Cognitive and Neuroimaging Markers of Vascular Cognitive Impairment

Detection of incipient cognitive impairment and dementia pathophysiology is critical to identifying preclinical populations and target potentially disease modifying interventions towards them. There are currently concerted efforts for such detection in Alzheimer’s disease (AD). By contrast, the examination of cognitive markers and their relationship to biomarkers for vascular cognitive impairment (VCI) is far less established, despite VCI being highly prevalent and often concomitantly presenting with AD. Critically, vascular risk factors are currently associated with the most viable treatment options via pharmacological and non-pharmacological intervention, hence developing selective and sensitive methods for the identification of vascular factors have important implications for modifying dementia disease trajectories. As outlined in Chapter one, this thesis focuses on uncovering spatial navigation deficits in established and preclinical VCI and investigates potential brain dysconnectivity in the frontoparietal regions and overlapping navigation systems. Chapter two reveals egocentric orientation deficits in established VCI to distinguish it from AD. In Chapter three, the VCI case study, RK, who previously displayed spatial navigation deficits is followed up three years after initial diagnosis. Results suggest an ongoing egocentric orientation deficit whilst there are improvements in cognitive scores assessed using conventional neuropsychological assessments. Diffusion tensor imaging (DTI) analysis suggests reduced superior longitudinal fasciculus (SLF) integrity to parietal segments. Chapter four shows that a novel test battery of navigation and ERP components capture deficits that precede the onset of general cognitive decline assessed by typical neuropsychological assessment in preclinical VCI. Taken together, this research advances our conceptual understanding of the pathological changes to cognition that characterise VCI and at-risk individuals

BRAIN COMPUTER INTERFACE (BCI) ON ATTENTION: A SCOPING REVIEW

Technological innovations are now an integral part of healthcare. Brain-computer interface (BCI) is a novel technological intervention system that is useful in restoring function to people disabled by neurological disorders such as attention deficit hyperactivity disorder (ADHD), amyotrophic lateral sclerosis (ALS), cerebral palsy, stroke, or spinal cord injury. This paper surveys the literature concerning the effectiveness of BCI on attention in subjects under various conditions. The findings of this scoping review are that studies have been made on ADHD, ALS, ASD subjects, and subjects recovering from brain and spinal cord injuries. BCI based neurofeedback training is seen to be effective in improving attention in these subjects. Some studies have also been made on healthy subjects.BCI based neurofeedback training promises neurocognitive improvement and EEG changes in the elderly. Different cognitive assessments have been tried on healthy adults.   From this review, it is evident that hardly any research has been done on using BCI for enhancing attention in post-stroke subjects. So there arises the necessity for making a study on the effects of BCI based attention training in post-stroke subjects, as attention is the key for learning motor skills that get impaired following a stroke. Currently, many researches are underway to determine the effects of a BCI based training program for the enhancement of attention in post-stroke subjects

Virtual Reality as a Diagnostic Tool: A Systematic Review of Studies using Virtual Reality Technology for the Assessment of Mild Cognitive Impairment and Dementia

Dementia, a devastating, progressive disease, is typically assessed using a combination of cognitive testing, physical examination and physical tasks that test the patient’s ability to engage in instrumental activities of daily living (IADL). These tests are designed to evaluate skills such as memory, general motor skills, gaze etc. that enable us to function. Clinical settings have limited access to space and tools that can be used to design said tests. Virtual reality is a cost-effective alternative that can be utilized in such settings to diagnose MCI and dementia. Unfortunately, the research in this area thus far is scarce. This paper aims to assess the feasibility of and strengths and weaknesses associated with using virtual reality simulations as a diagnostic tool to assess neurodegenerative conditions like MCI and dementia. It will involve a systematic look at preexisting literature and offer suggestions for future research based on its findings.Master of Science in Information Scienc

Editorial: Executive function(s): Conductor, Orchestra or Symphony? Towards a Trans-Disciplinary Unification of Theory and Practice Across Development, in Normal and Atypical Groups

There are several theories of executive function(s) that tend to share some theoretical overlap yet are also conceptually distinct, each bolstered by empirical data (Norman and Shallice, 1986; Shallice & Burgess, 1991; Stuss and Alexander, 2007; Burgess, Gilbert, & Dumentheil, 2007; Burgess & Shallice, 1996; Miyake et al., 2000). The notion that executive processes are supervisory, and most in demand in novel situations was an early conceptualization of executive function that has been adapted and refined over time (Norman & Shallice, 1986; Shallice, 2001; Burgess, Gilbert & Dumentheil, 2007). Presently there is general consensus that executive functions are multi-componential (Shallice, 2001), and are supervisory only in the sense that attention in one form or another is key to the co-ordination of other hierarchically organized ‘lower’ cognitive processes. Attention in this sense is defined as (i) independent but interrelated attentional control processes (Stuss & Alexander, 2007); (ii) automatic orientation towards stimuli in the environment or internally–driven thought (Burgess, Gilbert & Dumontheil, 2007); (iii) the automatically generated interface between tacit processes and strategic conscious thought (Barker, Andrade, Romanowski, Morton and Wasti, 2006; Morton and Barker, 2010); and (iv) distinct but interrelated executive processes that maintain, update and switch across different sources of information (Miyake et al., 2000). One problem is that executive dysfunction or dysexecutive syndrome (Baddeley & Wilson, 1988) after brain injury typically produces a constellation of deficits across social, cognate, emotional and motivational domains that rarely map neatly onto theoretical frameworks (Barker, Andrade & Romanowski, 2004). As a consequence there is debate that conceptual theories of executive function do not always correspond well to the clinical picture (Manchester, Priestley & Jackson, 2004). Several studies have reported cases of individuals with frontal lobe pathology and impaired daily functioning despite having little detectable impairment on traditional tests of executive function (Shallice & Burgess, 1991; Eslinger & Damasio, 1985; Barker, Andrade & Romanowski, 2004; Andrés & Van der Linden, 2002; Chevignard et al., 2000; Cripe, 1998; Fortin, Godbout & Braun, 2003). There is also some suggestion that weak ecological validity limits predictive and clinical utility of many traditional measures of executive function (Burgess et al, 2006; Lamberts, Evans & Spikman, 2010; Barker, Morton, Morrison, McGuire, 2011). Complete elimination of environmental confounds runs the risk of generating results that cannot be generalized beyond constrained circumstances of the test environment (Barker, Andrade & Romanowski, 2004). Several researchers have concluded that a new approach is needed that is mindful of the needs of the clinician yet also informed by the academic debate and progress within the discipline (McFarquhar & Barker, 2012; Burgess et al., 2006). Finally, translational issues also confound executive function research across different disciplines (psychiatry, cognitive science, and developmental psychology) and across typically developing and clinical populations (including Autism Spectrum Disorders, Head Injury and Schizophrenia – Blakemore & Choudhury, 2006; Taylor, Barker, Heavey & McHale, 2013). Consequently, there is a need for unification of executive function approaches across disciplines and populations and narrowing of the conceptual gap between theoretical positions, clinical symptoms and measurement

Cognitive Abilities in Hearing Loss: Perceived and Performance Abilities of Adults Related to Attention, Memory, and Social Cognition

Hearing loss is the most common sensory deficit noted in aging adults. It is commonly known to reduce an individual’s ability to detect, identify, and localize sounds and speech and to cause issues in communication. However, there are other less commonly discussed impacts that hearing loss has beyond the auditory system. Literature suggests a correlation between hearing loss and cognition in aging adults. Similar to hearing loss, the domains of cognition experience performance and functional changes across the life span. In an aging adult, changes related to cognition are also suggested to be associated with hearing loss. This study aimed to add to the corpus of literature surrounding the relationship between hearing loss and cognition, specifically memory, attention, executive functioning, and social cognition in adults with and without hearing loss. The purpose of this multi-methods study was to describe if group differences in adults with and without hearing loss existed between perceived and performance-related cognitive abilities. The study focused on twenty-eight adults between the ages of 50-69 years; fourteen adults had normal hearing, while fourteen adults had hearing loss which ranged in the mild to moderate sensorineural range. Based on age and hearing loss, adults were separated into four distinct groups: normal hearing between the ages of 50-59 years, hearing loss between the ages of 50-59 years, normal hearing between the ages of 60-69 years, and hearing loss between the ages of 60-69 years. Performance-related cognitive abilities were assessed through five different cognitive assessments: the Weschler Memory Scale, Weschler Adult Intelligence Scale, Faux Pas stories, Advanced Clinical Solutions, and Bluegrass Short-Term Memory task. Perceived abilities were addressed through structured, open-ended questions that centered around the impacts of hearing and hearing loss and an individual’s communication abilities. The first aim examined how adults described the impacts of hearing loss and their communicative abilities. Individual responses highlighted what impacts adults thought hearing loss had beyond communication and their communicative abilities. The majority of adults expressed that they did not have any communication errors and could accurately express their own thoughts/viewpoints/emotions and understand others’ thoughts/viewpoints/emotions. The second aim determined that group differences were present on memory subtests from the Weschler Memory Scale and a subtest from the Weschler Adult Intelligence Scale. While there was no significant difference between responses on the Bluegrass Short-Term Memory task, there was a group interaction on left frontal theta oscillation (memory & decision-making related), and right frontal beta frequency (attention-related) during data collection on EEG resting state eyes open. The final aim determined that there were group differences on the social cognitive assessment. Auditory and cognitive processing have previously been viewed as separate and distinct factors that are crucial for communication, yet the growing body of literature suggests that these elements are actually intimately coupled. This research yielded evidence that even a mild HL in adults between the ages of 50-69 is associated with changes in cognitive functioning, specifically on memory, attention, and social cognition. Singularly, the auditory system and cognitive domains are each complex, yet these must be assessed as factors that have the potential to influence each other. The open-ended questions revealed that researchers and clinicians need to continue to address the wideranging impacts of hearing loss among adults. While adults did recognize impacts of hearing loss beyond communication, some participants also reported no thoughts on the impact beyond communication. This is a strong suggestion that adults need to be further educated about hearing loss as a critically prevalent public health matter

Cognitive Aging

Given the global demographic shift towards an aging population, there is a pressing need to understand how aging affects cognition. This collection of articles, from across the globe, represents some of the diverse aspects of cognitive aging. These articles investigate the fundamental processes and mechanisms underlying the neural and cognitive changes associated with normal and pathological aging. They describe the many facets of cognition, memory, language and thinking that are affected by the aging process. The articles will hopefully fascinate readers, and entice them to learn more about how such research is conducted, as well as serving as avenues for exploration to compensate for deficits in cognitive function. The studies are cutting edge and offer insight into the development of the theories that best account for the changes in brain and behaviour that affect us all

Neuroimaging of Human Balance Control: A Systematic Review

This review examined 83 articles using neuroimaging modalities to investigate the neural correlates underlying static and dynamic human balance control, with aims to support future mobile neuroimaging research in the balance control domain. Furthermore, this review analyzed the mobility of the neuroimaging hardware and research paradigms as well as the analytical methodology to identify and remove movement artifact in the acquired brain signal. We found that the majority of static balance control tasks utilized mechanical perturbations to invoke feet-in-place responses (27 out of 38 studies), while cognitive dual-task conditions were commonly used to challenge balance in dynamic balance control tasks (20 out of 32 studies). While frequency analysis and event related potential characteristics supported enhanced brain activation during static balance control, that in dynamic balance control studies was supported by spatial and frequency analysis. Twenty-three of the 50 studies utilizing EEG utilized independent component analysis to remove movement artifacts from the acquired brain signals. Lastly, only eight studies used truly mobile neuroimaging hardware systems. This review provides evidence to support an increase in brain activation in balance control tasks, regardless of mechanical, cognitive, or sensory challenges. Furthermore, the current body of literature demonstrates the use of advanced signal processing methodologies to analyze brain activity during movement. However, the static nature of neuroimaging hardware and conventional balance control paradigms prevent full mobility and limit our knowledge of neural mechanisms underlying balance control

Effects of Diversity and Neuropsychological Performance in an NFL Cohort

Objective: The aim of this study was to examine the effect of ethnicity on neuropsychological test performance by comparing scores of white and black former NFL athletes on each subtest of the WMS. Participants and Methods: Data was derived from a de-identified database in South Florida consisting of 63 former NFL white (n=28, 44.4%) and black (n=35, 55.6%) athletes (Mage= 50.38; SD= 11.57). Participants completed the following subtests of the WMS: Logical Memory I and II, Verbal Paired Associates I and II, and Visual Reproduction I and II. Results: A One-Way ANOVA yielded significant effect between ethnicity and performance on several subtests from the WMS-IV. Black athletes had significantly lower scores compared to white athletes on Logical Memory II: F(1,61) = 4.667, p= .035, Verbal Paired Associates I: F(1,61) = 4.536, p = .037, Verbal Paired Associates: II F(1,61) = 4.677, p = .034, and Visual Reproduction I: F(1,61) = 6.562, p = .013. Conclusions: Results suggest significant differences exist between white and black athletes on neuropsychological test performance, necessitating the need for proper normative samples for each ethnic group. It is possible the differences found can be explained by the psychometric properties of the assessment and possibility of a non-representative sample for minorities, or simply individual differences. Previous literature has found white individuals to outperform African-Americans on verbal and non-verbal cognitive tasks after controlling for socioeconomic and other demographic variables (Manly & Jacobs, 2002). This highlights the need for future investigators to identify cultural factors and evaluate how ethnicity specifically plays a role on neuropsychological test performance. Notably, differences between ethnic groups can have significant implications when evaluating a sample of former athletes for cognitive impairment, as these results suggest retired NFL minorities may be more impaired compared to retired NFL white athletes

Distinguishing Performance on Tests of Executive Functions Between Those with Depression and Anxiety

Objective: To see if there are differences in executive functions between those diagnosed with Major Depressive Disorder (MDD) and those with Generalized Anxiety Disorder (GAD).Participants and Methods: The data were chosen from a de-identified database at a neuropsychological clinic in South Florida. The sample used was adults diagnosed with MDD (n=75) and GAD (n=71) and who had taken the Halstead Category Test, Trail Making Test, Stroop Test, and the Wisconsin Card Sorting Test. Age (M=32.97, SD=11.75), gender (56.7% female), and race (52.7% White) did not differ between groups. IQ did not differ but education did (MDD=13.41 years, SD=2.45; GAD=15.11 years, SD=2.40), so it was ran as a covariate in the analyses. Six ANCOVAs were run separately with diagnosis being held as the fixed factor and executive function test scores held as dependent variables. Results: The MDD group only performed worse on the Category Test than the GAD group ([1,132]=4.022, p\u3c .05). Even though both WCST scores used were significantly different between the two groups, both analyses failed Levene’s test of Equality of Error Variances, so the data were not interpreted. Conclusions: Due to previous findings that those diagnosed with MDD perform worse on tests of executive function than normal controls (Veiel, 1997), this study wanted to compare executive function performance between those diagnosed with MDD and those with another common psychological disorder. The fact that these two groups only differed on the Category Test shows that there may not be much of a difference in executive function deficits between those with MDD and GAD. That being said, not being able to interpret the scores on the WCST test due to a lack of homogeneity of variance indicates that a larger sample size is needed to compare these two types of patients, as significant differences may be found. The results of this specific study, however, could mean that the Category Test could be used in assisting the diagnosis of a MDD patient