Clinical Trials

Inclusion Criteria:

1. History of unilateral supratentorial ischemic stroke that occurred at least 9 months but not more than ten 10 years prior to enrollment.
2. Age >22 years and <80 years.
3. FMA-UE score of 20 to 50 (inclusive of 20 and 50).
4. Ability to communicate, understand, and give appropriate consent. Subjects should be able to follow two-step commands.
5. Right- or left-sided weakness of upper extremity.
6. Active wrist flexion/extension; active abduction/extension of thumb and at least two additional digits.

Exclusion Criteria:

1. History of hemorrhagic stroke
2. Presence of ongoing dysphagia or aspiration difficulties.
3. Subject receiving medication that may significantly interfere with the actions of VNS on neurotransmitter systems at study entry. A list of excluded medications will be provided to Investigators.
4. Prior injury to vagus nerve, either bilateral or unilateral (e.g., injury during carotid endarterectomy).
5. Severe or worse depression (Beck Depression Scale > 29) (Beck et al., 1961)
6. Unfavorable candidacy for device implant surgery (e.g., history of adverse reactions to anesthetics, poor surgical candidate in surgeon's opinion, etc.)
7. Current use of any other stimulation device, such as a pacemaker or other neurostimulator; current use of any other investigational device or drug.
8. Medical or mental instability (diagnosis of personality disorder, psychosis, or substance abuse) that would prevent subject from meeting protocol timeline.
9. Pregnancy or plans to become pregnant or to breastfeed during the study period.
10. Current requirement, or likely future requirement, of diathermy during the study duration.
11. Active rehabilitation within 4 weeks prior to consent.
12. Botox injections or any other non-study active rehabilitation of the upper extremity within 4 weeks prior to therapy through the post-30 day visit (Visit 6).
13. Severe spasticity of the upper limb (Modified Ashworth ≥3) (Bohannon and Smith, 1987).
14. Significant sensory loss. Sensory loss will be measured using the Upper Extremity sensory section of the Fugl Meyer Assessment of Physical Performance. The assessment addresses light touch (2 items) and proprioception (4 items).The highest points attained is 12; subjects with scores less than 6 will be excluded from the study.