Influence of diagnosis threat and illness cognitions on the cognitive performance of people with acquired brain injury.

Illness cognitions - cognitive representations of illness - have been found to influence health outcomes in chronic diseases: more adaptive illness cognitions generally lead to better outcomes. Concomitantly, diagnosis threat (DT) is a phenomenon whereby participants with acquired brain injury (ABI) underperform on neuropsychological tasks due to stereotype activation. This randomised study examined the impact of illness cognitions and DT on cognitive performance. People with ABI completed the Illness Cognitions Questionnaire and were then exposed to either a DT condition or a reduced DT condition (in which stereotype cues were reduced). They then completed memory and attentional tasks. Control participants performed only the tasks under one of the two conditions. Under the reduced DT condition, higher adaptive illness cognitions were associated with better memory and attentional performance. However, the DT condition diminished memory (but not attentional) performance in participants with a high level of adaptive illness cognitions, often leading to performance at the pathological level. This study confirms the detrimental impact of DT in people with ABI and highlights the necessity for clinicians to consider psychosocial influences when assessing and treating this population.

A closer look at children's metacognitive skills: The case of the distinctiveness heuristic.

The primary aim of this study was to document the developmental course of distinctiveness effects throughout childhood. Specifically, we examined whether the reduction in false recognition rates that is traditionally observed in children after distinctive encoding could be explained not only by enhanced discrimination between studied and new items but also by the implementation of a conservative response criterion resulting from the use of metacognitive expectations about the quality of memories (i.e., distinctiveness heuristic). Two experiments were conducted in which children in three age groups-4-5, 6-7, and 8-9 years-were asked to study a set of items presented in either pictorial (distinctive) or word (less distinctive) form. In Experiment 1, pictures and words were displayed in two separate lists, a design that is supposed to favor reliance on the distinctiveness heuristic. In Experiment 2, the two types of stimuli were presented within the same list, a design that is supposed to make using the metacognitive heuristic ineffective. Overall, Experiments 1 and 2 provide evidence that children as young as 4 years rely on the distinctiveness heuristic to guide their memory decisions, resulting in a reduction in the false recognition rate when items are presented using a pure-list design (Experiment 1) but not when they are presented using a mixed-list design (Experiment 2). The implications of these findings for our understanding of the development of metacognition and the involvement of metacognitive skills in children's memory performance are discussed.

The Role of Self-Transcendence and Cognitive Processes in the Response Expectancy Effect.

Neuropsychological assessment is known to be influenced by expectancy effects, which can either enhance (placebo) or diminish (nocebo) cognitive performance. Research suggests that the response expectancy effect is influenced by various individual and situational factors and that the placebo effect results in an increase in monitoring processes as measured indirectly. However, the impact on monitoring processes has not yet been studied by direct measures such as Judgement Of Learning (JOL). This study aimed to investigate the response expectancy effect on various neuropsychological tasks, including a task that directly assesses monitoring capacities (JOL). In addition to determining which cognitive functions are influenced by the expectancy effect, this study examined the moderating role of the self-transcendence dimension of personality. Eighty healthy subjects were exposed to three bogus conditions presented as allegedly having a positive, negative, or no impact on cognitive capacities. Then they completed, in random order, three blocks of tasks (executive, attentional, and memory), one in each condition. Results showed an effect of negative instructions on flexibility (poorer performance) and memory (better performance) scores. Furthermore, positive instructions led to better explicit monitoring capacities (JOL) than the neutral condition. These effects were moderated by self-transcendence, as only participants with moderate or high self-transcendence exhibited these effects. Overall, our results showed that the response expectancy effect emerges from a combination of individual and cognitive factors.

Implicit Spoken Words and Motor Sequences Learning Are Impaired in Children with Specific Language Impairment.

OBJECTIVES: This study aims to compare verbal and motor implicit sequence learning abilities in children with and without specific language impairment (SLI). METHODS: Forty-eight children (24 control and 24 SLI) were administered the Serial Search Task (SST), which enables the simultaneous assessment of implicit spoken words and visuomotor sequences learning. RESULTS: Results showed that control children implicitly learned both the spoken words as well as the motor sequences. In contrast, children with SLI showed deficits in both types of learning. Moreover, correlational analyses revealed that SST performance was linked with grammatical abilities in control children but with lexical abilities in children with SLI. CONCLUSIONS: Overall, this pattern of results supports the procedural deficit hypothesis and suggests that domain general implicit sequence learning is impaired in SLI.

Implicit learning: A way to improve visual search in spatial neglect?

Studies have shown that neglect patients are able to use stimulus regularities to orient faster toward the neglected side, without necessarily being aware of that information, or at the very least without being able to verbalize their knowledge. In order to better control for the involvement of explicit processes, the present study sought to test neglect patients' ability to detect more complex associations between stimuli using tasks similar to those used in implicit learning studies. Our results demonstrate that neglect patients had difficulties implicitly learning complex associations, contrary to what we found with controls. The possible influence of attentional and working memory impairments are discussed.

Executive Functions Deficits After Severe Traumatic Brain Injury: The GREFEX Study.

OBJECTIVE: To assess the sensitivity of traditional neuropsychological tests and of a behavioral inventory of executive disorders in a large sample of patients with chronic severe traumatic brain injury. METHODS: A total of 112 patients were compared with 780 healthy controls from a larger database. The GREFEX battery included 7 widely used tests and the Behavioral Dysexecutive Syndrome Inventory (proxy rating). A previously described statistical methodology was used, controlling for age, education, and gender. Summary scores were computed and performance was dichotomized on the basis of 5th percentile cutoffs from controls' z scores. RESULTS: The frequency of cognitive impairment was high (55.4%) but lower than that of behavioral changes (81.5%). Double dissociations were observed between cognitive and behavioral assessments. Behavioral changes exhibited larger effect-sizes as compared with cognitive impairments. Logistic regression analysis showed that 3 cognitive tests (verbal fluency, Stroop reading, and Trail Making Test-B) and 3 behavior z scores (hypoactivity, anticipation, and hyperactivity) best discriminated patients from controls. CONCLUSION: Behavioral changes were more frequent and severe than cognitive deficits, at least as assessed with traditional testing. The present results also suggest that a shortened battery may provide a rapid screening method with reasonable sensitivity to detect deficits of executive functions in patients with severe traumatic brain injury.

Support for distinct subcomponents of spatial working memory: a double dissociation between spatial-simultaneous and spatial-sequential performance in unilateral neglect.

Over the last decade, many studies have demonstrated that visuospatial working memory (VSWM) can be divided into separate subsystems dedicated to the retention of visual patterns and their serial order. Impaired VSWM has been suggested to exacerbate left visual neglect in right-brain-damaged individuals. The aim of this study was to investigate the segregation between spatial-sequential and spatial-simultaneous working memory in individuals with neglect. We demonstrated that patterns of results on these VSWM tasks can be dissociated. Spatial-simultaneous and sequential aspects of VSWM can be selectively impaired in unilateral neglect. Our results support the hypothesis of multiple VSWM subsystems, which should be taken into account to better understand neglect-related deficits.

Beyond the experience: Detection of metamemorial regularities.

We examined the mechanisms involved in the development of the easily learned, easily remembered (ELER) heuristic in three groups of young children (4-5 years, 6-7 years, and 8-9 years). A trial-to-acquisition procedure was used to evaluate how much these children's judgment of learning depended on the ELER heuristic. Moreover, a new experimental paradigm, composed of six phases-a pretest, four training phases, and a posttest-was employed to implicitly influence the validity of the ELER association that underlies this metacognitive rule. Results revealed that the ELER heuristic develops early (4-5years), but its use is reduced after implicit training. Furthermore, executive monitoring was found to account for the smaller changes observed in older children (8-9 years) after training. From a developmental perspective, these findings present a coherent picture of children's learning of metacognitive heuristics, wherein early automatic and implicit learning is later followed by effortful control.

Can the exploration of left space be induced implicitly in unilateral neglect?

The purpose of the present study was to explore the ability of neglect patients to detect and exploit the predictive value of a cue to respond more quickly and accurately to targets on their contralesional side in a Posner spatial cueing task. The majority of the cues (i.e. 80%) were invalid, indicating that the target would appear on the opposite side, although patients were not informed of this bias. Our results demonstrate that some neglect patients were able to extract the cue's predictability and use it to orient faster toward the left. This cueing effect was present even in patients who were subsequently unable to describe the predictive character of the cues, and thus was not modulated by reportable awareness of the cue-target relation.

Are children conservative, liberal, or metacognitive? Preliminary evidence for the involvement of the distinctiveness heuristic in decision making.

The experiment tested whether young children are able to reduce their false recognition rate after distinctive encoding by implementing a strategic metacognitive rule. The participants, 72 children aged 4, 6, and 9 years, studied two lists of unrelated items. One of these lists was visually displayed (picture condition), whereas the other was presented auditorily (word condition). After each study phase, participants completed recognition tests. Finally, they answered questions about their explicit knowledge of the distinctive encoding effect. The results revealed that even the youngest children in our sample showed a smaller proportion of intrusions in the picture condition than in the word condition. Furthermore, the results of the signal detection analyses were consistent with the hypothesis that the lower rate of false recognitions after picture encoding results from the implementation of a conservative response criterion based on metacognitive expectations (distinctiveness heuristic). Moreover, the absence of correlation between children's explicit knowledge of the distinctiveness rule and their effective use of this metacognitive heuristic seems to indicate that its involvement in memory decisions could be mediated by implicit mechanisms.

Age difference in dual-task interference effects on procedural learning in children.

The current study aimed to investigate the role played by explicit mechanisms during procedural learning in two age groups of children (7 and 10 years) using a dual-task paradigm. To do this, we explored the effect of an interference task during the early and late phases of a mirror tracing learning task. The results showed a differential impact of the secondary task on the two age groups, but only during the first learning phase; the performance of 10-year-olds was affected by the second task, whereas in 7-year-olds no performance difference was found between the single- and dual-task conditions. Overall, our study suggests that there are differences in the amount of effortful processing in which 7- and 10-year-olds engage at the beginning of the learning process; procedural learning in young children is mainly implicit, as attested by its lesser sensitivity to an interference task, whereas high-level explicit mechanisms seem to contribute to the procedural performance of 10-year-olds. However, these explicit mechanisms, even if they have an effect on performance, might not have an impact on the learning curve given that no difference in rate of acquisition was found between age groups. These findings are discussed in the light of classical conceptions of procedural learning.

Visual neglect: is there a relationship between impaired spatial working memory and re-cancellation?

In visual search tasks, neglect patients tend to explore and repeatedly re-cancel stimuli on the ipsilesional side, as if they did not realize that they had previously examined the rightward locations favoured by their lateral bias. The aim of this study was to explore the hypothesis that a spatial working memory deficit explains these ipsilesional re-cancellation errors in neglect patients. For the first time, we evaluated spatial working memory and re-cancellation through separate and independent tasks in a group of patients with right hemisphere damage and a diagnosis of left neglect. Results showed impaired spatial working memory in neglect patients. Compared to the control group, neglect patients cancelled fewer targets and made more re-cancellations both on the left side and on the right side. The spatial working memory deficit appears to be related to re-cancellations, but only for some neglect patients. Alternative interpretations of re-exploration of space are discussed.

The effects of age on objective and subjective recollection after visiting a virtual apartment.

While aging has been associated with decreased retrieval of episodic memory details, subjective ratings about memory quality seem to remain stable. This suggests that subjective memory judgments are based on different information according to age. Here, we tested the hypothesis that older people would rather base their subjective judgments on the retrieval of personal elements (such as emotions and thoughts), whereas younger people would rather base their judgments on the retrieval of event-related elements (such as time, place, and perceptual details). Sixty participants (20 to 79 years old) performed eight actions in a virtual apartment and were then asked to verbally recall each action with a maximum of associated elements and to rate the subjective quality of their memories. The elements reported were classified into "person-related" and "event-related" categories. Executive functions, memory performance on traditional memory tasks, and subjects' perception of memory functioning were also evaluated. Results revealed that aging was associated with reduced retrieval of event-related elements, which was explained by decreasing executive resources. However, age did not affect the retrieval of person-related elements, and the subjective memory judgments of older people were not based on these elements to a greater extent than those of younger people. Finally, our results highlight the value of virtual reality (VR) in memory evaluations since subjects' perception of memory functioning was associated with their performance in the VR task but not in traditional memory tasks.

Procedural learning in specific language impairment: effects of sequence complexity.

According to the procedural deficit hypothesis (PDH), abnormal development in the procedural memory system could account for the language deficits observed in specific language impairment (SLI). Recent studies have supported this hypothesis by using a serial reaction time (SRT) task, during which a slower learning rate is observed in children with SLI compared to controls. Recently, we obtained contrasting results, demonstrating that children with SLI were able to learn a sequence as quickly and as accurately as controls. These discrepancies could be related to differences in the statistical structure of the SRT sequence between these studies. The aim of this study was to further assess, in a group of 21 children with SLI, the PDH with second-order conditional sequences, which are more difficult to learn than those used in previous studies. Our results show that children with SLI had impaired procedural memory, as evidenced by both longer reaction times and no sign of sequence-specific learning in comparison with typically developing controls. These results are consistent with the PDH proposed by Ullman and Pierpont (2005) and suggest that procedural sequence-learning in SLI children depends on the complexity of the to-be-learned sequence.

Age-related differences in perceptuomotor procedural learning in children.

Procedural learning is generally considered to proceed in a series of phases, with cognitive resources playing an important role during the initial step. From a developmental perspective, little is known about the development of procedural learning or the role played by explicit cognitive processes during learning. The main objectives of this study were (a) to determine whether procedural learning performance improves with age by comparing groups of 7-year-old children, 10-year-old children, and adults and (b) to investigate the role played by executive functions during the acquisition in these three age groups. The 76 participants were assessed on a computerized adaptation of the mirror tracing paradigm. Results revealed that the youngest children had more difficulty in adapting to the task (they were slower and committed more errors at the beginning of the learning process) than 10-year-olds, but despite this age effect observed at the outset, all children improved performance across trials and transferred their skill to a different figure as well as adults. Correlational analyses showed that inhibition abilities play a key role in the performance of 10-year-olds and adults at the beginning of the learning but not in that of 7-year-olds. Overall, our results suggest that the age-related differences observed in our procedural learning task are at least partly due to the differential involvement of inhibition abilities, which may facilitate learning (so long as they are sufficiently developed) during the initial steps of the learning process; however, they would not be a necessary condition for skill learning to occur.

Dysexecutive syndrome: diagnostic criteria and validation study.

OBJECTIVE: Disorders of executive functions are among the most frequent cognitive deficits, but they remain poorly defined and are subject to heterogeneous assessment. To address this major issue, the Groupe de Réflexion sur l'Evaluation des Fonctions Exécutives (GREFEX) group has proposed criteria for behavioral and cognitive dysexecutive syndromes and has designed a battery including a specific heteroquestionnaire and 7 cognitive tests. We investigated the frequency of behavioral and cognitive dysexecutive disorders in patients suffering from various diseases and the association of these disorders with loss of autonomy. METHODS: A total of 461 patients aged between 16 and 90 years with severe traumatic brain injury, stroke, mild cognitive impairment, Alzheimer disease, multiple sclerosis, and Parkinson disease were recruited into this prospective cohort study by 21 centers between September 2003 and June 2006. Behavioral and cognitive dysexecutive disorders were examined using the GREFEX battery. RESULTS: A dysexecutive syndrome was observed in 60% of patients, concerning both behavioral and cognitive domains in 26% and dissociated in 34%. All behavioral and cognitive dysexecutive disorders discriminated (p = 0.001, all) patients from controls. The pattern of cognitive syndrome differed (p = 0.0001) according to the disease. Finally, behavioral (odds ratio [OR], 4.6; 95% confidence interval [CI], 2. 3-9.1; p = 0.0001) and cognitive (OR, 3.36; 95% CI, 1.7-6.6; p = 0.001) dysexecutive syndromes and Mini Mental State Examination score (OR, 0.79; 95% CI, 0.68-0.91; p = 0.002) were independent predictors of loss of autonomy. INTERPRETATION: This study provided criteria of dysexecutive syndrome and showed that both behavioral and cognitive syndromes contribute to loss of autonomy. Profiles vary across patients and diseases, and therefore systematic assessment of behavioral and cognitive disorders in reference to diagnostic criteria is needed.

Exploration of serial structure procedural learning in children with language impairment.

Recent studies on specific language impairment (SLI) have suggested that language deficits are directly associated with poor procedural learning abilities. Findings from our previous work are contrary to this hypothesis; we found that children with SLI were able to learn eight-element-long sequences as fast and as accurately as children with normal language (NL) on a serial reaction time (SRT) task. A probabilistic rather than a deterministic SRT paradigm was used in the current study to explore procedural learning in children with SLI to mimic real conditions of language learning. Fifteen children with or without SLI were compared on an SRT task including a probabilistic eight-element-long sequence. Results show that children with SLI were able to learn this sequence as fast and as accurately as children with NL, and that similar sequence-specific learning was observed in both groups. These results are novel and suggest that children with SLI do not display global procedural system deficits.

Exploration of perceptual and motor inhibition in children with traumatic brain injury.

Perceptual and motor inhibition were examined using conflict resolution tasks for 12 children with traumatic brain injury and 24 matched controls. Direct comparisons of inhibition performances between the two groups showed a specific and disproportionate impairment of motor inhibition (compared with perceptual inhibition) for the children with traumatic brain injury, which suggests that inhibition processes might be differentially impaired in children after traumatic brain injury.

Does cognitive impairment influence burden in caregivers of patients with Alzheimer's disease?

Alzheimer's disease (AD) is characterized by a progressive deterioration of various cognitive and behavioral abilities, and it also has a health impact on the patients' caregiver. Our aim was to determine the patient (and to a lesser extent the caregiver) characteristics that contribute most to the caregiver burden. We used the baseline data from the ICTUS study, a European longitudinal cohort of patients with mild to moderate AD. Data from 1091 patients and their caregivers was used for analysis. Three principal components analyses were performed on variables from the domains of cognition, neuropsychiatric symptoms, and daily function using the MMSE plus the ADAS-Cog, NPI, and IADL subscores, respectively. These were followed by a stepwise logistic regression to identify patient characteristics which best predict caregiver burden. The regression model (R2 = 0.35, p < 0.001) shows that the best explanatory variables are: 1) neuropsychiatric symptoms (NPI); 2) difficulties in the IADL; 3) time taken by caregiving; 4) demographic variables such as caregiver's age and patient sex; and 5) severity of cognitive impairment. In conclusion, our results demonstrate that although the strongest determinant of the caregiver burden is behavioral disturbance, the impact of the degree of cognitive impairment on burden is also significant.

[Spaced-retrieval in patients with Alzheimer's disease. Critical review and clinical applications]. / Utilisation de la technique de récupération espacée dans la prise en charge des patients atteints de maladie d'Alzheimer. Revue critique et applications cliniques.

Memory deficit is the most common and invalidating cognitive impairment in subjects with Alzheimer's disease (AD). So far, pharmacological treatment shows little efficacy on the memory deficits. Recent studies have shown that specific cognitive remediation techniques can help compensating for memory deficits in AD dementia, even in advanced stages. Spaced retrieval is a technique based on recalling information over progressively longer intervals of time. It helps the patients with dementia learning and memorizing new information and is particularly suited for activities of daily life improvement. This paper first review the efficacy of this method in different types of dementia and more specifically in Alzheimer's disease; second, the cognitive mechanisms underlying spaced retrieval and the cognitive and clinical factors determining its efficacy are presented. Then the advantages and feasibility of the spaced retrieval technique in common clinical practice are discussed, and specific recommendations are given.