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At least 1,531 records · Page 85Linked to original sources
PubMed1981

Diagnostic advantages of the Torok monothermal differential caloric test.

In the Torok monothermal differential caloric test, each ear is irrigated with 10 ml and 100 ml of water at 20 degrees C in 5 and 20 sec., respectively. The intensity of the induced nystagmus is expressed in terms of frequency at culmination. The ratio between the weak and strong caloric responses may be normal of disproportionately large or small. When large, the ratio exceeds 3.5 and is called vestibular decruitment, a sign of labyrinthine disease. A ratio of 1.1 or less is called vestibular decruitment, a sign indicative of posterior fossa abnormality. Of 54 patients showing decruitment, a central lesion was confirmed in 51, an identification rate of 94%. The test is thus valuable in differentiating labyrinthine from retrolabyrinthine lesions.

Adult↗
PubMedDate not supplied

Postural stability and rotational tests: their effectiveness for screening dizzy patients.

Results of independently interpreted computerized stationary platform posturography and white noise rotational tests were compared with diagnoses for 110 patients. Using the criterion that an abnormal result from either test classified the subject as abnormal, the sensitivity estimate for the pair of tests was 78% for persons with diagnoses known to result in vestibular dysfunction. The specificity estimate was 90%. Both a vestibulo-ocular and a vestibulo-spinal test were required for effective screening. Consecutive tests performed over five days showed the rotation test to be much less variable than posturography. Rotation testing is therefore preferred for following the performance of patients having disorders thought to cause fluctuating vestibular systems. Interobserver reliability rates were 83% for posturography and 93% for rotation tests.

Adult↗
PubMedDate not supplied

Active head turning and correlated cerebral potentials. Experimental and clinical aspects.

Fast voluntary horizontal head movements (n = 400, maximum acceleration 8,500 deg/sec2) were recorded together with surface EEG over pre- and post-central regions in 30 healthy volunteers while they were gazing at a head-fixed target in darkness. Artifacts of mechanical, myogenic and oculomotor origin could be precluded. Selective averaging of the fastest movements revealed a biphasic cortical potential. Median latency of its onset was 123.5 msec, of its first peak 189 msec, of the second peak 373 msec, with amplitudes ranging around 5.7 microV. Similar recordings in patients with uni- or bilateral vestibular nerve lesions demonstrated that strong stimulation of the joint vestibular and somatosensory (neck afferent) input facilitated characteristically related EEG activity: side differences of vestibular input could be measured on this level of the CNS, i.e. measured on the cortical level as additional information to the commonly used vestibulo-oculomotor response; patients with early, bilateral loss of vestibular functions showed a specific long-term adaptation of their related EEC activity. We conclude that clinical studies of this kind might aid in diagnosis of vertigo and related phenomena.

Adult↗
PubMedDate not supplied

Nonlinearity and asymmetry in the human vestibulo-ocular reflex.

The horizontal vestibulo-ocular reflex was studied in normal and unilaterally vestibulopathic human subjects; the latter before and after surgical vestibular ablation. Subjects were oscillated at 0.025-4 Hz, 50 o/s peak head velocity, and for 0.025 and 0.25 Hz, at 50-300 o/s peak head velocity. Gain (peak eye/head velocities), phase (delay in degrees between peak eye and head velocities), and asymmetry (including d.c. bias; the average eye velocity over the cycle) were assessed for each rotation. In patients preoperatively, gain was subnormal while phase lead was greater than normal only at lowest frequencies. As head velocity increased at 0.025 and 0.25 Hz, gain dropped in patients, but not in normals. Furthermore, d.c. bias at 0.25 Hz tended to shift abnormally toward the lesioned side in most patients. After surgery, gain dropped and phase lead rose for all stimuli, but showed varied recovery over 4 months. d.c. bias also rose after surgery, and showed an enhancement with increasing head velocity at 0.25 Hz. d.c. bias remained unchanged even after 4 months for 300 o/s rotations, but disappeared at low head velocity. d.c. bias (and other asymmetry measures) represents a lateralizing sign which can be improved by utilizing high head velocities at moderate frequencies.

Adult↗
PubMed1976

Directional hearing, temporal order and auditory pattern in peripheral and brain stem lesions.

Tests have been applied to the following subjects: (1) 25 normal individuals; (2) the same individuals during temporary impairement of the brain stem by barbiturate (3 mg/kg); (3) 32 patients affected by acute nucleo-reticular vestibular syndrome; (4) 7 patients affected by unilateral Menière's disease, and (5) 1 patient affected by acoustic neuroma with well preserved hearing. Directional hearing was tested by changing the delta i and delta t of two pure tones 400 and 600 Hz) presented through earphones or two fixed loudspeakers placed at +/- 30 degrees from the azimuth and with balanced intensity: temporal order and auditory patterns were tested with the same frequencies by changing the delta t or the order of presentation of the stimuli at fixed intensity. On the basis of the results obtained in the normal subjects, a distinction can be made between the patients affected by brain stem impairment and those affected by Menière's disease. In these patients it was very difficult to obtain reliable discriminations due to the failure of the affected cochlea, especially during an acute phase of the disease, to perform adequate time, intensity and frequency analysis. In brain stem patients, spontaneous or pharmacological, the directional hearing judgments were impaired whereas temporal order and auditory pattern discrimination were normal. It is suggested, therefore, that these various central-hearing tests do not investigate analogous performances, but on the contrary different ones. This difference can be attributed to different structures, or to different performance along the same pathways but also to an identical structure of different sensitivity to the noxious agents.

Auditory Pathways↗
PubMed2002

Pharmacologic treatment of inner ear: from basic science to the patient.

Most of the deafness are of sensorineural origin and are characterized by a loss of hair cells and of spiral ganglion neurons. At the present time, hearing aids are the only treatment. However, in some diseases of the inner ear, pharmacological treatment have been proposed and used successfully. In this paper, we will review some basic science aspects of the biology of the neurosensory structures of the inner ear, in particular of the auditory neurons, that lead to the rationale of some treatments for the inner ear diseases. Developmental studies, neuronal cell culture experiments, and analyses of gene knockout animals reveal a number of growth factors which are important for the rescue and repair of injured auditory neurons in the inner ear. These factors rescue the injured auditory neurons in vivo. Furthermore, perfusion of antioxydant to the cochlea prevented the hearing loss induced by cisplatin. These in vitro and in vivo experiments demonstrate that it is possible to manipulate the neurosensory structures of the inner ear and provide an effective treatment to prevent the degeneration of the neurons. The molecules or drugs can be administered locally to the inner ear through a direct perilymphatic perfusion or through the round window membrane. As an example, we will discuss the treatment of patients suffering from idiopathic sensorineural hearing loss which can be treated successfully by a perfusion through the round window membrane, improving their hearing threshold and their speech discrimination.

Animals↗
PubMed1975

[Acute unilateral peripheral vestibular upset in herpes simplex infection (author's transl)].

Report on a sudden peripheral vestibular upset 8 days after a serologically evidenced herpes simplex infection. Reference to the significance of virological-serological examinations in any cases of acute vestibular upset, sudden deafness and peripheral facial palsy. Discussion of etiology, pathology and probable localization of this affection, about which medical literature does not contain any relevant observations made in connection with herpes simplex infection. Electronystagmographic control of the course of the disease, demonstrating the complete restitution of the vestibular organ. Thus, justified assumption of rather a peripheral vestibular lesion.

Acute Disease↗
PubMed1975

[Hearing alterations in vertebro-basilar insufficiency (author's transl)].

The morphological facts are represented, to see hearing alterations as a possible consequence of vertebro-basilar insufficiency. The conception: "vertebro-basilar insufficiency" is defined. Compared to vestibular disturbances cochlear disturbances in vertebro-basilar insufficiency are extremely rare. Always we find sensorineural hearing loss or complete unilateral deafness, most combined with tinnitus. All publications we got reported, only 4 from otologists. The conception "sudden deafness" is defined by differential diagnosis. The vertebro-basilar insufficiency, secured by arteriographical or neurological examinations, is not the same as a syndrome of cervical spine with effects to the vertebro-basilar artery system, except the pathogenesis of this syndrom is evident. But this evidence is not given till now.

Audiometry↗
PubMed2005

Occult otologic fistulas as a cause of recurrent meningitis.

OBJECTIVE: Occult perilymph fistulas may be the cause of unexplained non-epidemic meningitis. MATERIAL AND METHOD: To review the case reports of 5 patients (3 females and 2 males aged 4-56) presenting with unexplained meningitis. All had sensorineural hearing loss of variable duration. RESULTS: All patients were submitted to CT, MRI and MRI cisternography. All underwent exploratory tympanotomy to seal the fistula. In all patients the fistula could be located and sealed. All had no further attacks of meningitis and those who had serviceable hearing did not show any further deterioration. CONCLUSION: In any case of recurrent meningitis an occult perilymph leak should be sought. A high degree of suspicion should exist if there are auditory or vestibular symptoms. Detecting and sealing of the defect will protect the patient against further attacks and deterioration of hearing.

Adult↗
PubMed1992

Immunohistochemical analysis of otic capsule osteogenesis in the Palmerston North autoimmune mouse.

Autoimmunity and the immune complex disease associated with it have been hypothesized to be the cause of several idiopathic diseases of the inner ear--including the new bone formation associated with otic capsule osteogenesis and otosclerosis. The Palmerston North (PN) autoimmune mouse strain, which exhibits both spontaneous systemic autoimmune disease and otic capsule bone formation, has been proposed as a model relating these two disease processes. To investigate the potential role of immunopathologic processes in PN otic capsule lesion formation, inner ears from PN mice were immunostained for the presence of IgG and complement (C3), two immunologic markers involved in the development of the vascular and perivascular changes associated with immune complex deposition. Both systemic autoimmune disease and otic capsule bony lesions were confirmed in all animals. However, immunohistochemical analyses did not establish a direct relationship between the two conditions as complement was absent in all lesions and IgG stained positive in only one instance. These results suggest that immune complex deposition is not directly involved in the otic capsule lesions of the PN mouse, and alternate mechanisms relating autoimmune disease and otic capsule osteogenesis must be explored.

Animals↗
PubMed1991

[Experimental research on vestibular compensation using posturography].

Vestibular compensation is a representation of nervous system plasticity which manifests as a gradual recovery of equilibrium function both in vestibulo-spinal system and vestibulo-oculomotor system. In order to assess whether the vestibular compensation is a homogeneous process among the different reflexes, the Authors have studied two groups of subjects affected by peripheral or central lesion. The development of the vestibular compensation has been evaluated by the rotation and posturographic tests. The results demonstrate a constant correlation between rotation and stabilometric parameters in the patients suffering from peripheral dizziness while there isn't any correlation between acceleratory and posturographic tests in patients affected by central vertigo. These results demonstrate that the compensation develops at the different levels of the balance function in a very different and independent way and that comparison of the rotation and posturographic patterns may be useful to establish the peripheral or central site of the lesions.

Adult↗
PubMed1991

Visually-induced sickness in normal and bilaterally labyrinthine-defective subjects.

A group of nine normal subjects (with no overt vestibular dysfunction) and a group of 6 bilaterally labyrinthine-defective subjects were exposed to a visual field rotating about an Earth-horizontal axis (orthogonal to the gravity axis). The visual stimulus was provided by a 3-m diameter sphere with random dots rotating at 30, 45, and 60 degrees per second (degree/s) about the stationary subject's roll, pitch and yaw axes. The subject's head was positioned at the center of the sphere such that it experienced apparent motion in all three axes. Results indicated that in the normal group, symptoms of motion sickness were reported in 21 of 27 test-trials. When labyrinthine-defective subjects were exposed to the roll and pitch stimulus, no sickness symptoms were reported or observed. These results strongly suggest that the vestibular system is necessary for sickness induced by moving visual fields.

Adult↗
PubMed1989

Vascular dizziness and transcranial Doppler ultrasonography.

Dizziness as defined herein will include an illusion of motion caused by various degrees of ischemia to the vestibular pathway or its interconnecting pathways. "Syndrome," such as the lateral medullary syndrome, denotes a macroinfarct, while a microinfarct or an area of incomplete infarct (where there may develop an incomplete degeneration of the neural tissue secondary to the arteriolar microatheromatous stenosis) may cause only one neurologic deficit, such as dizziness per se as the only symptom. However, the latter may presage a larger and more debilitating neurologic deficit. The transcranial Doppler, used to track sequentially the larger basal arteries of the brain, specifically the vertebrobasilar arterial system, is an addition to noninvasive diagnostic methods of separating vascular problems from other causes of dizziness.

Cerebrovascular Circulation↗
PubMed1989

Preservation of hearing in cholesteatomas with inner ear invasion.

Two cases of inner ear destruction by cholesteatoma are presented. There was total demineralization of the cochlea in one and significant vestibular destruction in the other. Eradication and exteriorization of the disease was accomplished with preservation of hearing in both cases. Safe management was enhanced by aggressive infection control and accurate surgical planning aided by current imaging techniques. The factors which protect auditory function in these lesions remain unclear. However, the site and extent of the disease as well as local tissue reaction leading to separation of the inflammatory process from the sensory epithelium appear to play a significant role in preservation of hearing despite the presence of invasive, destructive disease.

Adult↗