Technical development of the BAHA
- An historical review

By
 

Bo Håkansson, PhD
Professor in Biomedical Engineering

Contact address:

Chalmers University of Technology
Department of Signals and Systems
S- 41296 Göteborg
Sweden

Mail: boh@chalmers.se

Webb: www.chalmers.se

The first generation of the BAHA HC-100: 1981-1986

When it was found that a bayonet coupling principle reasonably well fulfilled all demands it was decided to reproduce the first prototype shown in Figure 8 in a small series of devices.

The first more or less handmade BAHA was manufactured by a skilled workshop technician at Wennberg finmekanik. This almost completely handmade device was called HC-100, see Figure 11.
 

 
Figure 11: First serial produced but handmade BAHA – the HC-100.

The critical task to handle in this design was the suspension of the transducer to the housing that is necessary to avoid feedback. In the HC-100 the feedback was a real challenge to handle because the transducer from Oticon was undamped and the microphones at that time were much more vibration sensitive than they are today i.e. the transducer vibrations created feedback via the housing to the microphone.

Like today the leading hearing aid companies developed their own sophisticated integrated circuits (IC) as amplifiers and they are not available for general use.

Page 1      Page 2      Page 3      Page 4      Page 5

Page 6      Page 7      Page 8      Page 9      Page 10

Page 11    Page 12    Page 13    Page 14    Page 15