Biomedical subjects

Sylvie Belleville

Publications and source records attributed to Sylvie Belleville.

16 recordsLinked to original sources

PubMed2006

Improvement of episodic memory in persons with mild cognitive impairment and healthy older adults: evidence from a cognitive intervention program.

The efficacy of cognitive training was assessed in persons with mild cognitive impairment (MCI) and persons with normal cognitive aging. Forty-seven participants were included in this study: 28 with MCI and 17 controls. Twenty-one participants received intervention (20 MCI and 9 controls) and 16 participants (8 MCI and 8 controls) received no intervention (waiting-list group). The intervention focused on teaching episodic memory strategies. Three tasks of episodic memory (list recall, face-name association, text memory) were used as primary outcome measures. Results were analyzed using analyses of variance. The intervention effect (pre- and post-intervention difference) was significant on two of the primary outcome measures (delayed list recall and face-name association). A significant pre-post-effect was also found on measures of subjective memory and well-being. There was no improvement in the performance of groups of individuals with MCI and normal elderly persons who did not receive the intervention. These results suggest that persons with MCI can improve their performance on episodic memory when provided with cognitive training.

Aged↗

PubMed2006

Use of the Hayling task to measure inhibition of prepotent responses in normal aging and Alzheimer's disease.

This study measures the effect of Alzheimer's disease (AD) and normal aging on the inhibition of prepotent responses. AD patients, normal aged controls, and young subjects were tested with the Hayling task, which measures the ability to inhibit a semantically constrained response, and with the Stroop procedure. AD patients showed a severe deficit in both error rates and response time on the Hayling task. Inhibition was also impaired on the Stroop procedure, both when using raw performance and when using an inhibition score that controlled for reading and naming speed. Normal aged participants showed modest impairment relative to young controls on both tests. Examination of individual performance in AD patients indicated that the impairment was found in most patients on the Hayling test but in only a subgroup of patients on the Stroop test.

Adult↗

PubMed2006

Mild cognitive impairment.

Mild cognitive impairment is a syndrome defined as cognitive decline greater than expected for an individual's age and education level but that does not interfere notably with activities of daily life. Prevalence in population-based epidemiological studies ranges from 3% to 19% in adults older than 65 years. Some people with mild cognitive impairment seem to remain stable or return to normal over time, but more than half progress to dementia within 5 years. Mild cognitive impairment can thus be regarded as a risk state for dementia, and its identification could lead to secondary prevention by controlling risk factors such as systolic hypertension. The amnestic subtype of mild cognitive impairment has a high risk of progression to Alzheimer's disease, and it could constitute a prodromal stage of this disorder. Other definitions and subtypes of mild cognitive impairment need to be studied as potential prodromes of Alzheimer's disease and other types of dementia.

Aged↗

PubMed2006

Memory for gist and detail information in Alzheimer's disease and mild cognitive impairment.

Two experiments examined different forms of gist and detail memory in people with Alzheimer's disease (AD) and those with amnestic mild cognitive impairment (MCI). In Experiment 1, 14 AD, 14 MCI, and 22 control participants were assessed with the Deese-Roediger-McDermott paradigm. Results indicated that false recognition of nonstudied critical lures (gist memory) was diminished in the AD compared with the MCI and control groups; the two latter cohorts performed similarly. In Experiment 2, 14 AD, 20 MCI, and 26 control participants were tested on a text memory task. Results revealed that recall of both macropropositions (gist information) and micropropositions (detail information) decreased significantly in AD and in MCI as compared with control participants. This experiment also revealed that the impairment was comparable between gist and detail memory. In summary, the results were consistent across experiments in the AD but not in the MCI participants. The discrepancy in MCI participants might be explained by differences in the degree of sensitivity of the experimental procedures and/or by the differences in the cognitive processes these procedures assessed.

Adult↗

PubMed2005

Study of verbal working memory in patients with Parkinson's disease.

The authors examined the nature of the working memory deficit in persons with Parkinson's disease (PD). Three hypotheses were tested: a limited storage capacity, an impaired executive component, and a reduction of psychomotor speed. Verbal working memory was assessed in 14 PD patients without dementia and 14 matched control participants. Participants were administered a classical verbal span test, working memory tasks that required either updating or manipulation capacities, and motor and psychomotor speed tasks. Patients' performance was comparable to that of control participants on the verbal span test. However, results on the working memory tasks indicated a deficit in manipulation with normal updating capacities. Motor and psychomotor slowing were found in the patient group, but slowing could not fully account for the impairment observed in the manipulation task. Results indicated that there is a genuine but selective working memory impairment in patients with PD.

Age Factors↗

PubMed2004

Working memory and mental practice outcomes after stroke.

OBJECTIVE: To examine the relationship between working memory and motor improvement obtained after a single training session combining mental and physical practice. DESIGN: Before-after trial. SETTING: Laboratory of a university-affiliated research rehabilitation center. PARTICIPANTS: A sample of 12 patients with stroke and 14 age- and gender-matched healthy subjects. INTERVENTION: In a single session, patients were trained with combined mental and physical practice to increase the loading on the affected leg while standing up and sitting down. MAIN OUTCOME MEASURES: Motor improvement as measured by the percentage change in limb loading on the affected limb after training and 24 hours later (follow-up), and the relationship between working memory and percentage motor improvement. RESULTS: The loading on the affected leg was improved after training (P< .01) and at follow-up (P< .05), and working memory scores at follow-up correlated significantly (P< .004 to P< .007) with the level of improvement. The visuospatial domain yielded the strongest correlation (r= .83), followed by the verbal (r= .62) and kinesthetic (r= .59) domains. CONCLUSIONS: These results suggest that the outcome (improved limb loading) of mental rehearsal with motor imagery depends on the ability to maintain and manipulate information in working memory.

Adult↗

PubMed2004

Age-related differences in response preparation: the role of time uncertainty.

This study explored the ability of younger and older participants to use a variable preparatory interval (PI) to enhance reaction time (RT) performance. In Experiment 1, 30 seniors and 15 young adults completed simple and choice RT tasks with short and long variable PIs. RT decreased with increasing PI duration in both younger and older adults, but the PI effect was larger in elderly individuals. The results of Experiment 2 (20 seniors and 20 young adults) showed an equivalent preparatory effect in older and younger adults when the probability of the shortest PI was increased. These findings suggest that older adults do not prepare as well as younger adults for unlikely events and that time uncertainty affects age-related differences in response preparation.

Adult↗

PubMed2004

Training mobility tasks after stroke with combined mental and physical practice: a feasibility study.

This study examines the potential of using mental practice (MP) to promote the learning of 2 mobility tasks in persons with stroke. Twelve patients were trained with MP to increase the loading of the affected limb while standing up from a chair and sitting down. Vertical forces were recorded using force plates under each foot and the chair. Changes in the loading of the affected limb and in task duration, immediately after 1 training session and 24 h later, served as outcomes. After training, the loading of the affected limb had increased (P < 0.001) during standing up (16.2%) and sitting down (17.9%), and the improvement remained significant 24 h later, indicating a learning effect. In contrast, the duration of the performance did not change with training. The results indicate that, in the early stage of learning with MP, changes in limb-loading strategies are a more sensitive measure of performance than is speed.

Adult↗

PubMed2004

[Executive function deficits in normal aging, Alzheimer's disease, and frontotemporal dementia].

An increasing number of studies suggest that executive functions are among the first cognitive functions to bear negative effects of normal aging. Executive functions also appear to be early affected in Alzheimer's disease and frontotemporal dementia. This article reviews studies in neuropsychology and experimental cognitive psychology with a focus on normal aging, Alzheimer's disease as well as frontotemporal dementia. Study results suggest that so called executive tasks are not equally impaired by normal ageing or dementia in agreement with the recent theoretical models, which state that a set of distinct elementary mechanisms subserve the executive control of cognitive behavior. These models are therefore particularly relevant to address issues stemming from aging.

Aged↗

PubMed2003

Item-related versus task-related activity during encoding and retrieval in verbal and non-verbal episodic memory: an event-related potential study.

In the past 10 years, functional neuroimaging studies have elucidated the role of the prefrontal cortex in memory encoding and retrieval. However, it is still unclear whether these activations reflect item- or task-related activities. In the present study, Event-Related Potentials (ERPs) were used to distinguish item-related activity from task-related activity in both encoding and retrieval processes. This activity was assessed with both verbal and non-verbal material. A recognition paradigm with words or random shapes was administered to 12 young participants. Memory elicited ERPs were compared to those evoked by control tasks that used similar material. The distribution of the N400 was found to be larger on left frontal than right frontal areas for verbal material, however, this was the case in the control and memory conditions as well. This finding likely reflects the sensitivity of this component to processing verbal material. The LPC amplitude was greater in the non-verbal encoding than the non-verbal control condition, whereas in retrieval it was larger than the control condition for both verbal and non-verbal material. Thus, item-related activity is determined by an interaction between properties of the material and the task instructions. Task-related activity was found for non-verbal material: compared to the control condition, the memory condition of non-verbal material elicited bilateral and right frontal activity in encoding and retrieval processes. No task-related effect was reported with the verbal material. Material differences in eliciting task-related effects are discussed in terms of their relation to elaborative and effortful processes.

Adult↗

PubMed2003

Temporal preparation strategy may inflate RT deficit in patients with Parkinson's disease.

Twelve patients with Parkinson's disease (PD) and 12 age-matched controls completed a visual reaction time (RT) task to assess the effect of temporal parameters on response preparation. Simple and choice RT conditions were presented in separate blocks. In both conditions, preparatory intervals of various durations (1, 3 and 5 s) were introduced between an auditory warning signal and the visual target. Within a block of trials, intervals varied randomly. The results indicated that PD patients responded slower than controls in both task conditions. Also, there was evidence for preparation in both groups, as RT decreased with increasing intervals. A three-way interaction indicated that PD patients' RT was longer than that of controls at the shortest interval in simple RT. This suggests that PD patients show a different pattern of temporal response preparation and that this may contribute to their deficit on RT tasks.

Acoustic Stimulation↗

PubMed2003

Locally oriented perception with intact global processing among adolescents with high-functioning autism: evidence from multiple paradigms.

BACKGROUND: According to predictions from the Weak Central Coherence (WCC) theory for perceptual processing, persons with autism should display a tendency to focus on minute details rather than on a more general picture (Frith & Happé, 1994). However, the evidence for this theory is not consistent with findings of an enhanced detection of local targets (Plaisted, O'Riordan, & Baron-Cohen, 1998b; Plaisted, Swettenham, & Rees, 1999), but a typical global bias (Mottron, Burack, Stauder, & Robaey, 1999; Ozonoff, Strayer, McMahon, & Filloux, 1994). METHOD: Adolescents with high-functioning autism and CA- (approximately 15 years) and IQ- (approximately 105-110) matched typically developing adolescents were administered a series of global-local visual tasks, including a traditional task of hierarchical processing, three tasks of configural processing, and a disembedding task that involved rapid perceptual processing. RESULTS: No group differences were found on either the traditional task of hierarchical processing or on tasks of configural processing. However, group differences were found on the disembedding task as the search for embedded, in relation to isolated stimuli, was slower for the typically developing adolescents but similar for the participants with autism. CONCLUSIONS: These findings are consistent with other reports of superior performance in detecting embedded figures (Jolliffe & Baron-Cohen, 1997; Shah & Frith, 1983), but typical performance in global and configural processing (Mottron, Burack et al., 1999; Ozonoff et al., 1994) among persons with high-functioning autism. Thus, the notions of local bias and global impairment that are part of WCC may need to be reexamined.

Adolescent↗

PubMed2003

Effect of manipulation and irrelevant noise on working memory capacity of patients with Alzheimer's dementia.

The effect of manipulation and distracting noise on immediate serial recall was measured in patients with dementia of the Alzheimer type (DAT), neurologically healthy elderly individuals, and young adults. In Experiment 1, the authors compared serial word recall with word recall in alphabetical order. Alphabetical recall requires the active manipulation of the contents of working memory. Findings indicated that DAT patients were severely impaired in the alphabetical recall task, whereas the performance of neurologically healthy elderly participants was comparable with the performance of young adult participants. In Experiment 2, the authors investigated the effect of different irrelevant auditory backgrounds on immediate digit recall. In this task, both elderly participants and DAT patients performed similarly to the group of young adult participants, indicating comparable efficacy to resist auditory distraction.

Adolescent↗

PubMed2002

Characterization of visuoconstructional disabilities in patients with probable dementia of Alzheimer's type.

The goal of this study was to systematically examine alterations underlying the graphical copying performance of Alzheimer's patients at different stages of cognitive decline, in light of a theoretical framework of visuoconstructional processing (Guérin, Ska, & Belleville, 1999). Eight patients with a diagnosis of probable Alzheimer's disease were studied. A group of 24 elderly subjects, of similar age to the patient group and slightly higher education, served as controls. The severity of the cognitive decline of each patient was measured with a standard neuropsychological battery. All subjects were administered a copying task and tasks measuring visual exploration, judgment of spatial relations and graphical planning. Group and individual results were analyzed. The group results suggested that visuoconstructional apraxia in patients with Alzheimer's type dementia is characterized by impaired visual exploration and judgment of spatial relations. Individual results revealed between-patient variability related to the severity of cognitive decline. Given the small number of patients, these observations need to be replicated with a larger-scaled study.

Aged↗

PubMed2002

How loss of meaning with preservation of phonological word form affects immediate serial recall performance: a linguistic account.

We present HP, a patient who following the occurrence of herpes simplex encephalitis, lost the ability to understand a subset of words while others remained preserved. Of particular interest is the fact that the meaningless items retained their lexical status. HP's immediate serial recall of meaningless words was thus compared with that of meaningful words to assess the unique contribution of semantic knowledge without the confounding influence of phonological word (lexical) form. The results revealed a clear recall advantage for meaningful over meaningless words, indicating a specific contribution to recall from the semantic level of representation. Furthermore, an error analysis showed that phonemic errors were most common when semantic information was lacking. Interestingly, the same error pattern was found for pseudo-words that shared phonological elements with meaningless words. These findings support a linguistic and interactive activation account of short-term serial recall, which assumes that all levels of representation, including semantic knowledge about words, contribute to recall performance. In addition, the findings provide preliminary evidence that this view may be extended to the recall of pseudo-words, as there appear to be some influences of semantic representation on pseudo-word recall.

Adult↗

PubMedDate not supplied

Episodic encoding in normal aging: attentional resources hypothesis extended to musical material.

The goal of the present study was to examine age-related changes in musical episodic memory for novel tunes. This was conducted by manipulating the encoding condition in a recognition paradigm. After receiving memory instructions (intentional condition), older and younger participants obtained equivalent hits. In contrast, when intentional encoding was accompanied by a dancing judgment (dancing + intentional condition), the recognition performance of the older persons was severely impaired. Impaired recognition was also found when participants only judged the excerpts without being instructed to memorize them (dancing judgment condition). Although older participants demonstrated a preserved ability to perform the dancing judgment on its own, this ability was not optimal and likely precluded the initiation of more elaborate encoding strategies. These results suggest that asking older persons to divide their attention in the study phase reduces the quality of their musical encoding. Given this extension to musical material, we discuss the notion that the age-related attentional resource decline appears to be domain-general rather than specific to verbal material.

Adult↗