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Biomedical subjects

J Jacquy

Publications and source records attributed to J Jacquy.

At least 55 records · Page 3Linked to original sources

Cerebellar hypermetria is larger when the inertial load is artificially increased.

Hypermetria is a classical cerebellar symptom designating the overshoot observed when a patient is asked to make a very fast and accurate movement. The movement studied here was wrist flexion. Hypermetria was found to be increased by artificially increasing the inertia of the moving hand. A normal subject adapted himself to increasing inertia by increasing both his agonist activity (the launching force) and its antagonist activity (the braking force). In the same circumstances, a patient with symptoms of cerebellar system dysfunction was found to be able to increase his agonist activity but not his antagonist activity.

Acceleration↗

Somatosensory evoked potentials at rest and during movement in Parkinson's disease: evidence for a specific apomorphine effect on the frontal N30 wave.

Studies attempting to relate the abnormalities of the frontal N30 components of the somatosensory evoked potentials (SEPs) to motor symptoms in Parkinson's disease (PD) have shown contradictory results. We recorded the frontal and parietal SEPs to median nerve stimulation in 2 groups of PD patients: a group of 17 patients presenting the wearing-off phenomenon, and a group of 10 untreated PD patients. The results were compared with a group of 13 healthy volunteers of the same age and with a group of 10 non-parkinsonian patients. All parkinsonian and non-parkinsonian patients were studied before ("off" condition) and after a subcutaneous injection of apomorphine ("on" condition). The gating effects of a voluntary movement (clenching of the hand) on the SEPs were also studied for the wearing-off group of PD patients (in states off and on) in comparison with the healthy subjects. At rest and in the off condition the amplitude of the frontal N30 was significantly reduced in the 2 groups of PD patients. We demonstrate that the movement gating ability of the PD patient is preserved in spite of the reduced amplitude of the frontal N30. This result suggests that the specific change in the frontal N30 in PD is not the consequence of a continuous gating of the sensory inflow by a motor corollary discharge. Clinical motor improvement induced by apomorphine was associated with a significant enhancement of the frontal N30 wave. In contrast, the subcortical P14 and N18 waves and the cortical N20, P22, P27 and N45 were not statistically modified by the drug. Apomorphine infusion did not change the absolute reduced voltage of the N30 reached during the movement gating. While the frontal N30 component of the non-parkinsonian patients was significantly lower in comparison to healthy subjects, this wave did not change after the apomorphine administration. In the wearing-off PD patient group the frontal N30 increment was positively correlated with the number of off hours per day. This specific apomorphine sensitivity of the frontal N30 was interpreted as a physiological index of the dopaminergic modulatory control exerted on the neuronal structures implicated in the generation of the frontal N30.

Aged↗

[Acute motor axonal neuropathy with favourable outcome after Salmonella Ohio infection].

We report one patient presenting an acute weakness following an infection with Salmonella Ohio. Diagnosis was Guillain-Barré syndrome (GBS). However, preservation of reflexes and electrophysiological study showing purely axonal pattern make this case different from typical GBS. Outcome was favourable. There are probably various forms of GBS and the axonal form do not always carry a bad prognosis as previously reported.

Adult↗

Progressive focal degenerative disease of the posterior associative cortex.

A 72-year-old man developed a very progressive neuropsychologic deficit 6 years ago, beginning with isolated visual topographic memory disturbances and visuo-constructive apraxia without additional manifestations of dementia. The syndrome worsened thereafter with the emergence of visual agnosia, simultagnosia, psychic paralysis of gaze, auditivo-verbal agnosia, and recently an amnestic syndrome with confabulation and confusion (at the end of 1989). CT scans, which remained unchanged over the years, showed mild, focal atrophic changes revealed by dilatation of the right occipital horn. His angiograms were normal. Two SPECT studies (with HMPAO measurements), performed 6 years from the onset, detected marked hypoperfusion in both parieto-occipital regions, mainly on the right side. Progressive focal degenerative disease without dementia is a relatively new syndrome, especially in cases with progressive aphasia. As noted in our patient, progressive disturbances initially localized in the right parieto-occipital region followed by posterior bilobar degeneration (pronounced on the right side) without dementia until late in the course may represent another exceptionally reported characteristic of this new syndrome. It is suggested that this variant of the Mesulam syndrome is more likely explained by progressive atrophy of the Alzheimer type.

Aged↗

[Long-latency auditory evoked responses in Parkinson disease and in parkinsonism induced by neuroleptics].

The amplitude and latency of the N100 wave (auditory evoked potentials) were studied in 28 normals, 85 parkinsonians, 24 extrapyramidal syndromes induced by neuroleptics and 12 neurological control patients. The latency decreases as an inverse function of the intensity of stimulation in normals, controls, treated parkinsonians and in extrapyramidal syndrome induced by neuroleptics. Untreated parkinsonians do not show an evident relation between the latency and the stimulation level. The amplitude of the N100 decreases when neuroleptic induced parkinsonism improves.

Aged↗

[Reversible dementia and polyneuritis in an elderly woman: a case of late-onset disseminated lupus erythematosus].

Reversible dementia and polyneuropathy in an elderly woman: a case of late onset systemic lupus erythematosus. We report the case of a 76-year-old woman with undiagnosed systemic lupus erythematosus. She presented with severe dementia. She was given prednisolone 20 mg daily with dramatic improvement occurring within one month. Electrophysiological study showed evidence of axonal neuropathy.

Aged↗

Sustained-release levodopa in parkinsonian patients with nocturnal disabilities.

It is now well recognized that poor quality of sleep, with fragmentation as the main characteristic, is a common problem in patients with Parkinson's disease. The effect of a sustained-release levodopa compound (Prolopa HBS) was assessed in a long-term (12 months) study of 15 patients presenting with distressing night time symptoms prolopa HBS was administered only ante noctem, without changing the usual daytime treatment. It appeared that alleviation of nighttime akinesia, reflected by the ability to turn around in bed, was perceived as the most worthwhile improvement.

Aged↗

Parkinsonian bradykinesia is due to depression in the rate of rise of muscle activity.

Parkinsonian bradykinesia is defined by a slowness in the execution of movement. We studied the pathophysiology of this symptom in rapid arm-reaching movements to a visual target carried out in a reaction-time task. The major cause of bradykinesia was found to be depression in the rate of rise of electromyographic activity. The amplitude of the peak of this activity did not change significantly. There was no change either in the sequential activation of muscles, in the amount of co-contraction activity, in the accuracy of aim toward the visual target, or in the movement trajectory.

Adult↗

[Cognitive evoked potentials in the diagnosis of senile dementia and dementia of Parkinson's disease: significance of multivariate analysis].

P300 latency is often delayed in dementia but some authors have questioned its value in clinical practice, because of the relatively low specificity and sensibility of the method. Numerous parameters (latency, duration, amplitude and surface) of N100, N200 and P300 waves were therefore studied in patients with senile dementia, subjects suffering from Parkinson's disease with dementia, and non-demented elderly patients. Using discriminant analysis, more than 90% of the patients were correctly classified. This method could thus be contributory in diagnosing dementia in clinical practice.

Cognition↗

[Opsoclonus associated with multisystemic sarcoidosis].

A 32 year old patient with unexplained cough developed an opsoclonus-ataxic-myoclonic syndrome. Chest X-ray film were normal at this onset but became pathologic, and the diagnosis of multisystemic sarcoidosis was made. The possibility of sarcoidosis being the cause of the opsoclonus is discussed.

Adult↗

[Cerebral crossed diaschisis caused by cerebellar lesion: role of the cerebellum in mental functions].

In 3 patients with a stroke limited to the posterior fossa, regional cerebral blood Flows were measured by the 133 Xe inhalation method (the first two cases) or by the SPECT with HMPAO method (the third case). The first patient had a median and paramedian hematoma of the left cerebellar hemisphere and the left dorsolateral portion of the pons. Remote cerebral hypoperfusion, measured 3 months later, was observed in both frontal premotor regions (but more marked in the right hemisphere) and in a circumscribed area of the right temporal region. The second patient had a right-sided ischaemic lesion of the anterior cerebellar lobe and the mesencephalic tectum. Contralateral parietal and rolandic hypoperfusion, measured 7 weeks after the stroke, was observed. The third patient had on old infarct of the right cerebellar hemisphere. The SPECT, measured 17 years later, showed a left fronto-parieto-temporal hypoperfusion and the absence of perfusion in the right cerebellar hemisphere. Preliminary data of neuropsychological assessment in our patients disclosed impairment in visuo-spatial and constructive organization, memory and learning compatible with the published findings in some patients and animals with predominantly cerebellar damage. These interesting findings should be confirmed in a large number of patients with age, sex, and sociocultural matched controls. In the absence of supratentorial insult, and during the hemodynamical stable phase, crossed cerebello-cerebral diaschisis is suggested in our 3 patients. Although it is too early to draw definite conclusions, our findings may: (1) confirm the functional interconnections between the cerebellum and the cerebrum in man and (2) provide functional basis for the behavioral function impairment reported in patients with cerebellar insult. Further rCBF, metabolism, and pathologic studies on this subject are required to elucidate this issue.

Cerebellar Diseases↗

[Contingent negative variation and regional cerebral blood flow in senile dementia and cerebral aging].

Relationships between contingent negative variation (CNV) amplitude, regional cerebral blood flow (CBF), mini mental status examination score (MMSE) and reaction time (RT) have been studied in young subjects, non-demented old subjects and patients with primary degenerative senile dementia. Significant correlations have been found between CNV amplitude and global CBF, MMSE score and reaction time. Factorial analysis has shown 3 factors weighted respectively by MMSE and CNV, antero-posterior ratio fort left hemispheric CBF and age, and antero-posterior ratio for right hemispheric CBF and reaction time. Discriminant analysis has shown 2 discriminant functions differentiating young from old subjects with 90% accuracy and demented from non-demented patients with 75% accuracy.

Adult↗

Multivariate analysis of the effect of climatic factors on the probability of cerebral infarction according to age.

This study investigates the effects of: the mean daily air temperature; the mean daily atmospheric pressure; and the temperature evolution (cooling, stable or reheating) on the probability of cerebral infarction. Data were collected during a three-year period in a country with a mild, maritime temperate climate. In men younger than 70, the probability of cerebral infarction mainly depends on temperature. Temperature is also the main statistically significant factor affecting the rate of cerebral infarction in women under 75; this effect is modulated by temperature evolution. Conversely, no clear effect of climatic factors could be found either on men older than 70 or women older than 75.

Adult↗

Right hemispheric activation on chronognosia: a preliminary study by rheoencephalography.

Using an impedance plethysmography technique, we measured the regional cerebral blood flow variation at rest and during time period estimation in 21 normal volunteers. A significant increase was observed in the right hemisphere. The overestimators without internal counting show a significant increase in the right frontal region. The underestimators without internal counting display no right frontal modification but their right temporo-occipital regions show a significant increase.

Adult↗