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At least 19 recordsLinked to original sources
PubMed1979

[Electromyographic differential diagnosis in cases of abducens nerve paresis with nuclear or distal neurogenic sive myogenic origine (author's transl)].

Abducens nerve paresis may be of nuclear, of peripheral distal neurogenic origine, or is simulated by a myogenic weakness of abduction. Polygraphic emg analysis of the oculoauricularphenomenon (oap) permits a differentiation. In the emg, the oap proved to be a physiologic and constant automatic and always bilateral interaction between the hemolateral abducens nerve and both Nn. faciales with corresponding and obligatory coinnervation of the Mm. retroauricularis of the external ear. In case of medullary, nuclear or internuclear lesions, the oap is disturbed, instable, diminished or abolished, whereas in distal neurogenic or myogenic paresis, even in complete paralysis the oap is bilaterally well preserved.

Abducens Nerve↗
PubMed1979

Neural correlates of nystagmus in abducens nerve.

1. The firing rates of action potentials of abducens nerve single fibers were recorded in the cat's orbit during a variety of vestibular and optokinetic stimulations. 2. Comparison was made of the neural firing rates associated with agonist and antagonist responses during slow and fast components of vestibular and optokinetic nystagmus. It was found that the relationship between the motoneuron firing rates and the eye motion was independent of the reflex with which they were associated--vestibular or optokinetic, or the type of response--agonist or antagonist. No neurons were observed that responded only during the fast or only during the slow nystagmus phase. Motoneuron firing rates were proportional to both velocity and position of the eye in a ratio of 1 (spikes/s)/(deg/s) to 7.2 (spikes/s)/deg. The behavior of the motoneurons was compatible with the hypothesis that thier firing rates are sufficient to overcome both elastic and viscous forces by which the muscles and ligaments hold the eye in the orbit. 3. For low-frequency head rotations, eye displacement and neural responses showed a small phase angle difference. At higher frequencies, however, while the eyes maintained a fixed relationship to the head rotation, the neural responses showed an increasing phase lead. One component of this phase lead compensated for the phase lag introduced by the orbital mechanics. The other was modeled as a constant delay of approximately 70 ms, which may be accounted for by neuromuscular transmission and transduction.

Abducens Nerve↗
PubMed1977

Abducens nerve palsy as initial symptom of trigeminal schwannoma.

The insidious onset and slow progression of symptoms may cause delay in the recognition of trigeminal schwannomas. Two cases with abducens nerve palsy as an initial symptom are reported, in both of whom the tumour was growing mainly below and anterior to the intracavernous portion of the internal carotid artery. Early detection of clinical symptoms and thorough radiological investigations are important in the early diagnosis of these lesions.

Abducens Nerve↗
PubMed1977

Ophthalmoplegic migraine with persistent abducens nerve palsy.

A 27-year-old woman had been suffering from recurring episodes of left-sided migraine since the age of 5. When 14 years old, a diplopia on looking to the left followed each episode; its length progressed with time and eventually became permanent. On examination a left abducens palsy was found. Arteriography failed to reveal the presence of aneurysm or other vascular anomalies.

Abducens Nerve↗
PubMed1975

Unilateral hypoglossal nerve atrophy as a late complication of radiation therapy ofhead and neck carcinoma: a report of four cases and a review of the literature on peripheral and cranial nerve damages after radiation therapy.

The case histories of four patients who developed hemiatrophy of the tongue from 3 to9 years after a course of curative radiation therapy for carcinomas of the head and neck are presented. These patients subsequently followed for from 1 1/2 to 6 years withoutlocal recurrence of the tumor, distant metastasis, or involvement of other cranial nerves, indicative of only a unilateral hypoglossal nerve atrophy. A review of the literatureshowed that peripheral and cranial nerve damages after radiation therapy have been reported for the optic nerve, hypoglossal nerve, oculomotor nerve, abducens nerve, recurrent laryngeal nerve, brachial plexus nerves and peripheral nerves of the extremeties. Reviewof clinical and experimental data indicated that in most cases, the damages were probably caused by extensive connective tissue fibrosis around and infiltrating the nerve trunks. Three possible types of peripheral and cranial nerve damages after radiation therapy are identified.

Cranial Nerves↗
PubMed1978

Direct inhibitory synaptic linkage of pontomedullary reticular burst neurons with abducens motoneurons in the cat.

1. Unit spikes of burst neurons were extracellularly recorded in the pontomedullary reticular formation of the cat. These neurons were identified by their burst activity coincident with the quick inhibitory phase of the contralateral abducens nerve during vestibular nystagmus and their antidromic activation from the contralateral abducens nucleus. 2. When the extracellular field potentials in and near the abducens nucleus were triggered by spikes of a contralateral burs neuron, the averaged potential consisted of an early di- or triphasic spike and a late slow positive wave. The early spike was an action current caused by impulses conducting along the axon of the burst neuron. 3. The action potentials of a contralateral burst neuron. 3. The action potentials of a contralateral burst neuron were employed to trigger a post-spike average of the membrane potential of abducens motoneurons. Then unitary IPSPs with monosynaptic latencies were revealed. This provided direct evidence that the burst neurons are inhibitory in nature. The amplitudes of unitary IPSPs ranged from 18 to 220 mu V. Each inhibitory burst neuron branched widely in the abducens nucleus and was estimated to make inhibitory connections with approximately 60% of the motoneuron pool. 4. The post-spike average of compound potentials of the abducens nerve triggered by action potentials of contralateral single inhibitory burst neurons revealed inhibition of spike activity with latencies and time courses compatible with those of unitary IPSPs in motoneurons. The inhibition was observed with all inhibitory burst neurons tested.

Abducens Nerve↗
PubMed1979

[Ophthalmomimics. Polygraphic EMG study on oculo-facial simultaneous movements and functions of the autochthonous ear muscles].

Ophthalmomimic is the interaction between the extraocular eye muscles and the mimic muscles. Beside their original phylogenetic assisting function in looking and hearing, the ophthalmomimic muscles now serve in psychological communication: The play with the white of the eye ball can be interpreted as devotion ("to turn a blind eye to"); attention ("to be all eyes"); caution ("to have small eyes and to prick up one's ears"). Further on are examined function and innervation of the involuntary M. retro-auricularis (M. transversus auriculae) of the external ear, so far neglected. Practical diagnostic use could be shown, among others, in early ocular forms of myasthenic syndromes and by the help of the oculoauricular phenomenon for the differentiation between nuclear and peripheral-distal pareses of the abducens nerve.

Abducens Nerve↗
PubMed1978

[Electrophysiology of vestibulo-ocular reflexes].

Electrophysiological and morphological properties of premotor neurones in the vestibulo-ocular system have been studied intracellularly in the unanesthetized "encéphale isolé" cat. 1. Secondary neurones of the vestibulo-abducens reflex, identified both by their antidromic and orthodromic responses, showed no nystagmic modulation of their activity. 2. Only 12% of the recorded population in the medial vestibular nucleus showed burst firing patterns correlated with the phases of nystagmus. 3. Two classes of neurones which did not respond to stimulation of the abducens nerve were recorded in the abducens nucleus. The first were inhibited by phasic vestibular stimulation and fired 180 degrees out of phase with the ipsalateral motor nerve discharge. The second type of neurones was excited by vestibular stimulation and fired in synchrony with the motor nerve activity.

Abducens Nerve↗
PubMed1976

Bilateral sixth nerve palsy. Analysis of 125 cases.

Bilateral abducens nerve pareses were nearly as common as unilateral cases in an inpatient setting (125:143). Cerebrospinal fluid abnormalities were more frequent among the bilateral cases, but generally the same causes produced unilateral and bilateral sixth nerve palsy. The relative ease of diagnosis was in contrast with the large number of undiagnosed or "vascular" cases in previous studies of outpatients. The degree of lateral rectus limitation proved to be of limited help in suggesting the cause or predicting recovery of oculomotor function. The etiology was of some prognostic value, with universal recovery of pressure palsies and rare improvement with tumor involvement. Myasthenia, orbital muscle entrapment, convergence spasm, divergence palsy, and pretectal pseudoconvergence entered into the differential diagnosis, but were only occasionally difficult to exclude.

Adult↗
PubMed1978

Retrolabyrinthine approach: technique and newer indications.

Excellent exposure of the cerebellopontine angle is obtained by an approach through the mastoid posterior to the labyrinth. Since the major portion of the dissection is extradural, this approach is associated with a very low morbidity. The retrolabyrinthine approach has been used for several years for selective partial section of the posterior root of the trigeminal nerve in cases of trigeminal neuralgia. Complete relief of pain has been accomplished in 25 of 28 cases, and the other 3 patients had partial relief of pain. The only complications in these patients were partial hearing impairment in 2, and 1 partial abducens nerve paralysis which subsequently recovered completely. Two patients required secondary closure of cerebrospinal fluid leaks. This approach has also been used for exploration and biopsy of cerebellopontine angle tumors and for treatment of other cranial nerve problems. We conclude that the retrolabyrinthine approach is the preferred route to the cerebellopontine angle in a variety of clinical conditions.

Abducens Nerve↗
PubMed1978

The sphenoid sinus, the neglected nasal sinus.

O. E. Van Alyea stated that "The sphenoid sinus is the most neglected of the nasal sinuses." It is neglected by disease because of its location, by the physician because of its subtle symptoms when diseased, and the surgeon because of its inaccessability. An accurate knowledge and understanding of the anatomy of the area help the physician diagnose and manage problems in this area. Eleven cases are used to illustrate the wide spectrum of pathologic conditions in and about the sphenoid sinus. Only two of the patients were asymptomatic. All of the others had deep-seated, retrobulbar headaches. Eight of 11 patients had cranial nerve involvement. The optic nerve was involved in six cases. The abducens nerve was involved in five of 11 cases and the maxillary nerve in four of 11 cases. Initial roentgenographic examination must include lateral and submental vertex views. The newer techniques of angiography, polytomography, and computerized tomography aid in determining the extent of the pathologic condition and the treatment approach.

Aged↗
PubMed1979

The incidence of complications during pregnancy after treatment of hyperprolactinemia with bromocriptine in patients with radiologically evident pituitary tumors.

The course of pregnancy achieved after bromocriptine therapy is described in nine patients with radiologically evident prolactin-secreting pituitary tumors. In six patients no complications occurred. No changes in sellar size or secondary endocrine deficiencies developed. In three patients, however, complications developed between the 22nd and 24th weeks of pregnancy. Despite prior external pituitary irradiation, one patient developed transient bitemporal hemianopsia and one patient had apoplexy of the pituitary tumor with transient paresis of the left abducens nerve. A third patient developed parasellar expansion of the pituitary tumor with bone destruction and paresis of the right abducens and oculomotor nerves. After transsphenoidal surgery the paresis of both nerves disappeared. Microscopically, the tissue removed at surgery was a chromophobe adenoma with focal fibrosis and calcifications without recent hemorrhages. In the course of more than 100 pregnancies achieved in The Netherlands after bromocriptine therapy, five patients reportedly developed complications of the pituitary tumor. At present, patients in whom complications can be expected cannot be predicted by the size or configuration of the sella turicica or the magnitude of elevation of the plasma prolactin level. In two patients external pituitary irradiation did not prevent complications during pregnancy.

Adult↗
PubMed1979

[Lumbar myelography with methylglucamine-iocarmate (dimer-x). A critical review of neurological complications (author's transl)].

A critical literature review is presented on the basis of our own clinical experiences with complications and distressing side effects of the lumbar Dimer-X myelography. Severe Complications such as spinal and conuscauda-symptoms, epileptic seizures, amnestic episodes and late palsies of the Abducens nerve in literature range between 1 and 9%. Unspecific side effects which cannot clearly be differentiated from pure post-lumbal puncture complaints are reported to occur in up to 28%. The probably underlying pathogenetic mechanisms are discussed together with former animal experiments which revealed a local toxity of the contrast medium at the central nervous tissue and the surrounding membranes.

Abducens Nerve↗
PubMed1979

Accessory abducens nucleus and its relationship to the accessory facial and posterior trigeminal nuclei in cat.

Retrograde transport of HRP by the abducens nerve results in the labelling of its principal nucleus and, in addition, a second nucleus about 2.5 mm ventrolateral to the principal nucleus. The presence of this second or accessory nucleus of the abducens in a mammal confirms the observations of several Nineteenth Century anatomists and rebuts the conclusions of more recent investigators who argued that the nucleus was allied instead to the facial or trigeminal nerves. The same HRP technique applied to the facial or trigeminal nerves shows that the accessory nucleus of the abducens is in the same parasagittal plane as the accessory nucleus of the facial nerve and the most caudal cells of the motor trigeminal nucleus. The accessory abducens and accessory facial nuclei fall in a ventrocaudal to dorsorostral line between the principal nucleus of the facial and the motor nucleus of the trigeminal with the accessory abducens just caudal and ventral to the accessory facial.

Abducens Nerve↗
PubMed1977

The dorsomedial nuclear group of cranial nerves in the frog.

The dorsomedial motor nuclei were demonstrated by the cobalt-labeling technique applied to the so-called somatic motor cranial nerves. The motoneurons constituting these nuclei are oval-shaped and smaller than the motoneurons in the ventrolateral motor nuclei. They give rise to ventral and dorsal dendrite groups which have extensive arborization areas. A dorsolateral cell group in the rostral three quarters of the oculomotorius nucleus innervates ipsilateral eye muscles (m.obl.inf., m.rect.inf., m.rect.med.) and a ventromedial cell group innervates the contralateral m. rectus superior. Ipsilateral axons originate from ventral dendrites, contralateral axons emerge from the medial aspect of cell bodies, or from dorsal dendrites, and form a "knee" as they turn around the nucleus on their way to join the ipsilateral axons. A few labeled small cells found dorsal and lateral to the main nucleus in the central gray matter are regarded as representing the nucleus of Edinger-Westphal. The trochlearis nucleus is continuous with the ventromedial cell group of the oculomotorius nucleus. The axons originate in dorsal dendrites, run dorsally along the border of the gray matter and pierce the velum medullare on the contralateral side. A compact dendritic bundle of oculomotorius neurons traverse the nucleus, and side branches appear to be in close apposition to the trochlearis neurons. A dorsomedial and a ventrolateral cell group becomes labeled via the abducens nerve. The former supplies the m. rectus lateralis, while the latter corresponds to the accessorius abducens nucleus which innervates the mm. rectractores. Neurons in this latter nucleus are large and multipolar, resembling the neurons in the ventrolateral motor nuclei. Their axons originate from dorsal dendrites and form a "knee" around the dorsomedial aspect of the abducens nucleus. Cobalt applied to the hypoglossus nerve reaches a dorsomedial cell group (the nucleus proper), spinal motoneurons and sympathetic preganglionic neurons. Of the dorsomedial motor cells, the hypoglossus neurons are the largest, and a branch of their ventral dendrites terminates on the contralateral side. Some functional and developmental biological aspects of the morphological findings, such as the crossing axons and the peculiar morphology of the accessory abducens nucleus, are discussed.

Abducens Nerve↗