Brain energy metabolism changes and neuropsychological impairment in Parkinson disease vs Alzheimer disease.

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative disorders, posing a significant public health risk. Although they are separate diseases, they have similar neuropsychological characteristics. Despite making up only a small portion of total body mass, the brain requires a disproportionately large amount of energy to maintain neuronal activity, synapse function, and cellular homeostasis. Disruption of energy metabolism is thus a major contributor to neurodegeneration. Energy metabolism has a wide-ranging impact on brain function, including cognitive and psychological processes, and gets increasingly compromised in neurodegenerative disorders. This chapter aims to offer a thorough overview of the link between altered brain energy metabolism and neuropsychological impairment in AD and PD.