Patterns and prevalence of cognitive dysfunction in systemic lupus erythematosus

OBJECTIVE

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease, in which cognitive dysfunction is common, but poorly understood. This study aims to characterize the prevalence and patterns of cognitive dysfunction in SLE.

METHOD

SLE patients (n = 95) and demographically matched healthy controls (n = 48) underwent cross-sectional cognitive testing using the 1-hr conventional neuropsychological test battery recommended by the American College of Rheumatology for use in SLE. We used standard deviations (SD) from the healthy control group to define impairment. For each cognitive test we compared SLE and control groups using independent samples t-tests (or alternatives when needed). We performed cluster analysis using a machine learning algorithm to look for patterns of cognitive dysfunction.

RESULTS

The SLE group performed significantly worse than healthy controls on every cognitive test. The largest differences were in the domains of verbal fluency, working memory and attention, while fine motor and psychomotor speed were the least affected domains. As expected, the prevalence of cognitive dysfunction varied depending on the SD cut-off used, with 49% of participants being >1.5 SD below the healthy control mean in at least two cognitive domains. Heat mapping showed variability in the pattern of dysfunction between individual patients and cluster analysis confirmed the presence of two clusters of patients, which were those significantly impaired versus those having preserved cognition.

CONCLUSIONS

Cognitive dysfunction is common in SLE but markedly heterogeneous across both cognitive domains and across the SLE group. Cluster analysis supports the use of a binary definition of cognitive dysfunction in SLE.

A Randomized Controlled Trial of Probiotics Targeting Gut Dysbiosis in Huntington’s Disease

Background: Gastrointestinal symptoms are clinical features of Huntington’s disease (HD), which adversely affect people’s quality of life. We recently reported the first evidence of gut dysbiosis in HD gene expansion carriers (HDGECs). Here, we report on a randomized controlled clinical trial of a 6-week probiotic intervention in HDGECs. Objective: The primary objective was to determine whether probiotics improved gut microbiome composition in terms of richness, evenness, structure, and diversity of functional pathways and enzymes. Exploratory objectives were to determine whether probiotic supplementation improved cognition, mood, and gastrointestinal symptoms. Methods: Forty-one HDGECs, including 19 early manifest and 22 premanifest HDGECs were compared with 36 matched-healthy controls (HCs). Participants were randomly assigned probiotics or placebo and provided fecal samples at baseline and 6-week follow-up, which were sequenced using 16S-V3-V4 rRNA to characterize the gut microbiome. Participants completed a battery of cognitive tests and self-report questionnaires measuring mood and gastrointestinal symptoms. Results: HDGECs had altered gut microbiome diversity when compared to HCs, indicating gut dysbiosis. Probiotic intervention did not ameliorate gut dysbiosis or have any effect on cognition, mood, or gastrointestinal symptoms. Gut microbiome differences between HDGECs and HCs were unchanged across time points, suggesting consistency of gut microbiome differences within groups. Conclusion: Despite the lack of probiotic effects in this trial, the potential utility of the gut as a therapeutic target in HD should continue to be explored given the clinical symptomology, gut dysbiosis, and positive results from probiotics and other gut interventions in similar neurodegenerative diseases.

Clinical associations of cognitive dysfunction in systemic lupus erythematosus

OBJECTIVE

Cognitive dysfunction in SLE is common, but clinical risk factors are poorly understood. This study aims to explore the associations of cognitive dysfunction in SLE with disease activity, organ damage, biomarkers and medications.

METHODS

We performed cross-sectional cognitive assessment using a conventional neuropsychological test battery, with normative values derived from demographically matched healthy subjects. Endpoints included two binary definitions of cognitive dysfunction and seven individual cognitive domain scores. Clinical parameters included disease activity (SLEDAI-2K) and organ damage (Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index). We performed regression analyses to determine associations between clinical parameters and cognitive endpoints.

RESULTS

89 patients with SLE were studied, with median age of 45 and disease duration of 15 years. Organ damage was significantly associated with severe cognitive dysfunction (OR 1.49, CI 1.01-2.22) and worse cognitive test performance in three of the seven individual cognitive domains. In contrast, no significant associations were found between SLEDAI-2K at the time of cognitive assessment and any cognitive endpoints on multivariate analysis. Higher time-adjusted mean SLEDAI-2K was associated with better verbal memory scores but had no significant associations with other cognitive endpoints. The presence of anti-dsDNA antibodies and high IFN gene signature were negatively associated with severe cognitive dysfunction; there were no significant associations with the other autoantibodies studied or any medications. Substance use was significantly associated with lower psychomotor speed. Only 8% of patients who had cognitive dysfunction on testing had been recognised by clinicians on their SDI score.

CONCLUSIONS

In SLE, cognitive dysfunction was positively associated with organ damage, but not associated with disease activity, and serological activity and high IFN signature were negatively associated. Cognitive dysfunction was poorly captured by clinicians. These findings have implications for preventative strategies addressing cognitive dysfunction in SLE.

Sleep, Circadian Rhythms, and Cognitive Dysfunction in Huntington's Disease

BACKGROUND

In healthy people, sleep and circadian disruption are linked to cognitive deficits. People with Huntington's disease (HD), who have compromised brain function and sleep and circadian disturbances, may be even more susceptible to these cognitive effects.

OBJECTIVE

To conduct a comprehensive review and synthesis of the literature in HD on the associations of cognitive dysfunction with disturbed sleep and circadian rhythms.

METHODS

We searched MEDLINE via OVID, CINAHL Plus, EMBASE via OVID, and PubMed in May 2023. The first author then screened by title and abstract and conducted a full review of remaining articles.

RESULTS

Eight studies investigating the influence of sleep and/or circadian rhythms on cognitive function in HD were found. In manifest HD, poorer sleep was associated with worse cognitive function. For behavioral 24-hour (circadian) rhythms, two studies indicated that later wake times correlated with poorer cognitive function. No reported studies in HD examined altered physiological 24-hour (circadian) rhythms and cognitive impairment.

CONCLUSION

Some associations exist between poor sleep and cognitive dysfunction in manifest HD, yet whether these associations are present before clinical diagnosis is unknown. Whether circadian disturbances relate to cognitive impairment in HD also remains undetermined. To inform sleep and circadian interventions aimed at improving cognitive symptoms in HD, future research should include a range of disease stages, control for external factors, and utilize robust cognitive batteries targeted to the aspects of cognitive function known to be adversely affected in HD.

Fibromyalgia, mood disorders, cognitive test results, cognitive symptoms and quality of life in systemic lupus erythematosus

OBJECTIVES

Cognitive dysfunction, and comorbidities such as mood disorder and fibromyalgia, are common in SLE. This study aims to explore the associations between fibromyalgia, mood disorders, cognitive symptoms and cognitive dysfunction in SLE patients, and their impact on quality of life.

METHODS

We tested cognition in SLE patients and healthy controls, and evaluated cognitive symptoms, mood disorder, fibromyalgia, fatigue and quality of life using patient-reported outcome measures. We examined associations of these comorbidities with both patient-reported cognitive symptoms and cognitive test performance.

RESULTS

High fibromyalgia symptom score and history of depression or anxiety were associated with cognitive dysfunction. There were no significant associations between current depression, anxiety symptoms or fatigue score and objective cognitive dysfunction. In contrast, mood disorder symptoms, history of mood disorder, fibromyalgia symptoms and fatigue all had significant associations with patient-reported cognitive symptoms. There were no significant associations between patient-reported cognitive symptoms and objective cognitive dysfunction. Objective cognitive dysfunction, patient-reported cognitive symptoms, history of mood disorder and fibromyalgia symptoms all had significant associations with poorer quality of life; fibromyalgia had the biggest impact.

CONCLUSIONS

Cognitive symptoms are common in SLE, but there were no associations between cognitive symptoms and objective cognitive dysfunction. Depression, anxiety and fibromyalgia were more consistently associated with patient-reported cognitive symptoms than with objective cognitive dysfunction. These factors all have a significant impact on quality of life. Understanding the discrepancy between patient-reported cognitive symptoms and cognitive test performance is essential to advance care in this area of unmet need.

Evaluation of the Montreal Cognitive Assessment as a screening tool for cognitive dysfunction in SLE

Objectives

Cognitive dysfunction in SLE is common and associated with significant morbidity but is currently underdetected. Early detection requires the use of screening tests, as formal diagnostic cognitive testing is time-consuming. This study aims to evaluate the Montreal Cognitive Assessment (MoCA) as a screening tool for cognitive dysfunction in SLE.

Methods

Patients with SLE (n=95) and demographically matched healthy control participants (n=48) underwent cognitive testing using the 1-hour neuropsychiatric test battery recommended by the American College of Rheumatology for use in SLE and the MoCA. We used regression analyses to determine associations between MoCA and cognitive test scores. We assessed several MoCA cut-offs for predicting cognitive impairment in terms of sensitivity, specificity, positive predictive value and negative predictive value. Receiver operating curve analyses were used to determine the diagnostic accuracy of the MoCA cut-off thresholds.

Results

We found a significant correlation between MoCA score and 9 of the 10 cognitive endpoints studied (all p<0.001). Receiver operating curve analysis suggested that a MoCA cut-off of <27 had highest diagnostic accuracy across the cognitive impairment definitions (area under the curve 0.76–0.78). Using a screening cut-off of <28, the MoCA had sensitivity of 83%–94% and specificity of 46%–59%, depending on the impairment definition used.

Conclusions

The MoCA correlates strongly with cognitive test results in SLE and has sufficient sensitivity for use as a screening tool with a cut-off of <28 as the optimal threshold. This tool can be incorporated into clinical practice for screening for cognitive dysfunction in SLE.

Hippocampal and striatal volumes correlate with spatial memory impairment in Huntington's disease

Spatial memory impairments are observed in people with Huntington's disease (HD), however, the domain of spatial memory has received little focus when characterizing the cognitive phenotype of HD. Spatial memory is traditionally thought to be a hippocampal-dependent function, while the neuropathology of HD centers on the striatum. Alongside spatial memory deficits in HD, recent neurocognitive theories suggest that a larger brain network is involved, including the striatum. We examined the relationship between hippocampal and striatal volumes and spatial memory in 36 HD gene expansion carriers, including premanifest (n = 24) and early manifest HD (n = 12), and 32 matched healthy controls. We assessed spatial memory with Paired Associates Learning, Rey-Osterrieth Complex Figure Test, and the Virtual House task, which assesses three components of spatial memory: navigation, object location, and plan drawing. Caudate nucleus, putamen, and hippocampal volumes were manually segmented on T1-weighted MR images. As expected, caudate nucleus and putamen volumes were significantly smaller in the HD group compared to controls, with manifest HD having more severe atrophy than the premanifest HD group. Hippocampal volumes did not differ significantly between HD and control groups. Nonetheless, on average, the HD group performed significantly worse than controls across all spatial memory tasks. The spatial memory components of object location and recall of figural and topographical drawings were associated with striatal and hippocampal volumes in the HD cohort. We provide a case to include spatial memory impairments in the cognitive phenotype of HD, and extend the neurocognitive picture of HD beyond its primary pathology within the striatum.

Greater time in bed and less physical activity associate with poorer cognitive functioning performance in Huntington's disease

Objective: This study aimed to investigate how sleep and physical activity habits related to cognitive functioning, in naturalistic settings, in early Huntington's disease (HD). Method: Forty-two participants with the expanded HD repeat (20 manifest, 22 premanifest) and 29 healthy controls wore Fitbit One sleep and activity monitors for 7 days and 7 nights. They used a smartphone application to complete daily sleep and activity diaries, sleep and mood inventories, and a brief battery of cognitive tests, which were completed on Day 8 of the study. All data were collected in naturalistic home and community settings. Results: Amongst participants with the expanded HD repeat, greater time spent in bed, measured by Fitbit, was associated with poorer accuracy and response speed on a test of visual memory, whereas lower levels of physical activity, measured by Fitbit, were associated with poorer accuracy on a test involving a working memory component. Neither time in bed nor physical activity is associated with a test of psychomotor speed. Groups were mostly similar across a range of Fitbit and self-report measures of sleep and physical activity, although the Manifest-HD group spent more time in bed than the Premanifest-HD and Healthy Control groups and had better self-reported sleep quality and more self-reported time spent sitting than the Healthy Control group and the Premanifest-HD group, respectively. Conclusions: Sleep timing and physical activity relate to cognitive functioning in HD and may be important targets for management in behavioral intervention studies aimed at improving cognition in HD. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

POS0731 CLINICAL ASSOCIATIONS OF COGNITIVE DYSFUNCTION IN SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)

Background:

Cognitive symptoms are commonly reported by SLE patients, but the prevalence and clinical associations of cognitive dysfunction (CD) is poorly understood.

Objectives:

To examine the relationship between SLE disease parameters and CD.

Methods:

Patients with SLE were consecutively recruited from 2018-2020. Cognitive assessment was performed using the one-hour conventional neuropsychiatric test battery recommended by the American College of Rheumatology for SLE1. Three binary definitions of CD and seven cognitive test z-scores were included in analysis. Clinical parameters included disease activity (SLEDAI-2K) and damage (SDI). Multivariate regression analysis was performed to determine associations with cognitive endpoints using variables with p <0.1 on univariate testing; likelihood ratio tests were used to select for inclusion from collinear pairs. A subgroup univariate analysis was performed to look for associations with interferon gene signature (IGS) and metabolic indices.

Results:

91 SLE patients and 48 age, sex, and premorbid IQ matched controls were recruited. The median (range) age was 45 (21-64) and median disease duration 13 years (0.2-39). 60% were Caucasian and the rest predominantly Asian, and all had good English proficiency. Prevalence of CD varied based on definition used; 18% had ≥2 cognitive domains ≥2 SD below the healthy control mean, whereas 48% were considered impaired if this threshold was reduced to ≥1.5 SD below. Age and premorbid IQ were significantly associated with multiple cognitive endpoints, and SDI was associated with four endpoints including the most severe definition of CD. Increased parity and past strokes correlated with poorer cognition in two endpoints. In contrast, clinical variables such as SLEDAI, antiphospholipid antibodies and past seizures only correlated with one endpoint each. There were no associations with other antibodies or any medications including glucocorticoids. Subgroup analysis showed univariate associations of CD with increased waist circumference, hypertriglyceridemia and low IGS.

Conclusion:

Clinical associations of CD in SLE vary according to the cognitive domain or impairment definition used. SDI was the disease-related factor most consistently associated with CD, while IGS was negatively and metabolic features positively associated with CD. Studies of CD in SLE should use standardised methods to determine CD.

References:

[1]Liang et al. The American College of Rheumatology nomenclature and case definitions for neuropsychiatric lupus syndromes. Arthritis Rheum. 1999;42(4).

Table 1.

Multivariate Analysis of Clinical Predictors of Cognitive Dysfunction in SLE

Cognitive Dysfunction Definitions1Individual Cognitive Domains (Tests)2 domains-1.5 SD1 domain-2 SD2 domains-2 SDVisual Memory(ROCF recall)Verbal Memory(CVLT 1-5)Verbal Fluency(COWAT FAS)Working Memory(LNS score)Processing Speed(Coding score)Complex attention(TMT B time)Psychomotor Speed(Finger tap)Odds ratio(logistic regression)Coefficient (linear regression)Age1.06*1.06*-0.03*-0.014*-0.03**Premorbid IQ0.89**0.86**0.85*0.056**0.044**0.072**0.028**0.026*0.05**0.017SLEDAI0.860.89Time-adjusted mean SLEDAI0.14**-0.012PGA0.79**0.44SDI1.91*-0.25**-0.15**-0.22**Past stroke or TIA7.9413.19*-0.97**Past seizures-0.65*-0.24Methotrexate-0.23Anti Ro0.22Anti-cardiolipin0.38*Any APLS abs0.037**Parity2.21**-0.05-0.051-0.22**Substance use2.58-0.49*-0.62*

1Impairment defined by number of cognitive domains either 1.5 or 2 SD below healthy control group mean*p value <0.05 **p value <0.005 Abbreviations: SLEDAI - SLE Disease Activity Index, PGA - Physician global assessment, SDI - SLE International Collaborating Clinics Damage Index, TIA - Transient Ischaemic Attack, abs - Antibodies, APLS - Antiphospholipid Syndrome, ROCF - Rey-Ostrrieth Complex Figure Test, CVLT - California Verbal Learning Test, COWAT - Controlled Oral Word Association Test, LNS and Coding - Letter Number Sequencing & Coding subsets of Wechsler Adult Intelligence Scale IV, TMT - Trail Making Test

Acknowledgements:

We would like to acknowledge the patients who contribute to the Australian Lupus Registry and Biobank (ALRB) and participated in this study. The ALRB has received sponsorship from AstraZeneca, UCB and Arthritis Victoria.

Disclosure of Interests:

None declared

Gut dysbiosis in Huntington's disease: associations among gut microbiota, cognitive performance and clinical outcomes

Huntington's disease is characterized by a triad of motor, cognitive and psychiatric impairments, as well as unintended weight loss. Although much of the research has focused on cognitive, motor and psychiatric symptoms, the extent of peripheral pathology and the relationship between these factors, and the core symptoms of Huntington's disease, are relatively unknown. Gut microbiota are key modulators of communication between the brain and gut, and alterations in microbiota composition (dysbiosis) can negatively affect cognition, behaviour and affective function, and may be implicated in disease progression. Furthermore, gut dysbiosis was recently reported in Huntington's disease transgenic mice. Our main objective was to characterize the gut microbiome in people with Huntington's disease and determine whether the composition of gut microbiota are significantly related to clinical indicators of disease progression. We compared 42 Huntington's disease gene expansion carriers, including 19 people who were diagnosed with Huntington's disease (Total Functional Capacity > 6) and 23 in the premanifest stage, with 36 age- and gender-matched healthy controls. Participants were characterized clinically using a battery of cognitive tests and using results from 16S V3 to V4 rRNA sequencing of faecal samples to characterize the gut microbiome. For gut microbiome measures, we found significant differences in the microbial communities (beta diversity) based on unweighted UniFrac distance (P = 0.001), as well as significantly lower alpha diversity (species richness and evenness) between our combined Huntington's disease gene expansion carrier group and healthy controls (P = 0.001). We also found major shifts in the microbial community structure at Phylum and Family levels, and identified functional pathways and enzymes affected in our Huntington's disease gene expansion carrier group. Within the Huntington's disease gene expansion carrier group, we also discovered associations among gut bacteria, cognitive performance and clinical outcomes. Overall, our findings suggest an altered gut microbiome in Huntington's disease gene expansion carriers. These results highlight the importance of gut biomarkers and raise interesting questions regarding the role of the gut in Huntington's disease, and whether it may be a potential target for future therapeutic intervention.

Functional MRI (fMRI) human mapping for indicating hippocampal content-specific responsivity and laterality

OBJECTIVE

Presurgical memory functional MRI (fMRI) mapping for temporal lobe epilepsy surgery is important because of the excision of structures in the temporal lobe (e.g., hippocampus) that are relevant for intact memory. Although the American Academy of Neurology recommends the use of fMRI for presurgical mapping of epilepsy of verbal and nonverbal memory to predict memory outcome, there are still no specific recommendations about which tests to use. In the current study, we evaluate the potential for clinical utility of two established neuropsychological tests of memory adapted into the fMRI setting.

METHOD

We used the Verbal Paired Associates (VPA) for assessment of verbal memory and the Object Learning and Location (OLL) task for assessment of visuospatial memory. To confirm that these tasks engage the hippocampus, we examined their neural underpinning and patterns of laterality in 20 healthy volunteers (mean age = 26.35).

RESULTS

During fMRI of the VPA task of verbal memory, we found a strong left-lateralized posterior hippocampal activation. Remembering the location of objects in the OLL task of visuospatial memory elicited right-lateralized hippocampal activation.

CONCLUSIONS

These findings demonstrate the utility of the VPA and OLL tests to delineate domain-specific activity and laterality and, as such, may provide supportive evidence to strengthen links between presurgical neuropsychological assessment and memory fMRI mapping for epilepsy surgery. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Discrete changes in the frequency and functions of autobiographical reminiscence in Huntington's disease

Autobiographical memory is widely posited to serve self, social and directive functions. Recent evidence suggests marked autobiographical memory impairments in Huntington's disease (HD), however, no study to date has determined how the perceived functions of autobiographical reminiscence may be altered in HD. The current study aimed to assess the self-reported frequency and function of autobiographical reminiscence in HD. We assessed autobiographical reminiscence in late premanifest (n = 16) and early stage HD (n = 14), relative to healthy controls (n = 30). Participants completed the Thinking About Life Experiences Scale Revised (TALE-R), which measures three putative functions of autobiographical memory (self, social, directive). People with manifest HD reported talking less frequently about the past compared to controls. In contrast, no group differences were found in terms of thinking about the past. Manifest HD participants further reported using their autobiographical memories for social functions less frequently compared to controls. No other group differences were evident in terms of self or directive functions of autobiographical memory. These self-report findings complement recent reports of autobiographical memory disruption on performance-based tasks in HD. Future studies exploring how changes in autobiographical reminiscence impact a sense of self continuity in HD will be important in this regard.

'Real-life' hippocampal-dependent spatial memory impairments in Huntington's disease

Hippocampal-dependent spatial memory impairments are seen in Huntington's disease animal models. Similar impairments were recently reported in Huntington's disease participants on analogous spatial memory tasks (e.g., virtual Morris Water Maze), however, these tasks do not translate well to the range of functions involved in day-to-day spatial cognition. In this study we examined 'real-life' hippocampal-dependent spatial memory in Huntington's disease participants. We studied premanifest Huntington's disease (N = 24), early manifest Huntington's disease (N = 14), and matched healthy controls (N = 33) with a virtual environment, which demanded spatial memory function on three levels: navigation, object location, and plan drawing. To examine the case for hippocampal-dependent spatial memory more closely, we compared the performance of our Huntington's disease participants to that of a group of temporal lobe epilepsy patients (N = 30) who were previously tested on the virtual environment. Spatial memory performance was also compared to two common neuropsychological tests of spatial cognition, the Paired Associates Learning from the Cambridge Neuropsychological Automated Test Battery, and the Rey-Osterrieth Complex Figure Test. People with early manifest Huntington's disease were impaired across all spatial memory tasks. Premanifest Huntington's disease participants were most notably impaired on the object location measure of the virtual environment, which is heavily dependent on hippocampal function, but showed no such impairments on the Paired Associates Learning or the Rey-Osterrieth Complex Figure Test. Object location memory and navigation performance did not differ between people with Huntington's disease and temporal lobe epilepsy. Aligned with studies in Huntington's disease animal models, 'real-life' spatial memory is impaired in people with Huntington's disease prior to clinical diagnosis. This alignment has important implications for testing treatments for Huntington's disease. From the standpoint of neurodegeneration, the dependence of our spatial memory measures on hippocampal function extends the focus of cognitive assessment research in Huntington's disease beyond its primary pathology within the striato-frontal circuit.

Reduced amygdala volumes are related to motor and cognitive signs in Huntington's disease: The IMAGE-HD study

In Huntington's disease (HD), the presence of neurodegeneration in brain regions other than the striatum has been recently gaining attention. The amygdala is one such area, which has been investigated in only eight structural magnetic resonance imaging studies to date, but with inconsistent findings. This is the largest MRI study to date examining manually traced amygdala volumes in HD participants and the relationship of amygdala volumes to clinical measures of HD. Our study included 35 healthy control participants, and groups of 35 pre-symptomatic, and 36 symptomatic HD participants. When comparing the pre-symptomatic and symptomatic HD groups together against the control group, amygdala volumes were significantly lower in HD than controls and in symptomatic HD than pre-symptomatic HD. When examining relationships between amygdala volumes and clinical measures of HD, significantly smaller amygdala volumes were associated with worse motor and cognitive signs. For pre-symptomatic HD participants who were close to disease onset, smaller amygdala volumes were also associated with higher levels of anxiety symptoms. These findings suggest that the amygdala is affected in pre-symptomatic and symptomatic HD, and that the amygdala is related to the clinical profile of HD before onset of motor symptoms.

Emotion recognition in Parkinson's disease: Static and dynamic factors

OBJECTIVE

The authors tested the hypothesis that Parkinson's disease (PD) participants would perform better in an emotion recognition task with dynamic (video) stimuli compared to a task using only static (photograph) stimuli and compared performances on both tasks to healthy control participants.

METHOD

In a within-subjects study, 21 PD participants and 20 age-matched healthy controls performed both static and dynamic emotion recognition tasks. The authors used a 2-way analysis of variance (controlling for individual participant variance) to determine the effect of group (PD, control) on emotion recognition performance in static and dynamic facial recognition tasks.

RESULTS

Groups did not significantly differ in their performances on the static and dynamic tasks; however, the trend was suggestive that PD participants performed worse than controls.

CONCLUSIONS

PD participants may have subtle emotion recognition deficits that are not ameliorated by the addition of contextual cues, similar to those found in everyday scenarios. Consistent with previous literature, the results suggest that PD participants may have underlying emotion recognition deficits, which may impact their social functioning. (PsycINFO Database Record

Cognitive assessment in Huntington disease clinical drug trials

Several Huntington disease (HD) clinical trials are in progress and on the horizon. Potential treatments are increasingly being targeted at ameliorating the cognitive decline in HD. This necessitates a careful consideration of trial designs, including endpoint strategies suitable for testing cognitive function. The aim of this chapter is to evaluate and consider the use of cognitive measures in HD clinical trials. We first consider the role of cognition in clinical trial endpoint models, including a review of previous HD clinical trials that have included cognitive measures. We evaluate strategies for selecting cognitive tools for HD clinical trials, and consider cognitive assessments that have been used in other neuropsychiatric disorders, namely Alzheimer disease and schizophrenia. Next, we describe a general framework for selecting patient-based outcomes in clinical trials, and apply this framework to the selection of cognitive outcomes. Using the HD-Cognitive Assessment Battery (HD-CAB), a new cognitive battery designed for clinical trials, we illustrate the evaluation of cognitive outcomes in terms of their responsivity, reliability, validity, appropriateness, precision, interpretability, feasibility, and acceptability. Finally, we articulate a pathway for continued development of cognitive tools that would pave the way for finding treatments that ameliorate cognitive decline in HD.

Probabilistic machine learning for the evaluation of presurgical language dominance

OBJECTIVE

Providing a reliable assessment of language lateralization is an important task to be performed prior to neurosurgery in patients with epilepsy. Over the last decade, functional MRI (fMRI) has emerged as a useful noninvasive tool for language lateralization, supplementing or replacing traditional invasive methods. In standard practice, fMRI-based language lateralization is assessed qualitatively by visual inspection of fMRI maps at a specific chosen activation threshold. The purpose of this study was to develop and evaluate a new computational technique for providing the probability of each patient to be left, right, or bilateral dominant in language processing.

METHODS

In 76 patients with epilepsy, a language lateralization index was calculated using the verb-generation fMRI task over a wide range of activation thresholds (from a permissive threshold, analyzing all brain regions, to a harsh threshold, analyzing only the strongest activations). The data were classified using a probabilistic logistic regression method.

RESULTS

Concordant results between fMRI and Wada lateralization were observed in 89% of patients. Bilateral and right-dominant groups showed similar fMRI lateralization patterns differentiating them from the left-dominant group but still allowing classification in 82% of patients.

CONCLUSIONS

These findings present the utility of a semi-supervised probabilistic learning approach for presurgical language-dominance mapping, which may be extended to other cognitive domains such as memory and attention.

Cognitive assessment strategies in Huntington's disease research

The number of studies examining cognition in Huntington's disease (HD) has increased dramatically in recent decades, and cognitive research methods in HD have become much more sophisticated. In this review, we provide a summary of the advances in cognitive research in HD to date, and outline the key considerations for researchers planning to include cognitive assessment in their studies of HD. In particular, we discuss consideration of structure-function relationships, selection of tests appropriate to the population, choice of materials and issues of intellectual property, consideration of variables which can confound studies of cognition in HD, practice effects, and specific issues for multi-site research. Finally, we discuss future directions for cognitive assessment in HD research.

Hippocampal 5-HT1A Receptor and Spatial Learning and Memory

Spatial cognition is fundamental for survival in the topographically complex environments inhabited by humans and other animals. The hippocampus, which has a central role in spatial cognition, is characterized by high concentration of serotonin (5-hydroxytryptamine; 5-HT) receptor binding sites, particularly of the 1A receptor (5-HT1A) subtype. This review highlights converging evidence for the role of hippocampal 5-HT1A receptors in spatial learning and memory. We consider studies showing that activation or blockade of the 5-HT1A receptors using agonists or antagonists, respectively, lead to changes in spatial learning and memory. For example, pharmacological manipulation to induce 5-HT release, or to block 5-HT uptake, have indicated that increased extracellular 5-HT concentrations maintain or improve memory performance. In contrast, reduced levels of 5-HT have been shown to impair spatial memory. Furthermore, the lack of 5-HT1A receptor subtype in single gene knockout mice is specifically associated with spatial memory impairments. These findings, along with evidence from recent cognitive imaging studies using positron emission tomography (PET) with 5-HT1A receptor ligands, and studies of individual genetic variance in 5-HT1A receptor availability, strongly suggests that 5-HT, mediated by the 5-HT1A receptor subtype, plays a key role in spatial learning and memory.

Learning and memory-related brain activity dynamics are altered in systemic lupus erythematosus: a functional magnetic resonance imaging study

Background

Memory impairment is prevalent in systemic lupus erythematosus (SLE); however, the pathogenesis is unknown.

Methods

We studied 12 patients with SLE without clinically overt neuropsychiatric manifestations and 11 matched healthy controls, aiming to characterize neural correlates of memory impairment, using structural and functional magnetic resonance imaging (MRI). The paradigm consisted of three encoding and free-recall cycles, allowing characterization of dynamics along consecutive retrieval attempts.

Results

During learning, patients with SLE and healthy controls showed brain activity changes in two principal networks, the default mode network (DMN) and the task-positive network (TPN). Patients with SLE demonstrated significantly less deactivation in the DMN and greater activation in the TPN, reflecting greater recruitment of both networks. The anterior medial prefrontal cortex (amPFC) of the DMN emerged as the only region where brain activity dynamics were altered both over the learning process ( p < 0.006), and within free-recall period attempts ( p < 0.034). Patients showed significant positive correlations between learning efficiency and hippocampal activity, and greater hippocampal functional connectivity, with pronounced connectivity to DMN structures.

Conclusions

Increased brain activation in patients with SLE during learning may reflect compensatory mechanisms to overcome memory impairment. Our findings localize this impairment to the amPFC, consistent with the behavioral pattern seen in SLE. Altered networking of the hippocampal subsystem of the DMN is consistent with hippocampal neuronal damage seen in SLE, and may reflect compensatory cortical reorganization to cope with dysfunction in these regions pivotal to mnemonic functions.

Structural and functional correlates of unilateral mesial temporal lobe spatial memory impairment

The aim of this study was to explore the effects of preoperative and postoperative lateralized mesial temporal damage on three measures of spatial learning: navigation, object location and plan drawing, and to determine the relationship between volumetry of the hippocampus and memory performance. Fifteen patients with well-characterized unilateral hippocampal sclerosis, 15 patients who had undergone unilateral anterior temporal lobectomy (ATL), and a comparison group consisting of 15 patients with idiopathic generalized epilepsy and 25 neurologically healthy participants explored a novel virtual environment. Volumetric analyses of both hippocampi were conducted on unilateral hippocampal sclerosis and idiopathic generalized epilepsy patients' T(1)-weighted magnetic resonance imaging scans. Performance of temporal lobe epilepsy (TLE) patients (either unilateral hippocampal sclerosis or anterior temporal lobectomy) on the different spatial memory variables, namely navigation, object location and plan drawing, was significantly worse relative to the comparison groups (either idiopathic generalized epilepsy or controls). Patients with right TLE did not differ from patients with left TLE on any of the spatial memory measures. An index of absolute hippocampal asymmetry did not correlate with any of the spatial memory measures. Together, our lesion and volumetry findings suggest that the domain of spatial memory is systematically related to the integrity of both right and left mesial temporal lobe, and is unlikely to be a strongly lateralized function. From the standpoint of cerebral organization (lateralization), the notion of material-specificity, which postulates that all components of verbal and spatial memory are lateralized in their entirety to the left and right hemispheres, respectively, requires modification. Instead it would appear that the notion of task-specificity is a more accurate description of patterns of lateralization of spatial memory.