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Biomedical subjects

H Petit

Publications and source records attributed to H Petit.

At least 19 recordsLinked to original sources
PubMed1992

Evidence for a common network of brain structures involved in parkinsonian tremor and voluntary repetitive movement.

Repeated measurements of regional cerebral blood flow (rCBF) were obtained in 7 patients who underwent a stereotactic thalamic electrode implantation in the nucleus ventralis intermedius (nVIM) of the thalamus for severe hemi-parkinsonian tremor. Using positron emission tomography and oxygen-15 labelled water, rCBF was studied in each patient in two conditions: in absence of tremor, e.g. under nVIM electrical stimulation, and in presence of tremor. X-ray tomograms permitted individual definition of anatomical regions of interest. In presence of tremor, normalized rCBF increases were observed in the following regions: postcentral (13.6 +/- 8.4%, P = 0.0003), precentral (7.7 +/- 8.8%, P = 0.016), paracentral (7.7 +/- 8.4%), supplementary motor (8.2 +/- 10.4%, P = 0.025), caudate nucleus (5.7 +/- 7.6%, P = 0.03), vermis (9.7 +/- 7.3%, P = 0.007), cerebellar grey nuclei (9 +/- 6%, P = 0.016) on the electrode side and on the contralateral vermis (17.8 +/- 7.5%, P = 0.0003) and cerebellar grey nuclei (22 +/- 6.3%, P = 0.0004). These results clearly indicate an activation of the sensory-motor cortex, as well as an involvement of the supplementary motor area and the cortico-cerebellar pathways in Parkinsonian resting tremor (PRT). They demonstrate that PRT shares common network of brain structures with repetitive voluntary movement.

Aged↗
PubMed1992

Some clinical aspects of late onset parkinsonism.

Thirty-six parkinsonian patients were selected by age of onset of over 70 and a minimum of five years duration of illness. The mean age of onset was 73.5 years and 30 patients were still alive after a mean of 7.2 years. We found that late onset Parkinson's disease has a relatively benign course with more "axial symptoms" especially dysarthria, freezing and postural instability. Dyskinesias and fluctuations are rare and dementia occurs in few patients in spite of their old age.

Aged↗
PubMed1992

Parkinson's disease and basal ganglia calcifications: prevalence and clinico-radiological correlations.

We reviewed computerized tomograms (CT) for basal ganglia and dentate nucleus calcifications in 79 patients with Parkinson's disease (PD), 54 patients with Alzheimer's disease (AD) and 109 controls aged 50 or more. When it was determined, no patient had disturbances in calcium metabolism. We found: (1) 30 subjects out of 242 (12.3%) with calcification located within the lenticular nucleus in 28. (2) Calcifications were unilateral in 11 and asymmetric in 11. (3) The prevalence of calcifications was 21.5% in PD, 9.2% in AD and 7.3% in controls and were significantly more severe in PD than in C and AD (P less than 0.02). (4) PD patients with calcifications were clinically indistinguishable from those without calcification. (5) Calcifications within the basal ganglia were not associated with a levodopa-resistance. We suggest the basal ganglia calcifications are more frequent in PD, but we cannot explain why, since post-synaptic lesions have never been showed in PD.

Aged↗
PubMed1992

Control of tremor and involuntary movement disorders by chronic stereotactic stimulation of the ventral intermediate thalamic nucleus.

The authors report on the long-term results of chronic stereotactic stimulation of the ventralis intermedius thalamic nucleus performed in 14 cases of disabling and intractable tremor. There were 10 patients with parkinsonian tremor and four with essential tremor. Three of the 10 parkinsonian patients had previously undergone contralateral thalamotomy. Tremor was assessed by clinical evaluation, surface electromyography, accelerometer, and videotape recordings before and after stimulation. The deep-brain electrode was implanted in the ventralis intermedius nucleus according to stereotactic procedure and connected to a subcutaneous pulse generator after a stimulation test period. Tremor suppression or reduction was obtained in all cases with high-frequency (130 Hz) stimulation. Marked functional improvement was maintained in 11 patients with a mean follow-up interval of 17 months. Levodopa-induced dyskinesias observed in five parkinsonian patients prior to surgery were improved or suppressed in four cases by thalamic stimulation. Stimulation was continued during the day and stopped at night in eight cases. Six patients were stimulated night and day to avoid a rebound effect which appeared as soon as the pulse generator was stopped. The only side effects were hand tonic posture in one case and persistent paresthesia in another case. The mechanism of action of this attractive treatment may be a functional alteration of the thalamic discharging area. The authors conclude that this technique is a good alternative to thalamotomy, especially when the risks of high-frequency coagulation are severe in frail and older patients.

Adult↗
PubMed1992

[Stiff-Man syndrome with late onset].

We report a case of Stiff-Man syndrome according to Gordon, Januszko and Kaufman's criteria. Onset at age 76, association with insomnia and a rapid course leading to death within 2 years were the characteristic features. CSF data, electromyographic and immunological findings suggest abnormalities of catecholaminergic and GABA ergic systems, with release of segmental or suprasegmental inhibitory influence. The presence of antibodies against glutamic acid decarboxylase, considered a useful marker of this syndrome, raises the possibility of an autoimmune pathogenesis.

Aged↗
PubMed1992

[Neuropsychological evaluation before and after thalamic stimulation in 9 patients with Parkinson disease].

Chronic thalamic-VIM stimulation was performed in 9 parkinsonian patients with disabling tremor and poor response to drugs. Neuropsychological assessment was performed before and after deep brain electrode implantation and stimulation. Mild cognitive disorders were observed prior to thalamic implantation. Neuropsychological testing failed to show intellectual function worsening after implantation and stimulation. We conclude that thalamic stimulation could be an appropriate treatment of untractable tremor as this could provide less neuropsychological side-effects than thalamotomy, especially in Parkinson's disease.

Aged↗
PubMed1992

[Transesophageal echography and peripheral arterial embolism. A new etiologic approach. Apropos of 87 cases].

This prospective study (September 1989 to November 1990) was undertaken to evaluate the utility of transesophageal echocardiography in acute peripheral ischaemic syndromes. After embolectomy or thrombolysis, 87 patients with an average age of 69.7 years underwent not only the usual investigations (conventional echocardiography, abdominal ultrasonography and Holter monitoring) but also transesophageal echocardiography within 2 days of the ischaemic events (lower limb 84%, multiple embolism 11%, recurrent embolism 13%). Atrial fibrillation was documented in 44 patients (50.5%), 19 patients had chronic arterial disease (22%), 8 patients had valvular heart disease (9%) and 2 patients had a blood disorder (2%). Transthoracic echocardiography only demonstrated one left ventricular apical thrombus whereas transesophageal echocardiography showed residual thrombus in 22 patients (25%) mainly in the left auricle but also in the descending thoracic aorta (8 patients) as a mobile, pediculated thrombus or lining an aortic aneurysm, thereby opening up new therapeutic possibilities. In addition, double aortic dissection was diagnosed in a patient who was not echogenic, isolated spontaneous contrast in 20 patients (23%) and other abnormalities in 7 patients (8%). Statistical analysis showed a significant relationship between the presence of thrombus and/or spontaneous contrast in the left atrium and/or left auricle and the size of the left atrium (Fisher test - p = 0.0073), and the presence of a supraventricular arrhythmia (chi 2 test).

Adult↗
PubMed1991

[Contribution of imaging to the study of aortic aneurysms].

All aortic aneurysms require a positive diagnosis, a differential diagnosis and an assessment of extension. Several exploratory methods can be contemplated. In patients with warning symptoms, conventional radiology may point to the diagnosis. The reference method remains retrograde aortography which may be either conventional and seriographic or, better, radiocinematic with orthogonal projections and, if possible, digital. The site and morphology of the aneurysm, and in particular its inner channel are thus demonstrated. Computerized tomography is less invasive and usually of great value, notably for the horizontal, thoracic and abdominal aorta, not only to confirm the diagnosis but also to determine the size of the inner channel, parietal thrombi and aortic walls, as well as relations with nearby structures. Other, totally non-invasive methods are widely utilized to explore aortic aneurysms. These are ultrasonography and its variants (notably Doppler-echocardiography and the transoesophageal route), and magnetic resonance imaging which provides three-dimensional and anatomical views of the vessel. These last two examinations alone usually confirm and outline the aortic aneurysms. They must therefore be utilized as first-line examination, arteriography it is various forms being reserved for emergencies or special cases.

Aorta, Abdominal↗
PubMed1991

[Amnesic syndrome caused by limited infarction in the right anterior thalamus].

A case of global and persistent amnesia due to a right polar and anterior thalamic infarction is reported. There was a moderate impairment of attention and categorization ability. The amnesia was primarily anterograde, with partial disturbance of short-term memory and severe deficit of long-term memory for verbal and visuo-spatial materials. A severe increase of pro-active interference was present. Retrograde memory was mildly affected. Two years later, a second infarction in the right thalamo-sub-thalamic territory occurred, increasing the deficits of attention, short-term memory and recall.

Adult↗
PubMed1991

[Mental akinesia and memory disorders following carbon monoxide poisoning].

A 32-year old woman presented with serious memory impairment and a mental syndrome named loss of psychic auto-activation or psychic akinesia following carbon monoxide poisoning. The MRI findings were bilateral pallidal lesions probably associated with thalamic lesions. The evolution was favourable.

Adult↗
PubMed1991

[Parkinsonian syndrome caused by carbon monoxide poisoning. Preliminary results of the treatment with bromocriptine].

Parkinsonism is the most frequent neurological complication of carbon monoxide intoxication. Its prognosis is severe and Dopa is ineffective. We treated 9 patients (mean age 60.89 +/- 6.10 years) with bromocriptine (5 à 30 mg daily). Webster's scores were improved under treatment. Our study suggests that early administration of bromocriptine might be an effective therapy of carbon monoxide induced parkinsonism.

Adult↗
PubMed1991

[Right unilateral auditory agnosia following left lenticular hemorrhage].

A 33-year old patient who had had left lenticular hemorrhage presented with an inability to understand with the right ear oral language and, in a less dramatic way, nonverbal sounds. This unilateral auditory agnosia was first associated with a right motor underutilization and right motor, sensitive, visual and auditive extinctions. Speech discrimination scores were 100% with the left ear and 15% with the right ear, even less in dichotic conditions. Tonal audiogram, as well as early and late components of the auditory evoked potentials were normal. Cerebral regional perfusion and metabolism were impaired over the left parietotemporal area. There was severe hypoactivation of the left hemisphere with right monaural verbal stimulations. Rehabilitation consisting of non-specific attention tasks and repetitions of words reaching only the right ear was undertaken 15 months after the stroke. The oral language comprehension improved, as did the left hemisphere activation, and the extinction phenomena disappeared, except for the auditory one. The unilaterality of the auditory agnosia could be due, in part, to a peculiar physiological processing in this patient, such as poor performance of his right ipsilateral auditory pathway which could be improved with practice. A striatal lesion could induce a spatial hemi-inattention as reflected by the multimodal extinction in this case. Besides, a lack of selective activation for verbal stimulation of the left hemisphere is suggested.

Adult↗