HBD and Stroke: By collecting resting-state fNIRS data from admitted patients and subsequently identifying the three key data points—HbD levels in the affected temporal region, HbT levels in the total region, and HbT levels in the unaffected frontopolar region—clinicians can more accurately and objectively differentiate stroke patients with upper limb motor dysfunction at different levels, formulate personalized diagnosis and rehabilitation plans, and potentially improve patients’ long-term outcomes.