Sound and Alzheimer's Disease-From Harmful Noise to Beneficial Soundscape Augmentation and Music Therapy.

Exposure to sound energy may be a risk factor or a therapeutic intervention for Alzheimer's disease (AD). On one hand, noise has a harmful effect on people with AD by contributing to hearing loss, sleep disturbance, oxidative stress, inflammation, and excitotoxicity. But on the other hand, clinical trials and nursing home interventions with soundscape augmentation involving natural sounds have shown promising results in alleviating psychophysiological symptoms in people with AD. Music therapy, an emerging non-pharmacological treatment, can improve cognition, reduce anxiety and depression, and enhance self-awareness in patients with AD. To ensure that music does not become noise in clinical trials, only favorite music at levels safe for hearing should be used. From a public health standpoint, noise countermeasures, soundscape augmentation with natural sounds, and active or passive engagement with music may be regarded as potentially powerful strategies for the prevention of AD.