Pontine lesion of the abducens fasciculus producing so-called posterior internuclear ophthalmoplegia.
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Abducens Nerve↗
Biomedical subjects
R L Oliveri
Publications and source records attributed to R L Oliveri.
Functional preservation of benzodiazepine receptors of the primary somatosensory cortex in Creutzfeldt-Jakob disease: a pharmacologic-evoked potential study.
In previous studies, we demonstrated that the benzodiazepine (BZP) receptors of the visual system are functionally preserved in Creutzfeldt-Jakob disease (CJD). We hypothesized that such a functional preservation is not confined to the visual system. In a 74-year-old woman suffering from CJD, three consecutive recording sessions of somatosensory cortical evoked potentials (SEPs) by right median nerve stimulation were carried out: (a) basal condition, without any pharmacologic treatment; (b) 1 min after i.v. administration of 10 mg diazepam (DZP); (c) 2.5 min after i.v. administration of 3 mg FMZ, a high-affinity receptor benzodiazepine antagonist. DZP greatly decreased the amplitude of SEP early components, whereas flumazenil (FMZ) reversed such an effect. The results of this study, paralleling our previous findings on the visual system in CJD, demonstrated functional preservation of BZP receptors in the somatosensory pathways as well.
Aged↗
Photic-induced epileptic negative myoclonus: a case report.
We present the first documented case of photic-induced epileptic negative myoclonus. A 17-year-old girl had experienced two generalized tonic-clonic seizures (GTCS) while watching television. The only EEG abnormality was a photoparoxysmal response (PPR), which was sometimes accompanied by loss of postural tone in both arms. Valproate was effective in abolishing photosensitivity. Negative myoclonus should be included among the ictal phenomena accompanying PPR.
Adolescent↗
Autosomal recessive hereditary motor and sensory neuropathy with focally folded myelin sheaths: clinical, electrophysiologic, and genetic aspects of a large family.
We describe 10 patients from a large family with early onset motor and sensory neuropathy. Six were still living at the time of the study. In all cases, early motor milestones had been achieved. Mean age at onset of symptoms was 34 months; these included progressive distal and proximal muscle weakness of lower limbs. Pes equinovarus developed in all patients during childhood. Slight facial weakness was present in four patients, and one of them also had bilateral facial synkinesia. Intellectual function was normal in all cases. There was no evidence of thickened peripheral nerves. All three adult patients (mean age, 27 years) were seriously handicapped and wheelchair-bound. Death occurred in the fourth to fifth decade of life and the duration of the illness varied from 27 to 39 years. Motor nerve conduction velocities ranged from 15 to 17 m/sec in the upper limbs of the youngest patients, and were undetectable in the adult patients. Sensitive action potentials were almost always absent. In all patients, auditory evoked potentials showed abnormally delayed interpeak I-III latencies. The most prominent pathologic finding was a highly unusual myelin abnormality consisting of irregular redundant loops and folding of the myelin sheath. The genealogic study gave strong evidence of autosomal-recessive inheritance. The molecular analysis failed to demonstrate either duplication in the chromosome 17p11.2-12, point mutations in the four exons of the PMP-22 (17p11.2) and the six exons of the Po (1q21-q25) genes, or linkage to chromosome 8q13-21.1.
Adult↗
De novo epileptic confusional status in a patient with cobalamin deficiency.
A 80-year-old man with cobalamin deficiency and no history of epilepsy developed a partial complex epileptic confusional status (ECS) unresponsive to acute i.v. diazepam. Brain CT scan and MRI investigation ruled out a focal cerebral lesion. Therapy with high doses (10,000 micrograms i.m. daily) of cobalamin alone was started, and the patient fully recovered in the following 72-hour. Control EEGs repeatedly performed days and weeks later showed progressive disappearance of the frontal interictal spiking, while the patient was on monotherapy with cobalamin (5,000 micrograms i.m. weekly). A month later the patient unfortunately discontinued replacement therapy and 13 weeks later he developed a fatal convulsive epileptic status. To our knowledge the association of ECS and cobalamin deficiency has not been previously reported.
Aged↗
Functional integrity of benzodiazepine receptors of the geniculo-striate visual pathways in Creutzfeldt-Jakob disease. A pharmacological evoked potential study.
We evaluated the effects of flumazenil (FMZ), a high-affinity benzodiazepine receptor antagonist, on flash-evoked visual potentials (FEPs) in a patient with Creutzfeldt-Jacob disease (CJD). FEPs were recorded in three different consecutive sessions: (1) basal condition, without any pharmacological treatment; (2) 3.5 min after i.v. administration of 5 mg FMZ; (3) 1 min after i.v. administration of 10 mg diazepam (DZP). FMZ provoked a marked increase in the amplitude as well as evident shortening of the latency of early FEP components. DZP reversed these effects. These results are in agreement with our previous findings of anatomical and functional integrity of the geniculo-striate pathways in human CJD and demonstrate functional integrity of benzodiazepine receptors in this visual system in CJD.
Creutzfeldt-Jakob Syndrome↗
Triphasic waves and cerebral tumors.
Three patients with cerebral tumor involving diencephalic midline structures (2 malignant gliomas, 1 craniopharyngioma) and no metabolic abnormalities developed disorientation in time and place or coma with triphasic waves (TW) seen on electroencephalograms. Serial EEG recordings showed persistence or disappearance of TW depending on poor or good outcome of the antiedema treatment. TW have been described with disorders affecting the brain diffusely, as metabolic encephalopathies, dementing processes, cerebral carcinomatosis and baclofen intoxication. The findings described here demonstrate that TW may occur in patients with brain tumor involving subcortical midline structures.
Aged↗
Sensory evoked potentials in Creutzfeldt-Jakob disease.
Eight patients presenting with intermediate or terminal evolution of Creutzfeldt-Jakob disease (CJD) were investigated by means of evoked potentials. Fifteen age-matched healthy subjects served as controls. The 8 patients had well-recognizable but simplified flash evoked potentials (FEPs) consisting of P1 and N2 waves followed by a single late positive (P2) deflection. Enlarged FEPs were found in 2 of the 8 patients. The somatosensory central conduction time was normal in 3 of 5 patients, and it resulted in upper normal limits or was moderately slowed in 2 patients. No enlarged somatosensory scalp potentials were recorded. Cortical somatosensory responses were characterized by an unrecognizable (4 patients) or delayed (2 patients) N33 wave. Brainstem auditory evoked responses, recorded in 6 patients, were normal. In CJD very important functional impairment of the sensory cortical areas is associated with absent or mild dysfunction of the subcortical sensory pathways.
Acoustic Stimulation↗
Nonmetabolic causes of triphasic waves: a reappraisal.
Two more patients with triphasic waves (TW) on their EEGs in the absence of metabolic disturbances are described. One patient had coma associated with cerebellar hematoma, the other had mild dementia associated with idiopathic calcifications of the basal ganglia and normal auditory brainstem responses, subcortical and cortical somatosensory evoked potentials. Neurologic examination failed to show asterixis in both patients. The literature on nonmetabolic causes of TW was also reviewed, and the clinical and anatomic reports of 10 patients have been analyzed: 7 patients had focal brainstem-diencephalic lesions (craniopharyngioma: 2 patients; thalamic gliomas: 3 patients; pontine stroke: 2 patients), and 3 patients suffered from diffuse subcortical or multifocal encephalopathies (Binswanger's encephalopathy: 1 patient; cerebral carcinomatosis: 1 patient; multifocal cerebral lymphoma: 1 patient). From the clinical point of view, patients with nonmetabolic diseases causing TW presented either disturbance of higher cerebral functions with no asterixis or sudden onset of coma. It is concluded that TW may result from focal brainstem/diencephalic lesions or from diffuse subcortical or multifocal encephalopathies in the absence of concomitant metabolic abnormalities. Nonmetabolic causes of TW should be suspected in patients presenting with neurologic disturbances not associated with asterixis.
Aged↗
Purulent meningitis due to spontaneous anterior sacral meningocele perforation. Case report.
A 36 year old woman with anterior sacral meningocele developed a purulent meningitis secondary to the rupture of the meningeal sac into the rectum. The value of neuroradialogical studies, especially CT, is emphasized.
Adult↗
Combined neurophysiological studies in Creutzfeldt-Jakob disease: a case report.
EEG and brain mapping (on basal conditions and after i.v. administration of diazepam) and visual, somatosensory and auditory evoked potentials have been performed on a patient at terminal evolution of CJD. These combined neurophysiologic studies indicated that very important functional impairments of either thalamic-frontal circuits and frontal, parietal and occipital cortex were associated with absent or mild dysfunction of the visual, somatosensory and auditory subcortical pathways. Combined neurophysiologic studies are important to better understand the pathophysiologic mechanisms of neurodegenerative diseases.
Aged↗
Computerized analysis of eye movements as a function of age.
Vertical and horizontal saccadic (SEMv, SEMh) and smooth pursuit eye movements (SPEM) were recorded in 66 normal subjects of different ages using a computerized system. No difference was found in SEMh recordings for the right versus the left eye or for gaze direction. In contrast, SEMv recordings of upgaze vs. downgaze showed a significant difference in performance index (peak velocity) and delay. SEMh and SEMv performance index and delay were significantly slowed in elderly subjects, although accuracy was not affected. SPEM analysis also revealed a decrease in velocity in elderly people indicating diminished tracking ability as a result of the aging process. These data suggest that senescence may influence some SEM and SPEM parameters. We thus emphasize the usefulness of having reliable normative data corrected for age.
Journal Article↗