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Interface to fes control system

Interface to fes control system description/claims

The present invention relates to a functional electrical stimulation (FES) system and method of using such a system. More particularly, the invention relates to a device and method for providing a person using functional electrical stimulation with a means of controlling the electrical stimulation provided to their limbs.

In the area of medical technology, much advancement have been made to assist individuals who have previously been considered to be disabled in some way, to lead a relatively normal life in spite of such disabilities. Such advancements include the provision of hearing aids and cochlear implants for the hearing impaired, as well as pacemakers for those who experience cardiac problems, to name a few. However with regard to persons suffering from spinal cord injury and those who have lost function of their limbs, the provision of a device or devices to return desired function to the individual has as yet proven difficult to implement. Functional electrical stimulation (FES) systems of various types are seen to have particular application in providing persons suffering from spinal cord injury or deficiency, such as paraplegia, with a capacity to make controlled movements of their dysfunctional legs.

Functional electrical stimulation systems use electronics to generate electrical impulses. These impulses are then delivered to the serves or muscles of a subject via electrodes to stimulate movement of the muscles that axe otherwise dysfunctional. In order for useful and controlled movements of limbs to be achieved several muscles must usually be operated in concert. This is normally achieved by an algorithm executed under the control of the FES system to deliver a pattern or sequence of stimulation impulses.

An important aspect of the successful implementation of such an FES system is the provision of a control technique that controls the limbs of a patient so that they follow a desired trajectory. It is extremely difficult, however, to choose a trajectory of the limbs so that a functional task such as standing is performed. In one proposal, control is provided by a touch pad interface which can be activated by the subjects fingers to some control types of movement, such as standing, sitting and walking.

Such touch pad interfaces as known in the art do not provide an intuitive interface for the subject with the FES system and assume that the subject has full hand control to enable use of such a device. Existing FES systems are, therefore, relatively difficult to learn how to use and require a certain amount of dexterity which has the potential to move subjects in undesirable ways.

Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention before the priority date of each claim of this application.

Throughout this specification the word “comprise”, or variations such as “comprises”, or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

According to a first aspect, the present invention is a functional electrical stimulation system for controlling the movement of a portion of a body of a subject comprising:

a measuring means having at least one sensor, mountable to a portion of the subjects body other said body portion, that outputs signals representative of the position and/or movement of said other portion of the subject's body; and

a control means that receives and processes the signals output by the measuring means and outputs control signals to a stimulating means adapted to provide electrical stimulation to said body portion in response to the position and/or movement of said other body portion determined by the measuring means.

In one embodiment of this aspect, the said other body portion is selected from the group comprising the torso, the head or one or both arms of the subject.

In a further embodiment, said body portion is one or both legs of the subject.

The present invention provides a system that can be relatively easily used, in one arrangement, to generate one or more desired angles between the respective thighs and lower legs of a paraplegic with the legs being controlled by electrical stimulation of the muscles so that the actual measured angle of the thigh and lower leg corresponds to the desired angles.

In a preferred embodiment, the measuring means measures the angle of the subject's torso relative to a predetermined plane. The predetermined plane can be a sagittal plane, a frontal plane or a horizontal plane. In one embodiment, the measuring means only measures the angle when the torso has stopped gross movement. In another embodiment, the measuring means measures the angle throughout the range of movement of the torso.

In another embodiment, the measuring means detects torso movements that are determined by the control means as indicative that the subject wishes to roll over when they are in a horizontal position, such as when they are asleep. Such torso movements will typically comprise twisting movements of the torso.

In yet another embodiment, the measuring means measures the angle of the torso relative to the position of one or both of the lower limbs of the subject.

In one embodiment, the measuring means can be carried by the subject. The measuring means may be carried in a harness or clothing worn by the subject. In another embodiment, the measuring means may be strapped about the torso of the subject. In an alternative embodiment, the measuring means or componentry thereof can be implantable within the subject.

In a preferred embodiment, the measuring means comprises one or more transducers that outputs signals representative of the position and/or movement of the transducer to the control means. Where the measuring means is measuring the angle of the torso relative to the lower limbs, a transducer can be mounted on the torso and on one or both of the lower limbs. More than one transducer mounted on the torso and/or the lower limbs can be envisaged. Each of the transducers in this case would output signals to the control means.

The control means preferably processes the output signals of the transducer or transducers and then outputs signals to the stimulating means to provide electrical stimulation to the muscles of the subject. The control means can execute an algorithm that leads to provision of electrical stimulation to the appropriate muscle(s) at the appropriate intensity as dictated by the subject or a predetermined programme. The output signals of the transducer or transducers and those of the control means to the stimulating means can comprise electrical or optical signals.

In a further embodiment, the control means can have a storage means having at least one predetermined action sequence storable therein. On receipt of signals from the measuring means, said at least one predetermined action sequence can be provided to the stimulating means. The predetermined action sequence can result in the subject moving from a standing to a sitting position, or moving from a sitting to a standing position, walking, or moving the legs in a pedaling action. Other suitable predetermined action sequences can be envisaged.

• Provisional Patent
• Utility Patent

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