Inclusion Criteria:  Primary diagnosis of stroke Less than one-month post-stroke Hemiparesis of one upper extremity Moderate upper extremity impairment  Exclusion Criteria:  History of prior stroke Comorbidities (severe neurological, orthopedic, rheumatoid, or cardiac impairments) Severe spasticity Severe cognitive impairments Inability to perform mental imagery Severe aphasia based on speech therapist evaluation Low English proficiency Severe pain