Pre-attentive Visual Processing in Alzheimer’s Disease: An Event-related Potential Study

2021 ◽  
Vol 17 (13) ◽  
pp. 1195-1207
Author(s):  
Eunchan Na ◽  
Kanghee Lee ◽  
Eun J. Kim ◽  
Jong B. Bae ◽  
Seung W. Suh ◽  
...  

Introduction: While identifying Alzheimer’s Disease (AD) in its early stages is crucial, traditional neuropsychological tests tend to lack sensitivity and specificity for its diagnosis. Neuropsychological studies have reported visual processing deficits of AD, and event-related potentials (ERPs) are suitable to investigate pre-attentive processing with superior temporal resolution. Objective: This study aimed to investigate visual attentional characteristics of adults with AD, from pre-attentive to attentive processing, using a visual oddball task and ERPs. Methods: Cognitively normal elderly controls (CN) and patients with probable AD (AD) were recruited. Participants performed a three-stimulus visual oddball task and were asked to press a designated button in response to the target stimuli. The amplitudes of 4 ERPs were analyzed. Mismatchnegativity (vMMN) was analyzed around the parieto-occipital and temporo-occipital regions. P3a was analyzed around the fronto-central regions, whereas P3b was analyzed around the centro-parietal regions. Results: Late vMMN amplitudes of the AD group were significantly smaller than those of the CN group, while early vMMN amplitudes were comparable. Compared to the CN group, P3a amplitudes of the AD group were significantly smaller for the infrequent deviant stimuli, but the amplitudes for the standard stimuli were comparable. Lastly, the AD group had significantly smaller P3b amplitudes for the target stimuli compared to the CN group. Conclusion: Our findings imply that AD patients exhibit pre-attentive visual processing deficits, known to affect later higher-order brain functions. In a clinical setting, the visual oddball paradigm could be used to provide helpful diagnostic information since pre-attentive ERPs can be induced by passive exposure to infrequent stimuli.

2019 ◽  
Author(s):  
Eunchan Na ◽  
Kanghee Lee ◽  
Eun Ji Kim ◽  
Jong Bin Bae ◽  
Seung Wan Suh ◽  
...  

Abstract Background: While identifying Alzheimer’s Disease (AD) in its early stages is crucial, traditional neuropsychological tests tend to lack sensitivity and specificity for its diagnosis. Based on the early visual attention deficits of adults with AD, which are apparent before cognitive deficits emerge, this study aimed to investigate visual attentional characteristics of adults with AD, from pre-attentive to attentive processing, using a visual oddball task and event-related potentials (ERPs).Methods: Cognitively normal elderly controls (NC, n=27) and patients with probable AD (AD, n=10) were recruited. Participants performed a three-stimulus visual oddball task and were asked to press a designated button in response to the target stimuli. The amplitudes of 4 ERPs were analyzed. Visual mismatch-negativity (vMMN) was analyzed around the parieto-occipital and temporo-occipital regions. P3a was analyzed around the fronto-central regions, whereas P3b was analyzed around the centro-parietal regions.Results: Late vMMN amplitudes of the AD group were significantly smaller than those of the NC group, while early vMMN amplitudes were comparable. Compared to the NC group, P3a amplitudes of the AD group were significantly smaller for the infrequent deviant stimuli but the amplitudes for the standard stimuli were comparable. Lastly, the AD group had significantly smaller P3b amplitudes than the NC group.Conclusion: Our findings imply that AD patients exhibit pre-attentive visual processing deficits, known to affect later higher-order brain functions. In a clinical setting, the visual oddball paradigm could be used to provide helpful diagnostic information since pre-attentive ERPs can be induced by passive exposure to infrequent stimuli.


2021 ◽  
pp. 1-16
Author(s):  
Kathleen H. Elverman ◽  
Elizabeth R. Paitel ◽  
Christina M. Figueroa ◽  
Ryan J. McKindles ◽  
Kristy A. Nielson

Background: Despite advances in understanding Alzheimer’s disease (AD), prediction of AD prior to symptom onset remains severely limited, even when primary risk factors such as the apolipoprotein E (APOE) ɛ4 allele are known. Objective: Although executive dysfunction is highly prevalent and is a primary contributor to loss of independence in those with AD, few studies have examined neural differences underlying executive functioning as indicators of risk for AD prior to symptom onset, when intervention might be effective. Methods: This study examined event-related potential (ERP) differences during inhibitory control in 44 cognitively intact older adults (20 ɛ4+, 24 ɛ4-), relative to 41 young adults. All participants completed go/no-go and stop-signal tasks. Results: Overall, both older adult groups exhibited slower reaction times and longer ERP latencies compared to young adults. Older adults also had generally smaller N200 and P300 amplitudes, except at frontal electrodes and for N200 stop-signal amplitudes, which were larger in older adults. Considered with intact task accuracy, these findings suggest age-related neural compensation. Although ɛ4 did not distinguish elders during go or no-go tasks, this study uniquely showed that the more demanding stop-signal task was sensitive to ɛ4 differences, despite comparable task and neuropsychological performance with non-carriers. Specifically, ɛ4+ elders had slower frontal N200 latency and larger N200 amplitude, which was most robust at frontal sites, compared with ɛ4-. Conclusion: N200 during a stop-signal task is sensitive to AD risk, prior to any evidence of cognitive dysfunction, suggesting that stop-signal ERPs may be an important protocol addition to neuropsychological testing.


2021 ◽  
pp. 1-30
Author(s):  
Hadeel Y. Tarawneh ◽  
Wilhelmina H.A.M. Mulders ◽  
Hamid R. Sohrabi ◽  
Ralph N. Martins ◽  
Dona M.P. Jayakody

Background: Objectively measuring auditory functions has been proposed as an avenue in differentiating normal age-related cognitive dysfunction from Alzheimer’s disease (AD) and its prodromal states. Previous research has suggested auditory event-related potentials (AERPs) to be non-invasive, cost-effective, and efficient biomarkers for the diagnosis of AD. Objective: The objective of this paper is to review the published literature on AERPs measures in older adults diagnosed with AD and those at higher risk of developing AD, i.e., mild cognitive impairment (MCI) and subjective cognitive decline. Methods: The search was performed on six major electronic databases (Ovid MEDLINE, OVID EMBASE, PsycINFO, PubMed, Scopus, and CINAHL Plus). Articles identified prior to 7 May 2019 were considered for this review. A random effects meta-analysis and analysis of between study heterogeneity was conducted using the Comprehensive Meta-Analysis software. Results: The search identified 1,076 articles; 74 articles met the full inclusion criteria and were included in the systematic review, and 47 articles were included into the analyses. Pooled analysis suggests that AD participants can be differentiated from controls due to significant delays in ABR, N100, P200, N200, and P300 latencies. P300 amplitude was significantly smaller in AD participants compared to controls. P300 latencies differed significantly between MCI participants and controls based on the pooled analysis. Conclusion: The findings of this review indicate that some AERPs may be valuable biomarkers of AD. In conjunction with currently available clinical and neuropsychological assessments, AERPs can aid in screening and diagnosis of prodromal AD.


2020 ◽  
Author(s):  
Kathleen H. Elverman ◽  
Elizabeth R. Paitel ◽  
Christina M. Figueroa ◽  
Ryan J. McKindles ◽  
Kristy A Nielson

Despite advances in understanding Alzheimer’s disease (AD), prediction of AD prior to symptom onset remains severely limited, even when primary risk factors such as the apolipoprotein-E (APOE) ε4 allele are known. Although executive dysfunction is highly prevalent and is a primary contributor to loss of independence in those with AD, few studies have examined neural differences underlying executive functioning as an indicator of risk for AD prior to symptom onset, when intervention might be effective. This study examined event-related potential (ERP) differences during inhibitory control in 44 cognitively intact older adults (20 ε4+, 24 ε4-), relative to 41 young adults. All participants completed go/no-go and stop-signal tasks. Overall, both older adult groups exhibited slower reaction times and longer ERP latencies compared to young adults. Older adults also had generally smaller N200 and P300 amplitudes, except at frontal electrodes and for N200 stop-signal amplitudes, which were larger in older adults. These patterns, along with intact task accuracy, support prior studies evidencing age-related neural compensation. Although ε4 did not distinguish elders during go or no-go tasks, this study uniquely showed that the more demanding stop-signal task was sensitive to ε4 differences, despite comparable task and neuropsychological performance with non-carriers. Specifically, ε4+ elders had slower frontal N200 latency and larger N200 amplitude, which was most robust at frontal sites, compared with ε4-. Thus N200 during a stop-signal task was sensitive to AD risk, prior to any evidence of cognitive dysfunction, suggesting that stop-signal ERPs may be an important protocol addition to neuropsychological testing.


2021 ◽  
Vol 12 ◽  
Author(s):  
Petra Csizmadia ◽  
István Czigler ◽  
Boglárka Nagy ◽  
Zsófia Anna Gaál

We do not know enough about the cognitive background of creativity despite its significance. Using an active oddball paradigm with unambiguous and ambiguous portrait paintings as the standard stimuli, our aim was to examine whether: creativity in the figural domain influences the perception of visual stimuli; any stages of visual processing; or if healthy aging has an effect on these processes. We investigated event related potentials (ERPs) and applied ERP decoding analyses in four groups: younger less creative; younger creative; older less creative; and older creative adults. The early visual processing did not differ between creativity groups. In the later ERP stages the amplitude for the creative compared with the less creative groups was larger between 300 and 500 ms. The stimuli types were clearly distinguishable: within the 300–500 ms range the amplitude was larger for ambiguous rather than unambiguous paintings, but this difference in the traditional ERP analysis was only observable in the younger, not elderly groups, who also had this difference when using decoding analysis. Our results could not prove that visual creativity influences the early stage of perception, but showed creativity had an effect on stimulus processing in the 300–500 ms range, in indexing differences in top-down control, and having more flexible cognitive control in the younger creative group.


2002 ◽  
Vol 16 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Antoinette R. Miller ◽  
J. Peter Rosenfeld ◽  
Matthew Soskins ◽  
Marianne Jhee

Abstract The P300 component of the event-related potential was recorded during two blocks of an autobiographical oddball task. All participants performed honestly during the first block (Phone), i.e., the oddball stimuli were phone numbers. During the second block (Birthday), in which the oddball stimuli were participants' birthdays, a Truth group (N = 13) performed honestly and a Malinger group (N = 14) simulated amnesia. Amnesia simulation significantly reduced P300 amplitudes, both between groups and within the Malinger group (Phone vs. Birthday), possibly because of an increase in task difficulty in the Malinger condition. Analysis of scaled amplitudes also indicated a trend for a feigning-related alteration in P300 topography. Bootstrapping of peak-to-peak amplitudes detected significantly more (93%) Malinger individuals than bootstrapping of baseline-to-peak amplitudes (64%). Bootstrapping also provided evidence of a feigning-related amplitude difference between oddball stimuli (i.e., Phone > Birthday) in 71% of Malinger group individuals. In this comparison, the peak-to-peak measure also performed significantly better in intraindividual diagnostics.


2020 ◽  
Vol 17 (2) ◽  
pp. 141-157 ◽  
Author(s):  
Dubravka S. Strac ◽  
Marcela Konjevod ◽  
Matea N. Perkovic ◽  
Lucija Tudor ◽  
Gordana N. Erjavec ◽  
...  

Background: Neurosteroids Dehydroepiandrosterone (DHEA) and Dehydroepiandrosterone Sulphate (DHEAS) are involved in many important brain functions, including neuronal plasticity and survival, cognition and behavior, demonstrating preventive and therapeutic potential in different neuropsychiatric and neurodegenerative disorders, including Alzheimer’s disease. Objective: The aim of the article was to provide a comprehensive overview of the literature on the involvement of DHEA and DHEAS in Alzheimer’s disease. Method: PubMed and MEDLINE databases were searched for relevant literature. The articles were selected considering their titles and abstracts. In the selected full texts, lists of references were searched manually for additional articles. Results: We performed a systematic review of the studies investigating the role of DHEA and DHEAS in various in vitro and animal models, as well as in patients with Alzheimer’s disease, and provided a comprehensive discussion on their potential preventive and therapeutic applications. Conclusion: Despite mixed results, the findings of various preclinical studies are generally supportive of the involvement of DHEA and DHEAS in the pathophysiology of Alzheimer’s disease, showing some promise for potential benefits of these neurosteroids in the prevention and treatment. However, so far small clinical trials brought little evidence to support their therapy in AD. Therefore, large-scale human studies are needed to elucidate the specific effects of DHEA and DHEAS and their mechanisms of action, prior to their applications in clinical practice.


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Jiangyi Xia ◽  
Ali Mazaheri ◽  
Katrien Segaert ◽  
David P Salmon ◽  
Danielle Harvey ◽  
...  

Abstract Reliable biomarkers of memory decline are critical for the early detection of Alzheimer’s disease. Previous work has found three EEG measures, namely the event-related brain potential P600, suppression of oscillatory activity in the alpha frequency range (∼10 Hz) and cross-frequency coupling between low theta/high delta and alpha/beta activity, each of which correlates strongly with verbal learning and memory abilities in healthy elderly and patients with mild cognitive impairment or prodromal Alzheimer’s disease. In the present study, we address the question of whether event-related or oscillatory measures, or a combination thereof, best predict the decline of verbal memory in mild cognitive impairment and Alzheimer’s disease. Single-trial correlation analyses show that despite a similarity in their time courses and sensitivities to word repetition, the P600 and the alpha suppression components are minimally correlated with each other on a trial-by-trial basis (generally |rs| < 0.10). This suggests that they are unlikely to stem from the same neural mechanism. Furthermore, event-related brain potentials constructed from bandpass filtered (delta, theta, alpha, beta or gamma bands) single-trial data indicate that only delta band activity (1–4 Hz) is strongly correlated (r = 0.94, P < 0.001) with the canonical P600 repetition effect; event-related potentials in higher frequency bands are not. Importantly, stepwise multiple regression analyses reveal that the three event-related brain potential/oscillatory measures are complementary in predicting California Verbal Learning Test scores (overall R2’s in 0.45–0.63 range). The present study highlights the importance of combining EEG event-related potential and oscillatory measures to better characterize the multiple mechanisms of memory failure in individuals with mild cognitive impairment or prodromal Alzheimer’s disease.


Author(s):  
Marco Cecchi ◽  
Dennis K. Moore ◽  
Carl H. Sadowsky ◽  
Paul R. Solomon ◽  
P. Murali Doraiswamy ◽  
...  

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