Our objective is to determine if we can change the level of excitability of the spinal cord circuitry that controls posture and locomotion so that the sensory information derived from the legs can control and generate standing and stepping. This may be possible by stimulating the spinal cord with an epidurally-placed electrode array. Therefore we may be able to overcome functional limitations that have occurred within the brain as a result of Parkinson's-induced pathology.
We will employ the commonly used chemically-induced pre-clinical model for Parkinson's to improve posture and locomotion following the lesion by surgically implanting electrodes to stimulate over the lumbosacral (lower spine) and the cervical (upper spine). We have a battery of tests to determine whether epidural stimulation treatments can make the spinal cord more functional and thereby compensate for the lack of control from the brain by taking advantage of the control that can be derived from sensory information from the legs. Theoretically, in the Parkinson's state there is no or at least much less loss of function in the spinal cord than the brain and therefore perhaps the spinal cord can compensate for this loss in improving the effectiveness of different movements.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
The proposed experiments are designed to improve standing, stepping and reaching in individuals with Parkinson's disease (PD). The intervention techniques to be used are designed to maximize movement capability by engaging the relatively unaffected neural circuits within the spinal cord. This intervention is designed to minimize the negative impact of PD by making redundant circuits within the spinal cord more functional. Other positive secondary effects of exercise may occur that could improve other functions.
We anticipate observing significantly improved ability to stand, step and to reach as a result of a combination of daily epidural stimulation of the cervical or lower lumbar spinal cord when these motor tasks are being practiced in pre-clinical models in which PD has been induced. We also expect to demonstrate the feasibility of overcoming the "freeze" phenomenon that is commonly present in PD.