CSF AND PLASMA BIOMARKERS FOR DIAGNOSING DEMENTIA IN OUTPATIENT CLINIC

Abstract

There is a great need for biomarkers that could diagnose Alzheimer’s disease (AD) early in the course of the disease. We accessed the usefulness of CSF and plasma biomarkers in outpatients. CSF Abeta40, Abeta42, total tau and plasma Abeta40, Abeta42 were measured in 239 outpatients attending the department of neurology at Hirosaki University hospital (37 AD, 14 MCI, 80 other dementia, 148 other neurological diseases, 12 normal controls). CSF Abeta40/42 ratio, CSF total tau, CSF AD index (CSF Abeta40/42 x CSF total tau), and plasma Abeta40/42 ratio were assessed. CSF Aß40/42 ratio, total tau, AD index were all increased significantly in AD and MCI patients. In AD patients, the specificity was around 82% in the all three indexes when the sensitivity was set at 90%. In AD patients, plasma Abeta40/Abeta42 ratio was significantly increased compared to normal control, however, the sensitivity and specificity was low. The specificity to diagnosis MCI was highest in CSF Abeta40/Abeta42, suggesting that the change of Abeta precedes that of tau. To predict the conversion of MCI to AD, CSF Abeta40/42 was useful. CSF Aß40/42, total tau, AD index were all useful for diagnosing AD. To diagnose MCI, CSF Abeta40/Abeta42 was useful.