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.     

A systematic review of the effectiveness of machine learning for predicting psychosocial outcomes in acquired brain injury: Which algorithms are used and why?

Clinicians working in the field of acquired brain injury (ABI, an injury to the brain sustained after birth) are challenged to develop suitable care pathways for an individual client’s needs. Being able to predict psychosocial outcomes after ABI would enable clinicians and service providers to make advance decisions and better tailor care plans. Machine learning (ML, a predictive method from the field of artificial intelligence) is increasingly used for predicting ABI outcomes. This review aimed to examine the efficacy of using ML to make psychosocial predictions in ABI, evaluate the methodological quality of studies, and understand researchers’ rationale for their choice of ML algorithms. Nine studies were reviewed from five databases, predicting a range of psychosocial outcomes from stroke, traumatic brain injury, and concussion. Eleven types of ML were employed with a total of 75 ML models. Every model was evaluated as having high risk of bias, unable to provide adequate evidence for predictive performance due to poor methodological quality. Overall, there was limited rationale for the choice of ML algorithms and poor evaluation of the methodological limitations by study authors. Considerations for overcoming methodological shortcomings are discussed, along with suggestions for assessing the suitability of data and suitability of ML algorithms for different ABI research questions.     

Effects of right and left hemisphere damage on performance of the "Right Hemisphere Communication Battery"

A Hebrew adaptation of Gardner and Brownell's (1986) "Right Hemisphere Communication Battery" (HRHCB) was administered to 27 right brain-damaged (RBD) patients, 31 left brain-damaged (LBD) patients, and 21 age-matched normal controls. Both patient groups showed deficits relative to controls and overall there was no difference between the two patient groups. A factor analysis of patients' scores on the HRHCB yielded two interpretable factors, a verbal and a nonverbal one. These factors were not lateralized. Performance of patients on the HRHCB correlated significantly and positively with performance on most tests of basic language functions, measured with a Hebrew adaptation of the "Western Aphasia Battery" (HWAB) and with other cognitive functions measured with standardized neuropsychological tests. There were stronger correlations of HRHCB with subtests of the HWAB in LBD patients and with nonlanguage cognitive tests in RBD patients. In the LBD group, HRHCB subtests' scores correlated negatively with lesion extent in frontal and temporal perisylvian regions. Such localization was not observed in RBD patients. The results argue against selective right hemisphere (RH) involvement in the RHCB, alleged to measure pragmatic aspects of language use, and show, instead, bilateral involvement. The results also argue against a modular organization of these functions of language use, especially in the RH.     

The relationship between acute stress disorder and posttraumatic stress disorder in severely injured trauma survivors

This prospective longitudinal study was designed to investigate the relationship between acute stress disorder (ASD) and the subsequent development of posttraumatic stress disorder (PTSD) in a population of severely injured hospitalised trauma survivors. Symptoms of ASD were assessed just prior to discharge in 307 consecutive admissions to a Level 1 Trauma Centre, with PTSD assessments completed at 3 and 12 months post-injury. A well-established structured clinical interview was adopted for both assessments. Only 1% of the sample met criteria for an ASD diagnosis (at a mean of 8 days post-injury), while the incidence of PTSD was 9% at 3 months and 10% at 12 months. Although all ASD symptom clusters contributed to the prediction of subsequent PTSD severity, logistic regression indicated that only re-experiencing and arousal predicted a categorical PTSD diagnosis. The dissociative symptoms that form the core of ASD were rarely endorsed and showed high specificity but low sensitivity, resulting in a high proportion of false negative diagnoses. Reducing the number of dissociative symptoms required for a diagnosis ameliorated, but did not resolve, the problem. In this particular population, the low sensitivity of the ASD diagnosis renders it a poor screening test for use in identifying high risk individuals for early intervention and prevention strategies.     

Cognitive behaviour therapy of acute stress disorder: a four-year follow-up

The aim of this study was to index the long-term benefits of early provision of cognitive behavior therapy to trauma survivors with acute stress disorder. Civilian trauma survivors (n = 80) with acute stress disorder were randomly allocated to either cognitive behavior therapy (CBT) or supportive counseling (SC) - 69 completed treatment, and 41 were assessed four years post-treatment for post-traumatic stress disorder (PTSD) with the Clinician Administered PTSD Scale. Two CBT patients (8%) and four SC patients (25%) met PTSD criteria at four-year follow-up. Patients who received CBT reported less intense PTSD symptoms, and particularly less frequent and less avoidance symptoms, than patients who received SC. These findings suggest that early provision of CBT in the initial month after trauma has long-term benefits for people who are at risk of developing PTSD.     

Acquired ‘theory of mind'' impairments following stroke

The ability to attribute thoughts and feelings to self and others (‘theory of mind') has been hypothesised to have an innate neural basis and a dedicated cognitive mechanism. Evidence in favour of this proposal has come from autism; a brain-based developmental disorder which appears to be characterised by impaired theory of mind, despite sometimes good general reasoning skills/IQ. To date no case of specific acquired theory of mind impairment has been reported. The present study examined theory of mind in adults who had suffered right hemisphere stroke, a group known to show pragmatic and social difficulties. In one study using story materials and two using cartoons, patients' understanding of materials requiring attribution of mental states (e.g. ignorance, false belief) was significantly worse than their understanding of non-mental control materials. Data from healthy elderly subjects, and a small group of left hemisphere patients (who received the tasks in modified form), suggest that this impairment on mental state tasks is not a function of task difficulty. The findings support the notion of a dedicated cognitive system for theory of mind, and suggest a role for the healthy right hemisphere in the attribution of mental states.     

Investigating the dose-response relationship between motor imagery and motor recovery of upper-limb impairment and function in chronic stroke: A scoping review

The recovery of upper-limb impairment and dysfunction post-stroke is often incomplete owing to the limited time in therapy focused on upper-limb recovery and the severity of the impairment. In these cases, motor imagery (MI) may be used as a precursor to physical therapies to initiate rehabilitation early on when it would be otherwise impossible to engage in therapy, as well as to increase the dose of therapy when MI is used in adjunct to physical therapy. While previous reviews have shown MI to be effective as a therapeutic option, disparity in findings exists, with some studies suggesting MI is not an effective treatment for post-stroke impairment and dysfunction. One factor contributing to these findings is inconsistency in the dose of MI applied. To explore the relationship between MI dose and recovery, a scoping review of MI literature as a treatment for adult survivors of stroke with chronic upper-limb motor deficit was performed. Embase, Medline and CINHAL databases were searched for articles related to MI and stroke. Following a two-phase review process, 21 papers were included, and data related to treatment dose and measures of impairment and function were extracted. Effect sizes were calculated to investigate the effect of dosage on motor recovery. Findings showed a high degree of variability in dosage regimens across studies, with no clear pattern for the effect of dose on outcome. The present review highlights the gaps in MI literature, including variables that contribute to the dose-response relationship, that future studies should consider when implementing MI.     

Effectuation of adaptive stability and postural alignment strategies are decreased by alcohol intoxication

Human stability control is a complex process comprising contributions from several partly independent mechanisms such as coordination, feedback and feed-forward control, and adaptation. Acute alcohol intoxication impairs these functions and is recognized as a major contributor to fall traumas. The study aimed to investigate how alcohol intoxication at .06% and .10% blood alcohol concentration (BAC) affected the movement spans and control of posture alignment. The angular positions of the head, shoulder, hip and knees relative to the ankles were measured with a 3D motion analysis system in 25 healthy adults during standing with eyes open or closed and with or without vibratory balance perturbations.Alcohol intoxication significantly increased the movement spans of the head, shoulders, hip and knees in anteroposterior and lateral directions during quiet stance (p ⩽ .047 and p ⩽ .003) and balance perturbations (p < .001, both directions). Alcohol intoxication also decreased the ability to reduce the movement spans through adaptation in both anteroposterior (p ⩽ .011) and lateral (p ⩽ .004) directions. When sober and submitted to balance perturbations, the subjects aligned the head, shoulders, hip and knees more forward relative to the ankle joint (p < .001), hence adopting a more resilient posture increasing the safety margin for backward falls. Alcohol intoxication significantly delayed this forward realignment (p ⩽ .022). Alcohol intoxication did not cause any significant posture realignment in the lateral direction. Thus, initiation of adaptive posture realignments to alcohol or other disruptions might be context dependent and associated with reaching a certain level of stability threats.     

哲学视野下脑卒中后心理障碍的辩证康复

脑卒中后的心理障碍不但影响患者的心理健康,还严重阻碍整个康复治疗的进程。心理疗法作为一种重要的心理障碍康复手段,其有效性已得到相关临床研究的证实。但如何根据临床具体情况选择适宜的心理疗法加速患者功能的康复,提高其生活质量和日常生活活动能力,最终帮助患者重返家庭和社会一直是临床关注的热点。为了更好地提高对卒中患者心理障碍的认识和干预,本文试从哲学的角度出发,结合各期心理障碍的特点,对脑卒中后心理障碍的康复作一论述。