ZEPU-SGI1PLUS Hand Training Study (ZEPUSGI1RCT)

Inclusion Criteria: * Presence of upper-limb motor dysfunction, with or without concurrent lower-limb impairment, due to one of the following conditions: (a) stroke, with onset between 2 and 24 months prior to enrollment; (b) incomplete spinal cord injury (neurological level C5 and below), classified as ASIA Impairment Scale C or D; (c) traumatic brain injury with persistent upper-limb functional limitation; or (d) orthopedic or post-surgical conditions involving the shoulder, elbow, wrist, or hand with persistent functional impairment for \> 3 months * Age between 18 and 60 years, inclusive * Ability to understand study procedures and follow instructions, and to provide written informed consent (or assent with guardian consent where applicable) * Body weight and limb anthropometry compatible with the ZEPU-SG1PLUS Hand Functional Comprehensive Training System per manufacturer specifications * Medically stable and cleared by a physician for robotic rehabilitation, with no active infection, uncontrolled cardiac or respiratory disease, severe osteoporosis, uncontrolled epilepsy, or untreated deep vein thrombosis Exclusion Criteria: * Complete spinal cord injury or profound motor paralysis preventing safe interaction with robotic devices * Severe cognitive impairment, defined as a Mini-Mental State Examination (MMSE) score \< 24, that would compromise safe participation * Severe spasticity of the upper limb, defined as a Modified Ashworth Scale score \> 3 * Unstable fractures, severe fixed joint contractures of the shoulder, elbow, wrist, or hand (e.g., \> 30°), or severe pain limiting safe robotic training * Uncontrolled cardiac arrhythmia, presence of a pacemaker, or other implanted electronic medical device incompatible with robotic sensors * Pregnancy