The relationship between beta‐amyloid accumulation and P3 event‐related potential in older adults: A pilot study

SummaryAlthough beta-amyloid, anxiety and depression have been linked cross-sectionally to reduced memory function in healthy older adults without dementia, prospective data evaluating these associations are lacking. Using data from an observational cohort study of 178 healthy older adults without dementia followed for 3 years, we found that anxiety symptoms significantly moderated the relationship between beta-amyloid level and decline in verbal (Cohen's d = 0.65) and episodic (Cohen's d = 0.38) memory. Anxiety symptoms were additionally linked to greater decline in executive function, irrespective of beta-amyloid and other risk factors. These findings suggest that interventions to mitigate anxiety symptoms may help delay memory decline in otherwise healthy older adults with elevated beta-amyloid.

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Hyperexcitability in Older Adults with Elevated Beta-Amyloid

10.21203/rs.3.rs-723001/v1 ◽

2021 ◽

Author(s):

Hannes Devos ◽

Kathleen Gustafson ◽

Ke Liao ◽

Pedram Ahmadnezhad ◽

Bradley Estes ◽

...

Keyword(s):

Older Adults ◽

Neuronal Excitability ◽

Memory Task ◽

Beta Amyloid ◽

Standard Uptake Value ◽

Event Related Potential ◽

Peak Latency ◽

Peak Amplitude ◽

Alpha Power ◽

Task Difference

Abstract Background: Growing evidence links beta-amyloid (Aβ) and neuronal hyperexcitability in preclinical mouse models of Alzheimer’s disease (AD). The aim of this study was to compare neuronal excitability between cognitively normal amyloid positive (CNAβ+) and those without elevated amyloid (CNAβ-) older adults. We hypothesized CNAβ+ participants would show hyperexcitability, indexed by greater peak P3 event-related potential peak amplitude, shorter peak latency, and changes in event-related power, compared to CNAβ-.Methods: CNAβ+ participants (n = 17, age: 73 ± 5, 11 women, MOCA scores 26 ± 2) and 17 CNAβ- participants group-matched for age, sex, and MOCA completed the a working memory task (n-back with n = 0, 1, 2) test while wearing a 256-channel EEG net. P3 peak amplitude and latency of the nontarget, target and task difference (nontarget – target), and event-related power, extracted from Fz (main outcome), Cz, and Pz were compared between groups using linear mixed models. Mean Aβ standard uptake value ratios (SUVR) were correlated with P3 amplitude and latency using Pearson r.Results: P3 peak amplitude of the task difference (p = 0.048) and P3 peak latency of non-targets trials (p = 0.006) at Fz differed between groups. Similarly, power was lower in the delta band (p = 0.04) for nontargets at Fz in CNAβ+ participants. CNAβ+ participants also demonstrated higher theta and alpha power in channels at Cz and Pz, but no changes in P3 ERP. Strong correlations were found between mean Aβ SUVR and latency of the 1-back (r = -0.69; p = 0.003) and 2-back (r = -0.69; p = 0.004) of the task difference at channel Fz in the CNAβ+ group.Conclusions: Our pilot data suggests that elevated amyloid in cognitive normal older adults is associated with hyperexcitability in P3 ERP. Further research is warranted to determine the validity of ERP in predicting clinical, neurobiological, and functional manifestations of AD.

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Neural and Retinal Characteristics in Relation to Working Memory in Older Adults with Mild Cognitive Impairment

Current Alzheimer Research ◽

10.2174/1567205018666210608114044 ◽

2021 ◽

Vol 18 ◽

Author(s):

Mabel Ngai Kiu Wong ◽

Daniel Wing Leung Lai ◽

Henry Ho-Lung Chan ◽

Bess Yin-Hung Lam

Keyword(s):

Older Adults ◽

Working Memory ◽

Cognitive Impairment ◽

Mild Cognitive Impairment ◽

Optical Coherence Tomography Angiography ◽

Brain Activity ◽

Memory Task ◽

Event Related Potential ◽

Neural Activities ◽

The Relationship

Objective: This study investigated the relationship between neural activities and retinal structures associated with working memory (WM) in older adults with mild cognitive impairment (MCI). Methods: Eleven older adults with MCI and 29 healthy controls (60 to 73 years old) were tested. All participants underwent an event-related potential (ERP) recording while performing the two-back memory task. The Optical coherence tomography angiography (OCT-A) was administered to examine the perfusion and vessel density in the retina. Results: Results showed that WM performance in the MCI group was negatively associated with ERP latencies in central parietal regions (CP6 and CP8) (ps< 0.05). The left nasal vessel and perfusion den- sities were negatively correlated with the latencies in these two central parietal regions and positively related to WM performance only in the MCI group (ps< 0.05). Conclusion: The findings on WM, central parietal brain activity, and left nasal vessel and perfusion densities in the retina help us gain a better understanding of the neural and retinal underpinnings of WM in relation to MCI.

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Higher Coffee Consumption Is Associated With Slower Cognitive Decline and Less Cerebral Aβ-Amyloid Accumulation Over 126 Months: Data From the Australian Imaging, Biomarkers, and Lifestyle Study

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.744872 ◽

2021 ◽

Vol 13 ◽

Author(s):

Samantha L. Gardener ◽

Stephanie R. Rainey-Smith ◽

Victor L. Villemagne ◽

Jurgen Fripp ◽

Vincent Doré ◽

...

Keyword(s):

Older Adults ◽

Cognitive Decline ◽

Protective Factor ◽

Coffee Consumption ◽

Imaging Biomarkers ◽

Coffee Intake ◽

Cognitively Normal ◽

Amyloid Accumulation ◽

Aβ Amyloid ◽

The Relationship

Background: Worldwide, coffee is one of the most popular beverages consumed. Several studies have suggested a protective role of coffee, including reduced risk of Alzheimer’s disease (AD). However, there is limited longitudinal data from cohorts of older adults reporting associations of coffee intake with cognitive decline, in distinct domains, and investigating the neuropathological mechanisms underpinning any such associations.Methods: The aim of the current study was to investigate the relationship between self-reported habitual coffee intake, and cognitive decline assessed using a comprehensive neuropsychological battery in 227 cognitively normal older adults from the Australian Imaging, Biomarkers, and Lifestyle (AIBL) study, over 126 months. In a subset of individuals, we also investigated the relationship between habitual coffee intake and cerebral Aβ-amyloid accumulation (n = 60) and brain volumes (n = 51) over 126 months.Results: Higher baseline coffee consumption was associated with slower cognitive decline in executive function, attention, and the AIBL Preclinical AD Cognitive Composite (PACC; shown reliably to measure the first signs of cognitive decline in at-risk cognitively normal populations), and lower likelihood of transitioning to mild cognitive impairment or AD status, over 126 months. Higher baseline coffee consumption was also associated with slower Aβ-amyloid accumulation over 126 months, and lower risk of progressing to “moderate,” “high,” or “very high” Aβ-amyloid burden status over the same time-period. There were no associations between coffee intake and atrophy in total gray matter, white matter, or hippocampal volume.Discussion: Our results further support the hypothesis that coffee intake may be a protective factor against AD, with increased coffee consumption potentially reducing cognitive decline by slowing cerebral Aβ-amyloid accumulation, and thus attenuating the associated neurotoxicity from Aβ-amyloid-mediated oxidative stress and inflammatory processes. Further investigation is required to evaluate whether coffee intake could be incorporated as a modifiable lifestyle factor aimed at delaying AD onset.

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