Affiliations: [a] School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX, USA
| [b] Department of Bioengineering, Erik Jonsson School of Engineering and Computer Science, University of Texas at Dallas, Richardson, TX, USA
| [c] Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Western Infirmary, Glasgow, UK
| [d] Texas Biomedical Device Center, Richardson, TX, USA
Correspondence:
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Address for correspondence: Michael Kilgard, PhD, School of Behavioral and Brain Sciences, University of Texas at Dallas, BSB14, 800 West Campbell Road, Richardson, TX, USA. Tel.: +1 972 883 2339; Fax: +1 972 883 2491; E-mail: kilgard@utdallas.edu.
Abstract: BACKGROUND:Recent studies indicate that vagus nerve stimulation (VNS) paired with rehabilitation can enhance neural plasticity in the primary sensory and motor cortices, improve forelimb function after stroke in animal models and improve motor function in patients with arm weakness after stroke. OBJECTIVE:To gain “first-in-man” experience of VNS paired with tactile training in a patient with severe sensory impairment after stroke. METHODS:During the long-term follow-up phase of a clinical trial of VNS paired with motor rehabilitation, a 71-year-old man who had made good motor recovery had ongoing severe sensory loss in his left hand and arm. He received VNS paired with tactile therapy in an attempt to improve his sensory function. During twenty 2-hour sessions, each passive and active tactile event was paired with a 0.5 second burst of 0.8 mA VNS. Sensory function was measured before, halfway through, and after this therapy. RESULTS:The patient did not report any side effects during or following VNS+Tactile therapy. Quantitative measures revealed lasting and clinically meaningful improvements in tactile threshold, proprioception, and stereognosis. After VNS+Tactile therapy, the patient was able to detect tactile stimulation to his affected hand that was eight times less intense, identify the joint position of his fingers in the affected hand three times more often, and identify everyday objects using his affected hand seven times more often, compared to baseline. CONCLUSIONS:Sensory function significantly improved in this man following VNS paired with tactile stimulation. This approach merits further study in controlled clinical trials.
Keywords: Vagal nerve stimulation, neuromodulation, neuroplasticity, motor function, upper extremity
