P300 indicates context-dependent change in speech quality beyond phonological change

Abstract

Objective. Non-invasive physiological methods like electroencephalography (EEG) are increasingly employed to assess human information processing during exposure to multimedia signals. In the quality engineering field, previous research has promoted the utility of the P300 event-related brain potential (ERP) component for indicating variation in quality perception. The present study provides a starting point to test whether the P300 and its two subcomponents, P3a and P3b, are truly reflective of changes in the perceived quality of transmitted speech signals given the presence of other, quality-unrelated changes in acoustic stimulation. Approach. High-quality and degraded variants of spoken words were presented in a two-feature oddball task, which required participants to actively respond to rarely occurring ‘target’ stimuli within a series of frequent ‘standard’ stimuli, thereby eliciting ERP waveforms. Target presentations involved either single quality changes or concurrent double changes in quality and the initial phoneme. Main results. In case additional phonological change was present, only varying quality of standard stimuli caused significant modulations in P3a and P3b characteristics (N = 32). Thus, the formation of different short-term quality references exerted a persisting influence on the auditory processing of transmitted speech. Significance. The obtained results elucidate the importance of contextual and content-related influencing factors for proving the validity of the P300 as a psychophysiological indicator of speech quality change. Associated questions regarding the transfer of ERP-based quality assessment into more practically relevant measurement contexts are discussed.

Effects of speech transmission quality on sensory processing indicated by the cortical auditory evoked potential

“…The present study puts forward analyses of electrophysiological data gathered in two companion studies (referred to below as study 1 [17] and study 2 [18]), each of which employed a three-stimulus variant of the classic oddball paradigm to examine effects of speech quality degradations on P3. Three-stimulus oddball tasks comprise three stimulus types that vary in presentation rate and task relevance [15]: 'Standards' occur with high frequency (e.g.…”

“…In study 1 [17], this underlying perceptual dimensionality of speech quality was varied in the standard and oddball (target, distractor) by applying either signalcorrelated noise ('noisiness'-impaired) or bandpass filtering ('coloration'-impaired) to a spoken word stimulus. In study 2 [18], two types of targets were presented, involving either a single change in quality (T-single) or double changes in quality and spoken word content (T-double). For the content manipulation, two words with different initial phonemes were presented.…”

“…Initial inspection of ERP waveforms for target stimuli obtained in studies 1 and 2 revealed visible negative deflections in the time range of N1, which appeared to be stronger for coloration-than noisiness-impaired oddball stimuli [17,18]. Nonetheless, these observations were entirely exploratory in character since only a priori formulated hypotheses concerning P3 parameters were tested in the previous analyses.…”

“…Amplitude and latency characteristics of the P3 (also: P300) component [15,16] of the event-related brain potential (ERP) [10] were implied as neural correlates of perceived quality change: Higher magnitudes of quality impairment were reliably accompanied by increased P3 amplitudes and reduced P3 latencies. Moreover, depending on the stimulus context, different kinds of quality impairment resulted in specific P3 response patterns [17,18]. These effects on P3 have been ascribed to varying 'neuronal effort' mobilized for perceptual and cognitive processing and corresponded closely with behavioral task performance [12-14, 17, 18].…”

Cortical entrainment to speech produced by cochlear implant talkers and normal-hearing talkers

“…Neurophysiological processing of sound is usually examined using event-related potentials (ERPs). The P3 component has been recently used to evaluate the effects of perceived quality changes in speech ( Uhrig et al, 2019a , b ) and it was reported that the peak amplitude and latency were modulated by sound quality. Likewise, others studies ( Martin et al, 1997 ; Martin and Stapells, 2005 ; Antons et al, 2010 , 2012 ; Porbadnigk et al, 2013 ) also showed that, as the level of degradation decreases when compared to the standard stimulus, which means it is harder for listeners to discriminate the deviant stimulus from the standard stimulus, the amplitude and latency of the P3 component become lower and longer, respectively.…”