Research advances on the mechanisms linking olfactory dysfunction to cognitive impairment in Alzheimer’s disease and related interventions

Olfactory dysfunction is a common sensory abnormality in the preclinical and early stages of Alzheimer’s disease (AD) and is closely associated with declines in memory, executive function, overall cognitive performance, and it may appear before overt cognitive symptoms. The olfactory system is closely interconnected with memory and emotional networks via the olfactory bulb, piriform cortex, entorhinal cortex, hippocampus, and orbitofrontal cortex. Studies have shown that β-amyloid (Aβ) deposition and tau pathology can affect the olfactory-medial temporal lobe network at an early stage. These pathologies interact with neurotransmitter imbalances, reduced synaptic plasticity, atrophy in relevant brain regions, and abnormalities in functional connectivity, leading to declines in olfactory discrimination, olfactory memory, and cognitive function. Olfactory-related interventions, such as aromatherapy, acupuncture, and moxibustion, may exert a neuroprotective effect by enhancing olfactory input, modulating the olfactory-cognitive network, and synergistically improving neuroinflammation, oxidative stress, pathological protein metabolism, and synaptic function. This article focuses on the mechanisms linking olfactory dysfunction to cognitive impairment in AD and summarizes research progress on the aforementioned intervention strategies. It aims to further elucidate the role of olfactory abnormalities in AD-related cognitive impairment and provide new insights for the early identification and clinical prevention and treatment of AD.