Rapid responses are electronic letters to the editor. They enable our users to debate issues raised in articles published on thebmj.com. Although a selection of rapid responses will be included online and in print as readers' letters, their first appearance online means that they are published articles. If you need the url (web address) of an individual response, perhaps for citation purposes, simply click on the response headline and copy the url from the browser window. Letters are indexed in PubMed.
The authors provide a thorough literature review of the recent advances in the clinical implementation of a very exciting set of advances in Analogue computing, but chose not to explore the technological basis of the implants in favour of clinical presentation.
For those interested, I have a dissertation available online which takes the reader through the fundamental differences between Digital and Analogue circuitry, through the original research papers from the 1950s through to the near present.
The dissertation is a combined literature review, summary of academic principles and critical appraisal of the quality of research and presentation, ending with a summary of the clinical application of the technology represented in this article.