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From: Ryan Pollard
Date: 21 Oct 2008
Time: 22:22:05 -0500
Remote Name: 70.57.41.136
I would have to agree with you on all points, Klaas. However, I understood the question about side effects to mean, Did our subjects report any unexpected consequences from wearing their devices during the study? Regarding the issues you raise, we did not test for side effects related to 1) neuroplasticity due to prolonged exposure to AAF, or 2) the occurrence of hearing loss caused by prolonged exposure to high volume levels. Like you, I would speculate that both are possible consequences of continued SpeechEasy use, particularly the hearing loss. For me, the issue of cortical changes in various auditory fields is the more fascinating. Rastatter et al. (1998) showed reduced power in the beta frequency range over auditory cortex during DAF and FAF, and other work unrelated to stuttering has shown reduction in N100 dampening and decreases in frontotemporal gamma band coherence during FAF (Heinks-Maldonado et al., 2005; Ford et al., 2005). Those studies only looked at acute effects, though, and I would be very interested to know if prolonged exposure to AAF leads to either short-term alterations in the effectiveness of existing synaptic connections, or long-term (possibly permanent) anatomical changes such as pruning or the growth of new connections. You’re quite correct that this particular area of inquiry is ripe for exploration.