Post-Stroke Working Memory Dysfunction: A Meta-Analysis and Systematic Review

Working memory load modulates anticipatory postural adjustments during step initiation

Working memory (WM) can influence selective attention. However, the effect of WM load on postural standing tasks has been poorly understood, even though these tasks require attentional resources. The purpose of this study was to examine whether WM load would impact anticipatory postural adjustments (APAs) during step initiation. Sixteen healthy young adults performed stepping tasks alone or concurrently with a WM task in a dual-task design. The stepping tasks involved volitional stepping movements in response to visual stimuli and comprised of simple and choice reaction time tasks and the Flanker task which consisted of congruent and incongruent (INC) conditions. In the dual-task condition, subjects were required to memorize either one or six digits before each stepping trial. Incorrect weight transfer prior to foot-lift, termed APA errors, reaction time (RT), and foot-lift time were measured from the vertical force data. The results showed that APA error rate was significantly higher when memorizing six-digit than one-digit numerals in the INC condition. In addition, RT and foot-lift time were significantly longer in the INC condition compared to the other stepping conditions, while there was no significant effect of WM load on RT or foot-lift time. These findings suggest that high WM load reduces the cognitive resources needed for selective attention and decision making during step initiation.

Structural brain networks correlating with poststroke cognition

Cognitive deficits are a common and debilitating consequence of stroke, yet our understanding of the structural neurobiological biomarkers predicting recovery of cognition after stroke remains limited. In this longitudinal observational study, we set out to investigate the effect of both focal lesions and structural connectivity on poststroke cognition. Sixty-two patients with stroke underwent advanced brain imaging and cognitive assessment, utilizing the Montreal Cognitive Assessment (MoCA) and the Mini-Mental State Examination (MMSE), at 3-month and 12-month poststroke. We first evaluated the relationship between lesions and cognition at 3 months using voxel-based lesion-symptom mapping. Next, a novel correlational tractography approach, using multi-shell diffusion-weighted magnetic resonance imaging (MRI) data collected at both time points, was used to evaluate the relationship between the white matter connectome and cognition cross-sectionally at 3 months, and longitudinally (12 minus 3 months). Lesion-symptom mapping did not yield significant findings. In turn, correlational tractography analyses revealed positive associations between both MoCA and MMSE scores and bilateral cingulum and the corpus callosum, both cross-sectionally at the 3-month stage, and longitudinally. These results demonstrate that rather than focal neural structures, a consistent structural connectome underpins the performance of two frequently used cognitive screening tools, the MoCA and the MMSE, in people after stroke. This finding should encourage clinicians and researchers to not only suspect cognitive decline when lesions affect these tracts, but also to refine their investigation of novel approaches to differentially diagnosing pathology associated with cognitive decline, regardless of the aetiology.

Dl-3-n-Butylphthalide Alleviates Secondary Brain Damage and Improves Working Memory After Stroke in Cynomolgus Monkeys

BACKGROUND

Remote secondary neurodegeneration is associated with poststroke cognitive impairment (PSCI). Dl-3-n-butylphthalide (NBP) improves PSCI clinically. However, whether it ameliorates PSCI by alleviating secondary neurodegeneration remains uncertain. Nonhuman primates provide more relevant models than rodents for human stroke and PSCI. This study investigated the effects of NBP on PSCI and secondary neurodegeneration in cynomolgus monkeys after permanent left middle cerebral artery occlusion (MCAO).

METHODS

Thirteen adult male cynomolgus monkeys were randomly assigned to sham (n=4), MCAO+placebo (n=5), and MCAO+NBP groups (n=4). The MCAO+placebo and MCAO+NBP groups received saline and NBP injections intravenously, respectively, starting at 6-hour postsurgery for 2 weeks, followed by soybean oil and NBP orally, respectively, for 10 weeks after MCAO. Infarct size was assessed at week 4 by magnetic resonance imaging. Working memory and executive function were evaluated dynamically using the delayed response task and object retrieval detour task, respectively. Neuron loss, glia proliferation, and neuroinflammation in the ipsilateral dorsal lateral prefrontal cortex, thalamus, and hippocampus were analyzed by immunostaining 12 weeks after MCAO.

RESULTS

Infarcts were located in the left middle cerebral artery region, apart from the ipsilateral dorsal lateral prefrontal cortex, thalamus, or hippocampus, with no significant difference between the MCAO+placebo and MCAO+NBP group. Higher success in delayed response task was achieved at weeks 4, 8, and 12 after NBP compared with placebo treatments (P<0.05), but not in the object retrieval detour task (all P>0.05). More neurons and less microglia, astrocytes, CD68-positive microglia, tumor necrosis factor-α, and inducible NO synthase were observed in the ipsilateral dorsal lateral prefrontal cortex and thalamus after 12 weeks of NBP treatment (P<0.05), but not in the hippocampus (P>0.05).

CONCLUSIONS

Our findings indicate that NBP improves working memory by alleviating remote secondary neurodegeneration and neuroinflammation in the ipsilateral dorsal lateral prefrontal cortex and thalamus after MCAO in cynomolgus monkeys.

Neurocognitive function as outcome and predictor for prefrontal transcranial direct current stimulation in major depressive disorder: an analysis from the DepressionDC trial

Transcranial direct current stimulation (tDCS) of the prefrontal cortex might beneficially influence neurocognitive dysfunctions associated with major depressive disorder (MDD). However, previous studies of neurocognitive effects of tDCS have been inconclusive. In the current study, we analyzed longitudinal, neurocognitive data from 101 participants of a randomized controlled multicenter trial (DepressionDC), investigating the efficacy of bifrontal tDCS (2 mA, 30 min/d, for 6 weeks) in patients with MDD and insufficient response to selective serotonin reuptake inhibitors (SSRI). We assessed whether active tDCS compared to sham tDCS elicited beneficial effects across the domains of memory span, working memory, selective attention, sustained attention, executive process, and processing speed, assessed with a validated, digital test battery. Additionally, we explored whether baseline cognitive performance, as a proxy of fronto-parietal-network functioning, predicts the antidepressant effects of active tDCS versus sham tDCS. We found no statistically significant group differences in the change of neurocognitive performance between active and sham tDCS. Furthermore, baseline cognitive performance did not predict the clinical response to tDCS. Our findings indicate no advantage in neurocognition due to active tDCS in MDD. Additional research is required to systematically investigate the effects of tDCS protocols on neurocognitive performance in patients with MDD.

The effect of processing speed on verbal and visual memory of adults with a chronic acquired brain injury

OBJECTIVE

Memory problems are among the most frequently reported cognitive complaints by individuals with an acquired brain injury (ABI). Processing speed and working memory deficits are often the result of ABI. These cognitive deficits significantly impact the acquisition and retention of information necessary for memory formation. This study investigated the influence of processing speed and working memory on immediate and delayed recall for verbal and visual memory, as well as overall memory recall in adults living with a chronic ABI.

METHODS

Sixty-three participants living with a chronic ABI, who were at least one-year post-injury, were cognitively assessed with the CNS-Vital Signs (CNS-VS) computerized cognitive battery and Wechsler Test of Adult Reading.

RESULTS

The CNS-VS Processing Speed significantly predicted delayed recall for verbal memory and overall memory performance. The CNS-VS Working Memory was not a significant predictor of memory recall.

CONCLUSIONS

Processing speed deficits negatively impact memory in individuals with a chronic ABI. These findings suggest the memory recall of adults with a chronic ABI is associated with poor processing speed and poor acquisition of information. Therefore, cognitive rehabilitation that improves processing speed should be the focus for individuals with ABI to improve memory performance as well as impaired processing speed.

Risk factors for post-cerebral infarction cognitive dysfunction in older adults: a retrospective study

OBJECTIVE

Our research aims to elucidate the significance of type 2 diabetes (T2D) and provides an insight into a novel risk model for post-cerebral infarction cognitive dysfunction (PCICD).

METHODS

Our study recruited inpatients hospitalized with cerebral infarction in Xijing hospital, who underwent cognitive assessment of Mini-Mental State Examination (MMSE) from January 2010 to December 2021. Cognitive status was dichotomized into normal cognition and cognitive impairment. Collected data referred to Demographic Features, Clinical Diseases, scale tests, fluid biomarkers involving inflammation, coagulation function, hepatorenal function, lipid and glycemic management.

RESULTS

In our pooled dataset from 924 eligible patients, we included 353 in the final analysis (age range 65-91; 30.31% female). Multivariate logistic regression analysis was performed to show that Rural Areas (OR = 1.976, 95%CI = 1.111-3.515, P = 0.020), T2D (OR = 2.125, 95%CI = 1.267-3.563, P = 0.004), Direct Bilirubin (OR = 0.388, 95%CI = 0.196-0.769, P = 0.007), Severity of Dependence in terms of Barthel Index (OR = 1.708, 95%CI = 1.193-2.445, P = 0.003) that were independently associated with PCICD, constituting a model with optimal predictive efficiency.

CONCLUSION

To the best of our knowledge, this study provides a practicable map of strategical predictors to robustly identify cognitive dysfunction at risk of post-cerebral infarction for clinicians in a broad sense. Of note, our findings support that the decline in serum direct bilirubin (DBil) concentration is linked to protecting cognitive function.

Supplementation with a Symbiotic Induced Neuroprotection and Improved Memory in Rats with Ischemic Stroke

After an ischemic stroke, various harmful mechanisms contribute to tissue damage, including the inflammatory response. The increase in pro-inflammatory cytokines has been related to greater damage to the neural tissue and the promotion of neurological alterations, including cognitive impairment. Recent research has shown that the use of prebiotics and/or probiotics counteracts inflammation and improves cognitive function through the production of growth factors, such as brain-derived neurotrophic factor (BDNF), by reducing inflammatory molecules. Therefore, in this study, the effect of the symbiotic inulin and Enterococcus faecium on neuroprotection and memory improvement was evaluated in a rat model of transient middle cerebral artery occlusion (tMCAO). In order to accomplish this, the animals were subjected to ischemia; the experimental group was supplemented with the symbiotic and the control group with the vehicle. The neurological deficit as well as spatial and working memory were evaluated using the Zea Longa scale, Morris water maze, and the eight-arm maze tests, respectively. Infarct size, the levels of BDNF, and tumor necrosis factor-alpha (TNF-α) were also assessed. The results show that supplementation with the symbiotic significantly diminished the neurological deficit and infarct size, improved memory and learning, increased BDNF expression, and reduced TNF-α production. These findings provide new evidence about the therapeutic use of symbiotics for ischemic stroke and open up the possibilities for the design of further studies.

Long-term psychological outcomes following stroke: the OX-CHRONIC study

BACKGROUND

Stroke survivors rate longer-term (> 2 years) psychological recovery as their top priority, but data on how frequently psychological consequences occur is lacking. Prevalence of cognitive impairment, depression/anxiety, fatigue, apathy and related psychological outcomes, and whether rates are stable in long-term stroke, is unknown.

METHODS

N = 105 long-term stroke survivors (M [SD] age = 72.92 [13.01]; M [SD] acute NIH Stroke Severity Score = 7.39 [6.25]; 59.0% Male; M [SD] years post-stroke = 4.57 [2.12]) were recruited (potential N = 208). Participants completed 3 remote assessments, including a comprehensive set of standardized cognitive neuropsychological tests comprising domains of memory, attention, language, and executive function, and questionnaires on emotional distress, fatigue, apathy and other psychological outcomes. Ninety participants were re-assessed one year later. Stability of outcomes was assessed by Cohen's d effect size estimates and percent Minimal Clinically Important Difference changes between time points.

RESULTS

On the Montreal Cognitive Assessment 65.3% scored < 26. On the Oxford Cognitive Screen 45.9% had at least one cognitive impairment. Attention (27.1%) and executive function (40%) were most frequently impaired. 23.5% and 22.5% had elevated depression/anxiety respectively. Fatigue (51.4%) and apathy (40.5%) rates remained high, comparable to estimates in the first-year post-stroke. Attention (d = -0.12; 85.8% stable) and depression (d = 0.09, 77.1% stable) were the most stable outcomes. Following alpha-adjustments, only perceptuomotor abilities (d = 0.69; 40.4% decline) and fatigue (d = -0.33; 45.3% decline) worsened over one year. Cognitive impairment, depression/anxiety, fatigue and apathy all correlated with worse quality of life.

CONCLUSION

Nearly half of participants > 2 years post-event exhibited psychological difficulties including domains of cognition, mood, and fatigue, which impact long-term quality of life. Stroke is a chronic condition with highly prevalent psychological needs, which require monitoring and intervention development.

Using a combined working memory - Semantic feature analysis approach to treat anomia in aphasia: A Pilot Study

INTRODUCTION

The purpose of the study was to pilot a working memory (WM) - and modified Semantic Feature Analysis (SFA) approach to treat word finding deficits in a group of people with aphasia (PwA). Two research questions were posed: 1. Will the group of PwA be able to complete the WM tasks used in the approach? 2. Will the approach improve naming performance in PwA?

METHOD

Three individuals with mild - moderate aphasia participated in this singlesubject multiple baseline treatment design. Pre-treatment assessments of language, and pre- to post-treatment assessments of WM abilities were carried out. The treatment protocol incorporated WM and linguistic tasks in order to improve naming accuracy across two treatment lists. Probes were carried out prior to treatment on each list, and at one-month following completion of treatment. Two outcome measures were obtained: Percent accuracy in completing the WM steps, and treatment effect sizes (Beeson & Robey, 2006). Additionally, modified t-tests (Crawford & Garthwaite, 2012; Crawford & Howell, 1998), were calculated in which post-treatment WM measures were compared against neurotypical control groups to detect any improvements in WM functions.

RESULTS

All three participants completed the WM steps with a high degree of accuracy. A range of small to large ESs were obtained for all three participants across the two treated lists, while no meaningful ESs were obtained for the control (untreated) list. All three participants demonstrated improved scores across most of the WM measures with significant improvements noted on certain WM assessments.

CONCLUSIONS

The findings revealed that the WM - SFA approach can be used successfully in individuals with mild - moderate aphasia. The proposed approach holds promise as feasible intervention designed to remediate anomia in PwA.

A Verbal Card Sorting Task to Measure Executive Functions

PURPOSE

The Wisconsin Card Sorting Test (WCST) is commonly used to measure nonverbal executive functions (EFs) in a variety of clinical populations. However, in some clinical populations (e.g., people with aphasia), deficits may be present in more linguistic (or verbal) domains and less pronounced in nonverbal domains. Thus, when determining possible deficits in these individuals, it is critical to assess both verbal and nonverbal cognitive abilities. The purpose of this study was to create a verbal card sorting task (VCST) to complement the WCST.

METHOD

We created the VCST by modifying a computerized version of the WCST, the Berg Card Sorting Task (BCST). We then compared 35 individuals with mild traumatic brain injury (mTBI) and 33 matched controls' performance on each task. We tested the VCST in individuals with mTBI first because they demonstrate impaired EFs but unimpaired language. We therefore expected the mTBI group to perform similarly on the VCST and BCST, suggesting that the two tasks measure EFs similarly.

RESULTS

In line with our hypothesis, the mTBI group had unimpaired inhibition and sustained attention but impaired shifting on each task. Component loadings for both tasks were also similar, and participants' inhibition and shifting scores positively correlated across the two tasks.

CONCLUSIONS

Together, these findings suggest that the VCST is a potentially useful tool for measuring verbal EF deficits. Our results also provide important insights into the EF impairments experienced by individuals with mTBI.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23230475.

Disentangling poststroke cognitive deficits and their neuroanatomical correlates through combined multivariable and multioutcome lesion-symptom mapping

Studies in patients with brain lesions play a fundamental role in unraveling the brain's functional anatomy. Lesion-symptom mapping (LSM) techniques can relate lesion location to cognitive performance. However, a limitation of current LSM approaches is that they can only evaluate one cognitive outcome at a time, without considering interdependencies between different cognitive tests. To overcome this challenge, we implemented canonical correlation analysis (CCA) as combined multivariable and multioutcome LSM approach. We performed a proof-of-concept study on 1075 patients with acute ischemic stroke to explore whether addition of CCA to a multivariable single-outcome LSM approach (support vector regression) could identify infarct locations associated with deficits in three well-defined verbal memory functions (encoding, consolidation, retrieval) based on four verbal memory subscores derived from the Seoul Verbal Learning Test (immediate recall, delayed recall, recognition, learning ability). We evaluated whether CCA could extract cognitive score patterns that matched prior knowledge of these verbal memory functions, and if these patterns could be linked to more specific infarct locations than through single-outcome LSM alone. Two of the canonical modes identified with CCA showed distinct cognitive patterns that matched prior knowledge on encoding and consolidation. In addition, CCA revealed that each canonical mode was linked to a distinct infarct pattern, while with multivariable single-outcome LSM individual verbal memory subscores were associated with largely overlapping patterns. In conclusion, our findings demonstrate that CCA can complement single-outcome LSM techniques to help disentangle cognitive functions and their neuroanatomical correlates.

Calling on clinicians to get social and emotional

OBJECTIVE

Disorders of social cognition, such as difficulties with emotion perception, alexithymia, Theory of Mind (ToM), empathy and disorders of emotion regulation, are prevalent and pervasive problems across many neurological, neurodevelopmental and neuropsychiatric conditions. Clinicians are familiar with how these difficulties present but assessment and treatment has lagged behind other traditional cognitive domains, such as memory, language and executive functioning.

METHOD

In this paper, we review the prevalence and degree of impairment associated with disorders of social cognition and emotion regulation across a range of clinical conditions, with particular emphasis on their relationship to cognitive deficits and also real-world functioning. We reported effects sizes from published meta-analyses for a range of clinical disorders and also review test usage and available tests.

RESULTS

In general, many clinical conditions are associated with impairments in social cognition and emotion regulation. Effect sizes range from small to very large and are comparable to effect sizes for impairments in nonsocial cognition. Socio-emotional impairments are also associated with social and adaptive functioning. In reviewing prior research, it is apparent that the standardized assessment of social cognition, in particular, is not routine in clinical practice. This is despite the fact that there are a range of tools available and accruing evidence for the efficacy of interventions for social cognitive impairments.

CONCLUSION

We are using this information to urge and call for clinicians to factor social cognition into their clinical assessments and treatment planning, as to provide rigorous, holistic and comprehensive person-centred care.

Stroke damages attentional maintenance in working memory

Stroke is the main cause of acquired disability in adults, and specific deficits in working memory (WM) are among the most common cognitive consequences. In neuropsychological routine, WM is most of the time investigated in the framework of the multicomponent model (Baddeley & Hitch, 1974, The psychology of learning and motivation, 47). Using a more recent theoretical WM model, the time-based resource-sharing (TBRS) model (Barrouillet et al., 2011, Psychol. Rev., 118, 175), the aim of the present study was to investigate in young post-stroke patients to which extent attentional maintenance is impaired in WM. To address this question, we discarded other factors known to directly influence WM performance, that is processing speed and short-term memory span. We proposed to 53 post-stroke patients and to 63 healthy controls a complex span paradigm in which participants were asked to alternate between the memorization of a series of images and a concurrent parity judgement task of a series of digits. To investigate the attentional maintenance processes, we manipulated the cognitive load (CL) of the concurrent task. CL effect is typically interpreted as the involvement of attentional maintenance processes. The task was adapted to each participant according to their processing speed and memory span. As expected, the results showed higher recall performance in healthy controls compared with post-stroke patients. Consistent with the literature, we also observed higher performance when the CL was low compared with high. However, the improvement in recall at low CL was smaller for post-stroke patients compared with controls, suggesting that post-stroke WM deficit could be in part due to a deficit of the attentional maintenance processes.

Changes in Resting-State Neural Activity and Nerve Fibres in Ischaemic Stroke Patients with Hemiplegia

Many neuroimaging studies have reported that stroke induces abnormal brain activity. However, little is known about resting-state networks (RSNs) and the corresponding white matter changes in stroke patients with hemiplegia. Here, we utilized functional magnetic resonance imaging (fMRI) to measure neural activity and related fibre tracts in 14 ischaemic stroke patients with hemiplegia and 12 healthy controls. Fractional amplitude of low-frequency fluctuations (fALFF) calculation and correlation analyses were used to assess the relationship between regional neural activity and movement scores. Tractography was performed using diffusion tensor imaging (DTI) data to analyse the fibres passing through the regions of interest. Compared with controls, stroke patients showed abnormal functional connectivity (FC) between some brain regions in the RSNs. The fALFF was increased in the contralesional parietal lobe, with the regional fALFF being correlated with behavioural scores in stroke patients. Additionally, the passage of fibres across regions with reduced FC in the RSNs was increased in stroke patients. This study suggests that structural remodelling of functionally relevant white matter tracts is probably an adaptive response that compensates for injury to the brain.

Improvement of cognition across a decade after stroke correlates with the integrity of functional brain networks

BACKGROUND AND OBJECTIVE

We recently reported improvements of working memory across 10 years post stroke among middle-aged individuals. However, the mechanisms underlying working-memory recovery are largely unknown. This study investigated the associations between long-term improvement of working memory and resting-state functional connectivity in two frontoparietal networks: the frontoparietal network and the dorsal attention network.

METHODS

Working memory was repeatedly assessed by the Digit Span Backwards task in 21 persons, within 1 year after stroke onset and again 10 years post stroke onset. Brain functional connectivity was examined by resting state functional magnetic resonance imaging at the 10-year follow-up.

RESULTS

A significant improvement of working memory was found among 21 persons after stroke (median age = 64) at the 10-year follow-up compared to the within-one-year assessment. The magnitude of performance improvement on the Digit Span Backwards task was significantly positively correlated with stronger brain connectivity in the frontoparietal network (r = 0.51, p = 0.018) measured at the 10-year follow-up only. A similar association was observed in the dorsal attention network (r = 0.43, p = 0.052) but not in a visual network (r = -0.17, p = 0.46) that served as a control network. The association between functional connectivity within the above-mentioned networks and Digit Span Backwards scores at 10-year after stroke was in the same direction but did not reach significance.

CONCLUSIONS

The present work relate stronger long-term performance improvement on the Digit Span Backwards task with higher integrity of frontoparietal network connectivity.

Eye movement desensitization and reprocessing for post-stroke post-traumatic stress disorder: Case report using the three-phase approach

Medically-induced post-traumatic stress disorder (PTSD) is substantially more prevalent than PTSD in the general population. In people with stroke, it can impact as many as 23% of patients, with negative effects on mental health as well as stroke-related disability. Medically-induced PTSD may have unique features compared to other forms of PTSD, and therefore there is a pressing need to evaluate existing treatments for PTSD in this context. The current study reports on the feasibility, safety, and efficacy of Eye Movement Desensitization and Reprocessing (EMDR) for PTSD subsequent to a pontine stroke. Using a quasi-experimental case design, a 44-year-old Caucasian woman received EMDR delivered via telehealth. Self-report measures were obtained at baseline, pre-EMDR, and post-EMDR, with brief neuropsychological testing pre/post-EMDR. After 3 sessions of EMDR, the patient no longer met criteria for PTSD, and showed clinically significant reductions in depressive and generalized anxiety symptoms. With proper safety provisions, it is feasible to deliver EMDR via telehealth to alleviate post-stroke PTSD. Reduced linguistic demands of EMDR may be particularly appealing for persons with neurological disorders as compared to other trauma therapies. Further work is also needed to understand the parameters of baseline neuropsychological function that could impact response to intervention.

Reversing the Ruin: Rehabilitation, Recovery, and Restoration After Stroke

PURPOSE OF REVIEW

Stroke is a common cause of disability in aging adults. A given individual's needs after stroke vary as a function of the stroke extent and location. The purpose of this review was to discuss recent clinical investigations addressing rehabilitation of an array of overlapping functional domains.

RECENT FINDINGS

Research is ongoing in the domains of movement, cognition, attention, speech, language, swallowing, and mental health. To best assist patients' recovery, innovative research has sought to develop and evaluate behavioral approaches, identify and refine synergistic approaches that augment the response to behavioral therapy, and integrate technology where appropriate, particularly to introduce and titrate real-world complexity and improve the overall experience of therapy. Recent and ongoing trials have increasingly adopted a multidisciplinary nature - augmenting refined behavioral therapy approaches with methods for increasing their potency, such as pharmaceutical or electrical interventions. The integration of virtual reality, robotics, and other technological advancements has generated immense excitement, but has not resulted in consistent improvements over more universally accessible, lower technology therapy.

Comparison of Rehabilitative Interventions That Ameliorate Post-stroke Working Memory Deficit: A Systematic Review

Stroke is one of the most common causes of disability in the world. It has sensory, motor, and cognitive symptoms. Many cognitive domains might get involved in a stroke. This systematic review focuses on working memory domain deficits after stroke and their various rehabilitation methods. This review is based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA) guidelines. For this review, we have searched PubMed, Google Scholar, and Science Direct databases and screened thoroughly with the inclusion criteria of free full-text English papers in the last 10 years that have exclusively studied humans. The articles included in the search are randomized control trials (RCTs), observational studies, meta-analysis studies, systematic reviews, and traditional reviews. Consequent quality assessment was done using the most commonly used tools for each type of study and eight papers were selected. From these papers, full-text articles were studied, analyzed, and tabulated. We found five different rehabilitation methods: transcranial direct-current stimulation, computer-assisted cognitive rehabilitation, physical activity, goal setting, and multimodal rehabilitation. We found that goal setting, computer-assisted cognitive rehabilitation, and multimodal rehabilitation can improve working memory deficits. While transcranial direct current stimulation and physical activity were inconsistent, further studies are needed. The small sample size, no follow-up, the inclusion of only a few studies, the size of the stroke, and comorbid conditions like mild cognitive impairment, dementia, and depression were the main limitations of this study. Future reviews must include a larger number of studies with large sample sizes, including follow-up as an inclusion criterion. We need more clinical trials on these methods for better knowledge.

Common Neuroanatomical Substrate of Cholinergic Pathways and Language-Related Brain Regions as an Explanatory Framework for Evaluating the Efficacy of Cholinergic Pharmacotherapy in Post-Stroke Aphasia: A Review

Despite the relative scarcity of studies focusing on pharmacotherapy in aphasia, there is evidence in the literature indicating that remediation of language disorders via pharmaceutical agents could be a promising aphasia treatment option. Among the various agents used to treat chronic aphasic deficits, cholinergic drugs have provided meaningful results. In the current review, we focused on published reports investigating the impact of acetylcholine on language and other cognitive disturbances. It has been suggested that acetylcholine plays an important role in neuroplasticity and is related to several aspects of cognition, such as memory and attention. Moreover, cholinergic input is diffused to a wide network of cortical areas, which have been associated with language sub-processes. This could be a possible explanation for the positive reported outcomes of cholinergic drugs in aphasia recovery, and specifically in distinct language processes, such as naming and comprehension, as well as overall communication competence. However, evidence with regard to functional alterations in specific brain areas after pharmacotherapy is rather limited. Finally, despite the positive results derived from the relevant studies, cholinergic pharmacotherapy treatment in post-stroke aphasia has not been widely implemented. The present review aims to provide an overview of the existing literature in the common neuroanatomical substrate of cholinergic pathways and language related brain areas as a framework for interpreting the efficacy of cholinergic pharmacotherapy interventions in post-stroke aphasia, following an integrated approach by converging evidence from neuroanatomy, neurophysiology, and neuropsychology.

Development and Validation of a Novel Robot-Based Assessment of Upper Limb Sensory Processing in Chronic Stroke

Upper limb sensory processing deficits are common in the chronic phase after stroke and are associated with decreased functional performance. Yet, current clinical assessments show suboptimal psychometric properties. Our aim was to develop and validate a novel robot-based assessment of sensory processing. We assessed 60 healthy participants and 20 participants with chronic stroke using existing clinical and robot-based assessments of sensorimotor function. In addition, sensory processing was evaluated with a new evaluation protocol, using a bimanual planar robot, through passive or active exploration, reproduction and identification of 15 geometrical shapes. The discriminative validity of this novel assessment was evaluated by comparing the performance between healthy participants and participants with stroke, and the convergent validity was evaluated by calculating the correlation coefficients with existing assessments for people with stroke. The results showed that participants with stroke showed a significantly worse sensory processing ability than healthy participants (passive condition: p = 0.028, Hedges’ g = 0.58; active condition: p = 0.012, Hedges’ g = 0.73), as shown by the less accurate reproduction and identification of shapes. The novel assessment showed moderate to high correlations with the tactile discrimination test: a sensitive clinical assessment of sensory processing (r = 0.52–0.71). We conclude that the novel robot-based sensory processing assessment shows good discriminant and convergent validity for use in participants with chronic stroke.

Remote ischemic preconditioning combined with atorvastatin improves memory after global cerebral ischemia-reperfusion in male rats

Introduction: Damage to hippocampus can occur through ischemia. Memory problems are among the most significant disabilities after stroke. Therefore, improving memory is of great interest in helping post-stroke patients. This study demonstrated that intraperitoneally injection of atorvastatin with a short cycle of ischemia-reperfusion in the left femoral artery improved hippocampal CA1 neurons injury and memory problems after global cerebral ischemia.

Materials and methods: In this article survey, we used 64 animals. Rats were divided into 8 groups, (n=8). Group 1: control; group 2: sham; group 3: global cerebral ischemia (GCI) only; group 4: remote ischemic preconditioning (RIP) + GCI; group 5: GCI + atorvastatin (ATO); group 6: GCI + vehicle; group 7: RIP + GCI + ATO; group 8: RIP + GCI + vehicle. We created global cerebral ischemia (GCI) with 20 min occlusion of the Common carotid artery.

Results and discussion: Remote ischemic preconditioning could improve rats performance in water maze tests along with a decrease in neuronal death. Also, atorvastatin combined with remote ischemic preconditioning was more effective for memory improvement and reduction of neuronal death. Inconsistent with our result, the function of the animals in the ischemia group was impaired. CA1 hippocampal neurons have an important role in memory and learning, and they can be damaged after cerebral ischemia. Therefore, ischemia can create memory problems. Remote ischemic preconditioning and atorvastatin had a neuroprotective effect and could improve rat performance in water maze test.

Conclusion: This study showed that remote ischemic preconditioning with atorvastatin could improve CA1 neuronal injury and memory.

Graphical abstract:

Impact of Startling Acoustic Stimuli on Word Repetition in Individuals With Aphasia and Apraxia of Speech Following Stroke

PURPOSE

The StartReact effect, whereby movements are elicited by loud, startling acoustic stimuli (SAS), allows the evaluation of movements when initiated through involuntary circuitry, before auditory feedback. When StartReact is applied during poststroke upper extremity movements, individuals exhibit increased muscle recruitment, reaction times, and reaching distances. StartReact releases unimpaired speech with similar increases in muscle recruitment and reaction time. However, as poststroke communication disorders have divergent neural circuitry from upper extremity tasks, it is unclear if StartReact will enhance speech poststroke. Our objective is to determine if (a) StartReact is present in individuals with poststroke aphasia and apraxia and (b) SAS exposure enhances speech intelligibility.

METHOD

We remotely delivered startling, 105-dB white noise bursts (SAS) and quiet, non-SAS cues to 15 individuals with poststroke aphasia and apraxia during repetition of six words. We evaluated average word intensity, pitch, pitch trajectories, vowel formants F1 and F2 (first and second formants), phonemic error rate, and percent incidence of each SAS versus non-SAS-elicited phoneme produced under each cue type.

RESULTS

For SAS trials compared to non-SAS, speech intensity increased (∆ + 0.6 dB), speech pitch increased (∆ + 22.7 Hz), and formants (F1 and F2) changed, resulting in a smaller vowel space after SAS. SAS affected pitch trajectories for some, but not all, words. Non-SAS trials had more stops (∆ + 4.7 utterances) while SAS trials had more sustained phonemes (fricatives, glides, affricates, liquids; ∆ + 5.4 utterances). SAS trials had fewer distortion errors but no change in substitution errors or overall error rate compared to non-SAS trials.

CONCLUSIONS

We show that stroke-impaired speech is susceptible to StartReact, evidenced by decreased intelligibility due to altered formants, pitch trajectories, and articulation, including increased incidence of sounds that could not be produced without SAS. Future studies should examine the impact of SAS on voluntary speech intelligibility and clinical measures of aphasia and apraxia.

The Potential and Limitations of Mobile Health and Insertable Cardiac Monitors in the Detection of Atrial Fibrillation in Cryptogenic Stroke Patients: Preliminary Results From the REMOTE Trial

Aim

This paper presents the preliminary results from the ongoing REMOTE trial. It aims to explore the opportunities and hurdles of using insertable cardiac monitors (ICMs) and photoplethysmography-based mobile health (PPG-based mHealth) using a smartphone or smartwatch to detect atrial fibrillation (AF) in cryptogenic stroke and transient ischemic attack (TIA) patients.

Methods and Results

Cryptogenic stroke or TIA patients (n = 39) received an ICM to search for AF and were asked to use a blinded PPG-based mHealth application for 6 months simultaneously. They were randomized to smartphone or smartwatch monitoring. In total, 68,748 1-min recordings were performed using PPG-based mHealth. The number of mHealth recordings decreased significantly over time in both smartphone and smartwatch groups (p < 0.001 and p = 0.002, respectively). Insufficient signal quality was more frequently observed in smartwatch (43.3%) compared to smartphone recordings (17.8%, p < 0.001). However, when looking at the labeling of the mHealth recordings on a patient level, there was no significant difference in signal quality between both groups. Moreover, the use of a smartwatch resulted in significantly more 12-h periods (91.4%) that were clinically useful compared to smartphone users (84.8%) as they had at least one recording of sufficient signal quality. Simultaneously, continuous data was collected from the ICMs, resulting in approximately 6,660,000 min of data (i.e., almost a 100-fold increase compared to mHealth). The ICM algorithm detected AF and other cardiac arrhythmias in 10 and 19 patients, respectively. However, these were only confirmed after adjudication by the remote monitoring team in 1 (10%) and 5 (26.3%) patients, respectively. The confirmed AF was also detected by PPG-based mHealth.

Conclusion

Based on the preliminary observations, our paper illustrates the potential as well as the limitations of PPG-based mHealth and ICMs to detect AF in cryptogenic stroke and TIA patients in four elements: (i) mHealth was able to detect AF in a patient in which AF was confirmed on the ICM; (ii) Even state-of-the-art ICMs yielded many false-positive AF registrations; (iii) Both mHealth and ICM still require physician revision; and (iv) Blinding of the mHealth results impairs compliance and motivation.

A multi-component, adaptive Working Memory Assessment Battery (WoMAB): validation and norms in an Italian population sample

BACKGROUND

Working memory (WM) abilities are frequently impaired in neurological disorders affecting fronto-parietal cortical/sub-cortical structures. WM deficits negatively influence interventional outcomes and everyday functioning. This study thus aimed at the following: (a) developing and standardizing an ecologically valid task for WM assessment ( Ice Cream Test, ICT); (b) validating and norming a novel WM test (Digit Ordering Test, DOT), as well as providing updated norms for digit span (DS) tasks, in an Italian population sample; (c) introducing a novel scoring procedure for measuring WM.

METHODS

One-hundred and sixty-eight Italian healthy participants-73 male, 95 females; age: 48.4 ± 19.1 (18-86); education: 12.1 ± 4.8 (4-21)-underwent a thorough WM assessment-DOT, ICT, and both forward and backward DS tasks (FDS, BDS). The ICT requires participants to act as waiters who have to keep track of customers' orders. For each task, WM and total (T) outcomes were computed, i.e., the number of elements in the longest sequence and that of recalled sequences, respectively. Norms were derived via the equivalent score (ES) method.

RESULTS

DS ratios (DSRs) were computed for both WM/S and T outcomes on raw DS measures (BDS divided by FDS). Age and education significantly predicted all WM tasks; sex affected FDS and DSR-T scores (males > females). WM measures were highly internally related.

DISCUSSION

The present work provides Italian practitioners with a normatively updated, multi-component, adaptive battery for WM assessment (WoMAB) as well as with novel outcomes which capture different WM facets-WM capacity and attentive monitoring abilities.

The Role of Social Connection/Engagement in Episodic Memory Change in Stroke

BACKGROUND AND OBJECTIVES

Positive associations between social connection/engagement and cognitive function are well documented. However, little is known about whether social connection/engagement can buffer the impact of serious brain injury such as stroke on cognitive functioning.

RESEARCH DESIGN AND METHODS

Participants were 898 individuals with incident stroke from the Health and Retirement Study (HRS) between 1998-2012. Multilevel modeling was used to examine how social connection/engagement were associated with episodic memory pre- and post-stroke. Models controlled for age, gender, education, race/ethnicity, number of health conditions, and functional health.

RESULTS

Participants who were lonely pre-stroke recalled significantly fewer words at time of stroke, and participants who had children residing within 10 miles pre-stroke showed significantly less decline in word recall over time. Participants who provided help to others pre-stroke showed less stroke-related decline in word recall. Within-person increase in partnered status, having friends, and helping others were related to better word recall in the post-stroke period.

DISCUSSION AND IMPLICATIONS

Higher pre-stroke levels of social connection/engagement predicted better episodic memory at stroke, smaller decline in episodic memory with stroke, and less decline in episodic memory over time. Increases in social connection/engagement from pre- to post-stroke also predicted better post-stroke episodic memory. Beyond the widely documented benefits of social connection/engagement to well-being, they may also increase cognitive stimulation and cognitive reserve and thus contribute to stroke recovery in the cognitive domain. Social connection/engagement is an important and modifiable risk factor in older adults.

Association between Blood Pressure, Blood Pressure Variability, and Post-Stroke Cognitive Impairment

After stroke, dynamic changes take place from necrotic-apoptotic continuum, inflammatory response to poststroke neurogenesis, and remodeling of the network. These changes and baseline brain pathology such as small vessel disease (SVD) and amyloid burden may be associated with the occurrence of early or late poststroke cognitive impairment (PSCI) or dementia (PSD), which affect not only stroke victims but also their families and even society. We reviewed the current concepts and understanding of the pathophysiology for PSCI/PSD and identified useful tools for the diagnosis and the prediction of PSCI in serological, CSF, and image characteristics. Then, we untangled their relationships with blood pressure (BP) and blood pressure variability (BPV), important but often overlooked risk factors for PSCI/PSD. Finally, we provided evidence for the modifying effects of BP and BPV on PSCI as well as pharmacological and non-pharmacological interventions and life style modification for PSCI/PSD prevention and treatment.