The symphony of cacophony Understanding the order in neurodegenerative diseases

Neurodegenerative diseases such as Alzheimer’s disease are notoriously heterogeneous; pathologically as well as in their clinical presentation in patients. There are differences between patients in terms of the pathways of progression, the speed of progression, and the effect the progression has on the patient’s cognition. This myriad of differences not only makes clinical diagnosis very challenging, but also has major implications for the efficacy of drug trials. As heterogeneous as these diseases are, there is an underlying order in their progression. An underlying method to their disruption of homeostasis. An underlying symphony leading to the cacophony.