Alzheimer’s disease and mild cognitive impairment biomarkers: Alzheimer’s disease (AD) is a progressive neurodegenerative disease of advancing age. It affects around 47 million people in the world and the number is estimated to increase to 152 million by 2050. Someone develops dementia every three seconds and the current annual cost of dementia is estimated at US $1 trillion, a figure set to double by 2030 (Alzheimer’s Disease International, 2019).