P. Hunter Peckham - US grants

The objective of this project is to develop an implantable stimulator system for electrical excitation of paralyzed skeletal muscle. This system will be utilized by high level (C5 and C6) spinal cord injury patients to provide controlled grasp and release in the hand. In this application, functional neuromuscular stimulation has previously been demonstrated to be effective by employing chronically indwelling percutaneous electrodes. Through the use of the implantable system, we expect that the ease of use of the system and its reliability will be improved, leading to greater independence for the quadriplegic patient. The objective of development of the implantable system will be met by: 1. Development of circuitry using a high density of integration to perform the stimulation function; 2. Development of techniques for encapsulation of the stimulator in a hermetic package suitable for extended periods of implantation (greater than 5 years); 3. Development of stimulation electrodes and lead wire interconnections which are suitable for use with the implantable stimulator; 4. Development of a programmable control transmitter which is worn externally by the subject and regulates the output of the implant stimulator in response to the control signals generated by the subject; 5. Evaluation of the entire system and individual subsystems (eg. electrodes, packaging) in vitro and in vivo, and modification of the design where necessary. The principal application of this study is the upper extremity in the quadriplegic subject. However, the technology being developed in this project is expected to be directly applicable to other neurological deficits, such as stroke and cerebral palsy, thus enabling researchers and clinicians to have a powerful new technique more available for rehabilitation of motor function.

Several closely related projects are presently ongoing to investigate normal motor control in the hand and the restoration of motor and sensory function in the hands and arms by functional neuromuscular stimulation (FNS). This program consists of several interrelated projects involving basic scientific and clinical research, and clinical evaluation of neuroprostheses with disabled individuals. Inherent muscle mechanical properties and the reflex alteration of these properties are being assessed in normal subjects to provide models of the neural control of hand function. The results of these studies will be valuable in assessing the validity of the current hypothesis that muscle stiffness is regulated by reflexes and will provide foals for the restoration of hand function by FNS. Research on the restoration of motor function in paralyzed extremities is carried out in several areas. The first area is the restoration of grasp and release using FNS. With electrical stimuli applied by way of intramuscular electrodes, functional hand control can be established. NIH is funding an investigation of the repeatability of open loop control of hand position and force, and research on the design of closed loop control systems for regulating the input-output properties of electrically stimulated muscles to provide enhanced performance. The second area is the development of new command-control sources (such as shoulder and wrist position) to provide methods for paralyzed individuals to control their active orthoses or prostheses. The third area is NIH supported research for the development of externally worn position and force sensors to be used in both the closed loop control systems described above, and for providing artificial sensation by stimulation of skin with intact sensation. The proposed motion study system will be used as an integral component of each of these projects. The projects have a common need for accurate measurement of the position in space of the elements of the upper extremity. In most applications, the information is processed in real time and used in a control (or feedback control) process. The availability of the Selspot II system would reduce or eliminate the substantial development time needed for fabrication of special purpose physical transducers and thus enable us to orient our investigations on the mechanisms of normal motor control and the enhancement of motor and sensory performance of the paralyzed extremity.

DESCRIPTION: (adapted from Investigator's abstract) The aim of this project is to implement and evaluate an advanced neuroprosthetic system for restoration of hand-arm function in human subjects who have sustained cervical level spinal cord injury. The neuroprosthesis will provide the person with C5 tetraplegia with control of grasp and release and elbow extension by electrical stimulation of the paralyzed muscles. These functions will enable the user to regain the versatile manipulative functions which will increase their ability to perform activities of daily living independently. The myoelectric control signal which provides the command input and the stimulation that activates the muscles will be implanted surgically. Thus, the user will be free from issues of sensor mounting and maintenance of cabling and connections to the leads and electrodes on the extremities. The neuroprosthesis to be implemented consists of an external control unit, a multichannel implanted stimulator-telemeter, and implanted electrodes which sense muscle activity (a myoelectric signal). The project will result in (1) completed fabrication of all implanted and external components of the advanced neuroprosthetic system, (2) enhancement of the outcome assessment techniques used to measure system performance, and (3) evaluation of its efficacy in five individuals. Outcome evaluations will measure the function of individual components of the neuroprosthesis and the performance of users in grasp-release tests and activities of daily living. These tests allow statistical comparisons of the user's abilities before surgery with those achieved after surgery, both with the neuroprosthesis turned on and turned off. The results of this project will demonstrate the feasibility of a totally implanted neuroprosthesis and the significant improvements in hand function achieved through its use. The long term objectives of this research are to provide innovative techniques for restoration of functional movement in persons with central nervous system disorders. This research will develop the fundamental modules of neuroprosthetic systems for restoration of control of movement and sensation and perform clinical research to demonstrate their feasibility. The proposed system also has application in the efforts to provide standing and walking in thoracic level spinal cord injury, stroke, and head injury. These types of applications have been considered in defining the proposed system, so that it will be versatile across different clinical applications.

Neural prostheses are systems which electrically stimulate neural tissue to restore function which is lost due to disease or injury. The objectives of the Neural Prostheses: Motor Systems IV Conference are to integrate engineering and clinical expertise in the development and application of devices to restore function for individuals with motor impairments; to expedite the transference of neural prostheses from the engineering laboratory to the clinic and the manufacturing industry; and to educate young researchers in a highly specialized but rapidly developing field. The meeting will be held July 23-28 1994 at the Deer Creek Resort and Conference Center near Columbus, Ohio. This international scientific meeting is the fourth in a series of conferences held every three years under the primary sponsorship of the Engineering Foundation (New York). Sessions will be held on neural prostheses for lower extremity, upper extremity, bladder, respiratory, and cardiac function; electrodes, leads, and connectors; muscle and muscle properties; feedback control strategies; command control; and technology transfer and multi-center trials. Participants at the meeting will develop a consensus of the state of the art of neural prostheses for motor control, focus discussion on the principle aspects of their development which are limiting clinical utilization of the systems, direct specific discussion to resolution of these deficiencies, and disseminate this information to the international community working in this field and to interested clinicians and patient-users. Participation at the conference will involve biomedical engineers, clinicians in the medical rehabilitation field, neuroscientists, representatives of the medical device industry, graduate students and post-doctoral fellows. Funds are requested by the conference chairpersons to support the travel and registration expenses of a portion of the invited participants and publication expenses.

9319988 Peckham This proposal from Case Western Reserve University requests partial support to conduct a symposium entitled Neural Prostheses: Motor Systems IV Conference. The symposium focuses on integration of engineering and clinical expertise in developing devices that restore function for individuals with motor impairments; to expedite the transference of neural prostheses from the engineering laboratory to the clinic and manufacturing industry; and to educate young researchers. The international scientific meeting is the fourth in a series of conferences held every three years. Sessions to be held include neural prostheses for lower extremity, upper extremity, bladder, and respiratory; electrodes, leads, and connectors; muscle and muscle properties; feedback control strategies; command control; and technology transfer. Presenter participants in the symposium are world leaders in neural prostheses for motor control. Funding requested from the NSF would provide partial support for invited participants. Four papers will be submitted for peer reviewed journal publication by symposium participants, thereby making symposium results available to a large audience. ***

The aim of this project is to implement and evaluate an advanced neuroprosthetic system for restoration of hand-arm function in human subjects who have sustained cervical level spinal cord injury. The neuroprosthesis will provide the person with C5 tetraplegia with control of grasp and release and elbow extension by electrical stimulation of the paralyzed muscles. These functions will enable the user to regain the versatile manipulative functions which will increase their ability to perform activities of daily living independently. Both the sensors which provide the control functions and the stimulation that activates the muscles will be implanted surgically. Thus, the user will be free from issues of sensor mounting and maintenance of cabling and connections to the leads and electrodes on the extremities. The neuroprosthesis to be implemented consists of an external control unit, a multichannel implanted stimulator-telemeter, implanted sensors which transduce joint angle, and electrodes which sense muscle activity (a myoelectric signal). This project will result in (1) completed development of all components of the neuroprosthetic system, (2) evaluation of the system in bench and in vivo testing, and (3) evaluation of its efficacy in five individuals. Outcome evaluations will measure the function of individual components of the neuroprosthesis and the performance of users in grasp-release tests and activities of daily living. These tests will allow statistical comparisons of the user's abilities before surgery with those achieved after surgery, both with the neuroprosthesis turned on and turned off. The results of this project will demonstrate the feasibility of a totally implanted neuroprosthesis and the significant improvements in hand function achieved through its use. The long term objectives of this research are to provide innovative techniques for restoration of functional movement in persons with central nervous system disorders. This research will develop the fundamental modules of neuroprosthetic systems for restoration of control of movement and sensation and perform clinical research to demonstrate their feasibility. The proposed system also has application in the efforts to provide standing and walking in thoracic level spinal cord injury, stroke, and head injury. These types of applications have been considered in defining the proposed system, so that it will be versatile across different clinical applications.

This protocol looks at the feasibility of using voluntary generated brain cortical activity as a control signal for a neuroprotheses that assists in restoring hand function. The work is based upon previous work reported by Wolpaw et al. and involves the detection of the mu rhythm (8-12 Hz) component in the EEG signal sensed over the central sulcus with conventional EEG electrodes.