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Biomedical subjects

U Reker

Publications and source records attributed to U Reker.

44 records · Page 3Linked to original sources
PubMed1976

[Pseudocaloric nystagmus (author's transl)].

A pseudocaloric nystagmus is, in its strict sense, a spontaneous nystagmus activated by the unspecific stimulus of syringing the auditory canal. 40 patients with a unilateral, peripheral-vestibular defect were examined electronystagmographically. With most patients the 30 degrees caloric stimulation gave an incorrect result of the degree of hypoexcitability with all parameters (duration, maximum frequency and maximum intensity). This incorrect result was most pronounced with patients after neurectomy of the vestibular nerve, who frequently had a heavily reduced reaction of the healthy ear. For quantitative measurement of genuine pseudocaloric effects, by a special method of examination (as for instance by consideration of the "maximum spontaneous nystagmus"), the "real" vestibular excitability was calculated. Data exceeding this value were regarded as genuine pseudocaloric nystagmus. At stimulation temperatures of 44 degrees to 17 degrees C they were so low as to be negligible. They were only found with 5 of the 40 patients and amounted to only 10-20% of the reaction of the healthy ear. However, with ice water there frequently were considerable pseudocaloric reactions. So testing with ice water is not appropriate.

Caloric Tests↗
PubMed1975

[Investigations on the vestibular recruitment (author's transl)].

Searching for some kind of vestibular recruitment that might be similar to the audiological recruitment as defined by Fowler, a caloric test was done at 44 degrees, 33 degrees, 30 degrees, 26 degrees, 17 degrees. The parameter of vestibular response was the maximum slow component speed, In total 36 Menière-patients were electronystagmographically examined. Out of the 36 only 16 were analyzed further for the question of vestibular recruitmen, who showed strictly unilateral lesions, who were attack-free since some months and who showed clear audiological recruitment at four different recruitment tests. The following results were obtained: 1. The values obtained for the sound side of Menière-patients correspond to values described as normal in literature. 2. The affected side showed less reaction at all temperatures, in no case there was a tendency to recruitment. 3. With considerable loss of excitability, a "flat curve" was resulting, indicating decruitment.

Audiometry↗
PubMed1975

[Is there a correlation between vestibular and cochlear hypofunction in Menière's disease? (author's transl)].

The vestibular findings in Meniere's disease show large variations. In the attack-free interval, with strict unilateral disease, very often there seems to be a vestibular hypoexcitability. This canal paresis is mostly manifesting itself by a reduction of the velocity of the slow phase, and not so much by the shortening of the duration of a calorically induced nystagmus. With vestibular end-organ-diseases the relative hypoexcitability is most pronounced with strong cold stimuli. The correlation between hearing loss and vestibular function loss of 16 Meniere patients was examined at different caloric stimuli from 44 degrees to 17 degrees C. The generally accepted mode for determining vestibular hypoexcitability (mean value of the 44 degrees and 30 degrees -stimulus) only showed a very slight correlation to hearing loss. The determination of vestibular hypofunction at different caloric stimuli--or, at least, the additional application of a strong cold stimulus--seems to give new and valuable vestibular diagnostic possibilities.

Audiometry↗
PubMed1975

["Central Recruitment" with unilateral conductive deafness (author's transl)].

Feldmann described a recruitment with conductive deafness using simultaneous tones for loudness-balancing. On 20 patients with unilateral conductive deafness a loudness-balance-test was performed in 4 different ways. The results were strongly method-influenced: 1 There was a substantial hysteresis between ascending and descending loudness-balancing. 2 The choice of the reference ear, i.e. the ear on which the intensity steps are fixed, appeared to be very important. Different results were obtained when the intensity steps were fixed on the good ear (and thus adapting for equal loudness on the bad ear) compared to the results when the intensity steps were fixed on the other ear.- With continuous tones, and when fixing the intensities on the good ear, a recruitment can be measured with conductive deafness, but it is only method-depending. For a reliable recruitment-diagnosis with the Fowler-test strictly defined test-conditions, considering method-depending influences, are necessary.

Audiometry↗
PubMed1975

[The fowler test (author's transl)].

On 20 patients with unilateral recruitment-positive deafness (Morbus Meniere) 4 variations of the loudness-balancing test were performed: A. Two methods with alternate tones:1st method (Jerger): alternate tones, affected ear as reference ear. Loudness on the good ear was adapted for loudness balancing(= "affected ear fixed"), 2nd method (Hood): alternate tones, "good ear fixed". B. Two methods with continuous tones: 3rd method: continuous tones on both ears, "affected ear fixed", 4th method: continuous tones on both ears, "good ear fixed". Results were compared with the corresponding data obtained with recruitment-negative patients. Statistical analysis showed that separation between recruitment-positive and negative patients was equally excellent with both methods with alternate tones. With Jerger's method (method 1) the tendency to recruitment is less pronounced. Overrecruitment does practically not exist. Under our testing conditions the standard values for positive, and also for negative recruitment (reference point 110 dB lower with method 1 (Jerger) as compared to method 2 (Hood). The different values with method 1 and method 2 were due to the choice of the affected or good ear as "fixed ear" (reference ear). Method 1 (Jerger) can be recommended for clinical use as there is less overrecruitment (unfavourable testing technique) and as an audiometer with 5 dB intensity-steps can be used.

Audiometry↗
PubMed1975

[Noise-induced hearing loss with chronic otitis media (author's transl)].

Two different otological noxes add up in their effect. In some cases, however, the first one may cause a reduction of the noxious effect of the second one. Opinions are divided as to whether the susceptibility to noise of an ear with chronic otitis media is increased or decreased. From 14,300 audiograms we selected those 131 cases with unilateral chronic otitis media and, at the same time, with a typical noise-induced recruitment-positive c5-dip on the other side. There were 86 cases with larger bone conduction hearing loss on the ear with chronic otitis media. In these cases, the bone conduction hearing loss, by all differential diagnostic criteria, could be judged to be caused by the chronic otitis media. On the other hand, in all those 45 cases which, on the side with chronic otitis media, had a bone conduction loss in form of a c5-dip, this was in each single case less pronounced than on the other ear. Regarding the susceptibility to noise, the reduction of sound intensity by the conductive deafness seems to be more important than noxious effects of the chronic otitis. Generally a substantial bone conduction hearing loss with chronic otitis media and noise exposure should be attributed to effects of the otitis.

Adult↗
PubMedDate not supplied

Methodological problems in the determination of homolateral stapedius reflex threshold.

Generally, a bilateral symmetry of the acoustic stapedius reflex is assumed. But a homolaterally higher sensitivity has been described. We examined 71 patients with complete unilateral deafness. With a TDH 39 headphone, stimuli of intensities up to 133 dB were conveyed to the deaf ear. A fairly accurate estimate of the normal homolateral threshold is obtained by correcting for the cross-hearing loss and by mathematical consideration of the relative probabilities of the positive and negative cases. Methodology-specific influences are discussed and a correction made for them. The homolateral reflex threshold is 9-14 dB lower than the contralateral reflex threshold.

Acoustic Stimulation↗