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59 Investigating the Relationship Between Neuropsychological Test Performance and Electrophysiological Measures of Semantic Functioning in Alzheimer's Disease.
- Allie R Geiger, Jasmin Guevara, Julia Vehar, Kayla Suhrie, Ava Dixon, Kevin Duff, Matthew Euler
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 467-468
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Objective:
Improving the timeline for intervention in Alzheimer's disease (AD) has considerable potential to delay and mitigate disability and suffering. Neuropsychological assessment is useful for distinguishing AD from normal aging and other dementias but is less useful in preclinical detection due to its limited sensitivity. The N400 (N4), a language-based EEG event-related potential (ERP) related to semantic functioning, is a promising candidate marker of AD with potential to improve early detection and monitoring of AD. For example, studies have shown that individuals with AD show a reduced N4 "effect"—a smaller difference in the size of the N4 to semantically congruent vs. incongruent word-pairs. The goal of this study is to assess the presence of the N4 effect in healthy seniors, and those with amnestic mild cognitive impairment (MCI) or mild AD, and to evaluate associations between performance on the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the N4 across these samples.
Participants and Methods:Fifty older adults (intact=27, combined MCI/mild AD group=23; "impaired") completed neuropsychological testing, including the RBANS, as part of a larger study. Participants were re-contacted and returned for EEG assessment between several weeks to one year later. During EEG recording, participants completed a word-pair judgement paradigm, which involved distinguishing between semantically congruent and incongruent word-pairs. Data was collected and analyzed according to customized N4 analysis scripts provided as part of ERPCORE, an online resource for acquiring and analyzing common ERP components (Kappenman et al., 2021; https://osf.io/thsqg/). The change in N4 amplitude between congruent and incongruent trials (the N4 effect) was used as an index of participants' semantic functioning. Participants' N4 effect was quantified using the mean amplitude from 300-550 milliseconds poststimulus at electrode Cz.
Results:Repeated measures ANOVAs indicated a significant effect of trial type on the N400 amplitude in the intact individuals (F(1, 26)=77.66, p<.001), which remained significant in the sample as a whole (F(1, 48)=65.18, p<.001). Although intact participants numerically showed a larger N4 effect (intact: M=-4.02, SD=2.37; impaired: M=-2.60, SD=3.40), the expected group-by-trial interaction was not significant (F(1, 48)=3.01, p=.089). Correlational analyses revealed no significant associations between the N4 effect and the RBANS Total Scale scores (r=-.14, p=.32), nor for the Immediate Memory (r=-.002, p=.99), Visuospatial/Constructional (r=-.069, p=.63), Language (r=-.15, p=.30) Attention (r=-.21, p=.14), or Delayed Memory (r=-.18 p=.58) indexes.
Conclusions:Results confirmed the presence of the N4 effect in intact participants and in the sample as a whole. Although the N4 effect was numerically smaller in the impaired group as expected, this difference was not significant in the present sample. Likewise, we observed no evidence for associations between the size of N4 effect and performance on RBANS indexes. Overall, the present study provides mixed evidence for the utility of the N4 as a biomarker in mild AD. Factors that may have contributed to the lack of associations between the N4 effect and the RBANS include the limited sample size and variable lengths of time between participants' initial cognitive assessments and EEG testing.
82 Examining the relationships between physiological, cognitive, and self-report indices of self-regulation
- Jasmin Guevara, Steven Carlson, Tuan Cassim, Yana Suchy, Matt Euler, Paula Williams
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 283-284
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Objective:
Self-regulation is typically operationalized in neuropsychological assessment through self-report scales and measures of attention and executive functioning. However, there have been mixed findings on the relationships between self-report measures and physiological and performance-based measures believed to represent self-regulation. Poorer self-regulation is related to an array of negative behavioral and health-related outcomes. Therefore, it is critical to understand the process of self-regulation and the relationships between measures neuropsychologists use to assess it. The current study aims to investigate the relationships between four purported measures of self-regulation: resting-state high-frequency heart rate variability (HRV; a stable individual difference variable that reflects parasympathetic capacity for adapting to changing environmental demands), behavioral performance on the Delis-Kaplan Executive Function System (D-KEFS) and the Conners Continuous Performance Test - 3rd Edition (CPT-3), and trait self-control on the Brief Self-Control Scale (BSCS). It was hypothesized that physiological and behavioral self-regulation variables would predict the BSCS, such that higher resting HRV and better performance on the cognitive measures would predict higher self-reported self-control.
Participants and Methods:Thirty-five healthy adults (Age M = 29.80, SD =8.52, 45.7% female) recruited from the community completed the BSCS, CPT-3, and D-KEFS as part of a larger battery. Participants also completed a 10-minute eyes-open resting condition during electrocardiogram recording. High-frequency power (0.15 - 0.4 Hz) was extracted and used to operationalize resting HRV. Linear regression was used to test the predictive relationships between the BSCS total score, resting HRV, CPT-3 scores, and a residualized executive functioning score from the D-KEFS that controls for non-executive lower-order cognitive processes.
Results:Regression analyses indicated that neither the D-KEFS composite, the CPT-3 indices, nor resting HRV were related to the BSCS. Resting HRV predicted the CPT-3 Hit Reaction Time (HRT; B = -2.97, p < .05) and HRT Standard Deviation (HRT SD; B = -4.55, p < .05). Resting HRV was unrelated to the D-KEFS executive composite score. CPT-3 performance variables and D-KEFS composite score were also unrelated to one another.
Conclusions:Results showed that the BSCS was unrelated to resting HRV, CPT-3, and D-KEFS performance. However, higher resting HRV was related to faster and more consistent responding on the CPT-3. These findings contradict previous research showing associations between the BSCS and performance on executive functioning measures. The relationship between resting HRV and reaction time on the CPT-3 is generally consistent with literature that suggests that higher resting HRV is associated with better cognitive performance. Although the association between resting HRV and executive functioning was not significant in this modest sample, it was comparable to that reported in a recent meta-analysis. Overall, despite limitations related to the small sample size, the results raise questions regarding the construct validity of common neuropsychological indices of self-regulation. Further research is needed to clarify the nature of the self-regulation construct and the relation of neuropsychological measures of behavioral self-regulation to physiological and self-report indices.