INS NYC 2024 Program

Poster	Poster Session 04 Program Schedule 02/15/2024 12:00 pm - 01:15 pm Room: Shubert Complex (Posters 1-60) Poster Session 04: Neuroimaging \| Neurostimulation/Neuromodulation \| Teleneuropsychology/Technology Final Abstract #38 Evaluating the N4 Effect Event-Related Potential as an Electrophysiological Marker in Alzheimer’s Disease Allie Geiger, University of Utah, Salt Lake City, United States Jasmin Guevara, University of Utah, Salt Lake City, United States Julia Vehar, University of Utah, Salt Lake City, United States Kayla Suhrie, University of Utah, Salt Lake City, United States Ava Dixon, San Jose State University, San Jose, United States Kevin Duff, Oregon Health & Science University, Portland, United States Matthew Euler, University of Utah, Salt Lake City, United States Category: Neurophysiology/EEG/ERP/fMRI Keyword 1: event-related potentials Keyword 2: dementia - Alzheimer's disease Keyword 3: neuropsychological assessment Objective: The N400 (N4) EEG event-related potential (ERP) is a promising, inexpensive, language-based marker of Alzheimer’s disease (AD) often elicited in tasks that involve violations of semantic expectation using word-pairs. For example, the N4 amplitude difference between semantically expected (duck & quack) and unexpected (umbrella & dog) experimental trials (i.e., “N4 effect”) has previously been related to cognitive performance and disease status in AD. Building off these findings, the present study sought to: 1) assess whether the N4 effect latency can predict cognitive test scores over and above established biomarkers of AD, and 2) evaluate latency as a marker of brain reserve in AD, by examining whether the N4 also moderates the relationship between cognitive test scores and biomarkers. That is, whether this relationship changes as a result of N4 latency variation, such that those with earlier latencies have a weaker relationship between biomarker status and cognition (i.e., intact cognition in the presence of biomarkers). Positive findings would suggest (1) that the N4 captures additional cognitive variance in AD beyond other biomarkers, and (2) that earlier N4 latencies might provide a novel, direct measure of brain reserve in AD. Participants and Methods: Seventy older adults (intact = 44, impaired [MCI/mild AD] = 26) completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). AD biomarker data (aβ, hippocampal volumes) was also collected. EEG recordings during a visual word-pair judgement paradigm (distinguishing semantically related and unrelated word-pairs) was later collected, and N4 ERPs were extracted. Due to its strong inverse relations with RBANS scores in the present sample, the N4 50% area latency was used for all analyses. Hierarchical and multiple regression analyses were used to assess our first and second goals, respectively. Models included important covariates (e.g., sex, education, days between cognitive testing and EEG), one of the biomarkers, latency, and in the multiple regressions, a biomarker x latency interaction. The RBANS Total score was the outcome for all models. Results: The N4 latency significantly predicted variance in RBANS Total scores above and beyond aβ (p = .009), and hippocampal volumes (p = .006). Latency accounted 6% of the variance in RBANS Total scores above aβ and 7% above hippocampal volumes. However, there were no significant interactions between the N4 effect and aβ (p = .37) or hippocampal volumes (p = .23) in predicting cognitive performance. Conclusions: Results indicate that N4 effect latencies capture additional variance in current brain functioning beyond that which can be detected with more static biomarkers. In contrast, the N4 effect does not moderate relations between cognition and static biomarkers, suggesting that it lacks utility as a marker of brain reserve. Overall, the effects of biomarkers and latency on cognition appear to be independent processes, supporting the N4 as an inexpensive and promising biomarker of AD. When combined with other biomarkers, the N4 effect latency may be provide additional information for tracking cognitive decline in individuals at risk for AD.

Poster

02/15/2024
12:00 pm - 01:15 pm
Room: Shubert Complex (Posters 1-60)

Poster Session 04: Neuroimaging | Neurostimulation/Neuromodulation | Teleneuropsychology/Technology

Final Abstract #38

Evaluating the N4 Effect Event-Related Potential as an Electrophysiological Marker in Alzheimer’s Disease

Allie Geiger, University of Utah, Salt Lake City, United States
Jasmin Guevara, University of Utah, Salt Lake City, United States
Julia Vehar, University of Utah, Salt Lake City, United States
Kayla Suhrie, University of Utah, Salt Lake City, United States
Ava Dixon, San Jose State University, San Jose, United States
Kevin Duff, Oregon Health & Science University, Portland, United States
Matthew Euler, University of Utah, Salt Lake City, United States

Category: Neurophysiology/EEG/ERP/fMRI

Keyword 1: event-related potentials
Keyword 2: dementia - Alzheimer's disease
Keyword 3: neuropsychological assessment

Objective:

The N400 (N4) EEG event-related potential (ERP) is a promising, inexpensive, language-based marker of Alzheimer’s disease (AD) often elicited in tasks that involve violations of semantic expectation using word-pairs. For example, the N4 amplitude difference between semantically expected (duck & quack) and unexpected (umbrella & dog) experimental trials (i.e., “N4 effect”) has previously been related to cognitive performance and disease status in AD. Building off these findings, the present study sought to: 1) assess whether the N4 effect latency can predict cognitive test scores over and above established biomarkers of AD, and 2) evaluate latency as a marker of brain reserve in AD, by examining whether the N4 also moderates the relationship between cognitive test scores and biomarkers. That is, whether this relationship changes as a result of N4 latency variation, such that those with earlier latencies have a weaker relationship between biomarker status and cognition (i.e., intact cognition in the presence of biomarkers). Positive findings would suggest (1) that the N4 captures additional cognitive variance in AD beyond other biomarkers, and (2) that earlier N4 latencies might provide a novel, direct measure of brain reserve in AD.

Participants and Methods:

Seventy older adults (intact = 44, impaired [MCI/mild AD] = 26) completed the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). AD biomarker data (aβ, hippocampal volumes) was also collected. EEG recordings during a visual word-pair judgement paradigm (distinguishing semantically related and unrelated word-pairs) was later collected, and N4 ERPs were extracted. Due to its strong inverse relations with RBANS scores in the present sample, the N4 50% area latency was used for all analyses. Hierarchical and multiple regression analyses were used to assess our first and second goals, respectively. Models included important covariates (e.g., sex, education, days between cognitive testing and EEG), one of the biomarkers, latency, and in the multiple regressions, a biomarker x latency interaction. The RBANS Total score was the outcome for all models.

Results:

The N4 latency significantly predicted variance in RBANS Total scores above and beyond aβ (p = .009), and hippocampal volumes (p = .006). Latency accounted 6% of the variance in RBANS Total scores above aβ and 7% above hippocampal volumes. However, there were no significant interactions between the N4 effect and aβ (p = .37) or hippocampal volumes (p = .23) in predicting cognitive performance.

Conclusions:

Results indicate that N4 effect latencies capture additional variance in current brain functioning beyond that which can be detected with more static biomarkers. In contrast, the N4 effect does not moderate relations between cognition and static biomarkers, suggesting that it lacks utility as a marker of brain reserve. Overall, the effects of biomarkers and latency on cognition appear to be independent processes, supporting the N4 as an inexpensive and promising biomarker of AD. When combined with other biomarkers, the N4 effect latency may be provide additional information for tracking cognitive decline in individuals at risk for AD.