Apraxia and Alzheimer’s Disease: Review and Perspectives

Apraxia is one of the cognitive deficits that characterizes Alzheimer’s disease. Despite its prevalence and relevance to diagnosing Alzheimer’s disease, this topic has received little attention and is without comprehensive review. The review herein is aimed to fill this gap by first presenting an overview of the impairment caused in different clinical situations: pantomime of tool use, single tool use, real tool use, mechanical problem solving, function and manipulation knowledge tasks, and symbolic/meaningless gestures. On the basis of these results, we then propose alternative interpretations regarding the nature of the underlying mechanisms impaired by the disease. Also presented are principal methodological issues precluding firm conclusions from being drawn.     

Recollection and Familiarity in Aging Individuals with Mild Cognitive Impairment and Alzheimer’s Disease: A Literature Review

Memory impairment is a central cognitive symptom in mild cognitive impairment (MCI) and Alzheimer Disease (AD). Recognition tasks are often used to characterize and define the nature of memory deficits. Dual-process theories posit that familiarity and recollection are independently involved in the recognition of previously encountered material and both contribute to successful recognition. Recent evidence indicates that there is a double dissociation in the neuronal substrates of those two processes. More precisely, it has been suggested that perirhinal and entorhinal areas are selectively involved in familiarity-based recognition, while the hippocampus is associated with recollection. Interestingly, these regions are among the first to be targeted by neurofibrillary tangles, one of AD’s neuropathological hallmarks. Impairment in recognition performance can occur in the very early stages of AD, such as MCI. To define the nature of recognition impairment in these clinical populations, we reviewed the current literature on familiarity and recollection performance in individuals with MCI and AD. Together with clinical features, methodological factors are taken into consideration in the interpretation of findings.     

Sleep Disorders and Cognitive Dysfunctions in Parkinson’s Disease: A Meta-Analytic Study

Neuropsychology Review - A relationship between sleep disorders and cognitive dysfunctions was reported in Parkinson’s Disease (PD), however, some studies did not confirm the link. A...     

Motor-Skill Learning in Alzheimer’s Disease: A Review with an Eye to the Clinical Practice

Since elderly people suffering from dementia want to go on living independently for as long as possible, they need to be able to maintain familiar and learn new practical skills. Although explicit or declarative learning methods are mostly used to train new skills, it is hypothesized that implicit or procedural techniques may be more effective in this population. The present review discusses 23 experimental studies on implicit motor-skill learning in patients with Alzheimer’s disease (AD). All studies found intact implicit motor-learning capacities. Subsequently, it is elaborated how these intact learning abilities can be exploited in the patients’ rehabilitation with respect to the variables ‘practice’ and ‘feedback.’ Recommendations for future research are provided, and it is concluded that if training programs are adjusted to specific needs and abilities, older people with AD are well able to (re)learn practical motor skills, which may enhance their autonomy.     

The Effects of Healthy Aging,Amnestic Mild Cognitive Impairment,and Alzheimer’s Disease on Recollection and Familiarity: A Meta-Analytic Review

It is well established that healthy aging, amnestic Mild Cognitive Impairment (aMCI), and Alzheimer’s Disease (AD) are associated with substantial declines in episodic memory. However, there is still debate as to how two forms of episodic memory – recollection and familiarity – are affected by healthy and pathological aging. To address this issue we conducted a meta-analytic review of the effect sizes reported in studies using remember/know (RK), receiver operating characteristic (ROC) and process dissociation (PD) methods to examine recollection and familiarity in healthy aging (25 published reports), aMCI (9 published reports), and AD (5 published reports). The results from the meta-analysis revealed that healthy aging is associated with moderate-to-large recollection impairments. Familiarity was not impaired in studies using ROC or PD methods but was impaired in studies that used the RK procedure. aMCI was associated with large decreases in recollection whereas familiarity only tended to show a decrease in studies with a patient sample comprised of both single-domain and multiple-domain aMCI patients. Lastly, AD was associated with large decreases in both recollection and familiarity. The results are consistent with neuroimaging evidence suggesting that the hippocampus is critical for recollection whereas familiarity is dependent on the integrity of the surrounding perirhinal cortex. Moreover, the results highlight the relevance of method selection when examining aging, and suggest that familiarity deficits might be a useful behavioral marker for identifying individuals that will develop dementia.     

Working Memory and Learning in Early Alzheimer’s Disease

Cognitive deficits associated with early Alzheimers disease (AD) have been recently operationalised in terms of an acquisition deficit and the research supporting this view is presented. However, there is still debate concerning the nature of this deficit and how underlying cognitive processes may be detrimentally affecting the ability to acquire new information in early AD. This review argues that the pattern of cognitive deficits contributing to the acquisition impairment in early AD patients may be readily interpreted within the context of a working memory model. Isolating the component processes of working memory that underlie the acquisition deficit in early AD patients will aid in the design of clinical applications that are focussed at enhancing the ability to acquire new information in everyday life.     

Detectable Neuropsychological Differences in Early Preclinical Alzheimer’s Disease: A Meta-Analysis

The development of methods for in vivo detection of cerebral beta amyloid retention and tau accumulation have been increasingly useful in characterizing preclinical Alzheimer’s disease (AD). While the association between these biomarkers and eventual AD has been demonstrated among cognitively intact older adults, the link between biomarkers and neurocognitive ability remains unclear. We conducted a meta-analysis to test the hypothesis that cognitively intact older adults would show statistically discernable differences in neuropsychological performance by amyloid status (amyloid negative = A-, amyloid positive = A+). We secondarily hypothesized a third group characterized by either CSF tau pathology or neurodegeneration, in addition to amyloidosis (A+/N+ or Stage 2), would show lower neuropsychology scores than the amyloid positive group (A+/N- or Stage 1) when compared to the amyloid negative group. Pubmed, PsychINFO, and other sources were searched for relevant articles, yielding 775 total sources. After review for inclusion/exclusion criteria, duplicates, and risk of bias, 61 studies were utilized in the final meta-analysis. Results showed A+ was associated with poorer performance in the domains of global cognitive function, memory, language, visuospatial ability, processing speed, and attention/working memory/executive functions when compared to A-. A+/N+ showed lower performances on memory measures when compared to A+/N- in secondary analyses based on a smaller subset of studies. Results support the notion that neuropsychological measures are sensitive to different stages of preclinical AD among cognitively intact older adults. Further research is needed to determine what constitutes meaningful differences in neuropsychological performance among cognitively intact older adults.     

Functional Neural Correlates of Anosognosia in Mild Cognitive Impairment and Alzheimer’s Disease: a Systematic Review

Neuropsychology Review - Functional neuroimaging techniques (i.e. single photon emission computed tomography, positron emission tomography, and functional magnetic resonance imaging) have been used...     

Cognitive Rehabilitation Therapies for Alzheimer’s Disease: A Review of Methods to Improve Treatment Engagement and Self-Efficacy

Cognitive rehabilitation therapies for Alzheimer’s disease (AD) are becoming more readily available to the geriatric population in an attempt to curb the insidious decline in cognitive and functional performance. However, people with AD may have difficulty adhering to these cognitive treatments due to denial of memory deficits, compromised brain systems, cognitive incapacity for self-awareness, general difficulty following through on daily tasks, lack of motivation, hopelessness, and apathy, all of which may be either due to the illness or be secondary to depression. Cognitive rehabilitation training exercises are also labor intensive and, unfortunately, serve as a repeated reminder about the memory impairments and attendant functional consequences. In order for cognitive rehabilitation methods to be effective, patients must be adequately engaged and motivated to not only begin a rehabilitation program but also to remain involved in the intervention until a therapeutic dosage can be attained. We review approaches to cognitive rehabilitation in AD, neuropsychological as well as psychological obstacles to effective treatment in this population, and methods that target adherence to treatment and may therefore be applicable to cognitive rehabilitation therapies for AD. The goal is to stimulate discussion among researchers and clinicians alike on how treatment effects may be mediated by engagement in treatment, and what can be done to enhance patient adherence for cognitive rehabilitation therapies in order to obtain greater cognitive and functional benefits from the treatment itself.     

Cognitive Differences Between Patients with Left-sided and Right-sided Parkinson’s Disease. A Review

At disease onset, patients with Parkinson’s disease (PD) typically report one side of the body to be more affected than the other. Previous studies have reported that this motor symptom asymmetry is associated with asymmetric dopaminergic degeneration in the brain. Research on the cognitive repercussions of this asymmetric degeneration has yielded inconsistent results. Here, we review studies that reported on the cognitive performance of patients with left-sided (LPD) or right-sided (RPD) motor symptom predominance. We present evidence that patients with RPD typically experience problems with language-related tasks and verbal memory, whereas patients with LPD more often perform worse on tasks of spatial attention, visuospatial orienting and memory and mental imagery. In general, no differences were found between both groups on tasks measuring attention and executive function. The association between motor asymmetry and cognitive performance indicates that PD does not lead to one typical cognitive profile. The effect of symptom laterality on the cognitive complaints should be considered in the assessment and treatment of each individual patient.     

Memory for Music in Alzheimer’s Disease: Unforgettable?

The notion that memory for music can be preserved in patients with Alzheimer’s Disease (AD) has been raised by a number of case studies. In this paper, we review the current research examining musical memory in patients with AD. In keeping with models of memory described in the non-musical domain, we propose that various forms of musical memory exist, and may be differentially impaired in AD, reflecting the pattern of neuropathological changes associated with the condition. Our synthesis of this literature reveals a dissociation between explicit and implicit musical memory functions. Implicit, specifically procedural musical memory, or the ability to play a musical instrument, can be spared in musicians with AD. In contrast, explicit musical memory, or the recognition of familiar or unfamiliar melodies, is typically impaired. Thus, the notion that music is unforgettable in AD is not wholly supported. Rather, it appears that the ability to play a musical instrument may be unforgettable in some musicians with AD.     

Functional Brain Connectivity Using fMRI in Aging and Alzheimer’s Disease

Normal aging and Alzheimer’s disease (AD) cause profound changes in the brain’s structure and function. AD in particular is accompanied by widespread cortical neuronal loss, and loss of connections between brain systems. This degeneration of neural pathways disrupts the functional coherence of brain activation. Recent innovations in brain imaging have detected characteristic disruptions in functional networks. Here we review studies examining changes in functional connectivity, measured through fMRI (functional magnetic resonance imaging), starting with healthy aging and then Alzheimer’s disease. We cover studies that employ the three primary methods to analyze functional connectivity—seed-based, ICA (independent components analysis), and graph theory. At the end we include a brief discussion of other methodologies, such as EEG (electroencephalography), MEG (magnetoencephalography), and PET (positron emission tomography). We also describe multi-modal studies that combine rsfMRI (resting state fMRI) with PET imaging, as well as studies examining the effects of medications. Overall, connectivity and network integrity appear to decrease in healthy aging, but this decrease is accelerated in AD, with specific systems hit hardest, such as the default mode network (DMN). Functional connectivity is a relatively new topic of research, but it holds great promise in revealing how brain network dynamics change across the lifespan and in disease.     

Family History and APOE-4 Genetic Risk in Alzheimer’s Disease

Identifying risk factors for Alzheimer's disease, such as carrying the APOE-4 allele, and understanding their contributions to disease pathophysiology or clinical presentation is critical for establishing and improving diagnostic and therapeutic strategies. A first-degree family history of Alzheimer's disease represents a composite risk factor, which reflects the influence of known and unknown susceptibility genes and perhaps non-genetic risks. There is emerging evidence that investigating family history risk associated effects may contribute to advances in Alzheimer's disease research and ultimately clinical practice.     

Antisaccades in Parkinson’s Disease: A Meta-Analysis

Neuropsychology Review - The usefulness of eye-tracking tasks as potential biomarkers for motor or cognitive disease burden in Parkinson’s disease (PD) has been subject of debate for many...     

A Systematic Review of Neurocognitive Functioning in Behçet’s Disease

Neuropsychology Review - Behçet’s disease (BD) is a vascular, inflammatory multisystem disorder with neuro-Behçet’s (NBD) diagnosed in a subset of patients with neurological...     

Early Detection of Memory Impairment in Alzheimer’s Disease: A Neurocognitive Perspective on Assessment

We propose that the earliest neuropsychological detection of Alzheimer’s disease (AD) can be informed by current views about the neuropathogenesis of AD and cognitive models of memory and its neurobiological substrates. The primary impairment in early AD is encoding/consolidation, resulting from medial temporal lobe (MTL) pathology. On theoretical and empirical grounds, paired associate learning (PAL) appears to be the ideal paradigm for detecting MTL dysfunction in early AD. It has not been embraced as a test of choice, however, and this critical review discusses why the paradigm may have not fulfilled its potential. We suggest that a new PAL variant, ‘associate-recognition’, may prove to be clinically efficacious.     

Family Support in Children’s Mental Health: A Review and Synthesis

A comprehensive review of structured family support programs in children’s mental health was conducted in collaboration with leadership from key national family organizations. The goals were to identify typologies of family support services for which evaluation data existed and identify research gaps. Over 200 programs were examined; 50 met criteria for inclusion. Programs were categorized by whether they were delivered by peer family members, clinicians, or teams. Five salient components of family support were identified: (a) informational, (b) instructional, (c) emotional, (d) instrumental, and (e) advocacy. Clinician-led programs were heavily represented (n = 33, 66%), followed by family-led (n = 11, 22%), and team-delivered (n = 6, 12%) programs. Key differences between programs delivered by clinicians or by peer family members were found in the degree of emphasis, research methodology, and outcomes. However, the content of the components was similar across all three program types. There are both important differences in emphasis across typologies of family support provided by clinicians, family members, or teams as well as important similarities in content. Family-delivered support may be an important adjunct to existing services for parents, although the research base remains thin. A research agenda to promote more rigorous evaluations of these services especially those delivered by peer family members is critical.     

Everyday material engagement: supporting self and personhood in people with Alzheimer’s disease

Phenomenology and the Cognitive Sciences - Threats to the self and personhood of people with ADRD include the disturbing images of Alzheimer’s disease as the death before death, culturally...