Biomedical subjects

F J Brügel

Publications and source records attributed to F J Brügel.

13 recordsLinked to original sources

PubMed1995

[The facial nerve in the petrous bone in thin-layer paratransverse and sagittal magnetic-resonance-tomographic T1-spin-echo and FLASH images].

PURPOSE: It is difficult to effect visualization and delineation of the facial nerve and its neighbouring structures in the temporal bone with conventional MRI examination protocols. We tested temporal bone MRI with 2 mm slices and compared T1-weighted FLASH (TR = 400 ms, TE = 10 ms, 90 degrees flip angle) and spin-echo (TR = 540 ms, TE = 15 ms) sequences. PATIENT AND METHODS: 5 volunteers and 14 patients were examined with the head coil of a 1.0T whole body MRI scanner (Impact, Siemens, Erlangen) with para-transversal images orientated parallel to the inferior outline of the clivus and sagittal images orientated along the brainstem. RESULTS: The facial nerve and its neighbouring structures could be reliably visualized and differentiated along its entire course. The FLASH sequence was superior to the spin-echo sequence. 8 of 11 patients with peripheral facial nerve palsy showed contrast enhancement. In two patients, local swelling of the affected facial nerve was evident. CONCLUSION: The MRI technique tested here seems promising for temporal bone examinations.

Adult↗

PubMed1994

[New aspects of hearing aid fitting].

Improved methods to diagnose a hearing loss and the enormous progress in the development of digital and programmable hearing aids have been helpful in promoting the social integration of patients, even of those affected by a profound deafness. Besides the hearing loss, recruitment effects and alteration of sound can also be compensated by the new hearing aids. However, one precondition is that the hearing aid fitting is carried out professionally, with plenty of time, and including the new hearing aid fitting methods. The new techniques developed in our hospital to optimize hearing aid fitting are pointed out. Fitting should start by considering what kind of ear mould and what kind of different modifications are to be taken. In a great number of patients we were able to verify that venting combined with the insertion of a Bakke- or Libby-horn increases not only the subjective acceptance of the hearing aid, but also significantly improves speech discrimination, particularly under background noise. The preselection of the hearing device and precise adjustment are based on the hearing loss in different frequencies, involving the principle that the frequency response of the hearing aid and the audiogram mirror each other accordingly, whereas the gain of the hearing aid can not be recognised exactly from the audiogram. In contrast to the POGO- and the NAL-method, we recommend a greater amplification, especially in the higher range of frequency. Today, the in-situ-measurement with a probe microphone is considered to be the method of choice for accurate frequency adjustment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

[Temporal resolution with a hearing aid in hearing impaired persons].

The purpose of hearing aid fitting is to improve the communication of the hearing impaired. Despite rigorous efforts to optimize hearing aid fitting there are still some patients who remain unsatisfied. The subject of research was to find improved methods of measuring, to increase the correlation between subjective information from the patient and objectively measurable data. With this goal in mind the variation of temporal resolution in hearing aid fitting was investigated in 88 patients comparing unaided and aided hearing basing on the method of determining the temporal resolution factor TRF at 500 Hz, 1500 Hz and 4000 Hz under free sound field conditions, as previously described by Schorn and Zwicker. The method is based on masking period patterns but measures only their maximum and minimum using continuous and 30-Hz square-wave amplitude modulated masking noise. The following three values of interest are measured: Threshold in quiet using interrupted continuous tones (500 ms on, 500 ms off) with the masker off; threshold masked by a continuous masker (octave-wide continuous noise) and threshold masked by a rectangulary modulated masker using 14 Hz, so that periods of 72 ms and pauses of 36 ms occur. TRF was defined as the ratio between the level differences derived from the three measured values. For normal hearing subjects this factor is about 1. The results show significant variation of the TRF comparing the data of the patients with and without hearing aids. The values for TRF unaided were 0.5 and 0.6 as well as under hearing aid.(ABSTRACT TRUNCATED AT 250 WORDS)

Audiometry, Pure-Tone↗

PubMed1993

[Value of in situ measurement for evaluating effective hearing aid amplification at high sound pressure levels].

A careful hearing aid fitting requires consideration of various characteristics of inner ear pathology. The recruitment phenomenon restricts the dynamic range of the impaired hearing and this increase the demands on the hearing aids for a satisfactory correction of the frequency characteristics as well as for an intensity reduction at higher sound pressure level SPL. For years data from coupler or KEMAR (Knowles Electronics Manikin of Acoustical Research) have served to estimate the real ear gain of a hearing aid at higher input levels. In previous papers we reported on some of the differences between coupler measurement and probe tube measurement. The object of this study was to investigate the differences between these two methods at higher input SPL. Therefore, we measured the real ear insertion gain as well as the output characteristics with a 2 cm3 coupler in 80 patients at input levels of 60 dB, 80 dB and 100 dB. The results show differences between the two methods up to 30 dB in both directions in the single patient. Furthermore, the highest compression rate was found in the middle and high frequency range which are crucial for speech discrimination. Consequently, probe tube measurement should be used not only to adjust the frequency characteristics of the hearing aid but also to characterise the real effect of Automatic Gain Control AGC and Peak Clipping PC on insertion gain at higher input SPL. Multichannel hearing aids should be used whenever possible to reduce the disturbances to speech discrimination at low frequencies.

Hearing Aids↗

PubMed1993

[Reliability of diagnostic procedures in facial paralysis with special reference to magnetic resonance tomography].

Facial nerve palsy is commonly examined using a variety of topodiagnostic and electrophysiological tests. More recently, MRI has also been used to study lesions of the facial nerve. Due to varying time intervals between the onset of symptoms and clinical examination, however, the diagnostic value of these procedures remains limited. In the present study, 30 patients with facial nerve palsy of diverse origin were examined with MRI (1.5 Tesla magnetom) using a special surface coil and 30 degrees parasagittal slices of 3 mm thickness. These special modifications enabled us to visualize the nerve in its entire course through the temporal bone. After the application of Gd-DTPA the enhancement of the contrast medium could be verified in all cases. A moderate enhancement in the geniculate ganglion as well as in the labyrinthine segment correlated with a good prognosis in terms of complete restoration of facial nerve activity, while an increased enhancement correlated with a poor prognosis. Our results indicate that MRI is of superior diagnostic value as compared to clinical and electrodiagnostic tests, at least in the patients we examined in this study. Still, further evaluations are necessary to justify a possible routine clinical use of this procedure.

Blood-Brain Barrier↗

PubMed1992

[What improvements can be gained by additional boring in hearing aid fitting?].

In several investigations the authors tried to find a objective correlation to the subjective positive reactions after venting an earmold. There was no notable effect neither on insertion gain nor on speech intelligibility in different background noise situations. In this study the most comfortable hearing level has been used. This stimulus is influenced by the suprathreshold loudness growth. The measurement has been carried out with and without venting. Comparing the results there can be seen only a little effect of venting at all frequencies. Might be that patient's report about improvement after venting results from the direct input of low frequencies through the vent to the eardrum. These frequency region plays a special part of hearing comfort to reach a comfortable sound quality.

Adult↗

PubMed1992

[Various uncomfortable loudness thresholds, their correlation and use in general practice].

In the present study we examined the relationship of the loudness discomfort level LDL of different signals. We carried out measurements in 97 patients, all of whom suffered from a sensorineural hearing loss. The results showed almost no difference between the LDL of pure tones and narrow band noise. The LDL of broad band noise showed a good correlation to the LDL of 250 Hz. Only the LDL of monosyllables ranged at a higher SPL. For an up-to-date hearing aid fitting, all forms of LDL should be taken into consideration. This is especially necessary when using digital hearing aids.

Adolescent↗

PubMed1991

[Cervical tinnitus after cervical vertebrae treatment].

There is a wide variety in the discussions on cervical tinnitus as a possibility of hearing disorders. Hearing loss at low frequencies and low frequent tinnitus are typical signs in this context. It is important to remember that these complaints occur not only with pathological changes in the cervical spine, but possibly also after treatment in this region. The patients presented here suffered from tinnitus or hearing loss after treatment of the cervical region. In all cases the cervical spine is clearly indicated as having triggered the signs. When diagnosing and treating patients with complaints of the cervical area, there should be close cooperation between the physician, the patient and the physiotherapist.

Audiometry↗

PubMed1991

[Coincidental appearance of laryngocele and laryngeal carcinoma].

The authors present a case of a 54-year-old male patient suffering from a laryngocele with concomitant laryngeal cancer. The patient had a three-month history of hoarseness. The clinical examination as well as the endoscopic evaluation did not reveal any signs of malignancy inside the larynx. MR imaging, however, showed an endolaryngeal cystic process surrounded by a soft tissue mass. Resection of the lesion revealed the concomitant occurrence of both laryngocele and laryngeal carcinoma. Etiology, symptoms, diagnostic management and differential diagnosis are presented and discussed according to the relevant literature.

Carcinoma, Squamous Cell↗

PubMed1991

[In-situ measurement as necessary component of hearing aid fitting].

The most important ear simulator measurement methods like 2-cm3 coupler, Zwislocki coupler, KEMAR were outlined. The disadvantages of these measurement methods were listed. So the ear simulator methods not take into account the individual anatomic conditions like the residual volume between the earmold and the eardrum, the impedance of the middle ear and the outer ear resonance. The influence on the sound pressure level in front of the eardrum caused by modifications of ear molds as another very important part of the hearing aid fitting, can not be assessed by measurement far away from the patients ear. All these individually varying factors only can be integrated into the hearing aid fitting by real ear measurement in front of the eardrum.

Acoustics↗

PubMed1991

[Effect of venting the ear mold on speech discrimination in masking noise].

In this study the importance of in situ measurement during the fitting of a hearing aid is clearly emphasized. Reliable evaluation of the real ear gain can be achieved only with this method, and hence the assessment of the advantages of earmold modifications on the hearing aid. In particular, the gain can be evaluated by the person fitting the aid. The insertion of a vent into an earmold raises the listening comfort of the hearing-impaired person. The speech intelligibility in background noise may also improve. We analysed the effect of earmold venting on speech intelligibility under different background noise conditions. We found that venting improves the speech intelligibility, especially in background noise simulating modulated speech. Our example clearly demonstrates the importance of an exact control of the hearing aid fitting by the physician. In one case a vent ended at the ear canal wall so that no improvement of hearing comfort could be expected. A new earmold was made and the effect on insertion gain was demonstrated when enlarging the vent step by step.

Audiometry, Speech↗

PubMed1990

[In situ measurements for determining the effect of additional boring of the earmold].

To investigate the effect of earmould venting on the insertion gain of hearing aids in patients' ear canal, the authors sealed 35 earmould ventings with soft silicone after measurement under normal conditions and repeated the measurement. The size of the ventings varied from 0.8 mm to 3.5 mm in diameter. The results show the expected SPL-reducing effect of the ventings between 500 Hz and 1,000 Hz. Below 500 Hz the effect found was only slight, because of the low amplification in this frequency range. Above 1 kHz an increasing sound pressure level was measured as a result of resonance effects. This study illustrates the effect of earmould venting on insertion gain. To improve the hearing aid fitting the earmould venting should be used, deliberately and specifically, far more often than at present. The resulting effects of earmould modifications of real ear gain can only be determined by in situ measurements on the patient's eardrum. This method also enables resonance to be compensationed for in a controlled manner.

Audiometry, Pure-Tone↗

PubMed1990

[Supraorbital tumor as manifestation of Jaffe-Lichtenstein fibrous dysplasia].

We report on the case of a 16 year old white female who presented at our outpatient clinic with a swelling of the left supraorbital region. Histologically a fibrous dysplasia Jaffe-Lichtenstein was found. Diagnostic procedures, possible complications, adequate therapy and prognosis of this disease are discussed and compared with the relevant literature.

Adolescent↗