Compared with the young people, the decrease of the physiological thyroid hormone level in the elderly after stroke may last longer resulting in dysfunction of the hypothalamic–pituitary-thyroid axis (HPT axis) which further aggravates cognitive impairment (Gkantzios et al., 2023; Lei et al., 2019; Murolo et al., 2022). The gene discussed is TG; the disease is Cognitive impairment.