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M Regard

Publications and source records attributed to M Regard.

65 records · Page 4Linked to original sources
PubMed1985

Dissociated hemispheric superiorities for reading stenography vs print.

In two lateralized tachistoscopic lexical decision experiments at different exposure durations, we found for high-frequency function words written in stenography a shift from a RVF advantage at long exposures to a LVF advantage at short exposures, while for the same words written in print a strong RVF effect persisted. We suggest that a reduction of exposure duration, together with the strong visuo-spatial features in stenography, activate right-hemispheric word recognition. Stenography, a non-orthographic and syllabic-ideographic writing system, could be a model to investigate different hemispheric reading processes in Western subjects.

Adult↗
PubMed1985

Left hemispheric functional compensation in prosopagnosia? A tachistoscopic study with unilaterally lesioned patients.

Clinical observations suggest left hemispheric compensation for prosopagnosia in patients with isolated right posterior lesions. To test this hypothesis we investigated six patients with right posterior lesions, three with and three without prosopagnosia, with a series of tachistoscopic matching experiments. Faces with and without paraphernalia, shapes, objects and words were presented at different exposure durations (unlimited, 1000, 200, 50 and 20 ms). Prosopagnosia patients performed better than non-prosopagnosia patients if pure faces (eyes, nose and mouth only) were presented for an unlimited time, but performed worse than non-prosopagnosia patients if exposure duration was reduced. Patients with prosopagnosia were especially handicapped when required to match emotional expressions. Both patient groups had no difficulty in matching objects and words, even at short exposure durations. The results are discussed with respect to a possible left hemispheric compensation in prosopagnosia patients.

Adult↗
PubMed1984

Experimentally induced semantic paralexias in normals: a property of the right hemisphere.

The recently proposed association between semantic paralexias and right hemispheric reading processes was investigated in normals with a tachistoscopic half-field reading experiment. With extremely brief lateralized exposure of nouns, permitting only 25% of correct reading, semantic paralexias were induced. These semantic substitutions occurred three times more often to LVF (right hemisphere) than to RVF (left hemisphere) presentations, whereas other errors were observed with similar frequency to both visual fields. We concluded that semantic paralexias, as they are observed in patients, occur in normals induced by reduced reading time and are the product of right hemispheric reading processes.

Adult↗
PubMed1984

Transient global amnesia: neuropsychological dysfunction during attack and recovery in two "pure" cases.

Two patients with transient global amnesia are reported. Comprehensive neuropsychological evaluation, during the amnesic episode, as well as follow-up examinations on memory were performed. The course of the amnesia was exemplified by two comparable memory tests in different modalities. Partial retrograde amnesia and complete anterograde amnesia were demonstrated during the transient episode. Objective recovery was found to be slower than subjectively experienced, but test performance was completely normal one month after onset.

Adult↗
PubMed1977

[Neuropsychological diagnosis and localization of brain lesions: their agreement with other examination visits (author's transl)].

Neuropsychological diagnoses were compared with those of clinical examination and the results of electro- and pneumoencephalography, angiography, brain-scan and with the final diagnoses in a random sample of 319 patients. A significant correspondence between neuropsychological findings and final diagnosis was found. The agreements were closer for the side than for the lobe of damage. The results indicate that the neuropsychological assessment usefully supplements other neurological methods in the diagnosis and localization of brain-damage.

Brain Diseases↗
PubMedDate not supplied

Dissociation of frontal and parietal components of somatosensory evoked potentials in severe head injury.

Reports on the topography of SEPs in non-comatose patients have drawn attention to a second thalamo-cortical loop connecting the thalamus with the frontal cortex, which has a close anatomical relation to the fronto-limbic structures frequently damaged in severe head injury (SHI). We studied whether the frontal component (P20/22) of the somatosensory evoked response (SEP), known to be due to a generator different from that of the traditionally analysed parietal SEP component (N20), would be differently affected by SHI. Moreover, we examined whether its analysis would improve the prognostic evaluation in the Glasgow outcome scale (GOS) after 3-6 months. In 50 patients examined within 72 h after the injury we found a dissociated impairment of frontal and parietal components in 24% of the recorded SEPs. When both frontal and parietal components were used as predictors, discriminant analysis correctly classified 94% of the patients into good (GOS good recovery and moderate disability) or poor (GOS severe disability, persistent vegetative state or death) outcome groups. Classification was less accurate and misclassifications grosser when considering parietal or frontal parameters alone. Our results show that (i) the evaluation of frontal components provides information different from that of the parietal SEPs, confirming the presence of different generators, and (ii) a combined analysis of the two components improves the prognostic evaluation with regard to the global outcome.

Adolescent↗
PubMedDate not supplied

Unilateral limbic epileptic status activity: stereo EEG, behavioral, and cognitive data.

We report data from four patients with unilateral epileptiform status activity within different structures of the temporal lobe, recorded during stereoelectroencephalographic presurgical evaluation. The ictal clinical symptoms accompanying neocortical and mesiobasal limbic discharges (two patients with complex partial status epilepticus) consisted of various psychosensory and vegetative signs, which can be understood on the basis of the spatiotemporal analysis of the discharges. The other two patients with circumscribed long-lasting mesiobasal limbic epileptiform activity represent unilateral pure limbic status epilepticus and were characterized by a marked behavioral syndrome (with stickiness, aggressivity, etc.) and a monomorphic gustatory aura continua, respectively. The latter patient, with left hippocampal discharges of nearly continuous epileptiform character, was also assessed with tachistoscopic tasks. Performance revealed cognitive impairment only in the epileptically discharging hemisphere and in dependence on the quality of the EEG pattern. After unilateral selective amygdalohippocampectomy, the two patients with limbic status epilepticus were seizure free and had markedly improved behavior and cognitive functions. Thus, patients with nonconvulsive status epilepticus represent an ideal model, although rare, to correlate behavior alterations and brain dysfunction.

Adolescent↗
PubMedDate not supplied

Lateralized lexical decisions and the effects of hemifield masks: a study of interhemispheric inhibition and release.

A lateralized tachistoscope experiment using 40 normal, right-handed men tested the predictions of three different theories of interhemispheric interactions. Lexical decision for function words was measured for each visual field under several conditions of simultaneous stimulation in the contralateral hemifield. When a nonsense word was presented simultaneously to the contralateral hemifield, performance decreased, especially for words in the weaker field, an effect which is inconsistent with the predictions of the direct access model. When the contralateral nonsense word was immediately masked, there was a significant improvement in performance over the nonmasked condition. Analysis of the masking effect showed that the data are inconsistent with a callosal relay model, but are consistent with a model of transcallosal inhibition.

Adult↗