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Distortion product otoacoustic emissions (DPOAE) originate from nonlinear mechanical sound processing in the inner ear, mainly due to normal outer hair cell function. Outer hair cell impairment can be detected by means of DPOAE. With a special primary tone level paradigm which optimises the primary tone level difference over a wide stimulus level range (L1 = 0.4 L2 + 39 dB, L2 = 20 to 65 dB SPL, f2 = 0.5 to 8 kHz, f2/f1 = 1.2), DPOAE can be measured at levels close to the psychophysical hearing threshold. From the DPOAE growth functions, which are constructed from measurements at different stimulus levels, a DPOAE threshold can be defined (Boege et al., 1998), which can be interpreted as a threshold of mechanical processing by the outer hair cells. In this study, DPOAE thresholds were examined in 9 patients with reversible cochlear hearing loss, i.e. sudden deafness or noise trauma. With increasing hearing loss, low primary tone level DPOAE in particular decreased, and thus the DPOAE threshold increased. The DPOAE threshold makes it possible to detect mechanical sensitivity losses in a frequency-specific manner. Thus, loss of mechanical amplification may be differentiated from a non-mechanical cause of hearing loss.

Epiglottitis, commonly described as a paediatric disease, also occurs in adults. Early diagnosis and immediate treatment are crucial because of the rapid and possibly lethal course of upper airway obstruction due to swelling. Initial treatment consists in securing the upper airway and in antibiotic treatment. Streptococci and, especially in children, Haemophilus influenzae b are the most common bacteria. Our study focused on clinical and epidemiological changes since children started to be vaccinated against Haemophilus influenzae b in Switzerland (1992). We reviewed patient histories of 31 adults and 88 children who were hospitalised with epiglottitis at the University Hospital of Berne between 1989 and 1999. Our findings show that the incidence of epiglottitis in children, a clinically, epidemiologically and bacteriologically homogeneous disease, has dramatically decreased. Epiglottitis in adults presents as a more heterogeneous disease without change since the beginning of the vaccination programme. Due to the variety of germs it is impossible to recommend vaccination for adults against Haemophilus influenzae b.

Congenital lip pits may occur alone or in combination with oral clefts. They characteristically present as symmetric pits close to the vermilion border of the lower lip, about 0.5 cm off the midline, and are usually connected with heterotopic salivary glands; occasionally, salivation may occur. Congenital lip pits are associated with clefts of the upper lip and/or the palate in about half of the cases. Hypodontia may also be observed. Lip pits with or without clefts are found in a few dominantly inherited syndromes, in most cases involving the autosomal dominant Van der Woude syndrome. 52 carriers of the Van der Woude gene are described. In 8 cases the syndrome occurred as a fresh mutation and the other 44 cases occurred in 5 families. Penetrance was complete and expression very variable. Sex distribution was 1:1. For genetic counselling purposes it can be concluded that all carriers of the Van der Woude gene can be identified. Every symptom (pits, micro-pits, cleft, submucous clefts, uvula bifida) may represent the only manifestation of the gene. The recurrence risks for offspring of gene carriers is 50%, but the risk of severe forms of cleft is much lower.