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Biomedical subjects

N Benoit

Publications and source records attributed to N Benoit.

9 recordsLinked to original sources
PubMed1992

Brain energy metabolism in bilateral paramedian thalamic infarcts. A positron emission tomography study.

Positron emission tomography (PET) studies of the cerebral metabolic rate of oxygen (CMRO2) were performed in seven consecutive patients with bilateral paramedian thalamic infarcts (BPTI), selected on neuroradiological and clinical criteria. The latter consisted of sudden onset of coma or confusion followed by a persistent amnesia of varying severity, with or without language impairment and frontal lobe signs. There was a highly significant decrease of CMRO2 for the whole cortex as well as for all the regions analysed: medial-frontal, latero-frontal, temporal, sensorimotor and posterior associative cortex. The mean regional metabolic ratios (region/whole cortex CMRO2) were not significantly different from controls, indicating an essentially uniform effect in the cortex, except the sensorimotor ratio which was significantly increased. Diffuse cortical hypometabolism most likely reflects thalamo-cortical deafferentation secondary to damage to the 'non-specific' thalamic nuclei, while sparing of the latero-ventral thalamus presumably explains the relative preservation of the sensorimotor cortex metabolism. Although no clear-cut individual relationship was found between magnitude of cortical hypometabolism and the severity and pattern of neuropsychological impairment, the data suggest that the former underlies and/or reflects the latter. Further studies with higher resolution PET devices might shed more light on the relationships between distinct cognitive patterns and specific topography of cortical hypometabolism in BPTI patients.

Adult↗
PubMed1991

[Examination and memory].

Examining memory is required in various circumstances. A simple rule never to be forgotten is that the examination of mnemonic capacities must not be separated from examination of other cognitive capacities. The first stage is clinical. The evaluation of mnemonic efficiency--i.e. the ability to store and retrieve new information--is the essential part of the examination and is carried out by means of standardized tests. Old memory, short-term memory, semantic memory and procedural memory must also be evaluated.

Humans↗
PubMed1991

Cognitive function in adult adrenoleukodystrophy: comparison with leukoaraiosis and multiple sclerosis.

Cognitive evaluation of 6 cases of adult adrenoleukodystrophy (ALD) included in a brain magnetic resonance (MR) study are reported: 2 males with adrenomyeloneuropathy and 4 women heterozygous for ALD. Cognition was normal in 4 and MR scan in 2 of them. In the 2 others, there were mild modifications of the white matter. One patient suffered of visual retention disturbances with abnormalities of the white matter in MR scan. In the last, cognitive decline was observed; MR scan showed atrophy of cortex and corpus callosum and periventricular high signal areas. Comparison with leukoaraiosis in healthy adults and with multiple sclerosis suggests that there is probably a relationship between cognition and extension of brain MR abnormalities. Time of appearance and frequency of cognitive dysfunction might be explained by the natural history of each of these diseases.

Adrenoleukodystrophy↗
PubMed1991

[Slowly progressive apraxia: a MRI and positron tomography in 4 cases].

Four right-handed patients (69, 58 and 68 year-old men; 85 year-old woman) complained of motor difficulties with their left hand (3 cases), or both hands predominant on the left side (1 case). Continuous (1 case) or intermittent (2 cases) myoclonus was noted in the left arm. These disorders gradually progressed for 3 to 10 years. Clinical examination disclosed absence of motor, sensory (except in 1 case), or visual deficit. There were no cerebellar signs, no parkinsonian features (except for mild rigidity in 1 case), and no oculomotor abnormality. On the other hand, neuropsychological examination showed evidence of visuo-constructive apraxia in all cases, dressing apraxia in 3/4 cases and writing impairment in 3/4 cases. There was no amnesia, no aphasia and no intellectual impairment. MRI showed atrophy of the parietal areas, predominant on the right side. A positron emission tomography study was performed in all cases, and twice in 1 case. Cortical energy metabolism was measured using either 18 F-fluorodeoxyglucose or 15 O-Oxygen, to calculate the cerebral metabolic rate of glucose (CMRglu) or oxygen (CMRO2) respectively. Cortical metabolism was significantly decreased in the whole cortex of the right hemisphere in 3 cases, and was also reduced in the cortex of the left hemisphere, significantly in 1/3 studied planes. Moreover, regional metabolic indices (CMRO2 or CMRglu/cortex) showed a significant decrease in both the right and left posterior associative areas (temporo-parieto-occipital cortex), predominantly marked on the right side in 3 cases, indicating bilateral cortical dysfunction. At follow-up, one patient became progressively demented, another had visuo-spatial disorders indicating a lesion of both parietal areas. The relationships of our cases with the slowly progressive apraxia syndrome and with corticobasal degeneration are discussed.

Aged↗
PubMed1989

Manic-like state after bilateral orbitofrontal and right temporoparietal injury: efficacy of clonidine.

A manic-like state occurred in a 44-year-old right-handed woman with bilateral orbitofrontal and right temporoparietal traumatic contusions. In a brief trial, we assessed the effect of clonidine, carbamazepine, dopa therapy, and placebo on manic symptoms and cognitive functions. Clonidine rapidly reversed the manic syndrome. The patient's behavior did not change with carbamazepine and worsened with levodopa. We suggest that the manic-like syndrome was related to noradrenergic overactivity secondary to the fronto-orbital lesions.

Adult↗
PubMed1986

Cognitive function in recent-onset demyelinating diseases.

To determine cognitive disturbances in recent demyelinating disease, we studied 21 patients with definite or probable multiple sclerosis (MS) of less than two years' duration and nine patients with recently isolated optic neuritis. None had any clinical or social evidence of cognitive impairment. Mild to moderate cognitive impairment. Mild to moderate cognitive impairment was present in 18 (60%) of 30 cases, affecting visual and/or verbal efficiency. These abnormalities were statistically significant when compared with the results of a control group of 29 patients. There was no correlation with a depressive status, between the presence of cognitive impairment and either the degree of handicap or the activity of the disease. The frequency of cognitive dysfunction (60%) appears to be comparable to that reported in other series in which MS evolution is over ten years. The natural history of cognitive functions in MS has to be identified. Neuropsychologic tests could be useful in the diagnosis of monosymptomatic or paucisymptomatic forms of MS (ie, visual or medullary).

Adult↗