Subjective memory complaints in young people; their relationship withobjective cognitive performance and the role of neuroticism / Quejas subjetivas de memoria en jóvenes; su relación con el rendimiento cognitivo objetivo y el papel del neuroticismo

Las percepciones de olvidos recurrentes o episodios de distracción en la vida diaria se denominan quejas subjetivas de memoria (QSM). Su naturaleza se ha estudiado ampliamente en adultos mayores, pero su importancia y relación con el rendimiento neurocognitivo no se han abordado por completo en adultos más jóvenes. Se han sugerido algunos rasgos psicológicos como posibles moderadores de la asociación entre el rendimiento de la memoria objetiva y subjetiva. El primer objetivo de este estudio fue analizar la correspondencia entre la percepción objetiva y subjetiva de los fallos de memoria en jóvenes. En segundo lugar, estudiamos si el rasgo psicológico del neuroticismo podría estar influyendo en esta relación. Para ello, medimos QSM, diferentes dominios cognitivos (memoria episódica y de trabajo y funciones ejecutivas) y neuroticismo en 80 hombres y mujeres jóvenes. Los resultados mostraron que solo la memoria episódica inmediata estaba estadísticamente relacionada con los QSM. Curiosamente, las relaciones negativas entre el rendimiento de la memoria objetiva y subjetiva solo aparecieron en participantes con mayor neuroticismo. Por lo tanto, las quejas de memoria reportadas por los jóvenes podrían reflejar un peor rendimiento de la memoria episódica inmediata, mientras que el neuroticismo jugaría un papel principal en la asociación entre los déficits de memoria y las QSM. Este estudio proporciona datos que pueden ayudar a comprender mejor las QSM en los jóvenes.(AU)

Perceptions of recurrent forgetfulness or episodes of distraction in daily life are referred to as subjective memory complaints (SMCs). Their nature has been extensively studied in older adults, but their significance and relationship with neurocognitive performance have not been fully ad-dressed in younger adults. Some psychological traits have been suggested as possible moderators of the association between objective and subjective memory performance. The first aim of this study was to analyze the corre-spondence between the objective and subjective perception of memory failures in young people. Second, we studied whether the psychological trait of neuroticism could be influencing this relationship. Todo this, we measured SMCs, different cognitive domains (episodic and working memory and executive functions), and neuroticism in 80 young men and women. Results showed that only immediate episodic memory was statisti-cally related to SMCs. Interestingly, the negative relationships between ob-jective and subjective memory performance only appeared in participants with higher neuroticism. Thus, memory complaints reported by young people could reflect poorer immediate episodic memory performance, whereas neuroticism would play a main role in the association between memory deficits and SMCs. This study provides data that can help to bet-ter understand SMCs in young people.(AU)

Environmental conditions shape learning in larval zebrafish.

Growing evidence reveals notable phenotypic plasticity in cognition among teleost fishes. One compelling example is the positive impact of enriched environments on learning performance. Most studies on this effect have focused on juvenile or later life stages, potentially overlooking the importance of early life plasticity. To address this gap, we investigated whether cognitive plasticity in response to environmental factors emerges during the larval stage in zebrafish. Our findings indicate that larvae exposed to an enriched environment after hatching exhibited enhanced habituation learning performance compared to their counterparts raised in a barren environment. This work underscores the presence of developmental phenotypic plasticity in cognition among teleost fish, extending its influence to the very earliest stages of an individual's life.

Acute Hyperglycemia Induced by Hyperglycemic Clamp Affects Plasma Amyloid-ß in Type 2 Diabetes.

Background: Individuals with type 2 diabetes (T2D) have an increased risk of cognitive symptoms and Alzheimer's disease (AD). Mis-metabolism with aggregation of amyloid-ß peptides (Aß) play a key role in AD pathophysiology. Therefore, human studies on Aß metabolism and T2D are warranted. Objective: The objective of this study was to examine whether acute hyperglycemia affects plasma Aß 1-40 and Aß 1-42 concentrations in individuals with T2D and matched controls. Methods: Ten participants with T2D and 11 controls (median age, 69 years; range, 66-72 years) underwent hyperglycemic clamp and placebo clamp (saline infusion) in a randomized order, each lasting 4 hours. Aß 1-40, Aß 1-42, and insulin-degrading enzyme (IDE) plasma concentrations were measured in blood samples taken at 0 and 4 hours of each clamp. Linear mixed-effect regression models were used to evaluate the 4-hour changes in Aß 1-40 and Aß 1-42 concentrations, adjusting for body mass index, estimated glomerular filtration rate, and 4-hour change in insulin concentration. Results: At baseline, Aß 1-40 and Aß 1-42 concentrations did not differ between the two groups. During the hyperglycemic clamp, Aß decreased in the control group, compared to the placebo clamp (Aß 1-40: p = 0.034, Aß 1-42: p = 0.020), IDE increased (p = 0.016) during the hyperglycemic clamp, whereas no significant changes in either Aß or IDE was noted in the T2D group. Conclusions: Clamp-induced hyperglycemia was associated with increased IDE levels and enhanced Aß 40 and Aß 42 clearance in controls, but not in individuals with T2D. We hypothesize that insulin-degrading enzyme was inhibited during hyperglycemic conditions in people with T2D.

CAIDE Score, Alzheimer's Disease Pathology, and Cognition in Cognitively Normal Adults: The CABLE Study.

Background: Cardiovascular Risk Factors, Ageing and Dementia (CAIDE) risk score serves as a credible predictor of an individual's risk of dementia. However, studies on the link of the CAIDE score to Alzheimer's disease (AD) pathology are scarce. Objective: To explore the links of CAIDE score to cerebrospinal fluid (CSF) biomarkers of AD as well as to cognitive performance. Methods: In the Chinese Alzheimer's Biomarker and LifestylE (CABLE) study, we recruited 600 cognitively normal participants. Correlations between the CAIDE score and CSF biomarkers of AD as well as cognitive performance were probed through multiple linear regression models. Whether the correlation between CAIDE score and cognitive performance was mediated by AD pathology was researched by means of mediation analyses. Results: Linear regression analyses illustrated that CAIDE score was positively associated with tau-related biomarkers, including pTau (p <  0.001), tTau (p <  0.001), as well as tTau/Aß42 (p = 0.008), while it was in negative association with cognitive scores, consisting of MMSE score (p <  0.001) as well as MoCA score (p <  0.001). The correlation from CAIDE score to cognitive scores was in part mediated by tau pathology, with a mediation rate varying from 3.2% to 13.2% . Conclusions: A higher CAIDE score, as demonstrated in our study, was linked to more severe tau pathology and poorer cognitive performance, and tau pathology mediated the link of CAIDE score to cognitive performance. Increased dementia risk will lead to cognitive decline through aggravating neurodegeneration.

Cross-cohort replicable resting-state functional connectivity in predicting symptoms and cognition of schizophrenia.

Schizophrenia (SZ) is a debilitating mental illness characterized by adolescence or early adulthood onset of psychosis, positive and negative symptoms, as well as cognitive impairments. Despite a plethora of studies leveraging functional connectivity (FC) from functional magnetic resonance imaging (fMRI) to predict symptoms and cognitive impairments of SZ, the findings have exhibited great heterogeneity. We aimed to identify congruous and replicable connectivity patterns capable of predicting positive and negative symptoms as well as cognitive impairments in SZ. Predictable functional connections (FCs) were identified by employing an individualized prediction model, whose replicability was further evaluated across three independent cohorts (BSNIP, SZ = 174; COBRE, SZ = 100; FBIRN, SZ = 161). Across cohorts, we observed that altered FCs in frontal-temporal-cingulate-thalamic network were replicable in prediction of positive symptoms, while sensorimotor network was predictive of negative symptoms. Temporal-parahippocampal network was consistently identified to be associated with reduced cognitive function. These replicable 23 FCs effectively distinguished SZ from healthy controls (HC) across three cohorts (82.7%, 90.2%, and 86.1%). Furthermore, models built using these replicable FCs showed comparable accuracies to those built using the whole-brain features in predicting symptoms/cognition of SZ across the three cohorts (r = .17-.33, p < .05). Overall, our findings provide new insights into the neural underpinnings of SZ symptoms/cognition and offer potential targets for further research and possible clinical interventions.

Philosophy of psychiatry: theoretical advances and clinical implications.

Work at the intersection of philosophy and psychiatry has an extensive and influential history, and has received increased attention recently, with the emergence of professional associations and a growing literature. In this paper, we review key advances in work on philosophy and psychiatry, and their related clinical implications. First, in understanding and categorizing mental disorder, both naturalist and normativist considerations are now viewed as important - psychiatric constructs necessitate a consideration of both facts and values. At a conceptual level, this integrative view encourages moving away from strict scientism to soft naturalism, while in clinical practice this facilitates both evidence-based and values-based mental health care. Second, in considering the nature of psychiatric science, there is now increasing emphasis on a pluralist approach, including ontological, explanatory and value pluralism. Conceptually, a pluralist approach acknowledges the multi-level causal interactions that give rise to psychopathology, while clinically it emphasizes the importance of a broad range of "difference-makers", as well as a consideration of "lived experience" in both research and practice. Third, in considering a range of questions about the brain-mind, and how both somatic and psychic factors contribute to the development and maintenance of mental disorders, conceptual and empirical work on embodied cognition provides an increasingly valuable approach. Viewing the brain-mind as embodied, embedded and enactive offers a conceptual approach to the mind-body problem that facilitates the clinical integration of advances in both cognitive-affective neuroscience and phenomenological psychopathology.

From "online brains" to "online lives": understanding the individualized impacts of Internet use across psychological, cognitive and social dimensions.

In response to the mass adoption and extensive usage of Internet-enabled devices across the world, a major review published in this journal in 2019 examined the impact of Internet on human cognition, discussing the concepts and ideas behind the "online brain". Since then, the online world has become further entwined with the fabric of society, and the extent to which we use such technologies has continued to grow. Furthermore, the research evidence on the ways in which Internet usage affects the human mind has advanced considerably. In this paper, we sought to draw upon the latest data from large-scale epidemiological studies and systematic reviews, along with randomized controlled trials and qualitative research recently emerging on this topic, in order to now provide a multi-dimensional overview of the impacts of Internet usage across psychological, cognitive and societal outcomes. Within this, we detail the empirical evidence on how effects differ according to various factors such as age, gender, and usage types. We also draw from new research examining more experiential aspects of individuals' online lives, to understand how the specifics of their interactions with the Internet, and the impact on their lifestyle, determine the benefits or drawbacks of online time. Additionally, we explore how the nascent but intriguing areas of culturomics, artificial intelligence, virtual reality, and augmented reality are changing our understanding of how the Internet can interact with brain and behavior. Overall, the importance of taking an individualized and multi-dimensional approach to how the Internet affects mental health, cognition and social functioning is clear. Furthermore, we emphasize the need for guidelines, policies and initiatives around Internet usage to make full use of the evidence available from neuroscientific, behavioral and societal levels of research presented herein.

The Effects of Carotid Revascularization on 1-Year Cognitive Performance in Patients With Carotid Artery Stenosis.

PURPOSE: The impact of carotid revascularization on cognitive function for patients with severe carotid artery stenosis remains uncertain. This study is aimed to investigate the 1-year neurocognitive outcomes of patients who accept carotid revascularization and identify the risk factors associated with postoperative cognitive decline. METHODS: From April 2019 to April 2021, patients with ≥70% carotid artery stenosis who were treated with carotid endarterectomy (CEA) or carotid artery stenting (CAS) were recruited for this study. The Montreal Cognitive Assessment (MoCA) instrument was used to evaluate cognitive function preoperatively and at 3, 6, and 12 months postoperatively. Logistic regression analysis was built to identify potential risk factors for postoperative long-term cognitive decline. RESULTS: A total of 89 patients who met the criteria were enrolled and completed 1-year follow-up. At 3, 6, and 12 months after carotid revascularization, the total MoCA score, attention, language fluency, and delayed recall score were significantly improved compared with the baseline scores (p<0.05). At 12 months, there was also a significant improvement in cube copying compared with baseline (p=0.034). Logistic regression analysis showed that the advancing age, left side, and symptomatic carotid artery stenosis were independent risk factors for cognitive deterioration at 12 months after surgery. CONCLUSIONS: Overall, carotid revascularization has a beneficial effect on cognition function in patients with severe carotid artery stenosis, while advancing age, left side, and symptomatic carotid artery stenosis were significantly related to a decreased cognitive score after carotid revascularization. CLINICAL IMPACT: This study focused on the changes in cognitive function within 1 year after carotid revascularization in patients with severe carotid stenosis. Of course, carotid revascularization can improve the cognition function in these patients. On the other hand, we found the advancing age, left side and symptomatic carotid artery stenosis were significantly associated with decreased cognitive scores at 1 year after carotid revascularization, which suggests that clinicians may need to be aware of patients with these characteristics.

Association Between Depressive Symptoms, Cognitive Status, and the Dual-Task Performance Index in Older Adults: A Cross-Sectional Study.

The Performance Index (P-Index) is a measure for evaluating mobility-related dual-task performance in older adults. The identification of specific clinicodemographic factors predictive of P-Index scores, however, remains unclear. This cross-sectional study analyzed data from 120 community-dwelling older adults (average age 71.3 ± 11.23 years) to explore clinicodemographic variables that influence P-Index scores during the instrumented timed up and go test. Unadjusted analyses suggested several factors, including age, gender, body mass index, Mini-Mental Status Examination scores, functional reach test performance, history of falls, ethnicity, Geriatric Depression Scale scores, alcohol consumption, and educational levels, as potential predictors of P-Index. However, adjusted multinomial multiple regression analysis revealed Geriatric Depression Scale and Mini-Mental Status Examination scores as the exclusive independent predictors of P-Index classifications, segmented into high, intermediate, or low (percentiles ≤ 25, 26-74, or ≥ 75, respectively). A significant association was observed between the manifestation of depressive symptoms, lower Mini-Mental Status Examination scores, and reduced cognitive-motor performance. The findings implicate depressive symptoms and low cognitive performance as substantial impediments to optimal dual-task mobility within this cohort. Further studies are warranted to examine the efficacy of cognitive stimulation and antidepressant therapy, in augmenting mobility-related dual-task performance among older adults.

The influence of depression and anxiety on cognition in people with multiple sclerosis: a cross-sectional analysis.

There are conflicting findings about the relationships between depression, anxiety, and cognitive dysfunction in people with multiple sclerosis (MS), and a paucity of research has examined the cumulative influence on cognition of depression plus anxiety. This study aimed to determine whether elevated symptoms of depression and anxiety alone or in combination are associated with worse cognition in people with MS. In this cross-sectional analysis, people with MS consecutively seen at a tertiary neuropsychiatry clinic completed the Hospital Anxiety and Depression Scale for symptoms of depression (HADS-D) and anxiety (HADS-A), and the Minimal Assessment of Cognitive Function in MS for cognitive indices. Accounting for covariates, regression models predicted cognitive indices from scores for HADS-D, HADS-A, and the interaction. Of 831 people with MS, 72% were female, mean age was 43.2 years, and median Expanded Disability Status Scale score was 2.0. Depressive symptoms were independently predictive of lower verbal fluency (Controlled Oral Word Association Test, p < 0.01), verbal learning (California Verbal Learning Test-II (CVLT-II) total learning, p = 0.02), verbal delayed recall (CVLT-II delayed recall, p < 0.01), and processing speed (Symbol Digit Modalities Test, p < 0.01; three-second Paced Auditory Serial Addition Test (PASAT), p = 0.05; two-second PASAT, p = 0.01). Anxiety in people with depression predicted decreased visuospatial function (Judgment of Line Orientation, p = 0.05), verbal learning (p < 0.01), verbal delayed recall (p < 0.01), visuospatial recall (Brief Visuospatial Memory Test-Revised, p = 0.02), and executive function (Delis-Kaplan Executive Function System, p < 0.01). Anxiety alone was not independently predictive of cognition. In conclusion, depression, especially with comorbid anxiety, is associated with cognitive dysfunction in people with MS.

Association between loneliness and cognitive function, and brain volume in community-dwelling elderly.

Introduction: We investigated the relationship between loneliness, cognitive impairment, and regional brain volume among elderly individuals residing in the Korean community. Methods: Data from the ARIRANG aging-cognition sub-cohort, collected between 2020 and 2022, were utilized for the present study. Loneliness was assessed using the UCLA-Loneliness Scale (UCLA-LS) questionnaire and the relevant item from Center for Epidemiologic Studies Depression Scale Korean version (CES-D-K). Cognitive impairment was measured through Mini-Mental State Examination (K-MMSE-2) and Seoul Neuropsychological Screening Battery (SNSB-C), with five sub-categories: attention, memory, visuospatial function, language, and executive function. Logistic regression was employed for prevalence ratios related to cognitive impairment, while linear regression was used for regional brain volume including white matter hyperintensity (WMH) and cortical thickness. Results: Our analysis involved 785 participants (292 men and 493 women). We observed increased cognitive impairment assessed by K-MMSE-2 [UCLA-LS: odds ratio (OR) 3.133, 95% confidence interval (CI) 1.536-6.393; loneliness from CES-D: OR 2.823, 95% CI 1.426-5.590] and SNSB-C total score (UCLA-LS: OR 2.145, 95% CI 1.304-3.529) in the lonely group compared to the non-lonely group. Specifically, the lonely group identified by UCLA-LS showed an association with declined visuospatial (OR 1.591, 95% CI 1.029-2.460) and executive function (OR 1.971, 95% CI 1.036-3.750). The lonely group identified by CES-D-K was associated with impaired memory (OR 1.577, 95% CI 1.009-2.466) and executive function (OR 1.863, 95% CI 1.036-3.350). In the regional brain volume analysis, loneliness was linked to reduced brain volume in frontal white matter (left: -1.24, 95% CI -2.37 ∼-0.12; right: -1.16, 95% CI -2.31 ∼ -0.00), putamen (left: -0.07, 95% CI -0.12 ∼-0.02; right: -0.06, 95% CI -0.11 ∼-0.01), and globus pallidus (-15.53, 95% CI -30.13 ∼-0.93). There was no observed association in WMH and cortical thickness. Conclusion: Loneliness is associated with cognitive decline and volumetric reduction in the frontal white matter, putamen, and globus pallidus.

Teaching strategies, cognitive factors and mathematics.

Mathematics teaching strategies have a positive impact on learning. However, there is a lack of studies on non-traditional approaches to early mathematics education in the specialized scientific literature. In this theoretical framework, a study to connect teaching methodology with the various cognitive processes implicated in learning has been designed. A total of 114 primary school students aged 74 and 84 months who were taught mathematics either with the method called Open Algorithm Based on Numbers or with the more traditional Closed Algorithm Based on Ciphers, participated in the study. After conducting a thorough examination of cognitive processes and early math performance using well-established assessment instruments, a comparative analysis was undertaken to explore the relationship between cognitive predictors of mathematical performance, while considering the mathematics teaching strategies used. Students were distributed according to their level of mathematical competence and teaching methodology and the type of schools (Charter or Public). The results from the multivariate statistical test showed that the teaching strategy was inconclusive for most of the cognitive factors studied. Significant differences according to mathematical performance were found for fluid intelligence, verbal short-term memory, and visuospatial working memory. Finally, no significant differences were found in the cognitive variables studied when considering the interaction between the teaching approach, school characteristics, and mathematical achievement as a reference.

Gut Microbiota Mediate the Neuroprotective Effect of Oolong Tea Polyphenols in Cognitive Impairment Induced by Circadian Rhythm Disorder.

Oolong tea polyphenols (OTP) have attracted wide attention due to their ability to reduce inflammatory response, regulate gut microbiota, and improve cognitive function. However, exactly how the gut microbiota modulates nervous system activity is still an open question. We previously expounded that supplementing with OTP alleviated neuroinflammation in circadian rhythm disorder (CRD) mice. Here, we showed that OTP can relieve microglia activation by reducing harmful microbial metabolites lipopolysaccharide (LPS) that alleviate CRD-induced cognitive decline. Mechanistically, OTP suppressed the inflammation response by regulating the gut microbiota composition, including upregulating the relative abundance of Muribaculaceae and Clostridia_UCG-014 and downregulating Desulfovibrio, promoting the production of short-chain fatty acids (SCFAs). Moreover, the use of OTP alleviated intestinal barrier damage and decreased the LPS transport to the serum. These results further inhibited the activation of microglia, thus alleviating cognitive impairment by inhibiting neuroinflammation, neuron damage, and neurotoxicity metabolite glutamate elevation. Meanwhile, OTP upregulated the expression of synaptic plasticity-related protein postsynaptic density protein 95 (PSD-95) and synaptophysin (SYN) by elevating the brain-derived neurotrophic factor (BDNF) level. Taken together, our findings suggest that the OTP has the potential to prevent CRD-induced cognition decline by modulating gut microbiota and microbial metabolites.

Dopaminergic mesolimbic structural reserve is positively linked to better outcome after severe stroke.

The concept of brain reserve capacity has emerged in stroke recovery research in recent years. Imaging-based biomarkers of brain health have helped to better understand outcome variability in clinical cohorts. Still, outcome inferences are far from being satisfactory, particularly in patients with severe initial deficits. Neurorehabilitation after stroke is a complex process, comprising adaption and learning processes, which, on their part, are critically influenced by motivational and reward-related cognitive processes. Amongst others, dopaminergic neurotransmission is a key contributor to these mechanisms. The question arises, whether the amount of structural reserve capacity in the dopaminergic system might inform about outcome variability after severe stroke. For this purpose, this study analysed imaging and clinical data of 42 severely impaired acute stroke patients. Brain volumetry was performed within the first 2 weeks after the event using the Computational Anatomy Toolbox CAT12, grey matter volume estimates were collected for seven key areas of the human dopaminergic system along the mesocortical, mesolimbic and nigrostriatal pathways. Ordinal logistic regression models related regional volumes to the functional outcome, operationalized by the modified Rankin Scale, obtained 3-6 months after stroke. Models were adjusted for age, lesion volume and initial impairment. The main finding was that larger volumes of the amygdala and the nucleus accumbens at baseline were positively associated with a more favourable outcome. These data suggest a link between the structural state of mesolimbic key areas contributing to motor learning, motivational and reward-related brain networks and potentially the success of neurorehabilitation. They might also provide novel evidence to reconsider dopaminergic interventions particularly in severely impaired stroke patients to enhance recovery after stroke.

Comparing the Oxford Digital Multiple Errands Test (OxMET) to a real-life version: Convergence, feasibility, and acceptability.

We aimed to assess the convergence, feasibility, and acceptability of the Oxford Digital Multiple Errands Test (OxMET) and the in-person Multiple Errands Test-Home version (MET-Home). Participants completed OxMET, MET-Home, Montreal Cognitive Assessment (MoCA), and questionnaires on activities of daily living, depression, technology usage, mobility, and disability. Forty-eight stroke survivors (mean age 69.61, 41.67% female, and average 16.5 months post-stroke) and 50 controls (mean age 71.46, 56.00% female) took part. No performance differences were found for healthy and stroke participants for MET-Home, and only found below p = .05 for OxMET but not below the corrected p = .006. Convergent validity was found between MET-Home and OxMET metrics (most r ≥ .30, p < .006). MET-Home accuracy was related to age (B = -.04, p = .03), sex (B = -.98, p = .03), disability (B = -0.63, p = .04), and MoCA (B = .26, p < .001), whereas OxMET accuracy was predicted by MoCA score (B = .40, p < .001). Feedback indicated that the OxMET was easy and fun and more acceptable than the MET-Home. The MET-Home was more stressful and interesting. The MET tasks demonstrated good convergent validity, with the OxMET digital administration providing a more feasible, inclusive, and acceptable assessment, especially to people with mobility restrictions and more severe stroke.

Social cognition in idiopathic generalised epilepsies.

Social cognition is a set of mental skills necessary to create satisfactory interpersonal relationships and feel a sense of belonging to a social group. Its deficits significantly reduce the quality of life in people with epilepsy. Studies on social cognition and its impairments focus predominantly on people with focal epilepsies. Idiopathic generalised epilepsies are a group of diseases that share similar clinical, prognostic and electrographic characteristics. Despite their typically normal intelligence, people with Idiopathic generalised epilepsies can suffer from learning disabilities and executive dysfunctions. Current studies also suggest social cognition impairments, but their results are inconsistent. This review offers the latest knowledge of social cognition in adults with Idiopathic generalised epilepsies. In addition, we provide an overview of the most frequently used assessment methods. We explain possible reasons for different outcomes and discuss future research perspectives.

Cognitive function in different motor subtypes of Parkinson's disease: A systematic review protocol.

Background and Aims: As the fastest-growing neurological disorder globally, a better understanding of Parkinson's disease (PD) is needed to improve patient outcomes and reduce the increasing economic and healthcare burden associated with the disease. Whilst classified as a movement disorder, this disease is highly heterogeneous, encompassing a broad range of both motor and non-motor symptoms (NMS). Cognitive impairment, presenting as either mild cognitive impairment or PD-dementia, is one of the most prevalent and disabling NMS. To better understand heterogeneity in PD, researchers have sought to identify subtypes of individuals who share similar symptom profiles. To date, this research has predominantly focused on motor subtyping, with many studies comparing these motor subtypes on non-motor outcomes, such as cognitive impairment. However, despite evidence of a motor-cognitive relationship in healthy aging, findings regarding the presence of a motor-cognitive relationship in PD are inconsistent. In our proposed systematic review, we will investigate motor subtyping studies that have evaluated the relationship between motor and cognitive function in PD. We aim to examine what is currently known about the relationship between motor and cognitive impairment in PD and evaluate the state of the field with respect to the subtyping methods and quality of cognitive assessment tools used. Methods: Systematic literature searches will be conducted in PubMed, PsycINFO, CINAHL, Scopus, and Web of Science. Results: Results will be synthesized using meta-analysis and, where meta-analysis is not feasible, narrative synthesis. Conclusion: Despite the preponderance of motor subtyping research in PD, our study will be the first to systematically review evidence regarding the association between motor subtypes and cognitive impairment. Understanding the nature of the motor-cognitive relationship in PD may lead to important insights regarding shared underlying disease pathology, which would have significant implications for early diagnosis, prognosis, and treatment of cognitive impairment in PD.

A comprehensive guide to research protocols for collecting and coding involuntary past and future thoughts.

The paper presents a comprehensive guide for researchers investigating mind-wandering and related phenomena such as involuntary past and future thinking. Examining such spontaneous cognitions presents a challenge requiring not only the use of appropriate laboratory-based procedures, but also the coding of complex qualitative data. This guide outlines two main stages of existing research protocols: data acquisition and data coding. For the former, we introduce an easily modifiable computerized version of the vigilance task, designed for broad application in studies focusing on eliciting and measuring involuntary thoughts in controlled laboratory conditions. Regarding data preparation and coding, we provide a detailed step-by-step procedure for categorizing and coding different types of thoughts, involving both participants and competent judges. Additionally, we address some of the difficulties that may arise during this categorization and coding process. The guide is supplemented by a clip demonstrating the main part of the experimental procedure and a step-by-step example of the subsequent data processing stages. We anticipate that this research guide will not only assist a broader group of researchers interested in investigating spontaneous cognition, but will also inspire future studies on spontaneous cognition and related phenomena.•There is a need for standardized approaches to working with qualitative data when investigating spontaneous thoughts.•The paper outlines a comprehensive protocol for collecting and coding involuntary past and future-oriented thoughts.•The paper also presents a detailed step-by-step procedure for data preparation and coding to categorize different types of thoughts, involving both participants and competent judges.