Central Auditory Plasticity: Changes in the N1-P2 Complex after Speech-Sound Training

Abstract

As perception improved, N1-P2 amplitude increased. These changes in waveform morphology are thought to reflect increases in neural synchrony as well as strengthened neural connections associated with improved speech perception. These findings suggest that the N1-P2 complex may have clinical applications as an objective physiologic correlate of speech-sound representation associated with speech-sound training.

Effect of auditory training on the middle latency response in children with (central) auditory processing disorder

“…Again, this is similar to other studies, which have also shown improvements in auditory behaviors that were correlated to electrophysiological enhancement, presumably from auditory training (2,9,12,38). Improvements in auditory behavior after training were consistent across all behavioral tests.…”

“…Improved speech discrimination subsequent to training has been reflected in MMN results in the work by Kraus et al (12). Additionally, Tremblay and associates (9,38) have shown that auditory training in speech syllables improves the perception of these sounds and enhances the N1-P2 auditory-evoked response to these speech sounds. The auditory training employed by Kraus et al (12) and Tremblay and colleagues (9,38) was more specific than that used in the present study.…”

“…For example, Jirsa (2) used a general auditory training program for a 7-week period (14 sessions), and demonstrated an increased P300 amplitude in children suspected of (C)APD. Additionally, Tremblay et al (9) used specific synthetic speech for training and testing over the course of 10 days, wherein their subjects demonstrated an increase in amplitude of the N1-P2 complex. It is difficult to determine if specific or nonspecific auditory training paradigms will yield the best results for either behavioral or electrophysiological measures; however, what does seem to be emerging is that auditory training can influence, in a positive way, physiologic and behavioral responses related to audition.…”

“…There is emerging evidence that auditory-evoked potentials can be used as an objective, noninvasive tool to investigate auditory processing and plasticity of auditory function in humans (2,(7)(8)(9)(10)(11). Kraus et al (12) observed that listeners with normal hearing who received extensive training in a subtle speech contrast task had corresponding changes in the MMN elicited by these speech differences, as well as improvements in behavioral discrimination performance.…”

The N1 complex to gaps in noise: Effects of preceding noise duration and intensity

“…N 1 -P 2 amplitudes have been related to changes in speech perception accompanying aging , sensory-neural hearing loss (Oates et al, 2002), training-related plasticity (Reinke et al, 2003;Tremblay and Kraus, 2002;Tremblay et al, 2001) and performance decrease by noise masking Whiting et al, 1998). The discrimination of temporal cues in speech has been studied with N 1 as a marker of detecting timevarying changes within a signal (Martin and Boothroyd, 1999) as well as the transition from friction noise to the following vowel (Ostroff et al, 1998;Tremblay et al, 2003).…”