Inclusion Criteria1. History of ischemic stroke that occurred at least 4 months prior to enrollment, but not more than 24 months prior
2. Age >30 years and <80 years
3. Right or left sided weakness of upper extremity
4. UEFM score within designated range.
5. At least 10 degrees of wrist extension, 10° of thumb abduction/extension, and at least 10° of extension in at least 2 additional digits
Exclusion Criteria1. History of hemorrhagic stroke
2. Any deficits in language or cognitive functioning that hinders participation, for example, (aphasia) or unable to follow 2 step commands.
3. Significant sensory loss.
4. Presence of ongoing dysphagia or aspiration difficulties.
5. Active major neurological or psychiatric diagnosis that would likely interfere with study protocol including prior history of brain lesions (including dementia, etc.), and current alcohol abuse, drug abuse, or epilepsy.
6. Subject receiving any therapy (medication or otherwise) at study entry that would interfere with VNS (e.g. drugs that interfere with neurotransmitter mechanisms). Additionally, no psychoactive medications - including nicotine - may be used during the acute study.
7. Prior injury to vagus nerve - either bilateral or unilateral (e.g., injury during carotid endarterectomy)
8. Severe depression
9. Not considered candidate for a device implant surgery (history of adverse reactions to anesthetics, poor surgical candidate in surgeon's opinion, etc.)
10. Any other implanted device such as a pacemaker or other neurostimulator; any other investigational device or drug
11. Medical or mental instability (diagnosis of personality disorder, psychosis, or substance abuse)
12. Pregnant or plan on becoming pregnant or breastfeeding during the study period
13. Currently require, or likely to require, diathermy during the study duration
14. Any health problem requiring surveillance with MRI imaging
15. Active rehabilitation within 4-weeks prior to therapy
16. Botox injections or any other non-study active rehabilitation of the upper extremity 4-weeks prior to and during therapy
17. Severe spasticity of the upper limb