Inclusion Criteria- Clinical diagnosis of stroke and radiographically proven ischemic or hemorrhagic stroke (MRI required for ischemic stroke, CT sufficient for hemorrhagic stroke).
- Subject reports a decline in attention or short-term memory that began at the time of their stroke.
- Stroke occurred at least one month prior to first stimulation session.
- Ability to provide informed consent.
- Speak English (required for performing the cognitive tests)
Exclusion Criteria- Any other brain disease that can affect cognition (e.g., multiple sclerosis, dementia).
- Active mental illness such as depression or anxiety
- Large stroke involving cortex under the stimulation site (using subject provided CT or MRI).
- Currently taking any drugs that are sodium and/or calcium channel blockers not including amlodipine. This includes some seizure medications along with nicardipine, nifedipine, nimodipine, verapamil and diltiazem.
- Any history of epilepsy.
- Subject report of recent drug or alcohol abuse - within the past year.
- Subject report of pregnant or breastfeeding.
- Moderate to severe aphasia preventing subject from communicating fully.
- Any pacemakers, intracranial electrodes, implanted defibrillators, or any other electrical implants.