Can we Train Patients With Chronic Stroke Out of Abnormal Hand Synergy?

Training and Non-Invasive Brain Stimulation in Chronic Stroke Reduce Abnormal Hand Synergy

This study plans to determine whether training can change abnormal flexion synergy in chronic stroke patients.

The aim of the current study is to investigate whether motor training in chronic stroke patients can change their abnormal flexion synergy. The investigators will study chronic stroke patients , who are defined as patients that sustained a stroke at least 6 months prior to our testing date.

Three functional aspects of each finger will be tested: maximal voluntary contraction (MVC), finger dexterity, and hand posture.

Prior to intervention, participants will have a baseline assessment including clinical tests, MVC, the individuation task, and the configuration task. Following the baseline assessment patients will receive intervention, training on the configuration task for 5 consecutive days. On the sixth day and as a one week follow-up after, subjects will have a post-intervention assessment containing the same tests performed in baseline.

This design will allow us to determine speed and accuracy during the configuration task, the individuation index, and possible changes in abnormal flexion synergy.

We initially registered the study as two arms (anodal tDCS and sham tDCS groups) but decided to make it one arm due to the number of participants we were able to recruit.

Inclusion Criteria:

• Age 21 and older
• Ischemic stroke greater than six months ago, confirmed by CT or MRI
• Residuals unilateral upper extremity weakness
• Ability to give informed consent and understand the tasks involved.
• Appearance of Flexion synergy in hand.
• Ability to extent finger at least for 5 degrees.

Exclusion Criteria:

• Cognitive impairment, with score on Montreal Cognitive assessment (MoCA) ≤ 20
• History of physical or neurological condition that interferes with study procedures or assessment of motor function (e.g. severe arthritis, severe neuropathy, Parkinson's disease)
• Contraindication to tDCS (deep brain stimulators or other metal in the head, skull defect, pacemaker)
• Inability to sit in a chair and perform upper limb exercises for one hour at a time
• Participation in another upper extremity rehabilitative therapy study or tDCS study during the study period
• Terminal illness
• Social and/or personal circumstances that interfere with ability to return for therapy sessions and follow up assessments
• Pregnancy
• Severe Neglect