3 Clinical Trials for Various Conditions
The long-term goal of this project is to develop a non-invasive, noise-based technique for enhancing somatosensation and thereby improving balance control in elderly fallers and older adults with somatosensory deficits.
This study will determine whether impaired hand function due to stroke can be improved by blocking nerve impulses to the unaffected arm. Following a stroke, the unaffected side of the brain might negatively influence the affected side. Studies in healthy volunteers show that function in one hand improves when ischemic nerve block (inflating a pressure cuff to block nerve impulses) is applied to the forearm of the other hand. This study will examine whether similar improvement also occurs in the affected hand of patients with chronic impairment after stroke. Stroke patients with sensory (numbness) or motor impairment (weakness) in the hand that has persisted at least 12 months after the stroke may be eligible for this study. Patients who have had more than one stroke, whose stroke affected both sides of the body, who have a history of deep vein thrombosis (blood clotting), or who are receiving anticoagulant (blood-thinning) treatment at the time of the study will not be enrolled. Participants will have physical and neurological examinations and will undergo the following procedures: Session 1 * Magnetic resonance imaging (if one has not been done within the previous 6 months): MRI uses a magnetic field and radio waves to produce images of body tissues and organs. For this procedure, the patient lies on a table that is moved into the scanner (a narrow cylinder) and wears earplugs to muffle loud knocking and thumping sounds that occur during the scanning process. The procedure lasts about 45 to 90 minutes, during which the patient lies still up to a few minutes at a time. * Mini Mental State Examination - Patients will take a short test to assess cognitive function. Sessions 2 (and possibly 3 and 4) * Motor task practice: Patients practice a motor task several times to achieve optimal performance. The task is a rhythmic, repetitive pinch grip at maximal strength at a frequency of one grip every 10 seconds. If technical difficulties arise during the session, the procedure will be repeated in sessions 3 and 4. Sessions 5 (and possibly 6) * Pinch grip and ischemic nerve block (INB): Patients perform the pinch grip task several times and then INB is applied. For INB, a blood pressure cuff is inflated around the arm at the level of the elbow for 35 to 50 minutes. The procedure causes temporary numbness, tingling, loss of muscle strength, and discoloration or the forearm and hand. Patients repeat the pinch grip task during the INB and again 20 minutes after the INB is released. If technical difficulties arise during the session, the procedure will be repeated in session 6. Session 7 This session is identical to session 5, except the INB is applied immediately above the ankle instead of on the forearm.
Stroke affects over 795,000 Americans every year and has an enormous impact on the well-being of American Veterans with 6,000 new stroke admissions every year. Many of these stroke survivors are living with disabilities that limit their everyday function. One of the major consequences of stroke is loss of sensation which manifests as inability to perceive touch, temperature, pain or limb movement. Lack of sensation hinders full functional recovery. Current treatments for sensory loss produce only limited improvements and do not achieve full recovery. Therefore, it is critical to develop new therapies to re-train sensory function. The investigators propose to evaluate a novel non-invasive brain stimulation treatment called repetitive Transcranial Magnetic Stimulation (rTMS). The effects of this technique on motor deficits following stroke have been studied, however rTMS for the treatment of sensory loss has not been examined to date. The investigators' study will examine for the first time if rTMS of a sensory brain region can improve sensory function in chronic stroke survivors.