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Open Access Publications from the University of California

Scholarly Works (37 results)

  • Article
  • Peer Reviewed
UC San Diego Previously Published Works (2021)
Background: Healthy aging is critically important for several reasons, including economic impact and quality of life. As the population of older adults rapidly increases, identifying acceptable ways to promote healthy aging is a priority. Technologies that can facilitate health promotion and risk reduction behaviors may be a solution, but only if these mobile health (mHealth) tools can be used by the older adult population. Within the context of a physical activity intervention, this study gathered participant's opinions about the use of an mHealth device to learn about acceptance and to identify areas for improvement. Methods: The Independent Walking for Brain Health study (NCT03058146) was designed to evaluate the effectiveness of a wearable mHealth technology in facilitating adherence to a physical activity prescription among participants in free-living environments. An Exit Survey was conducted following intervention completion to gauge participant's perceptions and solicit feedback regarding the overall study design, including exercise promotion strategies and concerns specific to the technology (e.g., privacy), that could inform more acceptable mHealth interventions in the future. The Digital Health Checklist and Framework was used to guide the analysis focusing on the domains of Privacy, Access and Usability, and Data Management. Results: Participants (n = 41) were in their early 70's (mean = 71.6) and were predominantly female (75.6%) and White (92.7%). Most were college educated (16.9 years) and enjoyed using technology in their everyday life (85.4%). Key challenges included privacy concerns, device accuracy, usability, and data access. Specifically, participants want to know what is being learned about them and want control over how their identifiable data may be used. Overall, participants were able to use the device despite the design challenges. Conclusions: Understanding participant's perceptions of the challenges and concerns introduced by mHealth is important, as acceptance will influence adoption and adherence to the study protocol. While this study learned from participants at studycompletion, we recommend that researchers consider what might influence participant acceptance of the technology (access, data management, privacy, risks) and build these into the mHealth study design process. We provide recommendations for future mHealth studies with older adults.
    Cover page: Learning From Older Adults to Promote Independent Physical Activity Using Mobile Health (mHealth)
    • Article
    • Peer Reviewed
    UC San Diego Previously Published Works (2018)
    During threat of shock, the startle reflex is potentiated, suggesting modulation by defensive mobilization. To determine whether startle potentiation is specific to aversive anticipation, startle reflexes were measured in the context of either aversive or appetitive anticipation in a between-subject study. Participants wore a device on the wrist that could deliver electrical shock (n = 49), or vibrotactile stimulation indicating monetary reward (n = 48). Cues signaling threat or safe periods were presented alone, or accompanied by presentation of affective and neutral pictures on half of the trials. Results indicated that the startle reflex was significantly potentiated when anticipating either shock or reward, compared to safe periods, both when no picture was presented, as well as during picture viewing. The difference between threat and safety in both reflex magnitude and skin conductance changes was larger for those anticipating shock, suggesting that the aversive context was more motivationally engaging. The pattern of reflex modulation as a function of picture valence varied under threat and safety, but was identical in the shock and reward groups, consistent with a hypothesis that anticipation of either aversive or appetitive events prompts heightened perceptual vigilance, potentiating the acoustic startle reflex.
      Cover page: Startle reflex modulation during threat of shock and threat of reward.
      • Article
      • Peer Reviewed
      UC San Diego Previously Published Works (2018)
      OBJECTIVES: Subjective cognitive decline (SCD), or self-reported cognitive decline despite normal neuropsychological test performance, is a risk factor for objective cognitive decline and Alzheimers disease (AD). While brain mechanisms contributing to SCD are not well defined, studies show associations with vascular risk factors and altered cerebral blood flow (CBF), raising the hypothesis that those with SCD might be experiencing vascular dysregulation, or a disruption in the normal relationship between CBF and cognition. We examined whether the association between CBF and verbal memory performance differs between those with SCD (SCD+) and those without SCD (SCD-). METHODS: Linear mixed-effects models were used to investigate whether the voxel-wise relationship between arterial spin labeling (ASL) MRI-measured CBF and verbal memory performance was modified by SCD among a group of 70 cognitively normal older adults (35 SCD+, 35 SCD-; mean age=72) matched on age, gender, and symptoms of depression. RESULTS: Results indicated that the SCD- group exhibited positive associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, and inferior frontal gyrus, whereas the SCD+ group displayed negative associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, hippocampus, fusiform gyrus, and inferior frontal gyrus. CONCLUSIONS: Findings suggest that, while higher CBF is supportive of memory function in those without SCD, higher CBF may no longer support memory function in those presenting with SCD, perhaps reflecting neurovascular dysregulation. (JINS, 2018, 24, 213-223).
        Cover page: Subjective Cognitive Decline Modifies the Relationship Between Cerebral Blood Flow and Memory Function in Cognitively Normal Older Adults.
        • Article
        • Peer Reviewed
        UC San Diego Previously Published Works (2018)
        OBJECTIVES: Subjective cognitive decline (SCD) is common in older adults; however, its utility in clinic-based samples remains controversial given its strong associations with mood symptoms. METHODS: Five hundred nineteen individuals aged 60-95 with a wide range of cognitive performance scores were referred by community health clinics for brief screening of cognitive complaints. Linear regression models examined the cross-sectional associations between SCD (5-item self-reported questions), symptoms of depression (Beck Depression Inventory [BDI]), and concurrent objective cognitive performance (Cognitive Composite) adjusting for demographics. RESULTS: There was not a significant association between SCD and concurrent objective cognition after adjusting for demographics and depression. In contrast, there was a significant association between SCD and depression after adjusting for demographics and objective cognition. There was also a consistent association between SCD and depression, but not between SCD and objective cognition, in those with high and low levels of SCD reporting, in all ranges of cognitive performance, and in those with mild to moderate depression. DISCUSSION: Results are consistent with previous findings and suggest that SCD does not accurately reflect concurrent cognitive performance in a clinic-based sample of older adults. Clinical interpretation of SCD should account for the role of depression.
          Cover page: Subjective Cognitive Decline Correlates With Depression Symptoms and Not With Concurrent Objective Cognition in a Clinic-Based Sample of Older Adults.
          • Thesis
          • Peer Reviewed
          UC San Diego Electronic Theses and Dissertations (2024)

          Older adults, including Non-Hispanic Whites (NHWs), Hispanics/Latinos, and those with neurodegenerative diseases (e.g., Parkinson’s Disease: PD), are at risk for dementia. Subjective cognitive decline (SCD; perceived cognitive difficulties) may be an early risk marker of dementia. However, its neural correlates and utility to predict concurrent objective cognition across these different risk groups remain understudied. This 3-paper dissertation investigated associations of SCD with concurrent objective cognition across older adults at risk for dementia: 1) mostly NHWs (87% Caucasian) (age= 72.90), 2) Hispanics/Latinos (age= 73.97) versus NHWs (age= 71.81), and 3) PD (age= 67.56). Study 2 augmented Study 1 by examining ethnic differences in SCD reporting between NHWs and Hispanics/Latinos, while Study 3 expanded findings to neurodegenerative disease. Archival data was used from the UCSD WISE Lab, Shiley Marcos Alzheimer’s Disease Research Center, and VA San Diego Healthcare System.

          Study 1 (Nakhla et al., 2024) investigated the relationship of self-reported SCD with objective cognition and cerebral blood flow (CBF) in a cognitively normal sample (N=52) with varying stroke risk status. Greater SCD severity was significantly associated with lower memory and entorhinal CBF in the total sample and in those with higher stroke risk (n=31). Study 2 (Nakhla et al., 2021) investigated if the relationship between self-reported SCD and objective cognition varies as a function of ethnicity [Hispanics/Latinos (N= 35) vs NHWs (N= 48)]. Higher self-reported SCD was associated with lower global cognition in Hispanics/Latinos, but not in NHWs. Study 3 (Nakhla et al., 2021) investigated the relationship between informant-reported SCD and objective cognition in a confirmed neurodegenerative disease sample, i.e., PD, (N= 139). Higher informant-reported SCD was significantly associated with poorer objective cognition (attention, learning, delayed recall, executive function).

          Collectively, these studies contributed to the literature by further characterizing SCD in three different and understudied older adult samples at risk for dementia: mostly NHWs, Hispanics/Latinos, and neurodegenerative disease (i.e., PD). Findings inform clinical practice by advancing our understanding of how SCD relates to objective cognition in different samples and provide evidence that SCD is related to early risk markers of dementia.

            Cover page: The Relationship Between Subjective Cognitive Decline and Objective Cognitive Performance Within Three Different Older Adult Samples
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2014)

            Objective

            Whether subjective cognitive complaints are suggestive of depression or concurrent cognitive impairment in older adults without dementia remains unclear. The current study examined this question in a large (N = 1000), randomly selected, community-based sample of adults aged 51 to 99 years without a formal diagnosis of dementia (Successful AGing Evaluation [SAGE] study).

            Methods

            The modified Telephone Interview for Cognitive Status (TICS-m) measured objective cognitive function, the Cognitive Failures Questionnaire (CFQ) measured subjective cognitive complaints, and the 9-item Patient Health Questionnaire (PHQ-9) measured depression. Spearman ρ correlations and linear regression models were conducted to examine the relationship among variables in the baseline SAGE sample.

            Results

            There was a weak association between TICS-m and CFQ scores (ρ = -.12); however, a moderate to large association was observed for CFQ and PHQ-9 (ρ = .44). Scores on the CFQ were not associated with TICS-m scores (β = -.03, P = .42) after controlling for PHQ-9 and variables of interest, such as age, gender, ethnicity, and physical functioning, while PHQ-9 was significantly associated with CFQ scores (β = .46, P < .001) after controlling for variables of interest.

            Conclusions

            Subjective cognitive complaints are more likely related to symptoms of depression rather than concurrent cognitive impairment in a large cross-section of community-dwelling adults without a formal diagnosis of dementia.
              • Article
              • Peer Reviewed
              UC San Diego Previously Published Works (2017)

              Objective

              Evidence suggests that famous face naming may be a cognitive ability especially sensitive to the early pathological processes of Alzheimer's disease (AD) and that those at risk for AD may demonstrate a Ribot temporal gradient (RTG), characterized by better performance for naming remote famous faces than for naming recent famous faces. Reductions in cerebral blood flow (CBF) and gray matter volume (GMV) have been implicated in the neuropathological cascade of AD and show utility as biomarkers of AD risk. We examined whether a RTG during famous face naming was associated with lower CBF and/or GMV among a group of cognitively normal older adults.

              Methods

              Voxel-wise independent samples t-tests were employed to contrast resting CBF values between those who exhibited a RTG (RTG+) during a famous face naming task and those who did not (RTG-) among a sample of 52 cognitively normal older adults (25 RTG-, 27 RTG+; mean age = 73). Groups were also compared on GMV using a voxel-wise general linear model.

              Results

              Significant group differences in CBF and GMV were found, whereby the RTG+ group demonstrated reduced CBF and GMV within medial temporal lobe regions (hippocampus, parahippocampal gyrus), relative to the RTG- group.

              Conclusions

              This represents the first study to show that cognitively intact older adults who demonstrate a RTG during famous face naming exhibit vascular dysregulation and structural changes similar to that seen in AD risk. Findings suggest that famous face naming ability may be particularly sensitive to the very early brain changes associated with AD.
                Cover page: Temporal gradient during famous face naming is associated with lower cerebral blood flow and gray matter volume in aging
                • Article
                • Peer Reviewed
                UC San Diego Previously Published Works (2024)

                Objective

                Subjective cognitive decline (SCD) is a potential early risk marker for Alzheimer's disease (AD), but its utility may vary across individuals. We investigated the relationship of SCD severity with memory function and cerebral blood flow (CBF) in areas of the middle temporal lobe (MTL) in a cognitively normal and overall healthy sample of older adults. Exploratory analyses examined if the association of SCD severity with memory and MTL CBF was different in those with lower and higher cardiovascular disease (CVD) risk status.

                Methods

                Fifty-two community-dwelling older adults underwent magnetic resonance imaging, neuropsychological testing, and were administered the Everyday Cognition Scale (ECog) to measure SCD. Regression models investigated whether ECog scores were associated with memory performance and MTL CBF, followed by similar exploratory regressions stratified by CVD risk status (i.e., lower vs higher stroke risk).

                Results

                Higher ECog scores were associated with lower objective memory performance and lower entorhinal cortex CBF after adjusting for demographics and mood. In exploratory stratified analyses, these associations remained significant in the higher stroke risk group only.

                Conclusions

                Our preliminary findings suggest that SCD severity is associated with cognition and brain markers of preclinical AD in otherwise healthy older adults with overall low CVD burden and that this relationship may be stronger for individuals with higher stroke risk, although larger studies with more diverse samples are needed to confirm these findings. Our results shed light on individual characteristics that may increase the utility of SCD as an early risk marker of cognitive decline.
                  Cover page: Greater subjective cognitive decline severity is associated with worse memory performance and lower entorhinal cerebral blood flow in healthy older adults
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2018)
                  Subjective cognitive decline (SCD) is common in older adults and may be an early marker of future cognitive decline. Research suggest that SCD is more closely related to concurrent symptoms of depression than to objective cognitive performance in non-Hispanic Whites, but it is unknown whether the associations of SCD, cognition, and depression manifest differently in Hispanic older adults. We examined if SCD is associated with objective cognitive performance or with depression symptoms in 145 Hispanic individuals ages 60 or older referred by community health clinics for screening of cognitive complaints. All participants lived near the U.S.-Mexico border, spoke Spanish only, or were Spanish-English bilingual. Memory-only and global cognitive composites were created from scores on Spanish versions of several neuropsychological tests. The Geriatric Depression Scale (GDS) and a five-item SCD questionnaire developed by our group were also completed. Multiple regression analyses showed no significant associations between SCD and memory or global cognitive composite scores after adjusting for age, sex, education, and GDS score. In contrast, there was a significant association between GDS and SCD after adjusting for age, sex, education, global and memory composite scores. Findings suggest that SCD does not accurately reflect current cognitive status in older Hispanics who present to their primary care physician with cognitive complaints. Clinicians should interpret SCD in this population within the context of information about symptoms of depression. Longitudinal research is needed in older Hispanics to better characterize SCD in this population and to determine if it can predict future cognitive decline.
                    Cover page: Subjective Cognitive Decline, Objective Cognition, and Depression in Older Hispanics Screened for Memory Impairment.
                    • Article
                    • Peer Reviewed
                    UC San Diego Previously Published Works (2018)
                    UNLABELLED: This paper reports on the findings and recommendations specific to older adults from the Tech Summit: Innovative Tools for Assessing Diet and Physical Activity for Health Promotion forum organized by the North American branch of the International Life Sciences Institute. The summit aimed to investigate current and emerging challenges related to improving energy balance behavior assessment and intervention via technology. The current manuscript focuses on how novel technologies are applied in older adult populations and enumerated the barriers and facilitators to using technology within this population. Given the multiple applications for technology in this population, including the ability to monitor health events and behaviors in real time, technology presents an innovative method to aid with the changes associated with aging. Although older adults are often perceived as lacking interest in and ability to adopt technologies, recent studies show they are comfortable adopting technology and user uptake is high with proper training and guided facilitation. Finally, the conclusions suggest recommendations for future research, including the need for larger trials with clinical outcomes and more research using end-user design that includes older adults as technology partners who are part of the design process. THEME INFORMATION: This article is part of a theme issue entitled Innovative Tools for Assessing Diet and Physical Activity for Health Promotion, which is sponsored by the North American branch of the International Life Sciences Institute.
                      Cover page: Diet and Activity Assessments and Interventions Using Technology in Older Adults.
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