Abstract
Overall, I thoroughly enjoyed reading The Preservation of Memory. The book takes on the daunting task of bridging memory research findings ranging from the cellular level through to real-life applications, and it carries this task out with aplomb. The breadth of the research covered by the volume is impressive, and it is therefore astonishing that the authors and editor manage to keep its length under 250 pages. The concise nature of the book will make it an ideal means for students, post-docs, and health care professionals alike to familiarize themselves with the main themes of memory research and its implication for treatment. Had a book such as this been available during my student days, it would have triggered many different research ideas, so my hope is that future generations of researchers and health care professionals will read it and make use of the knowledge thus acquired in their research and clinical care.
The book approaches the subject of “the preservation of memory” is neatly divided into four parts. Part I provides the reader with a short review of current memory concepts and the basic anatomy of the relevant brains structures involved in memory processes.
Chapter 1, by Rutherford and Bruno, sets the tone for the book by briefly outlining memory concepts and models, as well as their implications for aging and dementia. The authors begin with a basic history of memory research, before reviewing models of short- and long-term memory. The discussion of short-term memory models is mostly focused on classic models, such as that of Atkinson and Shifrin and that of Baddeley and Cowan; the relevant aging studies are also discussed. This is followed by a review of long-term memory models, which is, however, given much less space, as later chapters in the book discuss them in more detail. This brief introduction of the taxonomy of memory prepares the reader for the second chapter, which introduces the neuroanatomy of memory processing, with a particular focus on the hippocampus.
In the first sections of chapter 2, Leal and Yassa first briefly review the manner in which memory impairments present during aging. They review specific spatial and contextual memory deficits across species, with a particular focus on how memory interferences impact on aging memory performance. Object domain, spatial, temporal, and affective memory interferences are discussed, and the authors emphasize that such interferences are highly sensitive to the aging process. The authors then review the way in which medial temporal lobe structures deal with such interferences in memory, via pattern completion and associated neural networks. Finally, they review the way in which various neurotransmitter (e. g. acetylcholine, serotonin) affect pattern completion and separation processes, with the potential to modulate or alleviate memory deficits in aging.
Chapter 3 provides a more detailed discussion of recognition memory processes, with a particular emphasis on the dual- versus single-process model debate and its implication for aging and dementia. More explicitly, it discusses whether recollection and familiarity dissociate during aging or whether only one memory process can account for the aging findings. Chen and colleagues then introduce a new, more data-driven (i.e. model-free) approach, namely, state-trace analysis, to determine whether results from this approach support the dual- or the single-process model. The authors therefore conduct a meta-analysis of aging recognition memory studies over the last 10 years. The results and discussion of this data show that the model-free approach does seem to support dual-process accounts of recognition memory.
Chapter 4, the last chapter of part I introduces the concept of source memory and its implications for aging and dementia. Brady and Roche first define source memory as the retrieval of all forms of contextual information before reviewing the evidence to date in aging. They then discuss the main theories of the decline of source memory during aging, namely, the Associative Deficit Hypothesis, the Source Monitoring Framework, and the Misrecollection Hypothesis. It is unfortunate that the authors do not discuss in more detail how these different theories map onto the existing data, as this would have been very helpful. Still, this shortcoming is outweighed by their focus on the factors that influence the preservation of source memory. This is highly relevant to the overall theme of the book, and the factors that the authors discuss (physical exercise, mental enrichment, and memory strategies) are related to existing data, showing that all is not lost for source memory in aging. In contrast, various lifestyle and memory changes have a beneficial impact on highly contextual memories.
Part II of the book is focused on the assessment and prediction of memory problems in aging and dementia populations. Chapter 5, by Stringer et al., describes a new approach to the measurement of cognition, including memory, in older populations. The authors argue that current cognitive assessments are mostly done in clinics by trained health professionals, which limits the people that can be seen and also creates an artificial testing environment. They argue that everyday computer use could be potentially be used as a cognitive screening tool, as computer use would allow testing of motor function, higher cognitive functions, language and cognition, and games. This novel approach would allow for more ecological and widespread cognitive assessment.
Chapter 6, by Reichert et al., describes the Memory Education and Research Initiative (MERI), which tries to screen as many memory of a community as possible for potential pathological aging processes, such as dementia. More specifically, the MERI program tests participants who are concerned about their memory in a community setting. The participants undergo a comprehensive screening battery, including medical history, neuropsychological testing, and a clinical interview. Assessments can be repeated at 12- to 18-month intervals, and results of all tests are made available to other clinicians or health care professionals that the participants want to consult. The preliminary results show that the service is used by many people, with some coming for annual repeat assessments, which can have great benefits for dementia screening.
Part III of the book turns to practical applications of the memory processes explored so far. In chapter 7, Markopoulos explores how contextual information can be potentially used to boost memory retrieval. In particular, he shows how environmental context can be used as a cueing mechanism for memories. This is nicely put in context with the Encoding Specificity and Binding of Item and Context models of episodic memory. The literature reviewed in this connection shows that aging populations can use those strategies for better retrieval. Finally, the role of memory strategies in Alzheimer’s disease explored, showing that in Alzheimer’s disease there is a dissociation of contextual and item memory, with item memory remaining relatively intact in the early disease stages. Still, more ecological tests of environmental contexts show that this technique has promise in patient populations and deserves further attention.
Chapter 8, by Clark, explores a novel way of using specific encoding strategies to boost memory performance. Specifically, Clark looks at how survival specific encoding (i.e. putting the participant into a scenario where they have to remember information that is vital for their survival) has an impact on memory performance. The evidence to date clearly shows that such encoding can boost memory performance relative to other encoding conditions, which, it has been argued, is due to the evolutionary saliency of this task. Still, there are contradictory findings as to which context provides the best results, so this clearly needs further exploration. This is particularly relevant for the preservation of memory in aging and dementia, which would require the most efficacious encoding conditions.
Chapter 9 goes into more detail on how different episodic memory processes (i.e. familiarity vs recollection) are affected in aging. Tunney et al. review the human and animal literature on aging with a particular focus on Spontaneous Object Recognition, Relative Recency, and Object-in-Context. The authors note that the results of those tasks are not as clear-cut as is often argued; in particular, hippocampal lesions in rats can provide conflicting results across the tasks. In contrast, functional magnetic resonance imaging (fMRI) studies in humans show more consistent findings for the reviewed tasks, with aging people showing lower recollection performance although they seem to be able compensate for this via memory retrieval strategies. In the final section, Tunney and colleagues review the evidence on the impact of exercise on these different memory processes, which shows that either aerobic or resistance exercises can indeed improve performance in older participants.
Chapter 10 reviews the approaches of the different memory training programs which are currently available. West et al. focus in particular on three memory interventions: the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) trial, the Everyday Memory Clinic (EMC), and a theater arts program. Based on these programs, the authors review the main factors that are usually modulated via memory training programs. In particular, they review the evidence that broader gains can be achieved from the training, how change of self-evaluated belief can affect memory, and how memory training can transfer to other cognitive domains. Based on this evidence, the authors formulate a list of recommendations for memory training, including meta-memory (knowledge about memory and how it works), self-evaluative beliefs (changing the perception of the person undergoing to training with respect to what they want to achieve), strategies and practice (employing well-established encoding and retrieval strategies), social effects on training (to conduct training in a social setting), and real-world skills. The authors conclude that a multi-factorial combination of these methods would enable maximally effective memory training in elderly subjects.
Part IV, the final part of the book, takes a more practical approach to the challenge of memory in dementia. Chapter 11 focuses on keeping memories alive in patients with dementia. Malone and Redgrave stress the importance of developing creative arts solutions for boosting memory retrieval in dementia patients. They highlight this importance via a case study which employed different contextual props for themes (travel, seaside, love, and marriage) for dementia patients to recall memories. These memories, even if only fragmentary, were then used to create a story to which a whole group of dementia patients was invited to contribute their memories and thoughts to. The authors emphasize that the case study was a big success for the patients and the carers, as well as the home care staff, as it saw improved eating, sleeping, and well-being across the participants.
Chapter 12, by Smith, investigates how to include patients in the decision-making process to tailor their own memory re-learning program and make it relevant to their life. In particular, Smith emphasizes the pragmatic approach taken at the Living Lab at Liverpool John Moores University. The lab consists of a group of researchers and patients who come together to define the biggest memory challenges for the patients. After they identify the challenges, they explore solutions that can enable the patients to overcome these challenges in everyday life. Such user-led solutions are focused, in particular, on medication reminders, remembering to eat, and remembering to be active (in daily tasks, social engagements, etc.). An interesting aspect of this approach is that virtually all the solutions were technology-based, which has its own challenges.
In chapter 13, the concept of person-centered approaches and practical everyday approaches is discussed from a memory training perspective, as opposed to the technological perspective of the previous chapter. Smith and Oyebode first review the cognitive changes in everyday functioning in dementia before relating current theoretical concepts of episodic memory to everyday challenges the patients might face. They then review the major types of cognitive intervention for dementia, namely, cognitive stimulation, cognitive training, and cognitive rehabilitation. The aims, implementation, and evidence for each intervention are presented before the authors discuss a more person-centered approach to cognitive interventions and recommend methods for selecting the best intervention for each patient. Finally, the authors emphasize that other factors, such as the social environment and particularly the carer, should be taken into account before making a decision on the cognitive intervention.
Chapter 14, the final chapter of the book, reviews the role of technology in assisting people living with dementia. Renner and colleagues first review the different types of technology available to dementia patients and their families, which can be grouped into monitoring technology (usually monitoring the patient with little or no input from him/her), dementia detection systems (technology which tests the patient and send the information on to health care professionals to inform their clinical practice), and finally assistive technology (helping patients to perform everyday tasks). The authors focus on assistive technology and argue that everyday challenges can be addressed by this technology. They then propose to focus on prototype implementation and evaluation of this technology, which in turn can have a great practical impact on dementia patients and their families.
Viewed as a whole, the book explores how memory is affected in aging and disease and interventions that can help and empower people to overcome these challenges. Overall, I found the book was extremely informative, with some chapters conveying very detailed information although others painted with brushstrokes that were a bit broad for my taste. An additional shortcoming is that there in some cases the same concepts were discussed repeatedly across chapters, which is, however, a common issue in edited books. Finally, it would have been useful for some of the more practical chapters to relate more explicitly to the memory theories and models outlined in previous chapters. This is a gap which future research needs to address, but there is a potential for great progress in the area.