Programming Cochlear Implants is a pretty darned good book for a college educated CI candidate, CI “power user,” or even the parents of a “CI kiddie,” as it provides a nicely detailed view of CI’s, rather than what you can extract from the “FDA-sanitized” marketing hype from the CI manufacturers. This book has some very nice troubleshooting tips, especially for parents and school audiologists. Also, Chapter 7 on hearing assistance technology (HAT), which is mostly all on FM, is very good, as it lays out how configuring FM assistive devices with CI’s differs from hearing aids: In the opinion of The Hearing Blog, this chapter is worth the price of the book alone. One minor shortcoming, though, is that it does lack the channel interference table — The “recommended channels” — for Phonak MicroLink receivers operated on the 168mHz H-band and 216mHz N-band when they are connected to the commonly used Cochlear Freedom processor, and almost certainly the Nucleus 5 processor.¹
Update: In a call to Professor Schafer, she agreed with this point; and the table will be included in the second edition, when published.
Where this book is quite helpful to the CI user community is pointing out where Best Practices can be (and often are) skimped to speed things along in busy clinics; and when these shortcuts are taken, should serve as Warning Flags to the astute user or parent. A large part of these shortcuts are due to poor 3rd party reimbursement; but also it’s a bit troubling that the ramifications of the CI audiologist taking these shortcuts in terms of patient performance is not fully discussed in this book, i.e. it’s OK if the CI audiologist has an attitude of “it’s good enough for government work,” which, as an Engineer, this reviewer finds a bit lacking. Most notably, the common shortcut of assuming T levels of 10% of M levels on the AB and Med-El systems will result in an incorrect input dynamic range (IDR) being displayed: It will work, but in an unpredictable manner depending on the actual (measured) T levels the patient has. (Hat tip to Mike Marzalek of CItheory.com for teaching us this important point.)
However, there are two interrelated shortfalls in this book we hope the authors will address in the second edition: The first is a total lack of useful signal (timing) charts in Chapter 2, instead relying on awkward verbal descriptions of the various stimulation algorithms, as a picture is worth a thousand words. The second shortfall is the almost complete glossing over of current steering and beam forming, which are the processes of simultaneous firing of adjacent electrodes to shift the charge cloud to stimulate intermediate nerve endings for more pitch percepts (Med-El i100 & AB HiRes90k implant circuits); and firing of alternate polarity charges to adjacent electrodes to get a tighter, more focused charge pattern, to yield a “cleaner” stim (HiRes 90k only).²
One item notable by it’s absence is a Greenwood chart graphically explaining the cochlear tonotopic structure vs angular insertion depth of the electrode. Another item notable by its absence is any mention of Advanced Bionics’ ClearVoice noise reduction technology, which received the CE marque in January 2010 and was quickly rolled out across Canada & UK in February & March of that year. Granted, ClearVoice was just approved by the FDA in March 2012;³ but since this book is listed for sale in Britain on the Amazon.co.uk website, at least it was worthy of mention since it’s a released product; and was being beta tested at the AB factory as far back in September 2009.
There was also one minor author-date style annoyance while reading this book: The use of inline references for journal articles and books, as opposed to numbering and placing the footnotes at the bottom of each page. Yes, it’s permitted; and yes, it’s a bit more time consuming when typesetting to do this, but it’s a lot easier on the reader.
Overall, we give Programming Cochlear Implants a 4½ Star rating; and we highly recommend it to CI users, parents of CI kiddies, and to CI candidates.
1) Permitted FM Channels when using the Freedom Speech processor: From page 16 of Phonak’s FM Solutions for Cochlear Implants:
To avoid interference, the following channels are recommended to be used with the MicroLink Freedom
N Band: N09, N12, N13, N16, N17, N18, N52, N57, N61, N62, N64, N65, N68, N73, N76
H Band: H06, H07, H16, H17, H18, H19, H20, H47, H48, H57, H59, H77, H78, H79, H85, H86, H87, H88, H89, H90
2) This is indicated by the number of virtual channels, about 90 for the i100 and 120 for the HR90k; and manifests itself as more, and more closely spaced, pitch percepts. This is made possible by separate current sources for each electrode contact: The HR90k can fire both positive AND negative pulses simultaneously, while the i100 can fire multiple simultaneous positive OR negative pulses for basic current steering. To this day, even the new Nucleus 5 only has a single current source for all 22 contacts, as AB and MedEl have their technologies tightly wrapped up in worldwide patents.
3) 5/31/2012 correction: ClearVoice was approved by FDA in March 2012, not March 2010 as originally stated. The text has been changed to reflect this correction.
Wolfe, Jace, and Schafer, Erin C. 2010. Programming Cochlear Implants. San Diego: Plural Publishing. ISBN 978-1-59756-372-7