Changes of cerebrospinal fluid Aβ42, t-tau, and p-tau in Parkinson's disease patients with cognitive impairment relative to those with normal cognition: a meta-analysis

Abstract

The cerebrospinal fluid (CSF) signature of reduced amyloid beta 1-42 (Aβ₄₂), elevated total tau (t-tau), and phosphorylated tau181 (p-tau) is important for the early diagnosis of Alzheimer's disease (AD). Aβ₄₂, t-tau, and p-tau have been reported in numerous studies to contribute to predicting cognitive impairment in Parkinson's disease (PDCI). However, no consistent conclusion can be drawn so far. Literatures regarding Aβ₄₂, t-tau, and p-tau in CSF were systematically reviewed, and a meta-analysis was thus performed to evaluate the changes of these biomarkers in PDCI patients, including PD with mild cognitive impairment (PDMCI) and PD dementia (PDD) patients, relative to PD with normal cognition (PDNC) patients. Databases of "PubMed," "EBSCO," and "Springer" were retrieved for articles concerning Aβ₄₂, t-tau, and p-tau in PDCI patients relative to those in PDNC patients published from January 1, 2000 to February 1, 2017. The following keywords were set, namely, "dementia" or "cognitive impairment" or "mild cognitive impairment" and "cerebrospinal fluid" and "Parkinson*." Sixteen articles comprising 590 PDCI patients and 1182 PDNC patients were included. The results showed that CSF Aβ₄₂ level in PDCI cohort was lower than that in PDNC cohort (pooled Std.MD = -0.44, 95% CI [-0.61, -0.26], p < 0.00001). Reduced Aβ₄₂ (pooled Std.MD = -0.60, 95% CI [-0.75, -0.45], p < 0.00001) as well as elevated t-tau (pooled Std.MD = 0.21, 95% CI [0.06, 0.35], p = 0.006) and p-tau (pooled Std.MD = 0.36, 95% CI [0.02, 0.69], p = 0.04) could be observed in PDD cohort compared with PDNC cohort. Therefore, amyloid pathology and tauopathy may participate in the development of PDD, which is similar to AD.

Keywords: Cerebrospinal fluid; Dementia; Meta-analysis; Mild cognitive impairment; Parkinson’s disease.