Cerebrospinal fluid tau, phospho‐tau 181 and β ‐amyloid 1−42 in idiopathic normal pressure hydrocephalus: a discrimination from Alzheimer's disease

• Published in: European journal of neurology Vol. 14; no. 2; pp. 168 - 173
• Main Authors: Kapaki, E. N., Paraskevas, G. P., Tzerakis, N. G., Sfagos, C., Seretis, A., Kararizou, E., Vassilopoulos, D.
• Format: Journal Article
• Language: English
• Published: 01-02-2007
• ISSN: 1351-5101; 1468-1331
• DOI: 10.1111/j.1468-1331.2006.01593.x

The aim of the present study was the quantitation of total tau protein (
τ
T
), tau phosphorylated at threonine 181 (
τ
P‐181
) and
β
‐amyloid
1−42
(A
β
42) in the cerebrospinal fluid (CSF) of patients with idiopathic normal pressure hydrocephalus (iNPH), Alzheimer's disease (AD) and controls. Double sandwich ELISAs (Innogenetics) were used for the measurements. Total tau was significantly increased in iNPH and highly increased in AD as compared with the control group, whilst A
β
42 was decreased in both diseases. CSF
τ
P−181
levels were significantly increased only in AD, but not in iNPH as compared with the controls. A cut‐off level for
τ
T
at 300 pg/ml, successfully discriminated AD from normal aging with a 95.8% specificity and 91% sensitivity; whilst the
τ
P‐181
/
τ
T
ratio (cut‐off value 0.169) was more specific (100%) but less sensitive (92.5%). For the discrimination of iNPH from AD
τ
T
achieved low specificity (77.8%) but high sensitivity (92.5%), whilst
τ
P‐181
(cut‐off value 47.4) was both sensitive and specific (88.7% and 86.7% respectively) for the discrimination of these disorders. The present study, despite being clinical, supports the notion that CSF
τ
P‐181
alone or in combination with
τ
T
may be a useful marker in the discrimination of iNPH from AD.