[A comparison of low-chirp- and notched-noise-evoked auditory brainstem response]. / Frühe akustisch evozierte Potenziale: Low-Chirp-BERA versus Notched-Noise-BERA.

BACKGROUND: In order to obtain a low-frequency specific auditory brainstem response (ABR) there are less stimuli that plege a satisfying accordance with the ABR threshold and the behavioural threshold. This study investigates the so called low-chirp-ABR as to predict a low-frequency-amblyacousia and compares it to the notched-noise-500 Hz-ABR. MATERIAL AND METHODS: We evaluated behavioural and ABR thresholds to a low-chirp respectively a 500 Hz tone presented in notched noise masking from 32 patients with a severe hearing loss at low-frequencies and 28 patients with normal hearing. RESULTS: The average difference ± single standard deviation between low-chirp-ABR and behavioural threshold is 1.53 dB ± 7.68 dB in the group of patient with low-frequency hearing loss and 2.55 dB ± 5.46 dB in the group of normal hearing. On the contrary the difference between notched-noise-500 Hz- and behavioural thereshold averages 2.67 dB ± 9.29 dB (low-frequency hearing loss) respectively 8.82 dB ± 7.90 dB (normal hearing). In order to verify the equivalence between the several methods we did a equivalence test that shows that low-chip-ABR and behavioural threshold can be considered as equal to obtain a low-frequency threshold. In contrast the comparison of notched-noise-500 Hz-ABR and behavioural threshold proves no equivalence. CONCLUSION: We detected a significant equivalence between low-chirp-ABR and pure-tone audiometric. The ABR to a low-chirp stimulus seems to be rather precise in contrast to the notched-noise-500 Hz-evoked-ABR in order to diagnose a low-frequency-hearing loss.

[Vocal cord dysfunction. An important differential diagnosis to bronchial asthma]. / Vocal Cord Dysfunction. Eine wichtige Differenzialdiagnose zum Asthma bronchiale.

Vocal cord dysfunction (VCD) is described as a functional disorder of the vocal folds which leads to an intermittent, inspiratory 'paradoxical' glottal closure. We report on three women with frequent repetitive shortness of breath attacks caused by VCD. This was diagnosed by transnasal videofiberendoscopy, with glottal closure being seen during inspiration. Because of the different etiologies, one of the patients was treated with breathing and speech therapy, another received Omeprazol for laryngopharyngeal reflux, and the third was treated by intralaryngeal botulinum toxin injections. All three patients showed a reduction in attacks. Clinically, VCD seems to mimic asthma. However, with a thorough patient history and diagnostics, especially with transnasal laryngoscopy during a (triggered) attack, a precise diagnosis seems possible.