PubMed Health⌕ Search

Biomedical subjects

C Van Nechel

Publications and source records attributed to C Van Nechel.

At least 19 recordsLinked to original sources
PubMed2002

[Central vestibular syndromes].

The aim of this topic is on one hand to pick out the semiological features which can quickly show the way of central nervous system lesions related to the vestibular system and on the other hand to describe these main central vestibular syndromes. A particular attention is carried to central otolithics syndromes which often remain undiagnosed. They induce imbalance, non rotatory vertigo, intolerance to linear acceleration and most often there is no nystagmus on examination. Neurophysiological diagram are restricted to a minimum useful to the clinician.

Diagnosis, Differential↗
PubMed2002

[Optic neuropathy in Strumpell-Lorrain disease: presentation of a clinical case and literature review].

This report describes a 36-year-old female with bilateral optic atrophy. Physical examination was normal except for subclinical signs of lower limbs spasticity. Her father was affected of Strumpell-Lorrain disease. The clinical characteristics of Hereditary Spastic Paraplegia or Strumpell-Lorrain disease are: progressive spasticity of the lower limbs and pathological reflexes. Pathologically, this disease is characterized by a degeneration or demyelinization of the cortico-spinal system and, to a lesser extent, of the posterior cord and the spino-cerebellar system. Optic neuropathy and dyschromatopsy have already been reported in a small group of patients. Visual acuity ranged from 20/20 to 20/200. Visual field alterations consisted of superior bitemporal amputation. Fundus examination showed optic atrophy. The incidence of optic neuropathy in Strumpell-Lorrain disease is quite high but its presence is often overlooked. Most patients are asymptomatic, but signs of optic nerve dysfunction are evident at clinical examination. According to some authors, there is an inverse relationship between the impairment of walking and the visual dysfunction. This was also noted in our case.

Adult↗
PubMed1998

Visual suppression of vestibular nystagmus.

The realisation of combined movements of the head and eyes requires the capacity to modulate the vestibulo-ocular reflex (VOR) but the absence of sufficiently rapid visual feed back results in an open loop function. This reflex must be modulated by other mechanisms. Two options are discussed. A modulation of the gain of the reflex loop is not satisfactory for small combined movements of the head and eyes as it would no longer permit the effective compensation for unexpected perturbations of movement of the head. An additive mechanism modifying the VOR through the addition of an other ocular movement is limited by the constrictions of latency, speed and amplitude of such movement. According to experimental conditions, varying complementary effect of the two mechanisms seems to result in maximum efficiency. This paper attempts to include the mechanism of the ocular fixation index (OFI) among the models of study. The OFI applied to a pendular test is, by the nature of its stimulus, more physiologic and more capable of being integrated into existing models. In the usual conditions of the test, the additive model is probably dominant with a preponderant role in the ocular pursuit system. But whatever may be the part of each mechanism, the OFI is not only dependent on the integrity of the floccular inhibition of the VOR but on the numerous cortical and subcortical structures involved in the realisation of voluntary ocular movements. This information should encourage clinicians to investigate the ocular movements of patients presenting vertigo, particularly those with visual instability on head movements.

Caloric Tests↗
PubMed1998

[Association of idiopathic intracranial hypertension-Arnold-Chiari deformity: danger!].

PURPOSE: The idiopathic intracranial hypertension (IIH) can lead to a fatal issue in presence of an Arnold-Chiari malformation (ACM). METHOD: We report the case of an obese pregnant woman presenting intracranial hypertension without cerebral CT scan anomaly. The situation worsened in spite of acetazolamide use: alteration of the neurologic state and the ocular motility. RESULTS: A magnetic resonance imaging (MRI) shows a type I ACM. The decompression of the cerebrospinal fluid by superior way is performed (pressure at 60 mmHg, normal composition) and followed by the neurosurgical cure of the Chiari. This allowed a total recuperation. CONCLUSION: The IIH can be responsible for the decompensation of an ACM. A MRI and a rapid neurosurgical surgery are the rules without lumbar puncture temptation which can be fatal.

Acetazolamide↗
PubMed1997

[Adaptation of the central nervous system to optical correction].

Wearing spectacles imply an adjustment of the visual perception and eye movements. The visual cortex accounts for this plasticity, including at the adulthood, especially by the shift or the sprading of the receptor fields and the adjustment of the sensitivity of the primary visual cortex cells to spatial orientation and movement. The cerebellum modulates the vestibulo-ocular reflex gain. The adjustment latencies range from a few minutes to several days according to the disturbancy severity, the drug interferences and the age and medical history of the subject. Neurotrophins seem to be essential for this adjustment and might become an efficient tool to extend the plasticity period.

Adaptation, Physiological↗
PubMed1996

[Internuclear bilateral pseudo-ophthalmoplegia and dermatomyositis].

A 60 year-old woman complaining of diplopia presents an ocular motility disturbance mimicking internuclear ophthalmoplegia. Idiopathic dermatomyositis is diagnosed by the help of clinical, biological, electrophysiological and histological data. The outcome is favorable under corticotherapy. Ocular muscle involvement is rare in dermatomyositis. An overlap syndrome with another auto-immune disorder like myasthenia should be excluded in this kind of manifestation.

Dermatomyositis↗
PubMed1994

[Is treatment with corticotherapy or radiotherapy effective for involvement of ocular motility and for reduction of exophthalmos in Basedow's disease?].

It is acknowledged that high-dose corticotherapy, radiotherapy, or surgical decompression of the orbit are often efficient in dysthyroid optic neuropathy. Corticotherapy and radiotherapy are also given to patients with dysfunction of eye-muscle motility and/or proptosis in the absence of visual loss. The latter indication has been retrospectively evaluated in 13 patients. The limited character of our series is partially explainable by strict inclusion criteria (objective evaluation of muscle dysfunction and proptosis). We failed to demonstrate any significant functional improvement after oral corticotherapy and/or radiotherapy. It thus appears that our study sheds doubt on the actual efficacy of these treatments in patients presenting with not very evolutive involvement of eye-muscle motility. A larger study aimed at comparing the benefits and drawbacks of these treatments is consequently to be encouraged.

Adult↗
PubMed1993

[Ophthalmological manifestations of infantile Refsum's disease: apropos of 3 cases].

We describe the ophthalmic manifestations of 3 cases of infantile Refsum's disease. The gravity and the aspect of the retinal disorders which we have observed by ophthalmoscopy and electroretinography were quite different from one case to another, including two siblings. We then go on to discuss the pathogeny and the genetic basis of diseases due to a deficiency of the peroxisomal biogenesis.

Adolescent↗
PubMed1993

Acetazolamide-responsive hereditary paroxysmal ataxia: report of a new family.

Five family members were examined because of occurrence since childhood of recurrent episodes characterized by vertigo, dysarthria and gait ataxia. Analysis of the pedigree was consistent with an autosomal dominant mode of inheritance. Though asymptomatic between attacks, all the patients presented on examination a gaze-evoked and rebound nystagmus associated with a saccadic pursuit, a deficient optokinetic response and an inability to suppress the horizontal oculo-vestibular reflex by fixation; hypermetric saccades and truncal ataxia were also present in most of them. A sixth family member, aged 6 years, was found to present a gaze-evoked nystagmus but was completely asymptomatic. Response of the attacks to acetazolamide therapy (250 mg twice a day) was assessed in two patients and was either partial or complete. A positron emission tomography (PET) study was realized between ataxic spells in one patient and demonstrated a decrease of glucose metabolism in the whole cerebellum, the inferior part of the temporal lobes and the thalami. These PET data as well as the detailed neuro-ophthalmological findings bring new informations about acetazolamide-responsive hereditary paroxysmal ataxia, a rare but probably often misdiagnosed and treatable disorder.

Acetazolamide↗
PubMed1990

[Severe myopia and restrictive disorders of ocular motility].

High myopia may produce a masquerade syndrome, exhibiting clinical findings similar to those found in endocrine ophthalmopathy. Several hypotheses have been proposed as an explanation: sixth nerve paresis, structural changes in oculomotor muscles, contact between elongated globes and the bones of the orbital apices. These hypotheses are discussed after the presentation of a case with electroneuro-oculographic and tomodensitometric findings.

Aged↗
PubMed1990

[Congenital fibrosis of thr ocular muscles: a diagnosis for several clinical pictures].

Case report of four members of a family presenting a congenital fibrosis syndrome. The first case has the typical presentation with bilateral ptosis, bilateral hypotrophic, variable horizontal deviation, and restricted ocular movements in all directions. The second case has a unilateral ptosis with Marcus Gunn phenomenon and bilateral restriction of elevation. In the third case, the condition is purely unilateral and associated with a sensorimotor neuropathy. A fourth member presents a unilateral ptosis. Three other members have a simple strabismus without any oculomotor anomaly.

Adult↗