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Biomedical subjects

P Pollak

Publications and source records attributed to P Pollak.

At least 145 records · Page 8Linked to original sources
PubMed1987

Combined (thalamotomy and stimulation) stereotactic surgery of the VIM thalamic nucleus for bilateral Parkinson disease.

Stereotactic thalamotomy of the thalamic nucleus ventralis intermedius (VIM) is routinely used for movement disorders. During this procedure, it has been observed that high-frequency (100 Hz) stimulation of VIM was able to stop the extrapyramidal tremor. In patients with bilateral tremor of extrapyramidal origin, who were resistant to drug therapy, the therapeutic protocol associated (1) a radiofrequency VIM thalamotomy for the most disabled side, and (2) a continuous VIM stimulation for the other side using stereotactically implanted electrodes, connected to subcutaneous stimulators. VIM thalamotomy relieved the tremor in all operated cases. Side effects were mild and regressive. VIM stimulation strongly decreased the tremor but failed to suppress it as completely as thalamotomy did. This was due in part to the fact that programmable stimulator frequency rate is limited to 130 Hz, while it appeared that the optimal stimulation frequency was 200 Hz. This therapeutic protocol appears to be of interest for patients with bilateral extrapyramidal movement disorders.

Electric Stimulation Therapy↗
PubMed1987

[Ataxic hemiparesis caused by a thalamic lacuna].

A 64 year old man was admitted for an ataxic hemiparesis. Magnetic resonance imaging (MRI) suggested a lacunar infarct. The lesion was located in the postero-lateral part of the contralateral thalamus, sparing the internal capsule.

Cerebellar Ataxia↗
PubMed1986

[Incidence of polyneuropathies in chronic obstructive bronchopneumopathies].

In a prospective study 43 patients with chronic obstructive lung disease and severe respiratory insufficiency were systematically investigated for polyneuropathy, although they had no risk factor of that disease. Electrophysiological recordings showed slight or significant signs of polyneuropathy in 17 and 15 patients respectively, thus indicating that the condition is frequent. Clinically, it was often silent or manifested only by sensory disorders predominant in the lower limbs. Electrophysiology suggested axonal degeneration associated with some degree of demyelinization, and these lesions were found at histology to be present in sensory nerves. Histological examination of the muscles showed peripheral mixed neurogenic atrophy probably due to hypoxia. Major thickening of basal material was observed in capillaries of the endomysium and endoneurium. Statistical analysis of clinical parameters and respiratory function values in relation to the presence and importance of polyneuropathy showed that the only significant difference was the longer duration of hypoxia in patients with nerve involvement. Age, alcoholism and the other respiratory function values did not seem to be correlated with lesions of the peripheral nervous system.

Aged↗
PubMed1986

[Neuropathies and chronic respiratory insufficiency: electrophysiologic study].

In order to determine the frequency and the characteristics of neuropathies in chronic respiratory insufficiency, a systematic study of 43 patients affected by a chronic obstructive pulmonary disease was performed. In addition to neurological and electrophysiological examinations (including 6 nerve conduction studies on median, ulnar and peroneal nerves and EMG of 4 to 8 muscles), nerve and muscle biopsies (of the superficial peroneal nerve and lateral peroneus brevis muscle) were performed in 13 cases. Polyneuropathies were found in 74% patients: but mild in 39%, severe in 35%. Most were subclinical or poorly symptomatic. We determined the importance and distribution of abnormalities on the different nerves. From this we established that neuropathies are mixed but predominantly of the axonal type. Axonal degeneration and demyelination were confirmed by nerve biopsy; muscles presented neurogenic atrophy. Statistical analysis showed that the duration of hypoxemia was related to neuropathy. The pathogeny of these neuropathies is discussed.

Adult↗
PubMed1986

[Magnetic resonance imaging in multiple sclerosis. Sensitivity and correlation with the clinical picture].

The aim of imaging the brain in Multiple Sclerosis (MS) is to prove the dissemination of lesions, so critical for the diagnosis and so difficult to ascertain clinically. Our study included 21 patients with clinically definite (12) and probable (9) MS. A 21 patients underwent a neurological standard examination, a double-dose delayed CT scan and a Magnetic Resonance Imaging with a superconducting 0.5 Tesla magnet. Jointed slices were performed with a T2-weighted Spin-Echo sequence (TE 60, 120; TR 2000 msec). MRI detected 640 lesions in 20 patients while CT scan detected only 24 lesions in 9 patients. Technical limiting factors are discussed. Abnormalities in MRI were high-intense spots, blotches and streaks, located predominantly in the periventricular area. Capping lesions were common around the ventricular horns. "Plaques" were visualized in the posterior fossa. For each patient, the total surface of the lesions was calculated and was found to be related with the presence of lesions and with the cortical atrophy on CT scan. A correlation between the surface of lesions calculated by MRI and the disability scale was found especially in the group of patients with clinically proven cerebral lesions, while patients with predominantly spinal forms had a significantly lower surface of lesions. This finding could yield a new quantitative evaluation of the MS pathologic process which could be used to assess therapeutic efficacy.

Adult↗
PubMed1985

Effects of tiapride in tardive dyskinesia.

Tiapride, a selective D2 dopaminergic receptor blocking agent from the substituted benzamide class, was evaluated in a blind video-controlled trial in 10 psychiatric patients with tardive dyskinesia. There was a significant decrease in dyskinesia with a parallel increase in parkinsonism. This relationship between two opposite effects on movement suggests a common pathophysiological basis lying on a reciprocal hyper- and hypoactivity of the dopaminergic striatal system. Nevertheless, other mechanisms may be involved, for the evolution of individual parkinsonian and dyskinesia scores is not necessarily opposite: the tiapride-induced parkinsonism was generally acceptable and in two cases, the dyskinesia scores were reduced without an increase in parkinsonism. Therefore, more dyskinetic patients have to be evaluated in long-term studies with tiapride, before this drug could be recommended in tardive dyskinesia, when dyskinetic movements become intolerable.

Adult↗
PubMed1985

[Left anterior choroidal artery syndrome with language disorders and constructional apraxia].

The infarction in the territory of the anterior choroidal artery may induce a sensory motor impairment and neuropsychological symptoms close to those observed in some thalamic lesions. In a right handed man with a left sided infarction, language disturbances and constructional apraxia were observed. Cerebral blood flow measurements were performed 4 days after the stroke with the 133Xenon inhalation method. A decrease of mean hemispheric values was observed on both sides but more so on the left hemisphere, in the left frontoparietal regions. 98 days after the stroke language and constructional apraxia have partially improved. We have drawn a parallel between blood flow variations and neuropsychological signs. The cortical deafferentation caused by the interruption of the thalamo-cortical projections may explain the focalized decrease in cerebral blood flow values in the left hemisphere.

Adult↗
PubMed1984

[Paralysis of the hypoglossal nerve caused by 2 aneurysms and a dissecting aneurysm of the internal carotid artery].

Palsies of the lower cranial nerves caused by a compressive pathological carotid artery are not common. Three cases of paralysis of the hypoglossal nerve, hypoglossal and vagus, hypoglossal, glossopharyngeal and vagus nerves, are reported. In 2 patients the symptoms were related to an extracranial carotid artery aneurysm below the base of the skull and in 1 patient to a spontaneous carotid dissecting aneurysm. It is possible that some localized arterial dissecting aneurysms evolve to a localized aneurysmal sac, especially if they are located between Cl and the base of the skull. The tongue paralysis disappeared in 2 patients.

Adult↗
PubMed1983

[Electromyographic study of 4 lip muscles and acoustic findings in parkinsonian dysarthria].

The articulatory E.M.G. activity of lower lip muscles was investigated in 3 patients with Parkinson's disease and compared with normal subjects. Four paired muscles were recorded because of their antagonist function: 1) Orbicularis oris inferioris and depressor labii inferioris; 2) mentalis and buccinator. All patients evidenced well defined E.M.G. abnormalities. These consisted in the impairment of the functional organization of the antagonist muscles (lack of reciprocal inhibition), the existence of both a resting activity between utterances and a sustained hypertonic background activity during the utterance. This study was focused on the E.M.G. activity without concomitant observation of lip movement. Parallel oscillographic records of speech acoustic signals confirmed the characteristics of the voice of parkinsonian patients: low and uniform intensity, poor timbre, irregular speech rate and abnormalities of pitch.

Aged↗
PubMed1982

[Bromazepam in anxiety. Clinical evaluation (author's transl)].

In an open study, 30 patients with anxiety were treated with bromazepam 6 to 9 mg/day and followed-up for 15 days either as out-patients or in hospital. The results, assessed by anxiety scores, showed a 71,4% improvement, which was often perceptible as early as the third day of treatment. The best responses were obtained in patients who had not previously received anxiolytic drugs and in those who had less anxiety at the beginning of treatment. In two cases the drug was discontinued on account of daytime drowsiness.

Adolescent↗
PubMed1982

[Modification of extrapyramidal signs by apomorphine associated with various dopaminergic antagonists].

An acute administration of various doses of apomorphine, a dopaminergic agonist, and of dopaminergic receptor blockers (domperidone, sulpiride, haloperidol), was double-blindly achieved in a parkinsonian patient also suffering from dyskinesia. Apomorphine improved tremor and dyskinesia proportionnally to the dose. Domperidone did not prevent from this beneficial effect whereas sulpiride or haloperidol revealed a competitive antagonism versus apomorphine.

Aged↗
PubMed1979

Bromocriptine associated with a peripheral dopamine blocking agent in treatment of Parkinson's disease.

A peripheral dopaminergic blocking agent, domperidone (60 mg daily), or placebo was given, double-blind, to 17 parkinsonian patients who also received increasing doses of bromocriptine. Combined treatment with domperidone reduced total disability by 76% in 8 patients receiving a mean dose of 148 mg of bromocriptine daily. There was no vomiting and involuntary movements and psychic disturbances were similar to those in patients on levodopa and a peripheral decarboxylase inhibitor. In 9 patients taking placebo instead of domperidone, the average daily dose of bromocriptine could not be raised beyond 92 mg. The mean total disability score in this group was reduced by only 48%. Thus, peripheral blockade of dopamine receptors is a promising means of limiting the adverse side-effects of the treatment of parkinsonism with central dopaminergic receptor stimulating agents such as bromocriptine.

Adult↗
PubMedDate not supplied

Causal relation between alpha-synuclein gene duplication and familial Parkinson's disease.

The alpha-synuclein gene (SNCA) has been implicated in autosomal dominant forms of Parkinson's disease. We screened 119 individuals from families with this rare form of the disease for SNCA duplications by semiquantitative multiplex PCR. Two patients had duplications, which were confirmed by analysis of intragenic and flanking microsatellite markers. The phenotype in both patients was indistinguishable from idiopathic Parkinson's disease and no atypical features were present, by contrast with reports of families with triplication of the same gene. These results indicate that SNCA is more frequently associated with familial Parkinson's disease than previously thought, and that there is a clear dosage effect according to the number of supernumerary copies of this gene.

Adult↗
PubMedDate not supplied

Subthalamic stimulation for Parkinson's disease.

Deep brain stimulation by high frequency (HFS) has been developed starting in the thalamic target (Vim) from pragmatic observations and subsequently followed by other targets, such as the subthalamic nucleus (STN) and pallidum as an application of current knowledge from basic preclinical research in neuroscience. The mechanism involved by this neurosurgical approach is not completely solved. For Vim we have formed the hypothesis that HFS induces a jamming of sensory-motor loops but for the STN, from our experimental research in rats we have shown that HFS induces functional inhibition of cell activity in the target nuclei. In our patients the implantation of the stimulation electrodes was carried out stereotactically, under local anesthesia, using ventriculography, MRI, microrecordings and clinical evaluation of the effects of stimulation on rigidity. When the stimulation is turned ON in the STN area a significant decrease in rigidity was determined by the neurologists. Stimulation or even penetration of the electrode may be responsible for transient dyskinesias. The average location of the clinically efficient contact of the chronic stimulating electrodes is statistically located at 5.02 +/- 0.71 1/12 degrees of AC-PC in the AP direction, at -1.5 +/- 0.66 1/8 degrees of the height of the thalamus in the ventricle direction, with laterality at 11.98 +/- 1.12 mm in the lateral direction. The beneficial effects of STN stimulation are significant providing that the electrodes are correctly placed into the target. There is strong improvement of the symptoms of the triad in which akinesia, rigidity, and tremor are reduced on average to 41. 6, 48.6, and 27%, respectively, when compared with the previous preoperative level. From our experience, HFS of the STN could be considered the surgical therapy of choice at advanced stages of Parkinson's disease.

Electric Stimulation Therapy↗