Jacqueline Zöllig

Prospective memory in schizophrenia : The impact of varying retrospective-memory load

The present study investigated event-based prospective memory in individuals with schizophrenia (n = 23) and healthy controls (n = 23). The retrospective-memory load was varied to disentangle the relative contributions of the retrospective and prospective components on prospective-memory functioning. A generalized prospective-memory deficit in schizophrenia emerged, with significant impairment evident even when retrospective-memory demands were minimal. Exploratory analyses suggest that both the retrospective and the prospective components contribute to the prospective-memory deficit in schizophrenia.

Sleep quality and cognitive function in healthy old age: the moderating role of subclinical depression.

OBJECTIVE Previous research has yielded inconclusive results on the relationship between self-reported sleep quality and cognitive performance in healthy old age. Discrepant findings have been reported regarding processing speed and attention, executive functions, and episodic memory. However, sleep quality has also been found to be related to cognitive performance in patients with depression. Our aim was to clarify the relationship between sleep quality and cognitive performance in healthy older adults, and to evaluate the moderating role of subclinical depression on this relationship. METHOD The Pittsburgh Sleep Quality Index was used to assess subjective sleep quality in 107 participants (age ≥ 61 years). A broad battery of neuropsychological tests measured basic cognitive processes, executive functions, and memory processes. RESULTS Subclinical depression moderated the link between sleep quality and cognitive performance. More precisely, poorer sleep quality was associated with lower performance in reasoning, semantic fluency, and shifting in those with high versus low levels of subclinical depression. CONCLUSION Our findings suggest that poor sleep quality might affect higher order cognitive processes, particularly in those reporting higher levels of subclinical depression. Findings on the relationships between sleep quality, cognitive functioning, and depressive symptomatology are discussed in relation to neurobehavioral theories of sleep.

Measuring compensation and its plasticity across the lifespan.

PURPOSE The present paper integrates two important aspects when studying compensation: (1) the knowledge about specific compensational mechanisms and (2) the consideration of lifelong changes in these mechanisms (i.e., plasticity of compensation). Hence, the paper addresses the questions (a) which neural networks are supporting successful cognitive performance across development, (b) what are the associated compensational mechanisms and (c) are these compensational mechanisms plastic across the lifespan. METHODS To answer these questions, we suggest to integrate behavioural and neuroimaging methods and present specific methods and their advantages and disadvantages. RESULTS We will illustrate the relevance of this integration by presenting data using ERPs and (s)LORETA to study compensational processes across the lifespan in a higher order cognitive function, i.e., delayed intentional behaviour. A higher activation in old adults or adolescents in successful trials compared to young adults is considered compensatory as specialized cortical regions are selectively recruited in response to task demands. CONCLUSIONS Findings show that whereas the performance outcome might be the same across age groups, underlying processes and activations might be fundamentally different. We conclude with a discussion about specific implications of this integrative approach when studying the adaptive potentials and limits of human cognition.

Forming intentions successfully: Differential compensational mechanisms of adolescents and old adults

INTRODUCTION Forming an intention is a key aspect of prospective memory, i.e., the ability to encode, retain, and later realize an intention with a delay of minutes, hours or days. Behavioural and neurophysiological findings from both prospective and retrospective memory research suggest that the efficiency of encoding processes is reduced at both ends of the lifespan and that neural generators underlying successful encoding might differ in childhood and old age. Hence, the present study investigates compensational neural mechanisms during the encoding of intentions in adolescents and old adults compared to young adults. METHODS We compared Event-Related Potentials (ERPs) and their source localization in 14 adolescents (11-13 years), 14 young adults (18-25 years), and 14 old adults (64-79 years) in a prospective memory task that was embedded in a semantic categorization task. RESULTS Our data revealed three event-related modulations that differentiate between conditions (i.e., ongoing activity and successful intention formation trials) and groups. Source localizations of these modulations with standardized low-resolution electromagnetic tomography (sLORETA) revealed compensational activations in adolescents and old adults compared to young adults in successful intention formation trials: while adolescents showed a higher activation of secondary occipital regions in the time window of 500-1200 msec with a maximum around 800 msec, old adults activated prefrontal regions to a greater extent beginning at 700 msec, persisting until 1200 msec and expanding to middle temporal regions. CONCLUSION For a successful encoding of intentions adolescents and old adults recruit more neural generators than young adults. More importantly, the pattern of these compensational activations is different when comparing adolescents with young adults and old adults with young adults. These differences are discussed with regard to differential maturational changes in the brain.

Age-Related Differences in the Temporal Dynamics of Prospective Memory Retrieval: A Lifespan Approach.

The efficiency of prospective memory (PM) typically increases from childhood to young adulthood and then decreases in later adulthood. The current study used event-related brain potentials (ERPs) to examine the development of the neural correlates of processes associated with the detection of a PM cue, switching from the ongoing activity to the prospective task, retrieval of the intention from memory or task set configuration, and strategic monitoring of the environment. The study included 99 participants that were 7.5-83 years of age. Slow wave activity related to strategic monitoring was reliable across the lifespan suggesting that all ages were able to allocate attentional resources to facilitate PM. Additionally, components of the ERPs related to cue detection, switching, and task configuration were reliable across the lifespan, suggesting that similar processes contribute to PM at all ages. In children, PM errors may have resulted from a decoupling of processes supporting cue detection and switching from the ongoing activity to the prospective element of the task. In younger and older adults, PM errors appeared to result from the failure to detect PM cues in the environment. These findings lead to the conclusion that different processes may contribute to variation in PM across the lifespan.

Plasticity and imaging research in healthy aging: core ideas and profile of the International Normal Aging and Plasticity Imaging Center (INAPIC).

The key objective of the International Normal Aging and Plasticity Imaging Center (INAPIC) at the University of Zürich is to facilitate research on normal healthy behavioral and neural development and aging to explore the potential for plasticity and compensation across the lifespan. The INAPIC invites international research groups to submit proposals for collaborative projects on these subjects. It is unique in Europe in giving partner groups ‘plug and play’ access to state-of-the-art neuroimaging techniques, technical support, and assistance in data collection. This article introduces the core ideas of the INAPIC, its key research areas, and the available infrastructure.

Multi-domain training in healthy old age: Hotel Plastisse as an iPad-based serious game to systematically compare multi-domain and single-domain training

Finding effective training interventions for declining cognitive abilities in healthy aging is of great relevance, especially in view of the demographic development. Since it is assumed that transfer from the trained to untrained domains is more likely to occur when training conditions and transfer measures share a common underlying process, multi-domain training of several cognitive functions should increase the likelihood of such an overlap. In the first part, we give an overview of the literature showing that cognitive training using complex tasks, such as video games, leisure activities, or practicing a series of cognitive tasks, has shown promising results regarding transfer to a number of cognitive functions. These studies, however, do not allow direct inference about the underlying functions targeted by these training regimes. Custom-designed serious games allow to design training regimes according to specific cognitive functions and a target populations need. In the second part, we introduce the serious game Hotel Plastisse as an iPad-based training tool for older adults that allows the comparison of the simultaneous training of spatial navigation, visuomotor function, and inhibition to the training of each of these functions separately. Hotel Plastisse not only defines the cognitive functions of the multi-domain training clearly, but also implements training in an interesting learning environment including adaptive difficulty and feedback. We propose this novel training tool with the goal of furthering our understanding of how training regimes should be designed in order to affect cognitive functioning of older adults most broadly.

Prospective memory across the lifespan: Investigating the contribution of retrospective and prospective processes

ABSTRACT Prospective memory performance follows an inverted U-shaped function across the lifespan. Findings on the relative contribution of purely prospective memory and retrospective memory processes within prospective memory to this trajectory are scarce and inconclusive. We analyzed age-related differences in prospective memory performance across the lifespan in a cross-sectional design including six age groups (N = 99, 7–83 years) and investigated possible mechanisms by experimentally disentangling the relative contributions of retrospective memory and purely prospective memory processes. Results confirmed the inverted U-shaped function of prospective memory performance across the lifespan. A significant interaction between process type and age group was observed indicating differential relative contributions of retrospective memory and purely prospective memory processes on the development of prospective memory performance. Our results showed that mainly the pure prospective memory processes within prospective memory lead to lower prospective memory performance in young children and old adults. Moreover, the relative contributions of the retrospective memory and purely prospective memory processes are not uniform at both ends of the lifespan, i.e., in later adulthood the purely prospective memory processes seem to determine performance to an even greater extent than in childhood. Nevertheless, age effects were also observed in the retrospective component which thus contributed to the prospective memory performance differences between the age groups.

Multi-domain training enhances attentional control

Multi-domain training potentially increases the likelihood of overlap in processing components with transfer tasks and everyday life, and hence is a promising training approach for older adults. To empirically test this, 84 healthy older adults aged 64 to 75 years were randomly assigned to one of three single-domain training conditions (inhibition, visuomotor function, spatial navigation) or to the simultaneous training of all three cognitive functions (multi-domain training condition). All participants trained on an iPad at home for 50 training sessions. Before and after the training, and at a 6-month follow-up measurement, cognitive functioning and training transfer were assessed with a neuropsychological test battery including tests targeting the trained functions (near transfer) and transfer to executive functions (far transfer: attentional control, working memory, speed). Participants in all four training groups showed a linear increase in training performance over the 50 training sessions. Using a latent difference score model, the multi-domain training group, compared with the single-domain training groups, showed more improvement on the far transfer attentional control composite. Individuals with initially lower baseline performance showed higher training-related improvements, indicating that training compensated for lower initial cognitive performance. At the 6-month follow-up, performance on the cognitive test battery remained stable. This is one of the first studies to investigate systematically multi-domain training including comparable single-domain training conditions. Our findings suggest that multi-domain training enhances attentional control involved in handling several different tasks at the same time, an aspect in everyday life that is particularly challenging for older people. (PsycINFO Database Record

Affective Learning and Psychophysiological Reactivity in Dementia Patients

We examined the association of faces with biographical information that varied in emotional content in patients with Alzheimers disease and a healthy control group. During two experimental sessions, participants rated neutral male faces on dimensions of hedonic valence and emotional arousal, later paired with fictitious biographical information. Both groups changed their ratings of the faces according to the biographical content. Free recall and recognition were tested in the second session. Patients neither recalled the biographical information nor recognized the faces, whereas the controls did. In addition, psychophysiological measures were taken in response to the face stimuli. Patients showed significant heart rate modulation as a function of their emotion ratings, whereas the controls did not. No correlation of rating changes with skin conductance was found in any group. Results suggest that psychophysiological reactions such as heart rate changes may indicate preserved affective associative learning in dementia patients despite impaired explicit memory.