Carphology

The authors of this Nature paper add another layer of complexity to the idea that pathology and disease can be used interchangeably. In a large population-based cohort using plasma p-tau217 they identified that about a third of people aged >70 have neuropathological changes of Alzheimer’s disease, while nearly a quarter of those with these changes are cognitively unimpaired. Dementia, reassuringly, remains far less common. The study is a breakthrough in scalable biomarker research and illustrates that identifying pathology is not equivalent to making a diagnosis. As blood biomarkers are increasingly integrated into clinical practice, neurologists may soon find themselves explaining that a positive result means “something”, just not necessarily something actionable.