic variables of the lower limb, namely linear and angular movement of thighs, shanks and feet, but also the myoelectric signals of the surface muscles on the limbs that are most important for locomotion. The major potential of this multifactorial movement analysis is the possibility it offers to understand the role of the different factors in a given pathology. A pathophysiologic profile can then be drawn to synthetically represent the relative importance of a set of factors in the patient’s performance. Such a procedure can help the clinician to make decisions about the therapy. This measurement instrument must also be simple in use and application and obviously not harmful to the patient. It should preferably be wearable and autonomous to allow monitoring of the relevant variables not only in the clinical or laboratory environment, but also in the daily life of the patient or user with minimal interference and discomfort.

This type of instrument will be useful in three main application scenarios:

1. To provide objective data in evaluation of gait disorders. It is very important from a clinical stand point of view, since the interaction between mechanical and neural factors is determinant and cannot be directly estimated by visual inspection or manual analysis. The quantification that this type of instrument is expected to give is of great interest, for health personal committed in the treatment of neuromuscular or muscle-skeletal damage and dysfunction. It is also expected to be possible to analyse the modifications made by therapeutic intervention. From a legal point of view it is also very important to have an objective and precise way of impairment or damage evaluation, which should not be influenced by the observer opinion.
2. If the instrument is simple and comfortable enough for the patient, he/she can use it as self-assessment of progress of physiatrist activities, obtaining motivation in a sportive fashion of competition against him/her self, as well as a biofeedback system to improve performance in locomotion and avoid falls, the major cause of hip fracture in the elderly.
3. For those interested in movement analysis, it should be possible to study performance in sports, such as athletics or gymnastics players, as well as in industrial workers or other demanding occupational activities.

The PROLIMB project addresses these issues pursuing a holistic approach made possible by the involvement of research groups with a strong activity in the domains of textile engineering, microelectronics design and test, and signal processing, in collaboration with a physician, to produce a reliable and easy to use wearable sensor network for simultaneous acquisition and continuous monitoring of the human lower limbs locomotion parameters.

People / Institutions

José Machado da Silva, Ana Ferreira da Rocha, André Catarino, Carolina Vila-Chã, Fernando Oliveira, João Canas Ferreira, Maria Marques Abreu, Miguel Velhote Correia, Vítor Grade Tavares, José Ramos Duarte, Rui Machado de Lemos.

Participating Institutions: OET / INESC TEC; Centro de Ciência e Tecnologia Têxtil / UMinho (CCTT/UM)

Funding

FEDER- Fundo Europeu de Desenvolvimento Regional

FCT– Fundação para a Ciência e a Tecnologia – PTDC/EEA-ELC/103683/ 2008