Clinical and biochemical markers of neurodegenerative process in Alzheimer's disease

Abstract

Recently, numerous studies have been devoted to describing the heterogeneity of Alzheimer's disease (AD). The aim of our work was to study the clinical, biochemical, and neuropsychological signs of AD depending on the form of the disease. The study involved 173 patients with AD, of whom 65 patients with early onset and 108 with late onset at the stage of moderate cognitive impairment. All study participants underwent the Montreal Cognitive Assessment Scale (MoCA test), the Free and Cued Selective Reminding Test with Immediate Recall (FCSRT-IR), and a lumbar puncture with the determination of the levels of Aβ42 and Aβ40 biomarkers in the cerebrospinal fluid by enzyme immunoassay. The mean age of the patients with early onset of AD was 65.1±0.3 years, and with late onset - 78.6±0.5 years. According to our data, it was found that the majority of the patients with late-onset AD had a longer education (p=0.000) and had coffee more often (p=0.000) than the study participants with early onset of AD. We did not reveal the effect of alcohol and smoking on the neurodegenerative process. The patients with early-onset AD scored lower on the MoCA test than those with late-onset AD (p=0.000). The results of free recall and cue index on the FCSRT-IR test in the patients with late AD were significantly lower than in the patients with early AD onset (p<0.001). We found that the level of Aβ42 and the ratio of Aβ42/Aβ40 in the cerebrospinal fluid was significantly lower (p=0.000) in the patients with early AD onset. The results of our study prove the need for an integrated approach to diagnosing AD using clinical, neuropsychological,and biochemical research methods.