Harvard researchers think they have found the order in which protein pathology occurs in Alzheimer’s disease, with tau protein appearing to be the most closely connected with mild cognitive impairment.

They suggest that sequential use of the new PET technology that can show tau protein neurofibrillary tangles in the brain may eventually become standard to track disease progression.

However, writing in JAMA Neurology, they caution that their results are based on findings in just a handful of patients and need to be replicated.

The researchers analysed PET data on 60 clinically normal men and women (median age 73) who participated in the Harvard Aging Brain Study. Participants underwent a median of three amyloid-beta scans between 2010 and 2017, and two tau scans between 2013 and 2017.