Dementia and severe cognitive impairment are very closely linked to ageing . With the aging of the global population, the population of Alzheimer’s disease (AD) is expected to fourfold by 2050. The main neuropathological characteristics of the AD brain are extracellular neurotic plaques which is Aβ deposition and intracellular neurofibrillary tangles which is the hyper phosphorylated accumulation . These pathological changes are often accompanied by reactive microglial proliferation and loss of neurons and synapses. Cognitive decline, emotional, behavioural and sleep disorders, as well as restrictions on activities of daily living, often increase the burden on AD patients and their caregivers .
Efforts need to be made to improve the national dementia care system, strengthen the skills and knowledge training of medical personnel, and actively carry out global cooperation to prevent and treat the disease. Existing medical treatment for AD have limited effectiveness, expensive, and sometimes causing serious side effects. Therefore, alternative or complementary adjuvant treatment strategies, such as light therapy, transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), physical activity and intermittent hypoxic training (IHT) etc, have gained more and more attention. As a new noninvasive brain stimulation method, neuromodulation technology has attracted more and more attention in the treatment of AD cognitive impairment .