Jean-Luc Roulin

Working memory functioning in medicated Parkinson's disease patients and the effect of withdrawal of dopaminergic medication

Cognitive impairments in Parkinsons disease (PD) could be explained by a central executive (CE) deficit in A. D. Baddeleys (1986) working memory model. To test this hypothesis, verbal, spatial, and double span tasks were given to 12 medicated PD patients and control participants, with varying recall delays. The double span task was assigned to explore the coordinating and integrating function of the CE, and lengthening the recall delay was expected to implicate more attentional resources. PD patients had lower spans relative to controls in all tasks. However, the more specific implication of the CE was difficult to prove. One reason could be that PD patients were on dopaminergic treatment when tested. To control this effect, 12 PD patients on and off medication were studied in a second experiment using the same tasks. PD patients off medication had lower spans only in the double task; this result underlines the role of dopamine on working memory processes.

Working memory in medicated patients with Parkinson's disease: the central executive seems to work.

OBJECTIVE--To determine whether a deficit of the central executive can explain the attentional deficits of patients with Parkinsons disease. METHODS--Fifteen patients with idiopathic Parkinsons disease and 15 controls were given a dual task paradigm minimising motor demands and combining verbal, visual, or spatial span with two conditions of articulatory suppression. RESULTS--Although the spans were systematically lower in medicated parkinsonian patients than in controls, suggesting a decrease of central processing resources, there was no direct evidence for a deficit of the central executive. CONCLUSIONS--A deficit of the central executive either is not an inevitable feature of the disease, or is dependent on the nature of task (visuomotor v cognitive), or is corrected by dopaminergic medication.

Executive dysfunction in children with neurofibromatosis type 1: a study of action planning.

In this study, we tested the hypothesis that action planning is impaired in children with neurofibromatosis type 1 (NF1). Thirty-six children with NF1 were pair-matched to 36 healthy controls (HC) on age (range, 7-12 years), sex, and parental education level, and both groups were administered three action-planning tasks. To examine the relation of task performance to attention deficit hyperactivity disorder (ADHD), the NF1 group was divided into subsets of children who met or did not meet criteria for ADHD. Children with NF1 performed less well than HC on all planning tasks, and differences remained when controlling for IQ or a measure of visuospatial skill. Both the NF1 with ADHD subset and NF1 without ADHD subset performed more poorly than HC on two of the tasks, whereas only the NF1 with ADHD subset performed worse than HC on the third planning task. The results underscore the importance of evaluating executive function in children with NF1 and suggest that deficits in this domain may be only partially related to ADHD. Planning deficits in children with NF1 may be part of their cognitive phenotype. Identifying these deficits is relevant in determining factors contributing to learning problems and in developing appropriate interventions.

Phonological similarity in free and serial recall: The effect of increasing retention intervals

The phonological similarity effect (or acoustic confusion effect) consists of poor serial recall performance for lists composed of similar‐sounding words compared to lists of dissimilar‐sounding items. Building on the work of Nairne and Kelley (1999), the extent to which this classical verbal short‐term memory effect changes over the course of a retention interval was investigated. The impact of the phonological similarity on memory performance over time was compared in three paradigms: order reconstruction, serial recall, and free recall. Participants were presented with two blocks of 15 lists composed of five monosyllabic words, one block containing phonologically similar words and the other phonologically distinct words. Recall occurred either after 2, 8, or 24 seconds retention interval filled with a digit shadowing task. Our results confirmed and extended those of Nairne and Kelley. In order reconstruction and serial recall tasks, a classical phonological similarity effect (i.e., decrement in perform...

Evaluating short-term and working memory in older adults: French normative data

Short-term and working memory (WM) capacities are subject to change with ageing, both in normal older adults and in patients with degenerative or non-degenerative neurological disease. Few normative data are available for comparisons of short-term and WM capacities in the verbal, spatial and visual domains. To provide researchers and clinicians with a set of standardised tasks that assess short-term and WM using verbal and visuospatial materials, and to present normative data for that set of tasks. The present study compiled normative French data for three short-term memory tasks (verbal, visual and spatial simple span tasks) and two WM tasks (verbal and spatial complex span tasks) obtained from 445 healthy older adults aged between 55 and 85 years. Our data reveal main effects of age, education level and gender on older adults’ short-term and WM performances. Equation-based normalisation can therefore be used to take these factors into account. The results provide a set of cut-off scores for five standardised tasks that can be used to determine the presence of short-term or WM impairment in older adults.

Assessment of everyday executive functioning in children with frontal or temporal epilepsies

Executive functions are particularly vulnerable in case of brain disruption during childhood, when the brain is not fully mature. Some studies showed impairments of executive functions in children with epilepsy, but only a few of them investigated the impact of executive dysfunctions on daily life. The aim of this study was to understand the everyday executive functioning of children with epilepsy both at home and in school. We administered the Behavior Rating Inventory of Executive Function to parents and teachers of 53 children (7-16 years of age) with structural epilepsies or epilepsies of unknown cause of temporal lobe (n=25) or frontal lobe (n=28). The results indicated a global executive impairment in the whole group of patients, compared with normative data, with no difference between the group with temporal lobe epilepsy (TLE) and that with frontal lobe epilepsy (FLE), except for monitor domain, which seemed more frequently impaired in the group with FLE. Congruence between parent and teacher ratings was found. The frequency of seizures was not related to executive dysfunction, whereas the number of antiepileptic drugs tended to positively correlate with working memory impairment. Onset of epilepsy at a younger age was also related to more executive difficulties but only according to teacher ratings. Lastly, duration of epilepsy was strongly associated with executive deficits reported in the context of school. Our results support the executive dysfunction hypothesis in daily life of children with structural focal epilepsy or focal epilepsy of unknown cause and are consistent with the early brain vulnerability hypothesis currently prevalent in the context of child neuropsychology. The BRIEF appears to be a clinically useful tool for assessing executive function impairment in this clinical population.

The phonological loop in medicated patients with Parkinson's disease: presence of phonological similarity and word length effects.

OBJECTIVE: To test the verbal subsystem of Baddeleys working memory model (the phonological loop) in patients with Parkinsons disease. METHODS: Fifteen patients with idiopathic Parkinsons disease and 15 controls were tested with a span paradigm to assess the effects reflecting the functioning of the phonological loop: the phonological similarity effect (in verbal and visual presentation), and the word length effect (in visual presentation). RESULTS AND CONCLUSIONS: The patients did not show any dysfunction of the phonological loop, reflected by the presence of phonological similarity and word length effects, but had lower spans than controls. The implications of these results for the working memory model are discussed.

Assessment of thought–shape fusion: Initial validation of a short version of the trait thought–shape fusion scale

OBJECTIVE Thought-shape fusion (TSF) is a cognitive distortion that has been linked to eating pathology. Two studies were conducted to further explore this phenomenon and to establish the psychometric properties of a French short version of the TSF scale. METHOD In Study 1, students (n = 284) completed questionnaires assessing TSF and related psychopathology. In Study 2, the responses of women with eating disorders (n = 22) and women with no history of an eating disorder (n = 23) were compared. RESULTS The French short version of the TSF scale has a unifactorial structure, with convergent validity with measures of eating pathology, and good internal consistency. Depression, eating pathology, body dissatisfaction, and thought-action fusion emerged as predictors of TSF. Individuals with eating disorders have higher TSF, and more clinically relevant food-related thoughts than do women with no history of an eating disorder. DISCUSSION This research suggests that the shortened TSF scale can suitably measure this construct, and provides support for the notion that TSF is associated with eating pathology.

Distinction between Visuo-Spatial Short-Term-Memory and Working Memory Span Tasks

Six experiments are presented that examined the constraints underlying performance in two visuo-spatial span tasks. In the Location Span Test (LST), participants have to memorize the cells of a 5×5 matrix containing arrows, while in the Direction Span Test (DST) they have to memorize the cells pointed at by arrows. The main objective was to assess whether both tasks were similarly influenced by experimental factors. Results showed that performance improved with longer encoding time (1-s. vs. 3-s) only for the DST. Maintenance interval (0-s vs. 5-s) and order of item difficulty (ascending vs. descending) have no effect either on the LST or on the DST. Another experiment indicated that the DST is a better predictor of fluid intelligence. These results seem to provide evidence that the LST and the DST relate to different constructs. Implications of these findings for the distinction between short-term and working memory span tasks are discussed.

Multiple short‐term storage: A task to evaluate the coordination function of the central executive

We propose to explore more particularly one of the multiple aspects of working memory, the function of coordination of the central executive with a complex task, the double-stimuli task. This task requires the short-term maintenance of verbal information and of visuospatial information to be coordinated for the recall. The task is conceived in such way that one can ask either for the single recall of words, or for the single recall of locations, or for the recall of localized words. The double-stimuli task is studied using two methods, dual-task methodology (articulatory suppression, Moar box-tracking and standing balance position) and comparison with simple span tasks (word recall and location recall). For word recall and location recall in the double-stimuli task, we observe the classical interference effects: articulatory suppression impairs the performance on word recall without effect on location recall whereas with visuospatial interference tasks the reverse is true. A second analysis shows that when performance on the double-stimuli task (implying the maintenance of verbal material and visuospatial material at the same time) is compared with performances on short-term memory tasks (classical word span or location span using the same material), we observe a significant decrease in performance. In a third analysis a score specific to the complex task is calculated (corrected score) that takes into account the capacities of recall of words and locations. This score directly related to the capacities of coordination implied in the task is sensitive to the most attentional requirements of interference tasks. Contrary to what can be observed on the recall of locations, the standing balance position does not produce a significant decrease in performance. These results are consistent with an interpretation of the working memory according to which coordination of the subsystems is one of the functions of the central executive.