Psychophysics – is faster better?

From a presentation on ‘Psychophysics – is faster better?” from Cochlear at one of their quarterly talks. This is a summarised and layman’s version (my own interpretation, so there might be errors).

Cochlear was studying how the brain interprets sound. They said that electrode position was more important than the no. of virtual channels offered (an obvious dig at Advanced Bionics, who touts their high no. of virtual channels). The presentation also mentioned that there was a limit to the improvement in performance in increasing the electrical stimulation rate. Apparently, performance plateaus out at 300Hz.

One thing I noted was that some of the studies the presentation included were not statistically valid. For example, they included a study from the American Freedom clinical trial which had about 28 patients – this sample size is too small to draw valid conclusions. However, it must be noted that in perspective, a sample size this large is considered to be very good – it is difficult to find co-operative individuals of similar history and conditions who will participate in a study for a year or a more.

A participant asked a question on tonal languages ie Mandarin Chinese. The presenter said that the speech processors were designed primarily for speech perception, and that the problem with tonal languages was that it introduced another layer of perception on top of speech perception, which made hearing tonal languages much more difficult than English. This was a problem they were trying to address.