Status of Alzheimer's and Parkinson's Disease Detections and Treatments.

Alzheimer's disease and related dementias affect more than 55 million people worldwide, a number projected to double by 2050 as populations age. Beyond the devastating personal toll on patients and families, the global economic burden is estimated at approximately $1.3 trillion annually. Despite more than a century of research since the initial descriptions of Parkinson's disease (PD) in 1817 and Alzheimer's disease (AD) in 1906, the fundamental drivers of these disorders and effective strategies to prevent their progression remain poorly understood, despite billions of dollars invested in research. For decades, the accumulation and deposition of oligomeric amyloid-β and tau in AD, and α-synuclein in PD, have dominated conceptual frameworks guiding research and therapeutic development. This narrow focus may help explain why antiamyloid therapies have yielded only modest clinical benefits. Consequently, current drug development pipelines are increasingly moving beyond the amyloid cascade hypothesis and the singular emphasis on α-synuclein. Meanwhile, AD continues to be frequently misdiagnosed or diagnosed at advanced stages, often after irreversible neurodegeneration has already occurred. Encouragingly, the past decade has witnessed a major transformation in the early and accurate diagnosis of AD and PD, driven by the emergence of more affordable and precise diagnostic tools. Together, these advances suggest that an integrated framework combining molecular, digital, imaging, and genetic approaches may ultimately enable earlier diagnosis, personalized intervention, and more effective disease modification in AD and PD, raising the possibility of slowing disease progression before extensive brain damage develops.