Receive email when new articles are published onA study spanning 20 years helps nail down the timing of biomarker changes that occur in the period between normal cognition and a diagnosis of sporadic, something that hasn't previously been extensively investigated in longitudinal studies.
The level of p-tau181 in CSF increased 11 years before disease onset, and NfL levels, a measure of neurodegeneration, increased 9 years before diagnosis.The results also show "an apparent accelerated change in concentrations of CSF biomarkers followed by a slowing of this change up to the time of diagnosis," report the authors, led by Jianping Jia, MD, PhD, with the Innovation Center for Neurological Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China.
In terms of CSF Aβ42, the level of this biomarker in those who developed AD diverged from the level in controls an estimated 18 years before clinical diagnosis. At that time, the level was lower by a mean 59.13 pg/mL in the AD group. In terms of NfL, a difference between the groups was observed 9 years before diagnosis, with its trajectory progressively deviating from the concentrations observed in cognitively normal groups at that time, to a final mean difference in NfL of 228.29 pg/mL.
Mayeux acknowledged that one might consider the finding in this study to be limited owing to the inclusion of only individuals of Han Chinese ancestry.