Mechanisms Underlying Age- and Performance-related Differences in Working Memory

This study took advantage of the subsecond temporal resolution of ERPs to investigate mechanisms underlying age- and performance-related differences in working memory. Young and old subjects participated in a verbal n-back task with three levels of difficulty. Each group was divided into high and low performers based on accuracy under the 2-back condition. Both old subjects and low-performing young subjects exhibited impairments in preliminary mismatch/match detection operations (indexed by the anterior N2 component). This may have undermined the quality of information available for the subsequent decision-making process (indexed by the P3 component), necessitating the appropriation of more resources. Additional anterior and right hemisphere activity was recruited by old subjects. Neural efficiency and the capacity to allocate more resources to decision-making differed between high and low performers in both age groups. Under low demand conditions, high performers executed the task utilizing fewer resources than low performers (indexed by the P3 amplitude). As task requirements increased, high-performing young and old subjects were able to appropriate additional resources to decision-making, whereas their low-performing counterparts allocated fewer resources. Higher task demands increased utilization of processing capacity for operations other than decision-making (e.g., sustained attention) that depend upon a shared pool of limited resources. As demands increased, all groups allocated additional resources to the process of sustaining attention (indexed by the posterior slow wave). Demands appeared to have exceeded capacity in low performers, leading to a reduction of resources available to the decision-making process, which likely contributed to a decline in performance

The influence of executive capacity on selective attention and subsequent processing

Recent investigations that suggest selective attention (SA) is dependent on top-down control mechanisms lead to the expectation that individuals with high executive capacity (EC) would exhibit more robust neural indices of SA. This prediction was tested by using event-related potentials (ERPs) to examine differences in markers of information processing across 25 subjects divided into two groups based on high vs. average EC, as defined by neuropsychological test scores. Subjects performed an experimental task requiring SA to a specified color. In contrast to expectation, individuals with high and average EC did not differ in the size of ERP indices of SA: the anterior Selection Positivity (SP) and posterior Selection Negativity (SN). However, there were substantial differences between groups in markers of subsequent processing, including the anterior N2 (a measure of attentional control) and the P3a (an index of the orienting of attention). EC predicted speed of processing at both early and late attentional stages. Individuals with lower EC exhibited prolonged SN, P3a, and P3b latencies. However, the delays in carrying out SA operations did not account for subsequent delays in decision making, or explain excessive orienting and reduced attentional control mechanisms in response to stimuli that should have been ignored. SN latency, P3 latency, and the size of the anterior N2 made independent contributions to the variance of EC. In summary, our findings suggest that current views regarding the relationship between top-down control mechanisms and SA may need refinement

Beyond Prognosis Communication: Exploring The Existential Dimensions Of Palliative Care Conversations With Adults With Advanced Cancer

Communication about prognosis is integral to effective palliative care. However, prognosis communication often entails considering mortality, which can trigger existential questions. We understand very little about how existential experience is communicated in palliative care conversations. To fill this gap, this dissertation addresses the following aims: (1) Clarify the concept of the existential experience within the context of adults with advanced cancer (Chapter 2); (2) Describe how patients, families, and clinicians communicate about existential experience in palliative care conversations (Chapter 3); and (3) Explore the intersection between prognosis communication and existential dimensions of conversation (Chapter 4). To accomplish Aim 1, we synthesized published qualitative literature regarding how adults with advanced cancer describe their existential experience. Using Rodgers’ evolutionary method of concept analysis, we conceptualize existential experience as a dynamic state, preceded by confronting mortality, defined by diverse reactions to shared existential challenges related to parameters of existence (body, time, others, and death), resulting in a dialectical movement between existential suffering and joy. To address Aims 2 and 3, we analyzed a randomly selected subset of an existing Palliative Care Communication Research Initiative (PCCRI) study dataset. PCCRI data includes verbatim transcripts of inpatient palliative care consultations with adults with advanced cancer. Using a qualitative descriptive approach, we found that overall, existential communication was woven within palliative care conversations, and related to key themes of: 1) Time as a pressing boundary; 2) Maintaining a coherent self; and 3) Connecting with others. In Chapter 4, we took a mixed methods approach, quantitatively stratifying the study sample by levels of prognosis communication and qualitatively describing existential dimensions of conversations within and across none, low, and high levels of prognosis communication. We found existential and prognosis communication were deeply interconnected. Additionally, existential communication was more common within conversations with higher levels of prognosis communication, representing an existential shift compared to the more physical focus of conversations with no prognosis communication. This dissertation generates new knowledge about how existential experience is communicated during naturally-occurring palliative care conversations. Our findings have implications for improving how we communicate with, and care for, individuals with advanced cancer and their families

End-of-Life Decision Making in Chronic Life-Limiting Disease: A Concept Analysis and Conceptual Model

Most deaths from chronic life-limiting diseases are preceded by end-of-life decisions, yet patients and caregivers are ill-equipped to make them. The lack of a common vocabulary surrounding end-of-life decision making and the paucity of conceptual models that explicate its components hamper improvements in clinical practice and research. Walker and Avant’s method for concept analysis was used to investigate uses of “end-of-life decision making” in the literature in order to identify its components (antecedents, attributes, consequences), describe stakeholder roles (patients, family/caregivers, health care providers), and develop a conceptual model. An iterative search strategy resulted in 143 included sources. These encompassed 1,127,095 patients (primarily older adults), 3,384 family/caregivers, and 588 healthcare providers. Evidence revealed that end-of-life decision making is a process, not a discrete event. This begins with preparation (antecedents), which involves the designation of a decision maker and iterative patient, family/caregiver, and healthcare provider communication across the chronic illness. These preparatory processes inform end-of-life decisions, which possess three attributes: 1) serial choices in the terminal illness phase that are 2) weighed in terms of their potential outcomes 3) through patient and family/caregiver collaboration. The components impact patients’ death experiences, caregivers’ bereavement, and healthcare systems (outcomes). The resulting conceptual model highlights the larger context of preparation (beyond advance care planning) and the prominent role of caregivers in the end-of-life decision making process. Enhanced measurement must account for the dose, content, and quality of the preparation and decision components that collectively contribute to outcomes, which holds implications for practice improvements and research

Does compensatory neural activity survive old-old age?

One mechanism that may allow older adults to continue to successfully perform certain cognitive tasks is to allocate more resources than their younger counterparts. Most prior studies have not included individuals beyond their 70s. Here, we investigated whether compensatory increases in neural activity previously observed in cognitively high-performing young-old adults would continue into old-old age. Event-related potentials were recorded from 72 cognitively high performing subjects, aged 18 to 96 years old, while they participated in a subject-controlled novelty oddball paradigm in which they determined viewing duration of standard, target, and novel visual stimuli. Compared to young and middle-aged subjects, both young-old and old-old subjects exhibited an impairment of preliminary mismatch/match detection operations, indexed by an attenuated anterior N2 component. This may have placed a greater burden on the subsequent controlled decision-making process, indexed by the P3, necessitating the allocation of more resources. The relationship between age and resource allocation, as measured by P3 amplitude, from midlife to very old age (45-96 years old) followed an inverted u-shaped curve (quadratic function). It peaked between the late 60s and early 70s. Thereafter, there was an inverse relationship between age and resource appropriation. This relationship remained significant after controlling for differences in task performance and MMSE. Examining the size of the P3 component across different age groups suggests that although cognitively high performing adults in their early 80s exhibit a reduction in P3 amplitude, they have a relatively well-preserved capacity to appropriate resources. However, by the late 80s, there is a robust decline (relative to young-old adults) in the size of the P3. Our results indicate that when carrying out controlled processing linked to directing attention to salient events, cognitively high performers reach the boundary of their capacity, albeit relatively late in life. This limits their ability to appropriate additional resources as compensatory activity for age-related impairments in earlier visual processing, and suggests that such a mechanism does not tend to "survive" old-old age

Age-related changes in early novelty processing as measured by ERPs

This study investigated age-related changes in the early processing of novel visual stimuli using ERPs. Well-matched old (n=30), middle-aged (n=30), and young (n=32) subjects were presented standard, target/rare, and perceptually novel visual stimuli under Attend and Ignore conditions. Our results suggest that the anterior P2 component indexes the motivational salience of a stimulus as determined by either task relevance or novelty. Its enhancement by focused attention does not decrease with age. Its responsiveness to novel stimuli is particularly striking in older adults. The age-related increase in the anterior P2 to novel visual stimuli does not appear to be due to impaired inhibitory control associated with aging. Rather, the enhanced anterior P2 to novel stimuli in older adults may be linked to age-related changes in the process of matching unusual visual stimuli to stored representations, which is indexed by the temporally overlapping anterior N2 component whose amplitude substantially decreases with age

Does modulation of selective attention to features reflect enhancement or suppression of neural activity?

Numerous studies have demonstrated that selective attention to color is associated with a larger neural response under attend than ignore conditions, but have not addressed whether this difference reflects enhanced activity under attend or suppressed activity under ignore. In this study, a color-neutral condition was included, which presented stimuli physically identical to those under attend and ignore conditions, but in which color was not task relevant. Attention to color did not modulate the early sensory-evoked P1 and N1 components. Traditional ERP markers of early selection (the anterior Selection Positivity and posterior Selection Negativity) did not differ between the attend and neutral conditions, arguing against a mechanism of enhanced activity. However, there were markedly reduced responses under the ignore relative to the neutral condition, consistent with the view that early selection mechanisms reflect suppression of neural activity under the ignore condition

Acceptability of psilocybin‐assisted group therapy in patients with cancer and major depressive disorder: Qualitative analysis

International audienceAbstractBackgroundThe present study explored the acceptability of psilocybin‐assisted group therapy from the perspective of patients with cancer and depression who participated in a clinical trial assessing the safety and efficacy of this novel intervention.MethodsGuided by the conceptual framework of acceptability, the authors conducted semi‐structured interviews with participants of the psilocybin trial. Data were analyzed using template and thematic analyses.ResultsParticipants’ (n = 28) perspectives on the acceptability of the group and simultaneous sessions was generally positive, both in terms of safety and efficacy: first, the groups contributed to increase participants’ sense of safety and preparedness as they were engaging in the therapy; and second, the groups fostered a sense of connection and of belonging, which served to enrich and deepen the meaning of participants’ experience, ultimately opening a dimension of self‐transcendence and compassion. Other subthemes related to factors influencing the acceptability of the group approach included: 1) the importance of the therapeutic framework, 2) the complementary value of individual sessions, 3) disruptive factors related to the group and/or simultaneous setting, and 4) opportunities and challenges related to group size and how to structure interactions.ConclusionsThis study enhances understanding of what promotes acceptability of the psilocybin‐assisted therapy group model for the treatment of MDD in cancer patients.Plain Language Summary We conducted exit interviews with participants of a phase 2 trial of psilocybin‐assisted therapy (PAT) conducted in a community cancer center, to assess the acceptability of a novel psilocybin delivery model combining simultaneous individual therapy and group sessions. Our findings support the acceptability of this intervention and suggest that in addition to being feasible, it might also enhance participants’ perceived safety and efficacy compared to uniquely individual or group delivery models of PAT. Our analysis highlights critical factors conditioning acceptability and suggests new ways PAT may be scaled and integrated into cancer care. </jats:sec