Associative Peripheral Stimulation (APS) is a non-invasive therapy intended for stroke rehabilitation involving transcutaneous electrical muscle stimulation paired with voluntary movement. This pilot study investigates whether APS applied during the acute phase of stroke recovery may reduce impairment and improve function in the affected upper extremity.

Inclusion Criteria:

1. Confirmed ischemic or hemorrhagic stroke no earlier than 7 days prior to enrollment;
2. Presentation of hemiparesis or paralysis of the upper extremity due to stroke;
3. Ability to comprehend and follow study instructions;
4. Ability to initiate finger extension (≥3°) at least three times per minute;
5. Fugl-Meyer Assessment (Upper Extremity) score of <47.

Exclusion Criteria:

1. Contraindications, intolerance, or high sensitivity to the experimental protocol;
2. History of upper-extremity disability prior to the index stroke;
3. Neurological conditions (other than stroke) affecting motor function;
4. Treatment of spasticity/increased tone in the affected upper extremity (e.g., with Botox injection);
5. Lack of access to a safe and suitable place of discharge for experimental sessions and follow-up visits.

Individual participant data shall not be made available to other researchers.