Experiences with the new Audiant XA-II implant and the behind-the-ear (BTE) device.

Patients with large conductive hearing loss do not always tolerate conventional air conduction or bone conduction hearing aids. They can be helped sometimes with an implantable bone conductor device. The so-called bone-anchored hearing aid consists of an implantable titanium skull screw and an external sound processor unit. In this study, we report our experiences with 10 subjects who have been implanted with the recently improved Audiant screw-type XA-II and their experience with the newly developed behind-the-ear (BTE) external processor, the at-the-ear processor and the body-level device with a new transducer with variable magnetic strength. Evaluation shows that the Audiant XA-II system is well accepted and does not show any tissue reaction. The BTE processor is an important new complement to the Audiant system. Furthermore, the system is effective in compensating the air-bone gap almost completely at the higher frequencies but only partially at the lower ones. The maximum output appears to limit its feasibility for perceptive losses beyond 20 dB (PTA). When this system is utilized for proper hearing loss, however, the system usually improves speech intelligibility both in quiet and in background noise. When the system is prescribed for hearing losses with a moderate or large perceptive component, the system is ineffective and leads to negative evaluations.

The suprachiasmatic nucleus of the rat hypothalamus in culture: an anatomical and electrophysiological study.

This study shows that foetal neurons from the suprachiasmatic area, after dissociation and culture, contain in vitro the same characteristics as are found in the in vivo situation. The main peptidergic neurotransmitters present in the suprachiasmatic nucleus in vivo, vasoactive intestinal polypeptide (VIP) and vasopressin, are expressed in vitro while the cytoskeleton of these cells possesses phosphorylated neurofilaments. The exclusive uptake of Lucifer Yellow liposomes by neurons is also refound in suprachiasmatic cultures. The electrophysiological results are in agreement with those characteristics found in vitro and in vivo.