Effects of Auditory Training in Older Adults.

PURPOSE: This study examines the effects of an auditory training program on the auditory and cognitive abilities of older adults. Auditory rehabilitation programs are generally designed for hearing aid users, and studies have demonstrated benefits for them. In this study, we seek to understand whether such a training program can also benefit older adults who do not wear hearing aids. We also examined if cognitive benefits can indeed be observed as a result of the training. METHOD: Sixty-four older adults were recruited and assigned into three groups: the experimental group (n = 20), the active control group (n = 21), and the no-training control group (n = 23). The experimental group underwent an auditory training program (Listening and Communication Enhancement [LACE]) during the training phase. Meanwhile, the active control group listened to short audio clips and the no-training control group did not participate in any program. An auditory test (Quick Speech-in-Noise [QuickSIN]) and a battery of cognitive tests were conducted before and after the training to examine the participants' performance on auditory ability, short-term memory, and attention. RESULTS: The results showed improvements in auditory and cognitive abilities during the training period. When assessing the training effects by comparing the pre- and the posttraining performances, a significant improvement on the QuickSIN task was found in the training group but not in the other two groups. However, other cognitive tests did not show any significant improvement. That is, the LACE training did not benefit short-term memory and attention. The improved performance on short-term memory during the training was not maintained in the posttraining session. CONCLUSION: Overall, the study has extended the auditory benefit from the LACE training to the typical aging population in terms of improved communication ability, but the effect of training on auditory abilities did not transfer to gains in cognitive abilities.

The form and function processing of lexical tone and intonation in tone-language-speaking children with autism spectrum disorder.

Studies on how the form versus function aspect of tone and intonation is processed by autistic individuals have mainly focused on speakers of non-tonal languages (e.g., English) with equivocal results. While the samples' heterogeneous cognitive abilities may be contributing factors, the phenotype of tone and intonation processing in autism may also vary with one's language background. Thirty-eight cognitively able autistic and 32 non-autistic Mandarin-speaking children completed tone and intonation perception tasks, each containing a function and form condition. Results suggested that the abilities to discriminate tone and intonation were not impaired at either the form or function level in these autistic children, and that these abilities were positively associated with one another in both autistic and non-autistic groups. The more severe the autism symptoms, the worse the form- and function-level of tone and intonation processing. While enhanced tone and intonation processing has been found in a subgroup of autistic children, it may not be a general characteristic of the autistic population with long-term tone language experience. These findings reveal typical tone and intonation processing at both the form and function levels in cognitively able Mandarin-speaking autistic children and provide evidence for associated tone and intonation processing abilities across levels.

Native Language Perceptual Sensitivity Predicts Nonnative Speech Perception Differently in Younger and Older Singaporean Bilinguals.

PURPOSE: We investigate in this study how individual variability in native language speech perception (termed Perceptual Sensitivity) influences nonnative speech perception in Singaporean Tamil-English bilinguals. Further, we assess if and how contextual and demographic factors influence Perceptual Sensitivity in the acquired languages and if the influence of Perceptual Sensitivity on nonnative speech perception is different across younger and older bilinguals. METHOD: Perceptual Sensitivity in the native languages was examined by implementing Tamil and English gating tasks in 87 Singaporean Tamil-English bilinguals from two age groups (younger: 19-33 years; older: 55-70 years). Mandarin lexical tone discrimination was implemented as a measure of nonnative speech perception. RESULTS: There was a wide range of variability in Perceptual Sensitivity scores in both languages across both age groups. Perceptual Sensitivity in the first native language (L1 Tamil) was a robust predictor of nonnative speech perception across both age groups, especially for the older bilinguals. However, general intelligence emerged as a stronger predictor than Tamil Perceptual Sensitivity in younger bilinguals. The influence of Tamil Perceptual Sensitivity on lexical tone perception was not tone-specific, supporting a general enhancement of lexical tone perception with better Tamil Perceptual Sensitivity. There was an influence of demographic factors on English Perceptual Sensitivity in older bilinguals, but not for Tamil and not in younger bilinguals. CONCLUSIONS: Our findings corroborate with previous studies in showing that native language Perceptual Sensitivity is positively associated with and predicts nonnative speech perception in younger and older adulthood regardless of language similarity but to varying degrees. Specifically, the influence of Perceptual Sensitivity on nonnative speech perception is stronger in older adulthood, suggesting a possible shift in reliance on crystallized language knowledge with age. Proficiency and use, among other demographic and language variables, do not appear to influence L1 Perceptual Sensitivity in a lesser used language (Tamil) as significantly as previously assumed.

Audio-Visual Interactions During Emotion Processing in Bicultural Bilinguals.

Despite the growing number of bicultural bilinguals in the world, the way in which multisensory emotions are evaluated by bilinguals who identify with two or more cultures remains unknown. In the present study, Chinese-English bicultural bilinguals from Singapore viewed Asian or Caucasian faces and heard Mandarin or English speech, and evaluated the emotion from one of the two simultaneously-presented modalities. Reliance on the visual modality was greater when bicultural bilinguals processed Western audio-visual emotion information. Although no differences between modalities emerged when processing East-Asian audio-visual emotion information, correlations revealed that bicultural bilinguals increased their reliance on the auditory modality with more daily exposure to East-Asian cultures. Greater interference from the irrelevant modality was observed for Asian faces paired with English speech than for Caucasian faces paired with Mandarin speech. We conclude that processing of emotion in bicultural bilinguals is guided by culture-specific norms, and that familiarity influences how the emotions of those who speak a foreign language are perceived and evaluated.

Individuals with congenital amusia do not show context-dependent perception of tonal categories.

Perceptual adaptation is an active cognitive process where listeners re-analyse speech categories based on new contexts/situations/talkers. It involves top-down influences from higher cortical levels on lower-level auditory processes. Individuals with congenital amusia have impaired pitch processing with reduced connectivity between frontal and temporal regions. This study examined whether deficits in amusia would lead to impaired perceptual adaptation in lexical tone perception. Thirteen Mandarin-speaking amusics and 13 controls identified the category of target tones on an 8-step continuum ranging from rising to high-level, either in isolation or in a high-/low-pitched context. For tones with no context, amusics exhibited reduced categorical perception than controls. While controls' lexical tone categorization demonstrated a significant context effect due to perceptual adaptation, amusics showed similar categorization patterns across both contexts. These findings suggest that congenital amusia impacts the extraction of context-dependent tonal categories in speech perception, indicating that perceptual adaptation may depend on listeners' perceptual acuity.

The influence of referent type and familiarity on word-referent mapping.

Is our memory for pairs of items dependent on item characteristics? The present study explores this question using a word learning paradigm; specifically, we examined whether referent characteristics, such as referent type (face/object) and familiarity (known/unknown), may influence word-referent mapping. Moreover, we examined this effect across two test sessions to determine if the influence of referent characteristics might be more pronounced over time, and across two age groups (young vs. older adults) to determine if there might be age-related differences. Participants were presented with pseudoword-referent mappings in four referent conditions (face/object × known/unknown) and then were tested with a recognition task immediately after learning, and again after a short delay. Our findings indicated that names for faces were not learned better than names for objects, despite previous literature suggesting that faces are processed differently. We also found that known referents (defined as having a pre-existing label for a referent) were learned better than unknown items but this familiarity advantage was only observed for faces and not for objects. While there were several age-related findings, these might be due to the longer delay between the immediate and delayed tests among the older adults relative to young adults. Taken together, our results suggest that certain referent characteristics do interact and influence our learning of and memory for such pairings.

Bilingualism shapes the other race effect.

It has recently been suggested that the other race effect (ORE), whereby own race faces are recognised better than those of other races, can be abolished by bilingualism.Bilingualism, however, is not a categorical variable but can vary dramatically in proficiency across the two languages. We therefore hypothesised that increasing bilingual proficiency should be associated with a diminishing ORE. To test this, we asked a group of bilingual Singaporean Chinese individuals to complete the Asian and Caucasian Cambridge Face Memory Tests. In contrast to recent work, our bilinguals did as a group exhibit an ORE, however, the magnitude of this effect decreased as reported cross-language proficiency increased; Chinese, rather than English, listening ability drove this association. This relationship persisted even when taking into account our participants' exposure to Caucasians, own race memory ability, age, and gender. Moreover, we discounted the possibility that bilingualism merely reflected participants' underlying intelligence. Increasing auditory bilingualism thus diminishes perceptual narrowing for faces. We propose that other race recognition ability reflects the base level of intrinsic, domain specific face memory, whereas the distance in recognition performance between own and other race faces is comprised of a domain general process related to stimulus individuation. Finally, our results have serious implications for how we can interpret prior research investigating the ORE, and culture's influence on visual perception, due to the confounding influence of bilingualism.

Impaired processing of facial happiness, with or without awareness, in developmental prosopagnosia.

Developmental prosopagnosia (DP) is associated with severe, lifelong deficits in face recognition, with such cases often cited as support for a dissociation between the processing of facial identity and emotion. Here we examine the evidence against this dissociation and propose that the processing of facial happiness, either with or without awareness, is actually integrated within the same neural network involved in facial identity recognition. We also test this hypothesis on a group of DP cases and neurotypical controls (NT) by adapting them to expressionless neutral faces, intact happy faces and hybrid faces. Despite these hybrid faces being explicitly identified as expressionless due to their higher spatial frequencies taken from a neutral face, their low spatial frequencies convey happy facial expressions that participants are unaware of. After adaptation, participants were asked to judge the facial expressions of face stimuli that were morphed incrementally in varying degrees of sad through to happy. Both groups exhibited emotion adaptation aftereffects to the intact happy faces, although this effect was smaller in DP. Whereas NT produced emotion adaptation aftereffects without awareness of the happy emotion in the hybrid faces; as a group, those with DP did not. Furthermore, our DP cases also exhibited deficits in judging the emotion of the happiest morphed test faces. Our results indicate that the processing of happy facial expressions, with or without awareness, is likely integrated within the face recognition network. We hypothesise that the previously identified abnormalities in the fusiform gyrus in those with DP is the most likely structure responsible for these deficits.

Pitch perception and production in congenital amusia: Evidence from Cantonese speakers.

This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production.

Effect of Subliminal Lexical Priming on the Subjective Perception of Images: A Machine Learning Approach.

The purpose of the study is to examine the effect of subliminal priming in terms of the perception of images influenced by words with positive, negative, and neutral emotional content, through electroencephalograms (EEGs). Participants were instructed to rate how much they like the stimuli images, on a 7-point Likert scale, after being subliminally exposed to masked lexical prime words that exhibit positive, negative, and neutral connotations with respect to the images. Simultaneously, the EEGs were recorded. Statistical tests such as repeated measures ANOVAs and two-tailed paired-samples t-tests were performed to measure significant differences in the likability ratings among the three prime affect types; the results showed a strong shift in the likeness judgment for the images in the positively primed condition compared to the other two. The acquired EEGs were examined to assess the difference in brain activity associated with the three different conditions. The consistent results obtained confirmed the overall priming effect on participants' explicit ratings. In addition, machine learning algorithms such as support vector machines (SVMs), and AdaBoost classifiers were applied to infer the prime affect type from the ERPs. The highest classification rates of 95.0% and 70.0% obtained respectively for average-trial binary classifier and average-trial multi-class further emphasize that the ERPs encode information about the different kinds of primes.

On the effect of subliminal priming on subjective perception of images: a machine learning approach.

The research presented in this article investigates the influence of subliminal prime words on peoples' judgment about images, through electroencephalograms (EEGs). In this cross domain priming paradigm, the participants are asked to rate how much they like the stimulus images, on a 7-point Likert scale, after being subliminally exposed to masked lexical prime words, with EEG recorded simultaneously. Statistical analysis tools are used to analyze the effect of priming on behavior, and machine learning techniques to infer the primes from EEGs. The experiment reveals strong effects of subliminal priming on the participants' explicit rating of images. The subjective judgment affected by the priming makes visible change in event-related potentials (ERPs); results show larger ERP amplitude for the negative primes compared with positive and neutral primes. In addition, Support Vector Machine (SVM) based classifiers are proposed to infer the prime types from the average ERPs, which yields a classification rate of 70%.

Effects of culture on musical pitch perception.

The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture-to-perception influences.

Effects of mono- and bicultural experiences on auditory perception.

The auditory system functions in the context of everyday life and the cultural environment in which we live. Although cultural-invariant, universal principles certainly contribute to sound processing, cultural factors play a role as well. In this review paper, we discuss two potential sources of cultural influence on auditory perception. We term the first type bottom-up, and use it to refer to the way that increased exposure to particular kinds of sound could shape our auditory and auditory-neural responses. The second type we term top-down, and use it to refer to the way our cultural upbringing broadly shapes how we think, which may in turn have an impact on how we perceive the world. An important consideration regarding cultural influences is that many individuals grow up with exposure to environmental stimulations of more than one culture. In our discussion, we will consider both mono- and bicultural experiences.

The bimusical brain is not two monomusical brains in one: evidence from musical affective processing.

Complex auditory exposures in ambient environments include systems of not only linguistic but also musical sounds. Because musical exposure is often passive, consisting of listening rather than performing, examining listeners without formal musical training allows for the investigation of the effects of passive exposure on our nervous system without active use. Additionally, studying listeners who have exposure to more than one musical system allows for an evaluation of how the brain acquires multiple symbolic and communicative systems. In the present fMRI study, listeners who had been exposed to Western-only (monomusicals) and both Indian and Western musical systems (bimusicals) since childhood and did not have significant formal musical training made tension judgments on Western and Indian music. Significant group by music interactions in temporal and limbic regions were found, with effects predominantly driven by between-music differences in temporal regions in the monomusicals and by between-music differences in limbic regions in the bimusicals. Effective connectivity analysis of this network via structural equation modeling (SEM) showed significant path differences across groups and music conditions, most notably a higher degree of connectivity and larger differentiation between the music conditions within the bimusicals. SEM was also used to examine the relationships among the degree of music exposure, affective responses, and activation in various brain regions. Results revealed a more complex behavioral-neural relationship in the bimusicals, suggesting that affective responses in this group are shaped by multiple behavioral and neural factors. These three lines of evidence suggest a clear differentiation of the effects of the exposure of one versus multiple musical systems.

Activity levels in the left hemisphere caudate-fusiform circuit predict how well a second language will be learned.

How second language (L2) learning is achieved in the human brain remains one of the fundamental questions of neuroscience and linguistics. Previous neuroimaging studies with bilinguals have consistently shown overlapping cortical organization of the native language (L1) and L2, leading to a prediction that a common neurobiological marker may be responsible for the development of the two languages. Here, by using functional MRI, we show that later skills to read in L2 are predicted by the activity level of the fusiform-caudate circuit in the left hemisphere, which nonetheless is not predictive of the ability to read in the native language. We scanned 10-y-old children while they performed a lexical decision task on L2 (and L1) stimuli. The subjects' written language (reading) skills were behaviorally assessed twice, the first time just before we performed the fMRI scan (time 1 reading) and the second time 1 y later (time 2 reading). A whole-brain based analysis revealed that activity levels in left caudate and left fusiform gyrus correlated with L2 literacy skills at time 1. After controlling for the effects of time 1 reading and nonverbal IQ, or the effect of in-scanner lexical performance, the development in L2 literacy skills (time 2 reading) was also predicted by activity in left caudate and fusiform regions that are thought to mediate language control functions and resolve competition arising from L1 during L2 learning. Our findings suggest that the activity level of left caudate and fusiform regions serves as an important neurobiological marker for predicting accomplishment in reading skills in a new language.

Neural processing of what and who information in speech.

Human speech is composed of two types of information, related to content (lexical information, i.e., "what" is being said [e.g., words]) and to the speaker (indexical information, i.e., "who" is talking [e.g., voices]). The extent to which lexical versus indexical information is represented separately or integrally in the brain is unresolved. In the current experiment, we use short-term fMRI adaptation to address this issue. Participants performed a loudness judgment task during which single or multiple sets of words/pseudowords were repeated with single (repeat) or multiple talkers (speaker-change) conditions while BOLD responses were collected. As reflected by adaptation fMRI, the left posterior middle temporal gyrus, a crucial component of the ventral auditory stream performing sound-to-meaning computations ("what" pathway), showed sensitivity to lexical as well as indexical information. Previous studies have suggested that speaker information is abstracted during this stage of auditory word processing. Here, we demonstrate that indexical information is strongly coupled with word information. These findings are consistent with a plethora of behavioral results that have demonstrated that changes to speaker-related information can influence lexical processing.

Language regions of brain are operative in color perception.

The effect of language on the categorical perception of color is stronger for stimuli in the right visual field (RVF) than in the left visual field, but the neural correlates of the behavioral RVF advantage are unknown. Here we present brain activation maps revealing how language is differentially engaged in the discrimination of colored stimuli presented in either visual hemifield. In a rapid, event-related functional MRI study, we measured subjects' brain activity while they performed a visual search task. Compared with colors from the same lexical category, discrimination of colors from different linguistic categories provoked stronger and faster responses in the left hemisphere language regions, particularly when the colors were presented in the RVF. In addition, activation of visual areas 2/3, responsible for color perception, was much stronger for RVF stimuli from different linguistic categories than for stimuli from the same linguistic category. Notably, the enhanced activity of visual areas 2/3 coincided with the enhanced activity of the left posterior temporoparietal language region, suggesting that this language region may serve as a top-down control source that modulates the activation of the visual cortex. These findings shed light on the brain mechanisms that underlie the hemifield- dependent effect of language on visual perception.

Neural correlates of nouns and verbs in early bilinguals.

Previous neuroimaging research indicates that English verbs and nouns are represented in frontal and posterior brain regions, respectively. For Chinese monolinguals, however, nouns and verbs are found to be associated with a wide range of overlapping areas without significant differences in neural signatures. This different pattern of findings led us to ask the question of where nouns and verbs of two different languages are represented in various areas in the brain in Chinese-English bilinguals. In this study, we utilized functional magnetic resonance imaging (fMRI) and a lexical decision paradigm involving Chinese and English verbs and nouns to address this question. We found that while Chinese nouns and verbs involved activation of common brain areas, the processing of English verbs engaged many more regions than did the processing of English nouns. Specifically, compared to English nouns, English verb presentation was associated with stronger activation of the left putamen and cerebellum, which are responsible for motor function, suggesting the involvement of the motor system in the processing of English verbs. Our findings are consistent with the theory that neural circuits for linguistic dimensions are weighted and modulated by the characteristics of a language.

Language affects patterns of brain activation associated with perceptual decision.

Well over half a century ago, Benjamin Lee Whorf [Carroll JB (1956) Language, Thought, and Reality: Selected Writings of Benjamin Lee Whorf (MIT Press, Cambridge, MA)] proposed that language affects perception and thought and is used to segment nature, a hypothesis that has since been tested by linguistic and behavioral studies. Although clear Whorfian effects have been found, it has not yet been demonstrated that language influences brain activity associated with perception and/or immediate postperceptual processes (referred hereafter as "perceptual decision"). Here, by using functional magnetic resonance imaging, we show that brain regions mediating language processes participate in neural networks activated by perceptual decision. When subjects performed a perceptual discrimination task on easy-to-name and hard-to-name colored squares, largely overlapping cortical regions were identified, which included areas of the occipital cortex critical for color vision and regions in the bilateral frontal gyrus. Crucially, however, in comparison with hard-to-name colored squares, perceptual discrimination of easy-to-name colors evoked stronger activation in the left posterior superior temporal gyrus and inferior parietal lobule, two regions responsible for word-finding processes, as demonstrated by a localizer experiment that uses an explicit color patch naming task. This finding suggests that the language-processing areas of the brain are directly involved in visual perceptual decision, thus providing neuroimaging support for the Whorf hypothesis.

Effects of age of acquisition on brain activation during Chinese character recognition.

The age of acquisition of a word (AoA) has a specific effect on brain activation during word identification in English and German. However, the neural locus of AoA effects differs across studies. According to Hernandez and Fiebach [Hernandez, A., & Fiebach, C. (2006). The brain bases of reading late-learned words: Evidence from functional MRI. Visual Cognition, 13(8), 1027-1043], the effects of AoA on brain activation depend on the predictability of the connections between input (orthography) and output (phonology) in a lexical network. We tested this hypothesis by examining AoA effects in a non-alphabetic script with relatively arbitrary mappings between orthography and phonology--Chinese. Our results showed that the effects of AoA in Chinese speakers are located in brain regions that are spatially distinctive including the bilateral middle temporal gyrus and the left inferior parietal cortex. An additional finding was that word frequency had an independent effect on brain activation in the right middle occipital gyrus only. We conclude that spatially distinctive effects of AoA on neural activity depend on the predictability of the mappings between orthography and phonology and reflect a division of labour towards greater lexical-semantic retrieval in non-alphabetic scripts.