tVNS Responsiveness Testing With Pupil Size

Prior treatment

• Have an implanted device such as a neurostimulator or cochlear implant
• Had a head injury or brain surgery
• Have any metal in the head such as shrapnel, surgical clips, or fragments from welding or metal work
• Have any implanted devices such as a neurostimulator or cochlear implant
• A first stroke less than 4 months prior to the participation
• Have any metal in the head such as shrapnel, surgical clips, or fragments from welding or metal work

Other illness

• Current or history of cardiac disease
• Current or history of tympanic membrane perforation
• Had a stroke or lesion (including tumor) in your brain
• Have any implanted device such as cardiac pacemakers, medical pumps, or intra-cardiac lines
• Had any brain-related conditions (i.e. multiple sclerosis, Parkinson, Alzheimer)
• Had any illness that caused brain injury (i.e. meningitis, aneurysm, brain tumor)
• Being treated for any psychiatric condition (i.e. depression, anxiety, PTSD, schizophrenia)
• Suspected of pregnancy
  • Post-stroke subjects:
• Current or history of cardiac disease
• Current or history of tympanic membrane perforation
• Serious uncontrolled medical conditions
• Have any implanted device such as cardiac pacemakers, medical pumps, or intra-cardiac lines
• Had any illness that caused brain injury (i.e. meningitis, aneurysm, brain tumor)
• Being treated for any psychiatric condition (i.e. depression, anxiety, PTSD, schizophrenia)

Age

• Younger than 18 years old or older than 89 years old
• Younger than 18 years old or older than 89 years old

Other

• Able-bodied subjects:
• Have a vision problem not corrected by glasses or contact lenses
• Suffer from frequent or severe headaches
• Had a fainting spell or syncope
• Had any head trauma that was associated with a loss of consciousness or diagnosed as a concussion
• Have a vision problem not corrected by glasses or contact lenses
• No persistent hemiparesis on the upper extremity (UE)
• No residual UE voluntary movement
• Excessive pain in any joint of the more affected extremity
• Unable to stand independently for 2 min., transfer independently to and from the toilet or perform sit-to-stand
• Suffer from frequent or severe headaches
• Had a fainting spell or syncope
• Had any head trauma that was associated with a loss of consciousness or diagnosed as a concussion
• Suspected of pregnancy
• A score of less than 24 on the Folstein Mini-Mental State Examination
• Excessive frailty or lack of stamina (e.g., cannot attend to instructions, stay awake, engage in functional activities, etc.)
• Excessive pain in any joint of the more affected extremity that could limit ability to cooperate with the intervention

• 18-89 years old across all races, genders, and ethnicities.
• Post-stroke subjects will have persistent hemiparesis on the upper extremity (UE) with some residual UE voluntary movement.