Neural correlates of speech quality dimensions analyzed using electroencephalography (EEG)

Abstract

Objective. By means of subjective psychophysical methods, quality of transmitted speech has been decomposed into three perceptual dimensions named 'discontinuity' (F), 'noisiness' (N) and 'coloration' (C). Previous studies using electroencephalography (EEG) already reported effects of perceived intensity of single quality dimensions on electrical brain activity. However, it has not been investigated so far, whether the dimensions themselves are dissociable on a neurophysiological level of analysis. Approach. Pursuing this goal in the present study, a high-quality (HQ) recording of a spoken word was degraded on each dimension at a time, resulting in three quality-impaired stimuli (F, N, C) which were on average described as being equal in perceived degradation intensity. Participants performed a three-stimulus oddball task, involving the serial presentation of different stimulus types:(1) HQ or degraded 'standard' stimuli to establish sensory/perceptual quality references. (2) Degraded 'oddball' stimuli to cause random, infrequent deviations from those references. EEG was employed to examine the neuro-electrical correlates of speech quality perception. Main results. Emphasis was placed on modulations in temporal and morphological characteristics of the P300 component of the event-related brain potential (ERP), whose subcomponents P3a and P3b are commonly linked to attentional orienting and task relevance categorization, respectively. Electrophysiological data analysis ( N = 28) revealed significant modulations of P300 amplitude and latency by the perceptual dimensions underlying both quality references and oddball stimuli. Significance. The present study exemplifies the utility of physiological methods like EEG for dissociating speech degradations not only based on perceived intensity level, but also their distinctive quality dimension.

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

“…temporal, physical, task etc see [20,21]) context. Yet, the immediate experience of quality might already be contained in the conscious percept of a given stimulus, hence rendering it a higher-order perceptual attribute of perceived quality [17,22] that is more evaluative than descriptive in character [23][24][25]. Decompositions of the 'classic P3' waveform have revealed at least two subcomponents, P3a and P3b, which are linked to attentional orienting and perceptual categorization, respectively [15,26,27].…”

“…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].…”

Smart Mind-based Approach to Control a Wheelchair Wirelessly

“…Previously, the authors attempted to integrate spoken words with brainwaves to develop a model to control a wheelchair. (6) EEG was employed in the proposed model to examine the neuroelectrical correlates of speech quality perception. The model is cost-effective but has low reliability and it is inapplicable for fully quadriplegic people.…”

A common framework for the evaluation of psychophysiological visual quality assessment

“…Due to the stimuli selection, no such component could be identified in this study. However, EEG not only allows to discern perceived quality from perceived intensity level, but also in terms of distinctive quality dimensions, such as "discontinuity", "noisiness" and "coloration" [49]. Also other ERP components are candidates for neural markers of perceived quality, e.g., the P1 component for visual comfort due to vertical disparities in stereoscopic images [9].…”