From a biologicalperspective, we propose that the optimization of cognitive function observed withHN in AD patients may be attributed to the following mechanisms: (1) Continuouscompanionship and emotional support may reduce the elevated cortisol levelsinduced by chronic stress, thereby reducing hippocampal neuronal damage.Improving patients’ psychological security may enhance synaptic plasticity andneuronal survival by activating the brain-derived neurotrophic factor (BDNF)signaling pathway. The gene discussed is BDNF; the disease is Alzheimer disease.