Impaired decision-making and time perception in individuals with stroke: Behavioral and neural correlates

Exploring the Therapeutic Effects and Mechanisms of Transcranial Alternating Current Stimulation on Improving Walking Ability in Stroke Patients via Modulating Cerebellar Gamma Frequency Band-a Narrative Review

The cerebellum plays an important role in maintaining balance, posture control, muscle tone, and lower limb coordination in healthy individuals and stroke patients. At the same time, the relationship between cerebellum and motor learning has been widely concerned in recent years. Due to the relatively intact structure preservation and high plasticity after supratentorial stroke, non-invasive neuromodulation targeting the cerebellum is increasingly used to treat abnormal gait in stroke patients. The gamma frequency of transcranial alternating current stimulation (tACS) is commonly used to improve motor learning. It is an essential endogenous EEG oscillation in the gamma range during the swing phase, and rhythmic movement changes in the gait cycle. However, the effect of cerebellar tACS in the gamma frequency band on balance and walking after stroke remains unknown and requires further investigation.

Exploring the correlation and causation between alpha oscillations and one-second time perception through EEG and tACS

Alpha oscillations have been implicated in time perception, yet a consensus on their precise role remains elusive. This study directly investigates this relationship by examining the impact of alpha oscillations on time perception. Resting-state EEG recordings were used to extract peak alpha frequency (PAF) and peak alpha power (PAP) characteristics. Participants then performed a time generalization task under transcranial alternating current stimulation (tACS) at frequencies of PAF-2, PAF, and PAF+2, as well as a sham condition. Results revealed a significant correlation between PAP and accuracy, and between PAF and precision of one-second time perception in the sham condition. This suggests that alpha oscillations may influence one-second time perception by modulating their frequency and power. Interestingly, these correlations weakened with real tACS stimulations, particularly at higher frequencies. A second analysis aimed to establish a causal relationship between alpha peak modulation by tACS and time perception using repeated measures ANOVAs, but no significant effect was observed. Results were interpreted according to the state-dependent networks and internal clock model.

Neuroimaging and Brain-Based Markers Identifying Neurobiological Markers Associated With Criminal Behaviour, Personality Disorders, and Mental Health: A Narrative Review

We begin the review by pointing to the common stigma associated with mental health issues, which often derives from a lack of understanding or incomplete knowledge. Neurobiological research provides us with a new lens to help challenge and dispel common assumptions and misunderstandings and gives an understanding of sexual behaviours that influence society. As such, it generates substantial evidence for the structural and functional asymmetry of the brains of individuals with mental disorders. However, this type of representation poses many challenges to traditional thinking and constantly provokes change in perspective and empathy towards those individuals. In the review, we go deeper into the effects of neurobiological findings on understanding criminal behaviours and personality disorders, looking further beyond behavioural health. These problems, which were once mainly discussed as moral ones or viewed from the perspective of character flaws, are analysed today through neurological considerations pointing to their complexity. When the root of bipolar disorder is revealed to be neurological, society will react with more information and understanding, hence reducing the stigmatisation and discrimination meted out to people with these problems. At a macro level, findings from neurobiology affect society in ways that go beyond individuals; social attitudes, laws, and policies about the services rendered are influenced. Operating as a catalyst within the community, neurobiological research helps to initiate social change through the creation of an informed, understanding public forum. Thus, it creates broader value for those dealing with behavioural and mental health challenges. The first and most important question of this narrative review is focused on identifying identifiable neurobiological markers that are closely related to criminal conduct, personality disorders, and mental health disorders. Through this review, we aim to present detailed insights into the neurological foundations that anchor these phenomena via a narrative analysis of contemporary literature. The potential implications are finding problems early to apply specific treatment and learning an advanced strategy for social attitudes. This will promote a more humanistic approach based on adequate information on the behavioural and mental health issues involved.

The effects of visual skills training on cognitive and executive functions in stroke patients: a systematic review with meta-analysis

The visual system and associated skills are of particular importance in stroke rehabilitation. The process of neuroplasticity involved in restoring cognitive function during this period is mainly based on anatomical and physiological mechanisms. However, there is little evidence-based knowledge about the effects of visual skills training that could be used to improve therapeutic outcomes in cognitive rehabilitation. A computerized systematic literature search was conducted in the PubMed, Medline, and Web of Science databases from 1 January 1960 to 11 Febuary 2024. 1,787 articles were identified, of which 24 articles were used for the calculation of weighted standardized mean differences (SMD) after screening and eligibility verification. The findings revealed moderate effects for global cognitive function (SMD = 0.62) and activities of daily living (SMD = 0.55) as well as small effects for executive function (SMD = 0.20) - all in favor of the intervention group. The analyses indicate that the results may not be entirely robust, and should therefore be treated with caution when applied in practice. Visual skills training shows positive effects in improving cognitive and executive functions, especially in combination with high cognitive load and in an early phase of rehabilitation. An improvement in activities of daily living can also be observed with this type of intervention. The high heterogeneity of the studies and different treatment conditions require the identification of a relationship between certain visual skills and executive functions in future research.

The testamentary capacity in acute stroke. A cross-sectional study

Succession law, which governs the creation and validity of wills, is closely tied to testamentary capacity (TC), the cognitive competence required for a valid will. This study explores TC in acute stroke patients and its connections to demographic and clinical characteristics. The research included first-time stroke patients admitted within 24 hours of symptom onset, meeting specific criteria. Data were collected, and assessment tools like the Addenbrooke's Cognitive Examination III (ACE-III) and Testamentary Capacity Assessment Tool (TCAT) were used. The study found that TCAT scores were not significantly affected by age or gender but positively correlated with education, the Barthel Index and ACE-III scores. They were negatively associated with National Institutes of Health Stroke Scale (NIHSS) and Modified Rankin Scale (mRS) scores. Specific cognitive domains, particularly memory and attention, were independent determinants of TCAT scores. This research introduces TCAT as a valuable tool for evaluating testamentary capacity in stroke patients and highlights the multifaceted nature of TC, emphasizing the need for a nuanced approach. As the population ages and complex medical conditions become more prevalent, understanding the interplay between cognitive functioning and testamentary capacity becomes increasingly crucial for both legal and medical professionals.

Time processing in neurological and psychiatric conditions

A central question in understanding cognition and pathology-related cognitive changes is how we process time. However, time processing difficulties across several neurological and psychiatric conditions remain seldom investigated. The aim of this review is to develop a unifying taxonomy of time processing, and a neuropsychological perspective on temporal difficulties. Four main temporal judgments are discussed: duration processing, simultaneity and synchrony, passage of time, and mental time travel. We present an integrated theoretical framework of timing difficulties across psychiatric and neurological conditions based on selected patient populations. This framework provides new mechanistic insights on both (a) the processes involved in each temporal judgement, and (b) temporal difficulties across pathologies. By identifying underlying transdiagnostic time-processing mechanisms, this framework opens fruitful avenues for future research.

Excluded and myopic: Social exclusion increases temporal discounting

Social exclusion is a painful yet ubiquitous experience that modulates affect, behavior, and cognition. Decision-making is an essential cognitive ability that some forms of it are altered following social exclusion. However, how intertemporal decision-making is influenced by social exclusion is scarcely studied. Here, using Future Life Alone paradigm we demonstrated that experiencing social exclusion increases temporal discounting. We further tested whether the increased temporal discounting is mediated by either time perception or risk-taking. Our results revealed that although time perception is influenced by social exclusion, neither time perception nor risk-taking mediated the changes in temporal discounting. Our results are providing further evidence corroborating that social exclusion evokes cognitive deconstruction and therefore alters temporal discounting.

Embodied decision biases: individually stable across different tasks?

In everyday life, action and decision-making often run in parallel. Action-based models argue that action and decision-making strongly interact and, more specifically, that action can bias decision-making. This embodied decision bias is thought to originate from changes in motor costs and/or cognitive crosstalk. Recent research confirmed embodied decision biases for different tasks including walking and manual movements. Yet, whether such biases generalize within individuals across different tasks remains to be determined. To test this, we used two different decision-making tasks that have independently been shown to reliably produce embodied decision biases. In a within-participant design, participants performed two tasks in a counterbalanced fashion: (i) a walking paradigm for which it is known that motor costs systematically influence reward decisions, and (ii) a manual movement task in which motor costs and cognitive crosstalk have been shown to impact reward decisions. In both tasks, we successfully replicated the predicted embodied decision biases. However, there was no evidence that the strength of the biases correlated between tasks. Hence, our findings do not confirm that embodied decision biases transfer between tasks. Future research is needed to examine whether this lack of transfer may be due to different causes underlying the impact of motor costs on decisions and the impact of cognitive crosstalk or task-specific differences.

Temporal judgments of actions following unilateral brain damage

Sense of time is a complex construct, and its neural correlates remain to date in most part unknown. To complicate the frame, physical attributes of the stimulus, such as its intensity or movement, influence temporal perception. Although previous studies have shown that time perception can be compromised after a brain lesion, the evidence on the role of the left and right hemispheres are meager. In two experiments, the study explores the ability of temporal estimation of multi-second actions and non-biological movements in 33 patients suffering from unilateral brain lesion. Furthermore, the modulatory role of induced embodiment processes is investigated. The results reveal a joint contribution of the two hemispheres depending not only on different durations but also on the presence of actions. Indeed, the left hemisphere damaged patients find it difficult to estimate 4500 ms or longer durations, while the right hemisphere damaged patients fail in 3000 ms durations. Furthermore, the former fail when a biological action is shown, while the latter fail in non-biological movement. Embodiment processes have a modulatory effect only after right hemisphere lesions. Among neuropsychological variables, only spatial neglect influences estimation of non-biological movement.

Can mental practice adjunct in the recovery of motor function in the upper limbs after stroke? A systematic review and meta-analysis

BACKGROUND:

Studies indicate that mental practice can be an adjuvant rehabilitation, improving motor functions.

AIM:

To synthesize the evidence on the intervention with the mental practice for the rehabilitation of the upper limb after stroke in the context of a dependent task.

METHODS:

The review was registered on the PROSPERO with protocol number: CRD42020166624. We searched the PubMed, Medline, Embase, Central, PEDro, and Web of Science from randomized clinical trials from 1975 to 2022. A literature review was conducted with 13 studies that synthesized findings on mental practice such as adjuvant rehabilitation in the recovery of the upper limb after stroke based on Fugl-Meyer Assessment (FMA) Motor and action research arm test (ARAT) scores.

RESULTS:

The sample size was 232 were part of the intervention group and 180 of the control group. The findings no showed results in favor of mental practice after stroke accordingly to ARAT and FMA Motor scores (P > 0.05).

CONCLUSION:

Current evidence does not support the use of the mental practice to increase the recovery of the upper limb after stroke, although the evidence is conflicting for some aspects of the technique.

Palliative care after stroke: A review

BACKGROUND

Palliative care is an integral aspect of stroke unit care. In 2016, the American Stroke Association published a policy statement on palliative care and stroke. Since then there has been an expansion in the literature on palliative care and stroke.

AIM

Our aim was to narratively review research on palliative care and stroke, published since 2015.

RESULTS

The literature fell into three broad categories: (a) scope and scale of palliative care needs, (b) organization of palliative care for stroke, and (c) shared decision making. Most literature was observational. There was a lack of evidence about interventions that address specific palliative symptoms or improve shared decision making. Racial disparities exist in access to palliative care after stroke. There was a dearth of literature from low- and middle-income countries.

CONCLUSION

We recommend further research, especially in low- and middle-income countries, including research to explore why racial disparities in access to palliative care exist. Randomized trials are needed to address specific palliative care needs after stroke and to understand how best to facilitate shared decision making.