RESUMEN

INTRODUCTION: Cognitive deficit in multiple sclerosis (MS) is a frequent early feature in the disease course, which conditions patients' overall disability. The goals of this study were to validate a reproducible brief screening battery written in French and to examine cognitive risk profiles in patients with a mild physical disability. METHODS: Cognitive performances of 40 patients with EDSS <4.5 were compared with those of a control group. The study was completed with an analysis of socio-demographic, clinical and psychological variables (questionnaires). RESULTS: Three tests were discriminative with satisfactory predictive values (positive: 88 percent; negative: 96 percent) and a time duration <30 minutes: PASAT (hard condition), backward digit span, learning stage of California Verbal Learning Test. Four variables were associated with cognitive deficit: educational level <11 years, age >40 years, pathological laughing-crying, unemployment. CONCLUSIONS: Our brief battery is an easy and reproducible tool. Completed with warning signs indicating the need for neuropsychological screening, this tool provides the practitioner with a global means of assessing disease activity and potentially therapeutic efficacy.

Asunto(s)

RESUMEN

The patient described in the companion paper by Vignal, Chauvel, and Halgren (this issue) was studied with event related potentials (ERPs) recorded directly within the brain substance, as well as with neuropsychological tests before and after therapeutic cortectomy. Large ERPs were evoked in the prefrontal cortex to faces, as compared to sensory controls and words. The largest such ERPs were highly localised to the same right anterior inferior prefrontal site where direct electrical stimulation resulted in face hallucinations. Face-selective ERPs were also evoked in the right prefrontal sites that had shown projected activity during face hallucinations, and near the right anterior superior temporal sulcus. Selective responses began about 150msec after face onset. Words, but not faces or sensory controls, evoked large ERPs in distinct locations, mainly in the left hemisphere. A successful surgical therapy was performed by removing the cortex surrounding the right prefrontal site where face-selective responses were recorded and where face hallucinations were evoked by stimulation. This cortectomy resulted in a severe deficit in the recognition of emotional facial expressions, especially fear. No change was noted, however, in the recall of emotional words, or other tasks. The current results provide strong support for the early, specific, and sustained involvement of a multi-focal network in the right inferior fronto-temporal cortex in face-processing.

RESUMEN

The respective effects of three antidepressant drugs (moclobemide, 450 mg/j; viloxazine, 300 mg/j; maprotiline, 150 mg/j) on vigilance, attention, and memory were compared. Young depressed outpatients (n = 46) entered a double-blind, randomized, monocentre clinical trial lasting for 6 weeks. Drug actions were assessed through the regular determination of critical flicker fusion point (CFF), reaction times (SRT), and a battery to measure memory components. None of the three drugs caused deterioration in cognitive functions. On the other hand, moclobemide improved both vigilance and attention (CFF, SRT) and some crucial components of memory (general memory scores, delayed word recall, recognition of familiar faces). This effect was rapid, stable, and superior to those of viloxazine and maprotiline. It may be explained by moclobemide's selective and reversible inhibition of monoamine oxidase A, as well as by the lack of any anticholinergic action.

Asunto(s)

RESUMEN

Knowledge on the diverse processes involved in memory has been gained from multiple approaches, all necessary for the development of molecules aimed at enhancing memory. However, the neurobiological aspects of apprenticeship and memory remain to be fully elucidated. Long-term storage of information in the nervous system is under the control of glycoprotein synthesis. The chemistry of storage has been extensively studied in mollusks because of their simple neuroarchitecture. In mammals, the phenomenon of hippocampic long-term potentialization (HLTP), to a large extent linked to modification of glutamatergic transmissions, has been demonstrated. Stimulation of N-methyl-DL-aspartase (NMDA) receptors induces an influx of calcium, which is needed for HLTP maintenance, as are the activation of protein kinase C (PKC) and the synthesis of new proteins, for example calmodulin. At the molecular level, a cascade of biochemical events leads to modifications of neuronal connections, thus constituting the basis of memory. Memory-improving substances can be classified according to their theoretical mechanism of action: molecular pharmacology (agents inducing phenomena that mimic HLTP), neurotransmission (molecules acting on the cholinergic, noradrenergic, serotoninergic, GABAergic or dopaminergic systems), pathophysiology (substances antagonizing or correcting anomalies responsible for the memory deficiency, i.e., the cognitive enhancers). The development of memory-enhancing drugs has encountered many obstacles, notably the difficulty in evaluating the effectiveness of a medication in improving memory. It is imperative that guidelines be established for the clinical and experimental development of such substances as well as the standardization of tests in animals and man.

Asunto(s)