The conference was not solely about cochlear implants, it also covered various other auditory implants such as brainstem and bone-anchored implants, but I will only be covering the CI related parts. With over 230 presentations roughly ten minutes each in length it was necessary to have up to three concurrent sessions running at a given time -- making it impossible to catch everything. Fortunately it was well organized and I only missed a couple of presentations of interest due to conflicts. There were also over 250 poster presentations in the exhibit hall. I was able to talk to reps from all the major CI companies, posed questions to several of the researchers, and met some really interesting individuals. Four days of MSO (Maximum Sensory Overload) from which I am still attempting to recover!
The topics in which I was most interested were:
- Basic Research
- Electrophysiology
- Coding Strategies/Electrode Design/Mapping Strategies
- Music Perception
- Tests of relatively newly released technologies (e.g. Fidelity 120)
- Analyzing current technologies, looking for areas needing improvement
- Tests of new technologies in development
Most of the scientific studies presented were specific to a particular brand, however a few were multi-brand. All the brands are performing well with no huge differences.
As CI performance has improved, the need for better tests has increased. Some of the easiest tests are starting to see a ceiling effect, in which a significant number of subjects score at or near 100%. While that can be quite satisfying on a personal level, it does not provide useful information when testing existing or new strategies. Other tests don't adequately reflect real-world performance. Many new test methods were proposed and some should work their way into the mainstream in the coming years. So, CI users, be prepared for more challenging tests.
There were a couple of presentations regarding tracking implant reliability. Apparently there are differences between manufacturer's definitions of device failure as well as their reporting methods. Some effort is being put forth to globally standardize CSR (Cumulative Survival Rate) reporting.
Now that Advanced Bionics' Fidelity-120 strategy has been commercially available for over a year, as one would expect it was the subject of quite a few studies. There is some indication that speech recognition in noise, and overall speech discrimination in tonal languages, is improved to a degree using F-120. Studies of music perception were a bit of a conundrum: while there was no significant improvement in objective music testing scores (melody, timbre and rhythm identification), subjective scores for music enjoyment were significantly higher across the board.
Spread of Excitation (SOE) was a hot topic. SOE is the longitudinal spread of electrical energy across the cochlea. SOE can be measured using the return telemetry from the CI, which takes readings from electrodes on either side of a fired electrode (or electrode group). Several studies indicate that narrower SOE correlates with improved speech and pitch discrimination performance. Another study suggests that SOE narrows over time after implantation, which could be one factor why most CI recipients' performance improves over time.
There is also work going on to create stimulation strategies that reduce SOE by applying reverse-phase stimulation to adjacent electrodes. The goal is to improve tonal quality, which could benefit both music and speech perception.
I was glad to find several studies in progress on pitch alignment and mapping. One study used a 3D model of the cochlea and electrode position created from CT Scans to estimate the overall pitch alignment. Another used patient-controlled software to subjectively adjust their map. There is indication of improved speech understanding with a custom fit pitch map.
The prior two subjects are the BIG TWO for me: Pitch Map and Tone Quality. I think they go hand-in-hand. Even though my pitch perception has improved over the four months I have been activated, it has a long way to go and I doubt it will get there on its own. I am looking forward to the day I can sit down at a mapping session and realign my pitch map so that intervals and octaves are accurate. Having improved tone quality should not only help perform that process, it should improve the overall sound quality of the final result.
I was encouraged by the variety and volume of research being conducted to improve CIs. I was also glad to have the opportunity to provide encouragement to a couple of researchers working on my Big 2. And my CI performed like a dream. For the past 10 years or so, before my CI, I would have had a great deal of trouble communicating, and would have completely depended on the captioning (CART system) that was provided during presentations. It was liberating to actually watch a speaker and glance at their presentation graphics, rather than paying most attention to a caption screen. The most difficult listening situation of the conference was during the Karaoke sessions at the Med El booth in the exhibit hall at lunch breaks. They really cranked the volume -- but at least it was (somewhat perversely) entertaining!
If you are interested in reading abstracts from the presentations, there is a PDF file of the conference program book available on the CI 2008 website.
The 11th conference will be held June-July 2010 in Stockholm, Sweden, with the 12th in Baltimore, Maryland in April 2012. Go if you can.
