PubMed Health⌕ Search

Biomedical subjects

R Laszig

Publications and source records attributed to R Laszig.

At least 109 records · Page 6Linked to original sources
PubMed1989

Implantation of the Melbourne/Cochlear multiple-electrode extracochlear prosthesis.

The Melbourne/Cochlear multiple-electrode extracochlear implant is designed for deaf patients who are unsuited to multiple-electrode intracochlear implantation. The implant consists of a receiver-stimulator package connected via a lead wire assembly to six individual stimulating electrodes. There is a choice of two alternative surgical procedures, both of which are via a combined middle ear approach using anterior and posterior tympanotomies. Four active electrodes shaped into compressible platinum-iridium soft-balls are fed through the mastoid cavity and across the facial recess, and placed into cavities that are made over the cochlear turns that project to the medial wall of the middle ear. One hard-ball active electrode is placed into the round window niche. One hard-ball reference electrode is placed into the hypotympanum. An additional electrode wrapped around the lead wire assembly can be used as an alternative reference electrode. A specially designed insertion needle facilitates the placement and the fixation of the soft-ball electrodes.

Cochlear Implants↗
PubMed1989

[Catheter implantation for intra-arterial chemotherapy of malignant tumors of the head and neck].

Tumors of the head and neck are mainly squamous cell carcinomas of varying differentiation. If the tumor is advanced (T3-T4) or distant metastases are present, the tumor is often to be regarded as inoperable. If cure is unlikely or substantial functional impairment is to be expected, surgery may no longer seem reasonable, even for tumors limited to one side. Since either radiotherapy or chemotherapy alone or in combination are often disappointing or have considerable side-effects, it seems reasonable to try to inhibit malignant cell growth by administering a cytostatic agent by intra-arterial "superselective" chemotherapy using an implantable catheter. The method is simple, and the patients may also receive combined radiotherapy if necessary. Furthermore, ambulant treatment is possible, with a substantially reduced risk of infection. This is an advantage compared with other catheter techniques, particularly in view of the restricted expectation of life of patients with advanced tumor. The disadvantage of "A-port implantation" is that chemotherapy can only start after complete wound healing.

Antineoplastic Agents↗
PubMed1989

[Extracranial meningioma: a rare differential diagnosis of an intranasal tumor].

Meningiomas are common intracranial neoplasms, making up 19.5 per cent of all intracranial tumours. Meningiomas occurring outside the central nervous system are uncommon. In this report should be presented an extradural meningioma of the left nasal cavity, which was diagnosticated in an 78-year-old female. These slowly growing non-infiltrating tumours have no characteristical clinical symptoms, they cause nasal obstruction and sinusitis. The origin of these tumours is uncertain. Obviously intranasal meningiomas take their origin from the arachnoideal meningocytes which accompany the olfactory filaments through the lamina cribrosa to the extradural site.

Aged↗
PubMed1989

[Acrodysostosis: an autosomal inherited form of peripheral dysostosis].

We report a 13-year-old boy with peripheral dysostosis, nasal hypoplasia, brachydactyly and a tracheal stenosis of unknown origin. Acrodysostosis is usually caused by an autosomal gene, but in this case it was probably due to a new mutation. The frequently described mental retardation is not essential feature. Ectopic calcification has not been previously reported.

Adolescent↗
PubMed1989

[Suppression of tinnitus by electric stimulation in cochlear implant patients].

The use of electrical stimulation for the treatment of tinnitus was evaluated on 38 cochlear implant patients suffering from chronic tinnitus. In answer to a questionnaire 29 (76%) of the subjects reported a reduction of the tinnitus while using their speech processor; 15 even noted complete suppression. Sixteen patients used a processor delivering subthreshold current for 2 weeks. A placebo trial followed. Reduction of tinnitus was found in only 3 (19%) of the patients; however, 13 (81%) mentioned a substantial decrease of tinnitus when using their own device with above-threshold stimulation. The fact that tinnitus was also reduced on the contralateral side suggests that the acoustic masking effect must be the main determining factor rather than electrical stimulation. Therefore, the best therapy for the deaf seems to be the improvement of their hearing ability.

Adult↗
PubMed1989

[Differential diagnosis of parotid tumors: toxoplasmosis lymphadenitis of the parotid gland].

The most common clinical symptom of toxoplasmosis in adults is a cervicofacial lymphadenopathy. The cat is very important in the epidemiology of toxoplasmosis, but contact with cat excreta is most uncommon. The cause of oral transmission in adults is more likely to be eating undercooked contaminated meat containing tissue cysts, particularly raw pork. Toxoplasmosis as a cause of lymphadenopathy is an unusual, and normally postoperative, finding after parotidectomy for a "tumour". In the last 8 years we have seen ten patients with an acute toxoplasmosis infection. We report two patients showing clinical signs of a parotid gland tumour in whom we demonstrated an intraglandular toxoplasmosis lymphadenopathy before operation. We treated these patients successfully using pyrimethamine and sulphonamide, so that surgery was unnecessary.

Adult↗
PubMed1989

[Unusual electrocochleography cases].

The electrocochleographic findings of 3 unusual cases from about 350 performed on patients with various hearing loss are presented; they demonstrate the value of electrocochleography as a clinical tool in otological investigation. The first case was an electrocochleographically detected acute impairment of the first neuron, the second a hereditary hearing loss with endolymphatic hydrops, and the last shows the effect of an endolymphatic shunt on a hydropic hearing loss.

Adult↗
PubMed1988

[Psychophysical data and speech comprehension after 2 years with the Clark/Nucleus prosthesis].

Psychophysical data such as threshold and comfort levels indicate an extensive preservation of auditory nerve fibers. Changes of these data can point to increasing damage of nerve fibres due to long-term electrical stimulation or to obliteration of the cochlea when an intracochlear system is used. Unfavourable levels indicate negative influence on speech comprehension. The psychophysical data and the speech comprehension of 10 patients fitted with a Clark/NUCLEUS cochlear implant in the last 2 years have been analysed. During this period of time the threshold and comfort levels remained almost stable, whereas speech comprehension is still increasing, though to a lesser extent, after 2 years with the implant. These results indicate that the patients suffer neither an increasing destruction of auditory nerve fibres nor severe intracochlear changes.

Auditory Threshold↗
PubMed1988

[Changes in the compound action potential in patients with acoustic neuroma].

Thirty-eight patients with proven acoustic neuroma were divided into three groups: 13 patients with normal threshold on pure tone audiogram, 15 patients with a hearing loss of 40 dB-80 dB (HL) in the low and middle frequencies, and 10 totally or almost deaf patients. Results of the first two groups are reported, using intra-tympanic electrodes with alternating clicks of 90 dB (nHL) intensity and a stimulus rate of 20/s. A total of 500 sweeps were averaged. Widening of the CAP complex by a mean of 1.6 ms, compared to 1.1 ms in normal hearing subjects, was the most striking finding. Summation potentials (ratio of SP amplitude to CAP amplitude) were enlarged to 0.6, compared to 0.2 in healthy persons and 0.9 in patients suffering from Ménière's disease. CAP amplitudes as well as CM amplitudes were reduced to almost one-third of normal values. The most noticeable result was the loss of amplitude using very short interstimulus intervals. With a stimulus rate of 97/s amplitudes of acoustic neuroma patients were reduced by 49.9% - reduction in normal and Ménière patients was 41.6% and 41.3%. Acoustic neuroma patients show pathological inner ear potentials. Increased summation potentials are often found with Ménière patients, which are said to be caused by endolymphatic hydrops. For tumours of the acoustic nerve the hydrops theory does not seem likely; the loss of amplitude due to ++adaptation++ within the first neuron seems to point to mechanical reasons due to the pressure of the tumour itself.

Auditory Threshold↗
PubMed1988

[Changes in the hearing and discomfort thresholds in patients with the Clark/nucleus inner ear prosthesis].

The Nucleus 22-electrode cochlear implant should be fitted individually for both pitch and loudness. Loudness is related to the charge delivered, and is usually controlled by current amplitude. In special cases the loudness may be influenced by stimulation mode and pulse width. 3 examples demonstrate optimal fitting with low current intensities, using these possibilities. In addition the threshold level and comfortable level date were analysed over a 2-year period. No significant changes were found, indicating that electrical stimulation caused no damage to the remaining auditory nerve fibres.

Adult↗
PubMed1988

Magnetic resonance imaging (MRI) and high resolution computertomography (HRCT) in cochlear implant candidates.

Cochlear implant candidates must be thoroughly tested for their suitability pre-operatively. Electrical and electrophysiological tests as well as a psychological assessment are of fundamental importance in the selection process. The implantation of an intracochlear electrode requires specific information about the anatomy of the petrous bone and the endocochlear space. Such information can be obtained by using high resolution computed tomography (HRCT) or magnetic resonance imaging (MRI) using a surface coil. Over three years 438 patients were evaluated in our clinic as possible implant candidates. Out of these candidates 251 were evaluated using HRCT and 123 using MRI. In 39 (15.5%) cases we found bony abnormalities of the petrous bone using HRCT scans. 17 (13.8%) of the cases evaluated with MRI had no complete fluid filled spaces in the cochlea. Three patients who where identified as having ossified cochleas were subsequently implanted with an extracochlear device. MRI and HRCT have proved to be fundamental tools in determining patients suitable for implantation of an intracochlear electrode array.

Cochlea↗
PubMed1988

Uni-lateral hearing-loss with acoustic neuroma patients: electrocochleographic findings.

38 patients with proven acoustic neuroma were examined. Intratympanic electrocochleography was performed with alternating clicks of 90 dB (nHL) intensity and a stimulus rate of 20 per second; 500 sweeps were averaged. Widening of the Cochlear Action Potential (CAP)-complex by a mean of 1.6 ms was the most striking finding. Summating potentials (ratio of SP-amplitude to CAP-amplitude) were enlarged to 0.6, compared to 0.2 in healthy persons and 0.8 in patients suffering from Meniere's disease. The most noticeable result was the loss of amplitude using very short interstimulus intervals. With a stimulus-rate of 97 per second amplitudes of acoustic neuroma patients were reduced by 49.9%. Acoustic neuroma patients show pathological inner ear potentials. Some of the changes such as increased SP are found in patients with Meniere's disease, supposingly caused by endolymphatic hydrops. For tumours of the acoustic nerve the hydrops theory does not seem likely; the loss of amplitude due to adaptation within the first neuron seems to point to mechanical reasons due to the pressure of the tumour itself.

Audiometry, Evoked Response↗
PubMed1987

[Cogan syndrome: sudden, bilateral high-grade hearing loss].

We report 2 cases of Cogan's syndrome. One female patient had a typical interstitial keratitis and bilateral hearing impairment, the other had dramatically progressive deafness, combined with failure of the left vestibule and severe conjunctivitis resistant to treatment and otitis externa. The typical Cogan's syndrome with interstitial keratitis developed only a few weeks later. The disease is caused by an auto-immune response. The hearing impairment is mainly due to endolymphatic hydrops. Corticosteroids are the treatment of choice.

Adult↗
PubMed1986

[The promontory test and electrocochleography in deafness caused by mumps].

Contradictory histological findings in patients with deafness following mumps led us to conduct electrophysiological investigations. Promontory testing (PT) and measurement of cochlear microphonics (CM) enabled us to distinguish between neural and sensory deafness. On the basis of a careful history and serological tests in 19 cases of unilateral deafness we found that the hearing loss was probably caused by mumps. In all patients except one auditory sensations could be obtained by electric stimulation of the acoustic nerve whereas no CM were detectable even with strong stimuli of 100 dB tonepips. In view of the electrophysiological findings, doubt is cast on the neural genesis of deafness following mumps as assumed by Lehnhardt (1962).

Audiometry, Evoked Response↗
PubMed1986

[Remarks on inflammation of the pharyngeal bursa].

Inflammation of the pharyngeal bursa is a very rare disease causing symptoms similar to those of maxillary and sphenoidal sinusitis. We describe the typical symptoms in three cases and discuss the diagnosis, differential diagnosis and the treatment.

Adult↗
PubMed1986

[The promontory test and electrocochleography with reference to indications for cochlear implant].

A successful cochlear implant demands a functioning auditory nerve. A subjective and qualitative recording can be obtained by promontory testing (PT) whereas cochlear microphonics (CM) give information about the status of the hair-cells in the inner ear. The results of both tests together show different patterns: in sensory deafness in which a cochlear implant is indicated, no CM and no compound action potentials (CAP) can be obtained, whereas the patient reports hearing sensations (PT positive) in response to promontory testing. Deafness caused by lesions close to the second neurone of the auditory pathways can be localized by preserved CM and CAP, but there is no response to promontory testing. A ganglionic deafness ie. of the first neurone can be distinguished by preserved CM, absent CAP and a negative PT. The combined results of electrocochleography and promontory testing help in deciding whether a cochlear implant is indicated, and in localising the origin of the deafness, eg. neural or sensorineural. The possible results are illustrated by examples.

Adult↗
PubMed1986

[Cochlear implants].

Since the middle of 1984, the HNO-Klinik der Medizinischen Hochschule Hannover has provided deaf adults with a 22-channel cochlear implant (CI) device of Clark-NUCLEUS. The digital working system consists of an implantable stimulator/receiver and an externally worn speech processor. Energy and signals are transmitted transcutaneously via a transmitter coil. During the prevailing 26 operations (April 1986) the electrode array could be inserted at least 17 mm into the cochlea. The threshold and comfort levels of all patients were adjusted very quickly; the dynamic range usually grows during the first postoperative weeks. The individual rehabilitation results vary greatly, but all patients show a significant increase of vowel and consonant comprehension while using the speech processor and an improvement of words understood per minute in speech tracking from lip-reading alone to lip-reading with speech processor. Four months after surgery seven of 17 patients (group I) are able to understand on average 42.7 words per minute by speech tracking without lip-reading. Six patients (group II) recognise 69.2% of vowels and 42.5% of consonants by speech processor alone. Four patients (group III) can correctly repeat only vowels (52.3%) without lip-reading, but using the speech processor together with lip reading they have an improvement in consonant understanding of 37.9% and under freefield conditions they are able to understand up to 17.8% numbers of the Freiburg speech test.

Cochlear Implants↗