References of "Meulemans, Thierry"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailThe Childhood Executive Function Inventory (CHEXI): Confirmatory Factor Analyses and Cross-Cultural Clinical Validity in a Sample of 8- to 11-Year-Old Children
Catale, Corinne ULg; Meulemans, Thierry ULg; Thorell, Lisa B.

in Journal of Attention Disorders (in press)

The Childhood Executive Functioning Inventory (CHEXI) is a new rating instrument for executive functioning developed by Thorell and Nyberg (2008). Through exploratory factor analyses, this inventory has ... [more ▼]

The Childhood Executive Functioning Inventory (CHEXI) is a new rating instrument for executive functioning developed by Thorell and Nyberg (2008). Through exploratory factor analyses, this inventory has been shown to tap into working memory and inhibition-related behaviors in young children. In this study, we present the psychometric characteristics of the French adaptation of the CHEXI in 8- to 11-year-old children. In addition, we explore the cross-cultural validity of the CHEXI in discriminating between children with ADHD and normally developing children in two culturally different samples (Belgian and Swedish). Confirmatory factor analyses replicated the two-factor solution, referred to as inhibition and working memory, that was identified in the original study with Swedish children. Supplementary analyses indicated that both subscales have good psychometric properties. From a clinical point of view, the CHEXI was found to discriminate, with high sensitivity and specificity, between children with ADHD and normally developing controls in both cultural samples. Cross-cultural clinical implications are discussed. [less ▲]

Detailed reference viewed: 58 (10 ULg)
Full Text
Peer Reviewed
See detailThe Neural Correlates of Re-cancellation Behaviors in Unilateral Neglect: A Neuropsychological Approach
Wansard, Murielle ULg; Bastin, Christine ULg; Meulemans, Thierry ULg

Poster (2014, April)

The present study focused on re-cancellation behaviors in unilateral neglect (i.e., the tendency to search repeatedly items located on the right side in visual search tasks), and used a neuropsychological ... [more ▼]

The present study focused on re-cancellation behaviors in unilateral neglect (i.e., the tendency to search repeatedly items located on the right side in visual search tasks), and used a neuropsychological approach to identify the cerebral correlates of this deficit. Fourteen patients suffering from left neglect and 14 elderly age-matched controls performed a cancellation task without visual feedback. Neglect patients cancelled fewer targets than controls, and re-cancelled an abnormally high number of targets. Lesion maps were used to compare the location of brain damage in neglect patients with the highest versus the lowest percentage of re-cancellations. Anatomical data revealed that the right insula is commonly damaged in 5 out of 6 patients with the highest re-cancellation percentage, but is spared in the subgroup of patients with the lowest re-cancellation percentage. These results suggest that damage to the right insula may contribute to pathological visual search in spatial neglect, possibly by reducing interaction between the ventral and dorsal attention network (the latter being more directly involved in spatial processes). [less ▲]

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
See detailThe Benefits of Errorless Learning for Serial Reaction Time Performance in Alzheimer's Disease.
Schmitz, Xavier ULg; Bier, Nathalie; Joubert, Sven et al

in Journal of Alzheimer's Disease [=JAD] (2014), 39(2), 287-300

Identifying the conditions favoring new procedural skill learning in Alzheimer’s disease (AD) could be important for patients’ autonomy. It has been suggested that error elimination is beneficial during ... [more ▼]

Identifying the conditions favoring new procedural skill learning in Alzheimer’s disease (AD) could be important for patients’ autonomy. It has been suggested that error elimination is beneficial during skill learning, but no study has explored the advantage of this method in sequential learning situations. In this study, we examined the acquisition of a 6-element perceptual-motor sequence by AD patients and healthy older adults (control group). We compared the impact of two preliminary sequence learning conditions (Errorless vs. Errorful) on Serial Reaction Time performance at two different points in the learning process. A significant difference in reaction times for the learned sequence and a new sequence was observed in both conditions in healthy older participants; in AD patients, the difference was significant only in the errorless condition. The learning effect was greater in the errorless than the errorful condition in both groups. However, while the errorless advantage was found at two different times in the learning process in the AD group, in the control group this advantage was observed only at the halfway point. These results support the hypothesis that errorless learning allows for faster automation of a procedure than errorful learning in both AD and healthy older subjects. [less ▲]

Detailed reference viewed: 17 (5 ULg)
Full Text
Peer Reviewed
See detailProcedural learning across modalities in French-speaking children with specific language impairment
Gabriel, Audrey ULg; Meulemans, Thierry ULg; Parisse, Christophe et al

in Applied Psycholinguistics (2014)

It has been suggested that the language problems encountered in specific language impairment (SLI) arise from basal ganglia abnormalities that lead to impaired procedural memory. However, recent serial ... [more ▼]

It has been suggested that the language problems encountered in specific language impairment (SLI) arise from basal ganglia abnormalities that lead to impaired procedural memory. However, recent serial reaction time (SRT) studies did not reveal any differences between the SLI and typically developing (TD) groups on the measures of procedural memory linked to visual sequence learning. In this paper, 16 children with and without SLI were compared on two versions of SRT tasks: a visual task and an auditory one. The results showed that children with SLI were as fast as their TD peers in both modalities. All of the children obtained similar specific sequence learning indices, indicating that they were able to detect regularities in both modalities. Although children with SLI were as accurate as their TD peers for the visual SRT task, they made more errors than their TD peers in auditory SRT conditions. The results indicate that, in relation to procedural memory, the core of the impairment in SLI is not linked to difficulties in the detection of regularities. We argue that when children with SLI present some difficulties, the children’s weaknesses might depend on the type of processing involved (e.g., tasks involving auditory sequences). [less ▲]

Detailed reference viewed: 134 (33 ULg)
Full Text
Peer Reviewed
See detailValidation d’un test d’inhibition auprès d’enfants présentant un trouble déficitaire de l’attention avec/sans hyperactivité
Catale, Corinne ULg; Lejeune, Caroline ULg; Schmitz, Xavier ULg et al

in Canadian Journal of Behavioural Science = Revue Canadienne des Sciences du Comportement (2014), 46(1), 66-72

The objective of this study was to assess the development of inhibition in 5-11 years old children with the “Stroop fruit” task (see Archibald & Kerns, 1999; Catale & Meulemans, 2005) and to examine the ... [more ▼]

The objective of this study was to assess the development of inhibition in 5-11 years old children with the “Stroop fruit” task (see Archibald & Kerns, 1999; Catale & Meulemans, 2005) and to examine the clinical value of this tool. 346 French-speaking children without any developmental disorders or learning disabilities were included in this study. A clinical group of 25 children with attention deficit and hyperactivity disorder was also assessed with this task. Developmental analyses on age groups show an enhancement of performance in the interference condition between 5 and 8 years old. Furthermore, results also show that the clinical group performed significantly less accurately that the control group for the interference condition, which confirms the clinical interest of this tool. [less ▲]

Detailed reference viewed: 123 (17 ULg)
Full Text
Peer Reviewed
See detailDevelopment and validation of the working memory self-assessment scale
Fresson, Megan ULg; DEMOULIN, Valentine ULg; HIERNAUX, Anne ULg et al

Poster (2013, July)

Aim. Because working memory is involved in many daily life activities, its ecological evaluation is a key dimension of the neuropsychological assessment of people with cognitive impairments. The aim of ... [more ▼]

Aim. Because working memory is involved in many daily life activities, its ecological evaluation is a key dimension of the neuropsychological assessment of people with cognitive impairments. The aim of this study was to develop and validate a 30-items self-assessment scale of working memory, the WMSS (Working Memory Self-Assessment Scale). Method. The WMSS and a comprehensive assessment battery of working memory and executive functions were administered to sixty French-speaking individuals (20 young, 20 old, 20 old-old). Results. The internal validity of the scale was strong as estimated by the Cronbach’s alpha coefficient (α = .93). Concerning the external validity, several correlations were obtained between the WMSS and the cognitive composite scores. Unlike old subjects, the lower cognitive results young and old-old subjects had, the more working memory complaints they expressed. Discussion. The WMSS shows a satisfactory internal as well as external validity since young and old-old subjects who reported more difficulties (WMSS) are those who obtained lower cognitive results. The somewhat surprising relationship between the WMSS and the cognitive tasks in the old group can be explained by an increased perception of cognitive changes and a more complex life style in old subjects with better cognitive abilities. [less ▲]

Detailed reference viewed: 41 (4 ULg)
Full Text
Peer Reviewed
See detailIntact procedural motor sequence learning in developmental coordination disorder
Lejeune, Caroline ULg; Catale, Corinne ULg; Willems, Sylvie ULg et al

in Research in Developmental Disabilities (2013), 34(6), 1974-1981

The purpose of the present study was to explore the possibility of a procedural learning deficit among children with developmental coordination disorder (DCD). We tested 34 children aged 6–12 years with ... [more ▼]

The purpose of the present study was to explore the possibility of a procedural learning deficit among children with developmental coordination disorder (DCD). We tested 34 children aged 6–12 years with and without DCD using the serial reaction time task, in which the standard keyboard was replaced by a touch screen in order to minimize the impact of perceptuomotor coordination difficulties that characterize this disorder. The results showed that children with DCD succeed as well as control children at the procedural sequence learning task. These findings challenge the hypothesis that a procedural learning impairment underlies the difficulties of DCD children in acquiring and automatizing daily activities. We suggest that the previously reported impairment of children with DCD on the serial reaction time task is not due to a sequence learning deficit per se, but rather due to methodological factors such as the response mode used in these studies. [less ▲]

Detailed reference viewed: 63 (21 ULg)
Full Text
Peer Reviewed
See detailDiagnostic, assessment and remediation of the attention deficit and hyperactivity disorder (ADHD): The neuropsychologist’s point of view
Catale, Corinne ULg; Meulemans, Thierry ULg

in Neuropsychiatrie de l'Enfance et de l'Adolescence (2013), 3

Despite the advances made regarding both the characterization and classification of the disorder (e.g., DSM-IV), the diagnosis of the Attention Deficit and Hyperactivity Disorder (ADHD) in children ... [more ▼]

Despite the advances made regarding both the characterization and classification of the disorder (e.g., DSM-IV), the diagnosis of the Attention Deficit and Hyperactivity Disorder (ADHD) in children remains very difficult. The principal aim of this paper is to present the interest of a integrative approach in the understanding, diagnosis and identification of difficulties in ADHD children. More particularly, it aims to underline the interest of the cognitive approach in the understanding of this disorder in the day-to-day life functioning, as well as the benefits of this approach when a specific remediation is planned. [less ▲]

Detailed reference viewed: 42 (14 ULg)
Full Text
Peer Reviewed
See detailFrench Adaptation of the Childhood ExecutivFe Function Inventory (CHEXI): Confirmatory Factor Analysis in a Sample of Young French-Speaking Belgian Children
Catale, Corinne ULg; Lejeune, Caroline ULg; Merbah, Sarah ULg et al

in European Journal of Psychological Assessment (2013), 29(2), 149-155

Thorell and Nyberg (2008) recently developed the Childhood Executive Functioning Inventory (CHEXI), a new rating instrument for executive functioning in day-to-day life that can be divided into four ... [more ▼]

Thorell and Nyberg (2008) recently developed the Childhood Executive Functioning Inventory (CHEXI), a new rating instrument for executive functioning in day-to-day life that can be divided into four subscales: working memory, planning, inhibition, and regulation. By using an exploratory factor analysis on data from young Swedish children attending kindergarten, Thorell and Nyberg (2008) found a two-factor solution tapping working memory and inhibition. In the present study, we explored the psychometric characteristics of the French adaptation of the CHEXI. Ninety-five parents of 5- and 6-year-old children completed the CHEXI. Eighty-seven children from this sample were given clinical inhibition and working memory tasks. Confirmatory factor analyses confirmed the two-factor solution based on inhibition and working memory that was identified in the original study of Swedish children. Supplementary results indicated good internal and test-retest reliability for the entire scale, as well as for the two subscales identified. Correlation analyses showed no relationship between cognitive measures and the CHEXI subscales. Possible clinical applications for the CHEXI scales are discussed. [less ▲]

Detailed reference viewed: 45 (6 ULg)
Peer Reviewed
See detailThe way we learn this knowledge that dominates all other knowledge
Geurten, Marie ULg; Catale, Corinne ULg; Meulemans, Thierry ULg

Conference (2013)

Although much is known about how children use memory strategies, far fewer studies have examined how knowledge of those strategies improves during childhood or which variables are involved in this ... [more ▼]

Although much is known about how children use memory strategies, far fewer studies have examined how knowledge of those strategies improves during childhood or which variables are involved in this development. In this experiment, a scale designed to assess three main aspects of metamemory knowledge (internal strategy knowledge, external strategy knowledge, general knowledge) and a battery of executive tasks was administered to a group of 80 children aged 4, 6, and 11. At the same time, variables such as intelligence, vocabulary and parental education level were also taken into account. Stepwise analyses carried out on each of the three metamemory subscales showed that executive functions of inhibition and response monitoring, as well as verbal fluency, were single predictors of internal strategy knowledge for children aged 6 and 11. Only verbal fluency predicted external strategy knowledge. None of the variables included in the analyses could explain the children’s general knowledge of memory functioning or the 4-year-old group’s performance on any of the three subscales. Results are discussed in terms of ease of monitoring, access to explicit knowledge and influence of implicit learning. [less ▲]

Detailed reference viewed: 24 (4 ULg)
Peer Reviewed
See detailChildren’s Knowledge About Memory: Adaptation and French Validation of a Scale to Assess it.
Geurten, Marie ULg; Catale, Corinne ULg; Meulemans, Thierry ULg

in INS Abstract Book (2013)

The present study aimed at adapting and testing a French version of Kreutzer et al.’s metamemory interview (1975) in a group of 128 children aged of 4, 6, 9, and 12. Following Fritz et al. (2010 ... [more ▼]

The present study aimed at adapting and testing a French version of Kreutzer et al.’s metamemory interview (1975) in a group of 128 children aged of 4, 6, 9, and 12. Following Fritz et al. (2010), adjustments have been made to reduce language skill contamination as well as to increase the developmental appropriateness and sensibility of the scale. Results show the emergence of two sub-scales (“strategy knowledge” and “general memory knowledge”) on the factor analysis and reveal an excellent interrater reliability as well as a good internal consistency for the global scale and two sub-scales (respectively, Cronbach α = .79; .81 and .71). As expected with regard to the literature, a significant correlation has appeared between the metamemory scale and short-term memory capacities (convergent validity). Similarly, the metamemory score has shown its ability to predict children memory performance (predictive validity). Finally, the lack of correlation between most of the scale’s items and vocabulary measurement (Peabody Picture Vocabulary Test) and the very good ability of the scale to distinguish between age groups demonstrate that the adaptations made to improve the Kreutzer et al.’s scale in terms of language’s contamination and developmental sensibility have reached their goal. Regarding its psychometric properties, these results suggest that this interview can be considered as a useful and reliable tool for developmental research. Furthermore, they confirm the importance of metamemory knowledge in memory performance. Future studies will have to be carried out to show the utility of this scale in a clinical population. [less ▲]

Detailed reference viewed: 64 (19 ULg)
Full Text
Peer Reviewed
See detailAge-Related Differences in Perceptuomotor Procedural Learning in Children
Lejeune, Caroline ULg; Catale, Corinne ULg; Schmitz, Xavier ULg et al

in Journal of Experimental Child Psychology (2013), 116

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 ... [more ▼]

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: (1) to determine whether procedural learning performance improves with age by comparing groups of 7-yearold children, 10-year-old children, and adults, and (2) to investigate the role played by executive functions during the acquisition in these three age groups. Seventy-six subjects were assessed on a computerized adaptation of the mirror tracing paradigm. Results revealed that the youngest children had more difficulty 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 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 (so long as they are sufficiently developed) learning in the initial steps of learning process; however, they would not be a necessary condition for skill learning to occur. [less ▲]

Detailed reference viewed: 45 (17 ULg)
Peer Reviewed
See detailValidation of a French Version of a New Anxiety Trait Scale for Children
Geurten, Marie ULg; Meulemans, Thierry ULg; Fresson, Megan ULg et al

Poster (2013)

Anxiety diagnosis is relatively complex in children because intensity as well as symptoms of anxiety change during childhood (Bouden, Halayem, & Fakhfakh, 2002). The principal aim of this study was to ... [more ▼]

Anxiety diagnosis is relatively complex in children because intensity as well as symptoms of anxiety change during childhood (Bouden, Halayem, & Fakhfakh, 2002). The principal aim of this study was to validate through Confirmatory Factor Analyses (CFA) the a priori three-factor structure of the French version of the anxiety trait scale for children which includes psychological (“tend to be worried about everything”), behavioral (“tend to be upset, nervous or grumbling”), and somatic symptoms (“headache complaints”) of anxiety. This scale was previously found to discriminate, with high sensitivity and specificity, children with anxiety from control group. A first CFA performed on 288 6-12 year-old children showed an acceptable fit (2/df =2.66; RMSEA=.07 and CFI=.94). A second three-factor model was constructed and showed a better fit with a new sample of 287 children (2/df =2.18; RMSEA=.06 and CFI=.96), with a lower ECVI value for the model 2. For this model, the Cronbach’s alpha for each of the subscales ranged from .71 to .86, which confirmed the good internal reliability of the scale. This study provides a new three-factor structure for this anxiety scale and proposes normative data for French-speaking children. [less ▲]

Detailed reference viewed: 44 (9 ULg)
Peer Reviewed
See detailPerceptual andMotor Inhibition in ADHD:Evidence for a specific impairment?
Catale, Corinne ULg; Geurten, Marie ULg; Lejeune et al

in Abstracts book (2013)

Objective: Inhibition, one of the core executive processes in executive functioning (Miyake et al., 2000) is generally not considered as an unitary construct (see for example, Friedman & Miyake, 2004 ... [more ▼]

Objective: Inhibition, one of the core executive processes in executive functioning (Miyake et al., 2000) is generally not considered as an unitary construct (see for example, Friedman & Miyake, 2004; Nassauer & Halperin, 2003). Following the perceptual versus motor dissociation proposed by Nassauer and Halperin (2003), we studied perceptual and motor inhibition in children with AttentionDeficit andHyperactivity Disorder (ADHD). Participants and Methods: Sixteen 7-12 years old children with ADHD and 30 matched control children were administered a version of the Conflict Resolution task (Nassauer & Halperin, 2003) adapted for children. In this task, the perceptual inhibition task required the children to respond to the direction of a dog (running towards the left or the right) while ignoring its location (left or right) on a computer screen. In the motor inhibition task, the children had to press a key corresponding to the opposite direction of a centrally running dog. Results: Comparisons analyses of inhibition performances between ADHD children and matched controlled subjects showed that ADHD children performed significantly less accurately for stimulus-stimulus characteristic conflicts (i.e., perceptual inhibition) than for stimulus- response conflicts (i.e., motor inhibition), which suggests a specific impairment in perceptual inhibition in our group of ADHD children. Conclusions: In conclusion, this study supports the presence of two forms of inhibition which can be differentiated and specifically impaired in 7- to 12-year-old ADHD children. [less ▲]

Detailed reference viewed: 29 (6 ULg)
Peer Reviewed
See detailInterference of a secondary task on procedural learning in children
Lejeune, Caroline ULg; Desmottes, Lise ULg; Catale, Corinne ULg et al

in Belgian Brain Congress 2012: Abstract Book (2012, October 27)

Introduction Procedural learning is generally considered as involving different learning phases, with cognitive resources playing an important role only during the initial learning step. Through repeated ... [more ▼]

Introduction Procedural learning is generally considered as involving different learning phases, with cognitive resources playing an important role only during the initial learning step. Through repeated practice, the skill becomes progressively more automatic and the involvement of controlled cognitive functions is progressively reduced (Anderson, 2000;Doyon and Benali, 2005;Beaunieux et al., 2006). This view has been supported by studies in which the mirror-tracing paradigm was used to evaluate procedural learning, demonstrating the implication of the executive mechanisms in the first phase of perceptuomotor learning (Rouleau, 2002;Brosseau et al., 2007). However, from a developmental perspective, little is known about the progression of learning in procedural tasks, as well as about the role played by the explicit cognitive processes during learning in children. We recently showed that the cognitive mechanisms involved during the procedural task differed between age groups (Lejeune et al., in press). Indeed, we observed that 7-year-old children performed the procedural task in a less controlled fashion than 10-year-olds, who used a more conscious strategy, which permits them to reach better performance levels. The aim of the present study was to confirm the differential implication of explicit mechanisms in procedural learning in children by using a dual-task paradigm. Objective The present study used a dual-task paradigm in order to further investigate the role played by explicit mechanisms during the early and final stages of procedural learning in two ages-groups (7- and 10 year-olds). An auditory interference task was introduced at the beginning and at the end of the procedural learning phase. According to Sun, Merrill, and Peterson (2001), the introduction of an interference task should affect more the explicit processes than the implicit processes, the latter being more automatic. Thus, we predict that performance would be altered by in the dual-task condition only during the first phase of learning, and not during the automation phase. Furthermore, considering that the cognitive mechanisms underlying procedural learning would be different between 7- and 10-year-old children, we predicted that the impact of the dual-task would differ between the two aged-groups: the dual-task condition should affect performance in 10-year-old children but not in the 7-year-old group. Method Seventy-six children were presented with a Mirror Tracing task under single or dual-task conditions. For the Mirror Tracing task, we conformed to the procedure used in previous studies in children (Vicari et al., 2005;Prehn-Kristensen et al., 2009) and we opted for a 5 points star with the double outline of 1 cm. The instruction was to follow the contour of the figure in order to “catch” different picture without leaving the limits of the contour. There were two learning sessions; the task included 10 trials, with a short break (2 min) between trials, and a second 10 trial session was conducted after a one-week delay. In dual-task condition, participants had to perform the procedural learning task while performing at the same time the interference auditory task (which consisted to answer to questions presented continuously). Results Results showed that completion time and accuracy during the mirror tracing task improved with each successive trial in both groups: all children learned the procedural skill regardless of their age and the experimental condition. As predicted, results showed that the impact of the dual-task differed between aged-groups during the first learning phase. While 10-year-old children were significantly slower and less accurate in the dual-task condition than 10-year-old children in the single-task condition, no difference between learning conditions was revealed in the 7-year-old group. Interestingly, at the end of learning (trials 19 and 20), the interference effect had disappeared: there was no impact of the secondary task on procedural performance, whatever the age-group. Discussion In this study, we explored with a dual-task paradigm the role played by explicit mechanisms during the early and final stages of procedural learning in two age-groups (7- and 10 year-olds). During the first learning step, 10-year-old children in the single-task condition used a conscious strategy to perform the task, which permits them to reach better performance levels than 10-year-old children in the dual-task condition (which prevents them from using their controlled cognitive processes). On the contrary, no impact of the interference task was observed in 7-year-old children, who performed the mirror tracing task similarly in the single- and dual-task conditions. This result supports our hypothesis that, in the beginning of a perceptuo-motor learning task, youngest children perform the procedural task in a more implicit fashion comparatively to older children. Thus, while performance of 10-year-old children is congruent with a top-down conception of procedural learning (i.e., performance in the first learning stages would be sustained by high-level explicit mechanisms), this is not the case for youngest children whose explicit mechanisms are not yet mature. So, our results confirm that the involvement of explicit learning mechanisms is not a “necessary condition” for motor skill learning to occur, a point of view supported by the bottom-up skill learning approach which postulates that explicit declarative knowledge is not necessarily associated with procedural skill learning and that the knowledge acquired could be stored in an implicit mode from the beginning of learning (Karmiloff-Smith, 1992;Sun et al., 2001). [less ▲]

Detailed reference viewed: 59 (5 ULg)
Full Text
Peer Reviewed
See detailIs there a relationship between perseverations and spatial short-term memory deficits in unilateral neglect?
Wansard, Murielle ULg; Bartolomeo, Paolo; Gillet, Sophie ULg et al

in Abstract Book Belgian Brain Congress (2012, October 27)

Introduction Spatial neglect is a multicomponent syndrome characterized by an inability to orient or to respond to stimuli arising in the hemispace contralateral to a brain lesion. According to many ... [more ▼]

Introduction Spatial neglect is a multicomponent syndrome characterized by an inability to orient or to respond to stimuli arising in the hemispace contralateral to a brain lesion. According to many authors, spatial neglect can be explained by an attentional deficit, and more specifically by a lateral attentional bias towards the right (magnetic attraction) and/or difficulties in disengaging attention from items to the right side. However, attentional theories are not sufficient to explain some behaviors such as revisiting and perseverations. Recently, it has been suggested that revisiting and perseveration behaviors in visual search tasks shown in parietal neglect could be related to impairments in visuo-spatial working memory (Husain et al., 2001; Malhotra et al., 2005; Malhotra, Mannan, Driver, & Husain, 2004). This hypothesis is supported by studies (1) in which a contrast is made between cancellation tasks with and without visual control, the absence of visual feedback increasing left neglect (omissions) and repeated cancellations (perseverations) towards the ipsilesional space, and (2) in which the Corsi test is administrated in a vertical way. However, Ronchi et al. (2009) did not confirm the link between impairments in spatial short-term memory and perseverations. Indeed, these authors found no correlation between perseverations in star cancellation and spatial memory performance in the Corsi test. Nevertheless, they did not use a condition without visual feedback, which is considered as involving more spatial short-term memory than a condition with visual feedback. This methodological choice could explain the lack of relationship between short-term memory and perseverations in the Ronchi et al.’s study. The purpose of our study was to test the hypothesis of a spatial short-term memory deficit being an explanatory factor of perseverations in unilateral neglect. Methods We assessed twenty right-damaged patients suffering from left neglect. Neglect signs were evaluated with the Batterie d’Evaluation de la Négligence (BEN) (Azouvi et al., 2002). Twenty healthy older participants matched for age and sociocultural level served as controls. In order to explore the relationship between perseverations and spatial short-term memory, two different tasks were administrated: a computerized version of the Corsi test and a cancellation task. All tests were computerized and presented on a touchscreen. The subject’s spatial span corresponded to the longest sequence in which at least three out of four sequences were correctly reproduced. The cancellation task consisted of 32 “O” presented in two conditions: with (visible) and without (invisible) visual feedback. Patients were instructed to cancel out all targets only once. The number of omissions and perseverations was calculated for each participant in both conditions. Results Control participants performed better than neglect patients in the Corsi test; eleven neglect patients showed a deficit in spatial short-term memory. In the cancellation tasks, Wilcoxon matched-pairs signed ranks tests highlighted that perseverations and omissions were greater in the invisible condition for each group. In this condition, neglect patients made more omissions and perseverations (all ps <.05) than control subjects, while in the visible condition there was only a significant difference for the omissions. However, spatial short-term memory did not explain perseverations in invisible condition (R² = .17, F(1,18) = 3.66, p = .07). Discussion These findings suggest that a spatial short-term memory deficit cannot be considered as an explanatory factor for the perseveration behavior in unilateral neglect. Moreover, perseverations and omissions were greater in the invisible condition than in the visible one; therefore, the hypothesis of the magnetic attraction is not confirmed either. In the neglect patients’ group, the visual feedback decreases, and even eliminates the neglect symptoms (omissions and perseverations) compared to the invisible condition. In other words, the presence of visual feedback can help patients to explore their visual environment. We propose that, in the invisible condition, difficulties to plan a visual search could exacerbate both omissions and perseverations, leading to recursive search towards the right side of the space and thus promote failure to explore left space. However, further investigations will be necessary to confirm this hypothesis. [less ▲]

Detailed reference viewed: 64 (13 ULg)
Full Text
Peer Reviewed
See detailPrevious errorless sequence-learning promotes subsequent SRT performance in patients with Alzheimer's Disease
Schmitz, Xavier ULg; Bier, Nathalie; Joubert, Sven et al

Poster (2012, July 17)

Motor-learning capacities are known to be relatively preserved in Alzheimer's disease (AD), which is crucial in the context of the patient’s autonomy (e.g., Rouleau et al., 2002). However, it is important ... [more ▼]

Motor-learning capacities are known to be relatively preserved in Alzheimer's disease (AD), which is crucial in the context of the patient’s autonomy (e.g., Rouleau et al., 2002). However, it is important to determine the most appropriate techniques for such learning. In AD, implicit or procedural rehabilitation techniques would be more effective to train new skills than explicit or declarative learning methods (van Halteren-van Tilborg, 2007). Maxwell et al. (2001) showed that reducing errors during motor learning minimizes the building of declarative knowledge and would allow implicit knowledge accumulation. If errorless learning induces the formation of an implicit knowledge, this technique appears to be adapted to the learning of a perceptual-motor skill in patients with impaired controlled processes. Very few studies have investigated errorless learning in procedural learning situations, even though some data suggest that errorless learning would be efficient for learning instrumental activities of daily living (e.g., Thivierge et al., 2008). In this study we examined the acquisition of a new perceptual-motor skill in 12 patients with AD and 12 healthy older adults. We compared the impact of two preliminary sequence learning conditions (errorless vs. errorful) on a serial reaction time (SRT) performance. In SRT, the subject must react as quickly as possible to the appearance of a target on a screen by pressing the key corresponding to the position of the stimulus. The effectiveness of learning is demonstrated by a reaction time improvement when the target follows a repeating sequence. For patients with AD, results confirm that the advantage provided by prior learning occurs only in the errorless condition whereas both learning modes improve SRT performance in healthy participants. In conclusion, these results confirm that the errorless learning promotes the development of implicit knowledge and appears to be an effective method for procedural learning in Alzheimer's disease. [less ▲]

Detailed reference viewed: 61 (15 ULg)