Enhancing Diagnostic Accuracy of aMCI in the Elderly: Combination of Olfactory Test, Pupillary Response Test, BDNF Plasma Level, and APOE Genotype

Abstract

Background. Amnestic Mild Cognitive Impairment (aMCI) often progresses to Alzheimer's disease. There are clinical markers and biomarkers to identify the degenerative process in the brain. Objectives. To obtain the diagnostic values of olfactory test, pupillary response to tropicamide 0.01%, BDNF plasma level, and APOE ε4 in diagnosing aMCI. Methods. Cross-sectional, comparative analysis. Results. There were 109 subjects enrolled (aMCI: 51, normal cognition: 58) with age 64 ± 5.54 years. For diagnosing aMCI, cut-off point for the olfactory score was <7 out of 10 and >22% for pupil dilatation response. Low BDNF plasma level was related significantly with olfactory deficits and aMCI (P < 0.05). Four of five subjects with homozygote e4 presented with multiple-domain aMCI. This group displayed the lowest means of olfactory score and the highest means of pupillary hypersensitivity response (P < 0.0001). Combination of olfactory deficit and pupillary hypersensitivity response in detection of aMCI was beneficial with Sp 91% and PPV 87%. In conjunction with clinical markers, BDNF plasma level and presence of APOE e4+ improved Sp and PPV. Conclusions. Combination of olfactory test and pupillary response test was useful as diagnostic tool in aMCI. In conjunction with clinical markers, low level of BDNF plasma and presence of APOE e4 improved the diagnostic value.

Identification of Neuroprotective Factors Associated with Successful Ageing and Risk of Cognitive Impairment among Malaysia Older Adults

“…Higher plasma BDNF level was significantly associated with reduced risk of MCI in this study. Our finding is consistent with studies by Shimada et al [ 23 ] and Turana et al [ 24 ]. Generally, decreased BDNF levels in MCI may contribute to the development of neurodegenerative diseases such as dementia and Alzheimer's disease.…”

Amyloid beta soluble forms and plasminogen activation system in Alzheimer’s disease: Consequences on extracellular maturation of brain‐derived neurotrophic factor and therapeutic implications

“…These data suggest that the conversion from the pro‐BDNF to the mature BDNF is an important process that regulates hippocampal activity and memory processes. Thus, alteration of the BDNF/pro‐BDNF rate of conversion may have relevance to several brain pathologies, including neurodegenerative disorders such as AD …”

“…Thus, alteration of the BDNF/pro-BDNF rate of conversion may have relevance to several brain pathologies, including neurodegenerative disorders such as AD. [84][85][86]…”

Exercise-induced neuroprotective effects on neurodegenerative diseases: the key role of trophic factors

“…Plasma or serum BDNF levels decline with age and its decrease correlates with reduced hippocampal volume and poor cognitive performance [65][66][67]. Reduced brain and peripheral expression of BDNF has also been described in patients with MCI [68][69][70]. Moreover, Forlenza and colleagues described that reduced BDNF levels in the cerebral spinal fluid [CSF] are associated with progression from MCI to AD [71].…”