Brain degeneration in patients with Alzheimer’s disease (AD) results from the accumulation of pathological amyloid-β (Aβ) plaques and tau protein tangles, leading to altered plasma levels of biomarkers. However, few studies have investigated the association between plasma biomarkers and cognitive impairment in patients with AD. In this cross-sectional study, we investigated correlations between mini-mental state examination (MMSE) scores and levels of plasma biomarkers in patients with amnestic mild cognitive impairment (aMCI) and AD. Thirteen individuals with normal cognition, 40 patients with aMCI, and 37 patients with AD were enrolled. Immunomagnetic reduction was used to assess the levels of plasma biomarkers, including amyloid Aβ_1-40, Aβ_1-42, total tau protein (t-Tau), and phosphorylated tau protein (threonine 181, p-Tau181). Our analysis revealed a significant negative correlation between MMSE and both measures of tau, and a trend toward negative correlation between MMSE and Aβ_1-42. In a longitudinal study involving three patients with aMCI and two patients with AD, we observed strong negative correlations (r < −0.8) between changes in MMSE scores and plasma levels of t-Tau. Our results suggest that plasma levels of t-Tau and p-Tau181 can be used to assess the severity of cognitive impairment in patients with AD. Furthermore, the results of our preliminary longitudinal study suggest that levels of t-Tau can be used to monitor the progression of cognitive decline in patients with aMCI/AD.

Headache such as migraine is associated with stroke. Studies focused on primary headache disorders (PHDs) as a risk factor for stroke are limited. The purpose of this population-based cohort study was to explore whether patients with PHDs were at a high risk for developing stroke. A total of 1346 patients with PHDs were enrolled and compared with 5384 age-, gender- and co-morbidity-matched control cohorts. International Classification of Diseases, Clinical Modification codes were administered for the definition of PHDs, stroke, and stroke risk factors. Cox proportional-hazards regressions were performed for investigating hazard ratios (HR). PHDs patients exhibited a 1.49 times (95% CI :1.15–1.98, p < 0.01) higher risk for developing ischaemic stroke compared with that of control cohorts. Both migraine (HR = 1.22, 95% CI :1.13–1.97, p < 0.05) and tension-type headache (HR = 2.29, 95% CI :1.22–2.80, p < 0.01) were associated with an increased risk of ischemic stroke. Females with PHDs were at greater risk of developing ischaemic stroke (HR = 1.49, 95% CI :1.13–1.90, p < 0.01) than those without PHDs. PHDs patient aged 45 to 64 years displayed significantly higher risk to develop ischaemic stroke (HR = 1.50, 95% CI: 1.11–2.10, p < 0.05) than the matched controls. The impact of PHDs on ischaemic stroke risk became gradually apparent by different following time intervals beyond 2 years after first diagnosis. PHDs is suggestive of an incremental risk for ischaemic stroke with gender-dependent, age-specific and time-dependent characteristics.