[A version of this item appears in: Dementia: the Latest Evidence Newsletter (RWHT), Volume 2 Issue 7, February 2012].
Summary
People at risk of developing Alzheimer’s Disease (AD) could be pre-diagnosed ten years before the disease becomes manifest, according to a study published in the Archives of General Psychiatry. This has significance, because early detection of Alzheimer Disease (AD) might one day allow disease-modifying therapies to be initiated early on.
The research at Lund University (Sweden) involved 140 people with Mild Cognitive Impairment (MCI). The spinal fluid of participants involved in the clinical trial was tested for levels of the proteins found in people with AD. This study investigated the potential of cerebrospinal fluid (CSF) biomarkers for total tau (T-tau), phosphorylated tau (P-tau), and β-amyloid 1-42 (Aβ42) to predict the future onset of AD dementia in patients with mild cognitive impairment (MCI). It also compared these CSF biomarkers between early and late converters to AD.
During follow-up over 9 years, 53.7% patients developed AD and 15.7% developed other forms of dementia. CSF Aβ42 levels were reduced and T-tau and P-tau levels were elevated in patients who developed AD. CSF Aβ42 levels were reduced equally in patients with MCI who developed AD within 0 to 5 years (the “early converters”) compared with those who developed AD between 5 and 10 years (the “late converters”). CSF T-tau and P-tau levels were significantly higher in the early converters than the late converters.
“Aβ42:P-tau ratio predicted the development of AD within 9.2 years with a sensitivity of 88%, specificity of 90%, positive predictive value of 91%, and negative predictive value of 86%”.
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Reference
Buchhave, P. Minthon, L. [and] Zetterberg, H. [et al] (2012). Cerebrospinal Fluid Levels of β-Amyloid 1-42, but Not of Tau, Are Fully Changed Already 5 to 10 Years Before the Onset of Alzheimer Dementia. Archives of General Psychiatry, January 2012, Vol.69(1), pp.98-106. (Click here to view the PubMed abstract).
