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At least 1,063 records · Page 59Linked to original sources
PubMed1979

Neurotological diagnosis of vestibular disorders in children.

The most marked findings in a group of 66 children were a spontaneous nystagmus presenting in 29% of the cases, and an abnormal caloric reaction in 40%. For qualitative and quantitative assessments of the positional test and caloric stimulation, at our University ENT department at Erlangen we use the positiogram and frequency calorigram described here, which are particularly suitable for follow-up observations and for the purpose of providing an expert medical opinion.

Adolescent↗
PubMed1987

Rapidly fluctuating thresholds at the onset of experimentally-induced hydrops in the guinea pig.

Pigmented guinea pigs were chronically implanted bilaterally with a platinum electrode on each round window. After recovery the endolymphatic sac was destroyed and the duct blocked on one side only; the other side was employed as a control. The round window response thresholds on both sides were recorded several times per week over a three month period. There were three main results. A sensitivity loss of up to 20 dB was observed for frequencies between 250 Hz and 6.4 kHz within two weeks post-op. At the end of three months the threshold elevation for these frequencies was as much as 50 dB. On the other hand the thresholds for frequencies between 8 and 16 kHz remained within 10 dB of their pre-operative value for at least two months. The thresholds fluctuated with a shift of as much as 25 dB within 24 h. The threshold elevation was associated with a decrease in the latency, at threshold, of the round window AP response which at frequencies between 250 Hz and 6.4 kHz was as short as that for 8 kHz. This observation suggested that it was the base, only, of the cochlea which responded. The present study has indicated that experimentally induced endolymphatic hydrops in the guinea pig mimics well the progressive and fluctuating hearing loss characteristic of Ménière's disease.

Animals↗
PubMed1989

The deviation of the body's sway center with galvanic stimulation.

We investigated galvanic body sway of ten healthy adults and eight patients by using the averaging program for measuring T1 and T2, which were latencies at the onset and at the cutoff of galvanic stimulation, respectively, and the plotting program, which adopted 1.73 sec as T1 and 0.39 sec as T2, for calculating the coordinates of the body's sway center. We estimated galvanic body sway with the difference between the coordinate of the body's sway center during stimulation and that during no stimulation. The deviation in lateral direction on the healthy subjects ranged from 0.7 or 0.9 to 2.1 cm at right- or left-side stimulation. One of the patients with peripheral disorders revealed differences between right- and left-side stimulation. The other patients did not reveal any differences. In antero-posterior direction six of the healthy subjects deviated backward at right-side stimulation and nine subjects deviated backward at left-side stimulation. The patients with peripheral disorders did not reveal any differences. The other patients revealed some differences. Waves computed by the averaging program do not always show the quantity of galvanic body sway. The deviation of the body's sway center shows the quantity of body sway consistently. The body's sway center is considered to be a suitable parameter in the galvanic body sway test for statistical analysis.

Adult↗
PubMed1977

Use of performance-intensity functions for diagnosis.

Performance-intensity (PI) functions for phonetically balanced (PB) word lists were obtained for a group of normal listeners (27 ears), and for two groups of patients with cochlear (89 ears) and retrocochlear disorders (eight ears). Listeners with normal hearing or cochlear disorders exhibited mild to moderate reductions in discrimination score as the speech level was raised above the PB maximum. In contrast, patients with retrocochlear disorders showed a pronounced rollover phenomenon, characterized by a rapid decline in performance as the speech level was raised above the maximum discrimination score.

Audiometry↗
PubMedDate not supplied

Management of labyrinthine fistulae in chronic ear surgery.

The appropriate management of labyrinthine fistulae has been debated in the literature for years. After several recent cases of labyrinthine fistulae at our institution, a review of the published data regarding hearing outcome with fistula management was undertaken. Results of this critical review were presented at departmental grand rounds. The grand rounds presentation, data and discussion are presented to better illuminate the topic of labyrinthine fistula management.

Adult↗
PubMed2002

Robot-assisted stapedotomy: micropick fenestration of the stapes footplate.

OBJECTIVE: Micropick fenestration of the stapes footplate, a difficult step in stapedotomy, was selected for trials evaluating the potential for robotic assistance (RA) to improve clinical measures of surgical performance. STUDY DESIGN: In a surgical model of stapedotomy, we measured accuracy of fenestration to a desired point location and force applied to the stapes footplate. Performance variables were measured for 3 experienced and 3 less-experienced surgeons. RESULTS: RA significantly reduced the maximum force applied to the stapes footplate. For fenestration targeting, RA significantly improved accuracy for less-experienced surgeons and significantly worsened targeting for more-experienced surgeons. CONCLUSIONS: RA significantly improves performance for micropick fenestration in a surgical model of stapedotomy. For certain tasks, RA differentially affects performance for users of different experience levels. CLINICAL SIGNIFICANCE: These are the first results showing quantitative improvements in performance during simulated ear surgery using RA and differential effects of RA on performance for users of different experience levels.

Clinical Competence↗
PubMed2001

Pharmacological models for inner ear therapy with emphasis on nitric oxide.

Nitric oxide (NO)-mediated neurotoxicity may be an appropriate pathophysiological model with which to explain a variety of inner ear diseases characterized by acute or progressive hearing loss, tinnitus and vertigo. The localization of NO synthase (NOS) isoforms was examined in the inner ear of the pigmented guinea pig after intratympanic injection of 1 mg lipopolysaccharide (LPS) or 5 mg gentamicin (GM) using an immunohistochemical method, revealing the expression of NOS II in the inner ear. Production of NO in the isolated organ of Corti and utricle or in the isolated vestibular and cochlear hair cells after stimulation with L-arginine, glutamate, GM and LPS was investigated using the fluorescence indicator 4,5-diaminofluorescein diacetate. The fluorescence intensity of the sensory cells was augmented by stimulation with L-arginine, glutamate, GM and LPS. A significant increase in NO production was also noted in the LPS-treated animals. These findings imply that NO from constitutive NOS may mediate ototoxicity in the early phase, whereas NO from NOS II may contribute to the late phase of tissue damage in the inner ear. Based on this hypothesis, reduction of glutamatergic excitotoxicity and inhibition of NOS, scavenging superoxide and scavenging peroxynitrite are thought to attenuate NO-mediated otoneurotoxicity.

Animals↗
PubMed1990

Understanding dizziness. How to decipher this nonspecific symptom.

Dizziness is a common but often nonspecific symptom. Through careful history taking and physical examination, primary care physicians can usually determine the type of sensation (vertigo or light-headedness) and its source. Although most causes of dizziness are benign, disorders of the central nervous system tend to be ominous and require immediate referral to a specialist.

Central Nervous System Diseases↗
PubMed1979

Horizontal postrotatory nystagmus response in female subjects with adolescent idiopathic scoliosis.

Quantitative and qualitative assessment of vestibular function was made in 18 female subjects with adolescent idiopathic scoliosis and a control group of 25 female subjects without scoliosis. The Southern California Postrotary Nystagmus Test, which examines postrotatory nystagmus response, was used to assess the vestibular function of subjects in both groups. The results indicated that subjects with adolescent idiopathic scoliosis had a significantly decreased duration of postrotatory nystagmus as well as irregularities in nystagmus form. The recommendation was made that a neurological examination, including assessment of vestibular function, be incorporated into screening methods for scoliosis.

Adolescent↗
PubMed1987

Screening methods for caloric testing.

In order to evaluate the screening capacity and the reliability of monothermal caloric stimulation, the caloric results obtained in 272 patients have been reviewed. The results of a complete bithermal 4-test-set are compared with the results of the hot and cold stimulation considered separately. The supposition that a complete 4-test set is necessary only if the monothermal reaction shows significant asymmetry, is tested by determining how far this would lead to a correct evaluation compared with the final results obtained by the bithermal testing. The study shows that hot as well as cold monothermal screening would result in too many false positive as well as false negative findings. A test procedure consisting of an alternating bithermal stimulation is proposed as a technique for shortening the examination time. This technique has proven to be reliable and it is also more comfortable for the patient.

Caloric Tests↗
PubMed1977

Comparative ototoxicity of amikacin and gentamicin in cats.

The ototoxic potentials of two aminoglycoside antibiotics, amikacin and gentamicin, were compared in cats, using several otoxicity assessment techniques. Daily subcutaneous doses of 90 and 45 mg of amikacin per kg and 18 and 9 mg of gentamicin per kg (approximately six and three times the daily human dose) were administered to cats for extended periods of time until cochlear or vestibular dysfunction developed. Renal tissue damage and serum and perilymph antibiotic concentrations were also monitored. Amikacin selectively produced an impairment of cochlear function after an approximate cumulative dose of 3,600 mg/kg obtained after 41 days at 90 mg/kg per day or 78 days at 45 mg/kg per day, as determined by electrophysiological assessment. Gentamicin caused an impairment of vestibular function after an approximate cumulative dose of 700 mg/kg obtained after 42 days at 18 mg/kg per day or 68 days at 9 mg/kg per day, as determined by ataxia and impaired righting reflex. Gentamicin also moderately reduced electrophysiological cochlear responses and appeared to cause histological renal tissue change more frequently than did amikacin.

Acoustic Stimulation↗
PubMed1978

Vestibulogenic imbalance.

Vestibular lesions may cause imbalance that long outlasts vertigo. Photographic analysis in five cases showed defects not only of the tilting reactions, which are of labyrinthine origin, but also of certain other postural reactions, notably the counterpoising and protective stepping reactions. All of these reflexes are unconscious and consequently such patients are rendered unstable in several ways simultaneously and may have difficulty describing their symptoms.

Adult↗
PubMed1983

The effects of the "vestibular sedative" drug, Flunarizine upon the vestibular and oculomotor systems.

The effects of the "vestibular sedative" drug Flunarizine upon the oculomotor functions of pursuit and voluntary saccades and upon the vestibular response (to rotational stimuli) were assessed in twenty volunteer subjects. The study was then extended to three patients with chronic imbalance of central origin who had reported a beneficial symptomatic response to the drug. Three of the volunteer subjects were found to have a directional preponderance (presumed to arise from peripheral dysfunction). In the remaining seventeen normal subjects Flunarizine was found to reduce the amplitudes of fast phases of vestibular nystagmus. The directional preponderance in the other three subjects was redressed through production of fast phases which were of lower and more uniform amplitude. In the patients, in addition to a reduction in fast phase amplitude, there was a reduction or abolition of after nystagmus. In no case was any reduction in slow phase velocity observed. Pursuit and voluntary saccades were unaffected by the drug. It was concluded, on the basis that the fast phases of nystagmus are centrally generated, that Flunarizine has a central action rather than a depressant effect upon the vestibular end organ. In view of known oculomotor physiology and pharmacology it is proposed that vestibular sedatives act by depression of Type II vestibular neurons, and modification of the functional relationships between the vestibular nuclei, the perihypoglossal nuclei and the flocculus of the cerebellum. A trial of vestibular active drug is indicated particularly in patients in whom asymmetry of the vestibular response and/or abnormal after nystagmus is demonstrated.

Adult↗