Introduction: Studies with cerebrospinal fluid (CSF) biomarkers in patients with confirmed Alzheimer's disease (AD) pathology have shown that decreased levels of Abeta(1-42) and increased levels of tau and p-tau, are a specific feature of the AD type pathology.
Aim: To describe a new method for determining the AD-CSF-Index, through the values obtained with CSF biomarkers and thus optimize AD diagnosis.
Subjects and methods: We recruited a total of 61 subjects in the Alzheimer's unit and other cognitive disorders of the Hospital Clinic of Barcelona, of which 42 were cognitively healthy controls and 19 were diagnosed with AD according to the new research criteria proposed by Dubois et al: episodic memory impairment and atrophy of medial temporal areas using the Scheltens scale. The AD-CSF-Index was constructed from the addition of normalized values between the minimum and maximum values of amyloid and tau proteins.
Results: Subjects diagnosed with AD presented a significantly higher AD-CSF-Index (1.17) than healthy subjects (0.72) (p < 0.001; 95% CI of the difference = 0.32-0.57). In the ROC analysis, the AD-CSF-Index obtained the best results of all, showing the cut-off point of 0.93 a sensitivity of 92% and a specificity of 89%.
Conclusion: The AD-CSF-Index represents a novel approach that combines optimally the observed CSF biomarkers alterations, which allows establishing the diagnosis of AD with high sensitivity and specificity.