Motor and Neurophysiological Changes After Ischemic Conditioning in Individuals With Stroke

Motor and Neurophysiological Changes After Ischemic Conditioning in Individuals With Stroke

The goal of this clinical trial is to test ischemic conditioning (blood flow restriction) as a neuromodulatory technique to improve gait function in stroke. Neuromodulation is emerging as a promising adjunct strategy to facilitate changes in brain activity and improve motor behavior following a neurological injury such as stroke.

The main questions this trial aims to answer are:

• Can ischemic conditioning produce neuromodulatory changes in the lower limb primary motor cortex?
• Can ischemic conditioning be used as a neuromodulatory technique to improve strength and motor control in individuals with stroke when compared to sham ischemic conditioning?

Participants will take part in two sessions of ischemic conditioning where a cuff (similar to ones that measure blood pressure) will be placed around the thigh and inflated to one of two blood flow restriction pressures (real ischemic conditioning (real IC) and sham ischemic conditioning (sham IC)). Each participant will experience measures of brain activity and motor behavior testing before and after both sessions (real IC and sham IC).

Researchers will investigate ischemic conditioning as neuromodulation modality in stroke to see if ischemic conditioning can produce beneficial changes in brain activity and improvements on subsequent motor behavior tasks.

Inclusion Criteria:

• Single, stroke > 6 months since onset
• Residual hemiparetic gait deficits (e.g., abnormal gait pattern)

Exclusion Criteria:

• Lesions affecting the brainstem or cerebellum
• Other neurological disorders that may interfere with motor function
• Unhealed decubiti, persistent infections that may interfere with ability to perform test procedures
• Significant cognitive or communication impairment (Mini-Mental State Examination (MMSE<21)), which could impede the understanding of the purpose of procedures of the study
• Botulinum toxin (Botox) treatments to the lower limb within the past 6 months
• Pregnant women
• Contraindications to transcranial magnetic stimulation (TMS) or ischemic conditioning (IC) (Listed below)

TMS General Exclusion Criteria:

• Previous adverse reaction to TMS
• Skull abnormalities or fractures
• Concussion within the last 6 months
• Unexplained, recurring headaches
• Implanted cardiac pacemaker
• Metal implants in the head or face
• History of seizures or epilepsy
• Use of medications that could alter cortical excitability or increase risk of seizure (e.g., antidepressants, antipsychotics, anxiolytics, anticonvulsants)
• Current pregnancy

IC General Exclusion Criteria:

• History of thrombosis (i.e., blood clots) including venous thrombosis or deep vein thrombosis (DVT).
• Blood clots in the leg, or any condition in which compression of the thigh or transient ischemia is contraindicated (i.e., open wounds in the leg, bruising, nerve damage, etc.)
• Peripheral arterial grafts in the lower extremity
• History of uncontrolled hypertension
• History of peripheral vascular disease or hematological disease