Attention Bias to Pain Words Comes Early and Cognitive Load Matters: Evidence from an ERP Study on Experimental Pain

Attention bias (AB) is a common cognitive challenge for patients with pain. In this study, we tested at what stage AB to pain occurs in participants with experimental pain (EP) and tested whether cognitive load interferes with it. We recruited 40 healthy adults aged 18-27 years, and randomized them into control and EP groups. We sprayed the participants in the EP group with 10% capsaicin paste to mimic acute pain and those in the control group with water, accessing both groups’ behavioral results and event-related potential data. We found that high-load tasks had longer response times and lower accuracies than low-load tasks did and that different neural processing of words occurred between the groups. The EP group exhibited AB to pain at an early stage with both attentional avoidance (N1 latency) and facilitated attention (P2 amplitude) to pain words. The control group coped with semantic differentiation (N1) at first, followed by pain word discrimination (P2). In addition, AB to pain occurred only in low-load tasks. As the cognitive load multiplied, we did not find AB in the EP group. Therefore, our study adds further evidence for AB to pain, suggesting the implementation of cognitive load in future AB therapy.

First-language influence on second language speech perception depends on task demands

While listening to non-native speech, second language users filter the auditory input through their native language. We examined how bilinguals perceived second language (L2 English) sound sequences that conflicted with native-language (L1 Spanish) constraints across three experiments with different task demands. We used the L1 Spanish phonotactic constraint (i.e., rule for combining speech sounds) that vowels must precede s+consonant clusters (e.g., Spanish: estricto, “strict”). This L1 Spanish constraint may influence Spanish-English bilinguals’ processing of L2 English words such as strict because of a missing initial vowel, as in estrict. We found that the extent to which bilinguals were influenced by the L1 during L2 processing depended on task demands. When metalinguistic awareness demands were low, as in the AX word discrimination task (Experiment 1), cross-linguistic effects were not observed. When metalinguistic awareness demands were high, as in the vowel detection (Experiment 2) and lexical decision (Experiment 3) tasks, response times demonstrated that bilinguals were influenced by the L1 constraint when processing L2 words beginning with an s+consonant. We conclude that bilinguals are cross-linguistically influenced by L1 phonotactic constraints during L2 processing when metalinguistic demands are higher, suggesting that L2 input may be mapped onto L1 sub-lexical representations during perception. These results extend previous research on language co-activation and speech perception by providing a more fine-grained understanding of task demands and elucidating when and where cross-linguistic phonotactic access is present during bilingual comprehension.

Preverbal Infants Discover Statistical Word Patterns at Similar Rates as Adults: Evidence From Neural Entrainment

The discovery of words in continuous speech is one of the first challenges faced by infants during language acquisition. This process is partially facilitated by statistical learning, the ability to discover and encode relevant patterns in the environment. Here, we used an electroencephalogram (EEG) index of neural entrainment to track 6-month-olds’ ( N = 25) segmentation of words from continuous speech. Infants’ neural entrainment to embedded words increased logarithmically over the learning period, consistent with a perceptual shift from isolated syllables to wordlike units. Moreover, infants’ neural entrainment during learning predicted postlearning behavioral measures of word discrimination ( n = 18). Finally, the logarithmic increase in entrainment to words was comparable in infants and adults, suggesting that infants and adults follow similar learning trajectories when tracking probability information among speech sounds. Statistical-learning effects in infants and adults may reflect overlapping neural mechanisms, which emerge early in life and are maintained throughout the life span.

perception of brazilian Portuguese open and close mid vowels by native Russian speakers

The perception of Brazilian Portuguese (BP) mid vowels is mainly investigated by foreign researchers who work with learners of Brazilian Portuguese, native speakers of English or Spanish. In Brazil, this field has been poorly explored. This work contributes to filling this gap by investigating the perception of two Brazilian Portuguese minimal vowel pairs in the group of 103 native Russian speakers and nine French speakers, most of them residing in Brazil. The test has been designed to evaluate the perception of the mid high and low front vowels [e] - [ε], and the mid high and low back vowels [o] - [ɔ]. The test is conducted online and includes 30 trials distributed in three types of tasks: image identification (8 trials), vowel identification (4) and word discrimination (18). It also contains a short sociolinguistic questionnaire. Our findings indicate that native Russian speakers do not differentiate the Brazilian Portuguese mid vowels very well: the mean percentage of the correct answers in the Russophone group was 68%, while in the French group it was 87% and in the Brazilian control group 99%. No correlation was found between the percentage of correct answers and residence time in Brazil or type of language instruction. As next steps, we plan to investigate the differentiation of the Brazilian Portuguese open and close mid vowels by Russophones at the level of production. We also intend to create a training corpus and develop strategies for perception training of the Brazilian Portuguese mid vowels, monitoring their efficiency at different time points.

Effect of Powered Air-Purifying Respirators on Speech Recognition Among Health Care Workers

Powered air-purifying respirators (PAPRs) are used as personalized protective equipment for health care personnel. PAPRs offer health care workers added protection when dealing with patients who have high-risk infectious disease such as COVID-19. Unfortunately, PAPRs can produce notable levels of background noise. We hypothesize that PAPR use may be associated with increased hearing thresholds and impaired word discrimination and may ultimately have a negative impact on effective communication. Herein, we (1) determined sound levels generated by PAPRs and (2) measured hearing thresholds and word discrimination with and without operational PAPRs. All participants had normal hearing. When the PAPR was operational, mean ± SD thresholds increased from 4.5 ± 3.6 to 38.6 ± 5.6 dB HL ( P < .001). Word discrimination dropped from 100% in all participants in quiet to a mean 48% ± 14% with operational PAPR ( P < .001). Thus, we find that use of PAPR hoods results in hearing impairment comparable to moderate to severe hearing loss, and we suspect that users will experience communication difficulties as a result. Level of Evidence. Prospective study.

Tracking the Effects of Top–Down Attention on Word Discrimination Using Frequency-tagged Neuromagnetic Responses

Discrimination of words from nonspeech sounds is essential in communication. Still, how selective attention can influence this early step of speech processing remains elusive. To answer that question, brain activity was recorded with magnetoencephalography in 12 healthy adults while they listened to two sequences of auditory stimuli presented at 2.17 Hz, consisting of successions of one randomized word (tagging frequency = 0.54 Hz) and three acoustically matched nonverbal stimuli. Participants were instructed to focus their attention on the occurrence of a predefined word in the verbal attention condition and on a nonverbal stimulus in the nonverbal attention condition. Steady-state neuromagnetic responses were identified with spectral analysis at sensor and source levels. Significant sensor responses peaked at 0.54 and 2.17 Hz in both conditions. Sources at 0.54 Hz were reconstructed in supratemporal auditory cortex, left superior temporal gyrus (STG), left middle temporal gyrus, and left inferior frontal gyrus. Sources at 2.17 Hz were reconstructed in supratemporal auditory cortex and STG. Crucially, source strength in the left STG at 0.54 Hz was significantly higher in verbal attention than in nonverbal attention condition. This study demonstrates speech-sensitive responses at primary auditory and speech-related neocortical areas. Critically, it highlights that, during word discrimination, top–down attention modulates activity within the left STG. This area therefore appears to play a crucial role in selective verbal attentional processes for this early step of speech processing.

Vowel and Sibilant Production in Noise: Effects of Noise Frequency and Phonological Similarity

Purpose This study investigated vowel and sibilant productions in noise to determine whether responses to noise (a) are sensitive to the spectral characteristics of the noise signal and (b) are modulated by the contribution of vowel or sibilant contrasts to word discrimination. Method Vowel and sibilant productions were elicited during serial recall of three-word sequences that were produced in quiet or during exposure to speaker-specific noise signals. These signals either masked a speaker's productions of the sibilants /s/ and /ʃ/ or their productions of the vowels /a/ and /æ/. The contribution of the vowel and sibilant contrasts to word discrimination in a sequence was manipulated by varying the number of times that the target sibilant and vowel pairs occurred in the same word position in each sequence. Results Spectral noise effects were observed for both sibilants and vowels: Responses to noise were larger and/or involved to more acoustic features when the noise signal masked the acoustic characteristics of that phoneme class. Word discrimination effects were limited and consisted of only small increases in vowel duration. Interaction effects between noise and similarity indicated that the phonological similarity of sequences containing both sibilants and/or both vowels influenced articulation in ways not related to speech clarity. Conclusion The findings of this study indicate that sensorimotor control of speech exhibits some sensitivity to noise spectral characteristics. However, productions of sibilants and vowels were not sensitive to their importance in discriminating the words in a sequence. In addition, phonological similarity effects were observed that likely reflected processing demands related to the recall and sequencing of high-similarity words.

The Neuroanatomy of Speech Processing: A Large-Scale Lesion Study

The neural basis of language has been studied for centuries, yet the networks critically involved in simply identifying or understanding a spoken word remain elusive. Several functional-anatomical models of the critical neural substrates of receptive speech processes have been proposed, including auditory-related regions in the (1) left mid-posterior superior temporal lobe, (2) left anterior superior temporal lobe, or (3) bilateral in the mid-posterior superior temporal areas, and (4) motor-related regions in the left frontal lobe (in normal and/or noisy conditions). One difficulty in comparing these models is that they often focus on different aspects of the sound-to-meaning pathway and different types of stimuli and tasks. Two auditory tasks that are typically used in separate studies—nonword discrimination and word comprehension—often yield different conclusions. We assessed word/nonword discrimination and clear/noisy word comprehension in 160 individuals with focal brain damage: left (n=115) or right (n=19) hemisphere stroke, left (n=18) or right (n=8) anterior temporal lobectomy, and 26 neurologically-intact controls. Discrimination and comprehension doubly dissociated both behaviorally and neurologically. In support of a bilateral model, clear speech comprehension was near ceiling in 92% of left stroke cases, and right temporal damage was, for the first time, found to impair phoneme discrimination. Lesion-symptom mapping analyses for the word discrimination, non-word discrimination, and noisy word comprehension tasks each implicated most of the left superior temporal gyrus (STG) except the anterior most regions. Comprehension tasks also implicated the left pMTG, while discrimination tasks also implicated more dorsal sensorimotor regions in posterior perisylvian cortex.

Prelingual infants discover statistical word patterns at similar rates as adults: evidence from neural entrainment

The discovery of words in continuous speech is one of the first challenges faced by infants during language acquisition. This process is partially facilitated by statistical learning, the ability to discover and encode relevant patterns in the environment. Here, we used an EEG index of neural entrainment in 6-month-olds (n=25) to track their segmentation of words from continuous speech. Infants showed neural entrainment to embedded words that increased logarithmically over the learning period, consistent with a perceptual shift from isolated syllables to word-like units. Moreover, infants’ neural entrainment during learning predicted post-learning behavioural measures of word discrimination (n=18). Finally, the logarithmic increase in entrainment to words was comparable in infants and adults, suggesting that infants and adults follow similar learning trajectories when tracking probability information among speech sounds. Statistical learning effects in infants and adults may reflect overlapping neural mechanisms, which emerge early in life and are maintained throughout the lifespan.