Biomedical subjects

N Marlier

Publications and source records attributed to N Marlier.

4 recordsLinked to original sources

PubMed2000

Dual task performance after severe diffuse traumatic brain injury or vascular prefrontal damage.

The ability to perform two tasks simultaneously is a key function of the central executive of working memory (Baddeley, 1986). This study addressed dual-task performance after diffuse very severe traumatic brain injury (TBI) (mean coma duration = 21 days, mean post-traumatic amnesia = 70 days) or prefrontal damage due to a ruptured aneurysm of the anterior communicating artery (AACA). Mean time since injury was 8 and 16 months in the TBI and the AACA group respectively. A simple visual reaction time and random number generation were used as single and dual tasks. Randomization was self-paced, to control for individual differences in speed. Both patient groups had greater reaction time decrements than controls under the dual-task condition, suggesting a divided attention deficit. In addition, patients with AACA performed significantly poorer in random generation. These results suggest that patients with AACA and with severe TBI suffer from an impairment of the central executive system.

Adult↗

PubMed1996

Working memory and supervisory control after severe closed-head injury. A study of dual task performance and random generation.

Survivors of severe closed-head injury (CHI) frequently suffer from slowed information processing. Whether supervisory strategies are additionally impaired remains a point of debate. The first part of this study employed a self-paced dual task; the second part, a random generation task, performed at a paced rate, under single and dual task conditions. A measure of information processing speed was used as a covariate in statistical analysis. In the first experiment, in addition to slow processing, patients performed slightly poorer than controls on each task. In the second experiment, patients' performance (one randomness index in single task condition, and processing of dual task) was impaired even after statistical control of slow processing. These results suggest that there is at least some degree of impairment in supervisory strategies in addition to, but independent of, slowed processing. The clinical significance of this finding is discussed.

Adolescent↗

PubMed1993

Slowly progressive apraxia: two case studies.

Two patients with a slowly progressive and severe motor apraxia are presented. In one case, there was only apraxia; in the other there was moderate memory disturbance and a mild decline of global intellectual ability, suggesting a more widespread cognitive dysfunction. In this second case, recognition of the correct use of objects was also severely impaired, suggesting a disturbance of motor knowledge. In both cases, apraxia was asymmetrical, and associated with a contralateral atrophy of the upper parietal cortex, suggesting a differential involvement of separate action systems for each hand.

Aged↗

PubMedDate not supplied

Atypical cognitive disorders in a man with developmental surface dyslexia.

The neuropsychological profile of a man with a developmental surface dyslexia is presented here. This case study is of interest because J.C. exhibited a pattern of cognitive disorders rarely documented in previous data. Results showed that JC's difficulties in reading comprehension were closely related to complex memory disorders and were also associated with cognitive slowness. The present observations do not support the visual memory failure hypothesis. The data rather suggest that the core difficulty primarily lies with the nonautomatization of grapheme-phoneme correspondence rules, which in turn dramatically contributed to lexicon weaknesses. The hypothesis of a timing mechanism in reading disorders is discussed.

Adult↗