Mother and stranger: an electrophysiological study of voice processing in newborns.

In the mature adult brain, there are voice selective regions that are especially tuned to familiar voices. Yet, little is known about how the infant's brain treats such information. Here, we investigated, using electrophysiology and source analyses, how newborns process their mother's voice compared with that of a stranger. Results suggest that, shortly after birth, newborns distinctly process their mother's voice at an early preattentional level and at a later presumably cognitive level. Activation sources revealed that exposure to the maternal voice elicited early language-relevant processing, whereas the stranger's voice elicited more voice-specific responses. A central probably motor response was also observed at a later time, which may reflect an innate auditory-articulatory loop. The singularity of left-dominant brain activation pattern together with its ensuing sustained greater central activation in response to the mother's voice may provide the first neurophysiologic index of the preferential mother's role in language acquisition.

Reflex reading epilepsy: effect of linguistic characteristics on spike frequency.

Reading epilepsy is a rare reflex epilepsy in which seizures are provoked by reading. Several cases have been described in the literature, but the pathophysiological processes vary widely and remain unclear. We describe a 42-year-old male patient with reading epilepsy evaluated using clinical assessments and continuous video/EEG recordings. We administered verbal, nonverbal, and reading tasks to determine factors precipitating seizures. Linguistic characteristics of the words were manipulated. Results indicated that reading-induced seizures were significantly more numerous than those observed during verbal and nonverbal tasks. In reading tasks, spike frequency significantly increased with involvement of the phonological reading route. Spikes were recorded predominantly in left parasagittal regions. Future cerebral imaging studies will enable us to visualize the spatial localization and temporal course of reading-induced seizures and brain activity involved in reading. A better understanding of reading epilepsy is crucial for reading rehabilitation in these patients.

Language tasks used for the presurgical assessment of epileptic patients with MEG.

Determining the language dominant hemisphere and the intrahemispheric localization of this function are imperative in the planning of neurosurgical procedures in epileptic patients. New noninvasive diagnostic techniques are being developed to reduce the risks associated with more invasive techniques. The aim of this paper is to review the different protocols for lateralizing and/or localizing language functions using magnetoencephalography (MEG), a noninvasive technique. The reviewed studies include control and patient populations using various protocols which employ different expressive and receptive language tasks. The overall findings reveal high concordance between MEG and the intracarotid amobarbital test (IAT). Moreover, MEG allows intrahemispheric localization of receptive and expressive language functions. However, the different language tasks used with MEG, whether receptive or expressive, appear to activate the left temporal more than frontal areas. The best task to assess language comprehension in both adults and children appears to be a word recognition task. A verbal fluency task could be used to test language production in children and a verb generation task in adults.

The sound of mute vowels in auditory word-stem completion.

Some studies have argued that orthography can influence speakers when they perform oral language tasks. Words containing a mute vowel provide well-suited stimuli to investigate this phenomenon because mute vowels, such as the second in , are present orthographically but absent phonetically. Using an auditory word-stem completion task, we tested whether subjects were influenced by the presence of mute vowels. We ran experiments in two languages which contain numerous mute-vowel words: Tigrinya, which uses a syllabic/moraic writing system, and French, which uses an alphabetic writing system. We argue that Tigrinya and French speakers based their completion on the sound form of words, rather than the written one. We suggest that the presence of mute vowels at the underlying phonological level, rather than their orthographic representation, influences speakers in the word-stem completion task. Some effects previously attributed to orthography may instead be attributable to underlying phonological representations.

Non-invasive pre-surgical investigation of a 10 year-old epileptic boy using simultaneous EEG-NIRS.

Near-infrared spectroscopy (NIRS) is a novel imaging technique of potential value in the pre-surgical investigation of patients with refractory epilepsy. We recorded simultaneously electrophysiology (EEG; Compumedics, USA) and near-infrared spectroscopy (NIRS; ISS, USA) to examine the localization of the ictal onset zone and assess language lateralization in a young epileptic boy (L.H., 10 years) as part of his pre-surgical evaluation. L.H. underwent a prolonged EEG-NIRS recording while electro-clinical and electrical seizures were recorded. Results were compared to those obtained with other pre-surgical techniques (SPECT, FDG-PET, EEG-fMRI and EEG-MEG) and showed good concordance for ictal onset zone localization. A second NIRS session without EEG was carried out in order to investigate language lateralization. For this purpose, the patient performed a categorical verbal-fluency task during NIRS recordings. Results showed left-hemisphere dominance for language function in this young boy. This case report illustrates that multi-channel EEG-NIRS has the potential to contribute favourably to pre-surgical investigation in young patients.

Near-infrared spectroscopy as an alternative to the Wada test for language mapping in children, adults and special populations.

The intracarotid amobarbital test (IAT) is the most widely used procedure for pre-surgical evaluation of language lateralization in epileptic patients. However, apart from being invasive, this technique is not applicable in young children or patients who present mental retardation and/or language deficits. Functional magnetic resonance imaging (fMRI) is increasingly employed as a non-invasive alternative. Again, this method is more difficult to use with young children, especially hyperactive ones, since they have to remain motionless during data acquisition. The aim of this study was to determine whether near-infrared spectroscopy (NIRS) can be used as an alternative technique to investigate language lateralization in children and special populations. Unlike Wada test, NIRS is non-invasive, and it is more tolerant to movement artefacts than fMRI. In the present study, NIRS data were acquired in four epileptic children, a 12-year-old boy with pervasive developmental disorder and a 3-year-old, healthy child, as well as three healthy and two epileptic adults, while they performed a verbal fluency task and a control task. When applicable, the results were compared to the subjects' fMRI and/or IAT findings. Clear laterality of speech was obtained in all participants, including the two non-epileptic children, and NIRS results matched fMRI and IAT findings. These results, if replicable in larger samples, are encouraging and suggest that NIRS has the potential to become a viable, non-invasive alternative to IAT and fMRI in the determination of speech lateralization in children and clinical populations that cannot be submitted to more invasive techniques.

Verbal memory and verbal fluency tasks used for language localization and lateralization during magnetoencephalography.

OBJECTIVE: The aim of this study was to develop a presurgical magnetoencephalography (MEG) protocol to localize and lateralize expressive and receptive language function as well as verbal memory in patients with epilepsy. Two simple language tasks and a different analytical procedure were developed. METHODS: Ten healthy participants and 13 epileptic patients completed two language tasks during MEG recording: a verbal memory task and a verbal fluency task. As a first step, principal component analyses (PCA) were performed on source data from the group of healthy participants to identify spatiotemporal factors that were relevant to these paradigms. Averaged source data were used to localize areas activated during each task and a laterality index (LI) was computed on an individual basis for both groups, healthy participants and patients, using sensor data. RESULTS: PCA revealed activation in the left temporal lobe (300 ms) during the verbal memory task, and from the frontal lobe (210 ms) to the temporal lobe (500 ms) during the verbal fluency task in healthy participants. Averaged source data showed activity in the left hemisphere (250-750 ms), in Wernicke's area, for all participants. Left hemisphere dominance was demonstrated better using the verbal memory task than the verbal fluency task (F1,19=4.41, p=0.049). Cohen's kappa statistic revealed 93% agreement (k=0.67, p=0.002) between LIs obtained from MEG sensor data and fMRI, the IAT, electrical cortical stimulation or handedness with the verbal memory task for all participants. At 74%, agreement results for the verbal fluency task did not reach statistical significance. SIGNIFICANCE: Analysis procedures yielded interesting findings with both tasks and localized language-related activation. However, based on source localization and laterality indices, the verbal memory task yielded better results in the context of the presurgical evaluation of epileptic patients. The verbal fluency task did not add any further information to the verbal memory task as regards language localization and lateralization for most patients and healthy participants that would facilitate decision making prior to surgery.

Recruitment of the left precentral gyrus in reading epilepsy: A multimodal neuroimaging study.

PURPOSE: In a previous study, we investigated a 42-year-old male patient with primary reading epilepsy using continuous video-electroencephalography (EEG). Reading tasks induced left parasagittal spikes with a higher spike frequency when the phonological reading pathway was recruited compared to the lexical one. Here, we seek to localize the epileptogenic focus in the same patient as a function of reading pathway using multimodal neuroimaging. METHODS AND RESULTS: The participant read irregular words and nonwords presented in a block-design paradigm during magnetoencephalography (MEG), functional near-infrared spectroscopy (fNIRS), and functional magnetic resonance imaging (fMRI) recordings, all combined with EEG. Spike analyses from MEG, fNIRS, and fMRI-EEGs data revealed an epileptic focus in the left precentral gyrus, and spike localization did not differ in lexical and phonological reading. CONCLUSION: This study is the first to investigate ictogenesis in reading epilepsy during both lexical and phonological reading while using three different multimodal neuroimaging techniques. The somatosensory and motor control functions of the left precentral gyrus that are congruently involved in lexical as well as phonological reading can explain the identical spike localization in both reading pathways. The concurrence between our findings in this study and those from our previous one supports the role of the left precentral gyrus in phonological output computation as well as seizure activity in a case of reading epilepsy.

Distinct hemispheric specializations for native and non-native languages in one-day-old newborns identified by fNIRS.

This study assessed whether the neonatal brain recruits different neural networks for native and non-native languages at birth. Twenty-seven one-day-old full-term infants underwent functional near-infrared spectroscopy (fNIRS) recording during linguistic and non-linguistic stimulation. Fourteen newborns listened to linguistic stimuli (native and non-native language stories) and 13 newborns were exposed to non-linguistic conditions (native and non-native stimuli played in reverse). Comparisons between left and right hemisphere oxyhemoglobin (HbO2) concentration changes over the temporal areas revealed clear left hemisphere dominance for native language, whereas non-native stimuli were associated with right hemisphere lateralization. In addition, bilateral cerebral activation was found for non-linguistic stimulus processing. Overall, our findings indicate that from the first day after birth, native language and prosodic features are processed in parallel by distinct neural networks.

Physiological stress response to video-game playing: the contribution of built-in music.

Recent studies on video game playing have uncovered a wide range of measurable physiological effects on the organism, such as increases in cardiovascular activity and breathing responses. However, the exact source of these effects remains unclear. Given the well-known effects of sound on physiological activity, especially those of noise and of music, and on the secretion of the stress hormone cortisol in particular, we hypothesized that music may be a major source of stress during video game playing. We thus examined the effect of built-in music on cortisol secretion as a consequence of video game playing. Players were assigned quasi-randomly to either a Music or a Silence condition. Four saliva samples were taken, that is, after practice (T1), immediately after having played for 10 minutes (T2), 15 minutes after the end of the experiment (T3), and 30 minutes after the end of the experiment (T4). The results show that the Music group had significantly higher cortisol levels at T3, that is, when cortisol levels are assumed to reflect the stress induced by the game. These findings suggest for the first time that the auditory input contributes significantly to the stress response found during video game playing.

Singing abilities in children with Specific Language Impairment (SLI).

Specific Language Impairment (SLI) is a heritable neurodevelopmental disorder diagnosed when a child has difficulties learning to produce and/or understand speech for no apparent reason (Bishop et al., 2012). The verbal difficulties of children with SLI have been largely documented, and a growing number of studies suggest that these children may also have difficulties in processing non-verbal complex auditory stimuli (Corriveau et al., 2007; Brandt et al., 2012). In a recent study, we reported that a large proportion of children with SLI present deficits in music perception (Planchou et al., under revision). Little is known, however, about the singing abilities of children with SLI. In order to investigate whether or not the impairments in expressive language extend to the musical domain, we assessed singing abilities in eight children with SLI and 15 children with Typical Language Development (TLD) matched for age and non-verbal intelligence. To this aim, we designed a ludic activity consisting of two singing tasks: a pitch-matching and a melodic reproduction task. In the pitch-matching task, the children were requested to sing single notes. In the melodic reproduction task, children were asked to sing short melodies that were either familiar (FAM-SONG and FAM-TUNE conditions) or unfamiliar (UNFAM-TUNE condition). The analysis showed that children with SLI were impaired in the pitch-matching task, with a mean pitch error of 250 cents (mean pitch error for children with TLD: 154 cents). In the melodic reproduction task, we asked 30 healthy adults to rate the quality of the sung productions of the children on a continuous rating scale. The results revealed that singing of children with SLI received lower mean ratings than the children with TLD. Our findings thus indicate that children with SLI showed impairments in musical production and are discussed in light of a general auditory-motor dysfunction in children with SLI.

Word Detection in Sung and Spoken Sentences in Children With Typical Language Development or With Specific Language Impairment.

BACKGROUND: Previous studies have reported that children score better in language tasks using sung rather than spoken stimuli. We examined word detection ease in sung and spoken sentences that were equated for phoneme duration and pitch variations in children aged 7 to 12 years with typical language development (TLD) as well as in children with specific language impairment (SLI ), and hypothesized that the facilitation effect would vary with language abilities. METHOD: In Experiment 1, 69 children with TLD (7-10 years old) detected words in sentences that were spoken, sung on pitches extracted from speech, and sung on original scores. In Experiment 2, we added a natural speech rate condition and tested 68 children with TLD (7-12 years old). In Experiment 3, 16 children with SLI and 16 age-matched children with TLD were tested in all four conditions. RESULTS: In both TLD groups, older children scored better than the younger ones. The matched TLD group scored higher than the SLI group who scored at the level of the younger children with TLD . None of the experiments showed a facilitation effect of sung over spoken stimuli. CONCLUSIONS: Word detection abilities improved with age in both TLD and SLI groups. Our findings are compatible with the hypothesis of delayed language abilities in children with SLI , and are discussed in light of the role of durational prosodic cues in words detection.

Developmental patterns of expressive language hemispheric lateralization in children, adolescents and adults using functional near-infrared spectroscopy.

The development of language hemispheric specialization is not well understood in young children, especially regarding expressive language functions. In this study, we investigated age-related changes in expressive language lateralization patterns in a population of children (3-6 and 7-10 years old), adolescents (11-16 years old), and young adults (19-30 years old). During functional near-infrared spectroscopy recordings, all participants performed a verbal fluency task, which consisted in naming as many words as possible belonging to a given semantic category. Hemoglobin concentration changes were measured in bilateral frontal and temporal cortical areas. During the language task, results showed a strong left hemisphere response along with weaker right hemisphere activation in all groups. Age-related increases in hemodynamic responses were found bilaterally, with younger children showing smaller hemodynamic responses than adolescents and adults in both hemispheres. Overall, these findings confirm that a left hemisphere specialization is already established in young children and persists through adulthood. Early left hemisphere specialization for expressive language suggests that language development hinges on structural and functional properties of the human brain with little reorganization occurring with development.

A novel tool for evaluating children's musical abilities across age and culture.

THE PRESENT STUDY INTRODUCES A NOVEL TOOL FOR ASSESSING MUSICAL ABILITIES IN CHILDREN: The Montreal Battery of Evaluation of Musical Abilities (MBEMA). The battery, which comprises tests of memory, scale, contour, interval, and rhythm, was administered to 245 children in Montreal and 91 in Beijing (Experiment 1), and an abbreviated version was administered to an additional 85 children in Montreal (in less than 20 min; Experiment 2). All children were 6-8 years of age. Their performance indicated that both versions of the MBEMA are sensitive to individual differences and to musical training. The sensitivity of the tests extends to Mandarin-speaking children despite the fact that they show enhanced performance relative to French-speaking children. Because this Chinese advantage is not limited to musical pitch but extends to rhythm and memory, it is unlikely that it results from early exposure to a tonal language. In both cultures and versions of the tests, amount of musical practice predicts performance. Thus, the MBEMA can serve as an objective, short and up-to-date test of musical abilities in a variety of situations, from the identification of children with musical difficulties to the assessment of the effects of musical training in typically developing children of different cultures.

The contribution of functional near-infrared spectroscopy (fNIRS) to the presurgical assessment of language function in children.

Before performing neurosurgery, an exhaustive presurgical assessment is required, usually including an investigation of language cerebral lateralization. Among the available procedures, the intracarotid amobarbital test (IAT) was formerly the most widely used. However, this procedure has many limitations: it is invasive and potentially traumatic, especially for children. To overcome these limitations, neuroimaging techniques such as functional magnetic resonance imaging (fMRI) have been used. Again, these methods are difficult to use with children, who must remain motionless during data acquisition. Functional near-infrared spectroscopy (fNIRS) is a noninvasive functional imaging technique that is easily applied to pediatric and cognitively limited patients. It has been used recently in epileptic children for presurgical assessment of expressive and receptive language brain lateralization. The aim of this review is to present the contribution of fNIRS to the presurgical assessment of language function in children with neurological diseases.

Functional near-infrared spectroscopy for the assessment of overt reading.

Functional near-infrared spectroscopy (fNIRS) has become increasingly established as a promising technique for monitoring functional brain activity. To our knowledge, no study has yet used fNIRS to investigate overt reading of irregular words and nonwords with a full coverage of the cerebral regions involved in reading processes. The aim of our study was to design and validate a protocol using fNIRS for the assessment of overt reading. Twelve healthy French-speaking adults underwent one session of fNIRS recording while performing an overt reading of 13 blocks of irregular words and nonwords. Reading blocks were separated by baseline periods during which participants were instructed to fixate a cross. Sources (n = 55) and detectors (n = 16) were placed bilaterally over frontal, temporal, parietal, and occipital regions. Two wavelengths were used: 690 nm, more sensitive to deoxyhemoglobin (HbR) concentration changes, and 830 nm, more sensitive to oxyhemoglobin (HbO) concentration changes. For all participants, total hemoglobin (HbT) concentrations (HbO + HbR) were significantly higher than baseline for both irregular word and nonword reading in the inferior frontal gyri, the middle and superior temporal gyri, and the occipital cortices bilaterally. In the temporal gyri, although the difference was not significant, [HbT] values were higher in the left hemisphere. In the bilateral inferior frontal gyri, higher [HbT] values were found in nonword than in irregular word reading. This activation could be related to the grapheme-to-phoneme conversion characterizing the phonological pathway of reading. Our findings confirm that fNIRS is an appropriate technique to assess the neural correlates of overt reading.

Reproduction of inflectional markers in French-speaking children with reading impairment.

PURPOSE: Children with reading impairment (RI) experience difficulties in oral and written production of inflectional markers. The origin of these difficulties is not well documented in French. According to some authors, acquisition of irregular items by typically developing children is predicted by token frequency, whereas acquisition of regular items is predicted by type frequency. The authors hypothesized that acquisition of inflectional markers in French depends on the distribution of irregular, invariable, and regular (transparent) items within a grammatical category. METHOD: Fifteen children with RI age matched with 15 children with typical reading development repeated and read aloud sentences containing adjectives inflected for gender and verbs inflected for number. Inflected adjectives and verbs were matched for token frequency and phonological complexity, whereas distribution of invariable, transparent, and irregular items differed within each grammatical category. RESULTS: Results show higher error rates in the RI group, who produced more errors in reading than repetition, and more errors on inflected verbs than adjectives. Error distribution varied with the proportion of invariable, irregular, and transparent items within each grammatical category, confirming the authors' hypothesis. CONCLUSION: The authors concluded that morphological difficulties of children with RI group originated from a delay in extracting systematicity in verb and adjective inflectional marking.

A noninvasive, presurgical expressive and receptive language investigation in a 9-year-old epileptic boy using near-infrared spectroscopy.

The intracarotid amobarbital test (IAT) is used for presurgical evaluation of language lateralization. However, this procedure has many limitations, especially in children. As an alternative to IAT, in the case described here, near-infrared spectroscopy (NIRS) was used to investigate expressive and receptive language lateralization as part of the presurgical evaluation of a 9-year-old Yiddish-speaking boy with a probable left temporal epileptic focus. This child could not tolerate IAT or functional MRI. He underwent two NIRS recording sessions while performing expressive and receptive language tasks. Results indicated predominantly left-sided expressive language in Broca's area with ipsilateral cortical recruitment of more posterior regions. Receptive language showed a bilateral cerebral pattern, perhaps as an expression of cerebral plasticity or compensation in this young patient. This case report illustrates that NIRS may contribute to presurgical investigation and could become a noninvasive alternative to IAT and functional MRI in determining speech lateralization in children.

Knowing its gender without knowing its name: differential access to lexical information in a jargonaphasic patient.

According to recent models of word production, when we name a picture, we first retrieve the meaning of the object, and then we independently retrieve the written or sound form of the word corresponding to the picture. In languages like French, in which words have a gender, theoretical models disagree with respect to the moment at which this information is retrieved. The lemma model (Levelt et al., 1999) posits that we access this information before the sound or written form of the word is retrieved. In contrast, the"Independent network"(IN) model (Caramazza, 1997) model posits that we access gender after retrieval of either the sound or written form of the word. This paper reports a single-case study of an aphasic patient, BA, who showed deficits affecting spoken and written production in the presence of largely preserved comprehension abilities. Experimental testing indicated that she presented with a deficit functionally localized in the access to lexical representations. Results in picture naming and in gender identification also revealed that BA identified the gender above chance level, whether she produced a correct response, a phonemic error, or a neologism. In contrast, when she was unable to produce a spoken or written response, she could not identify the gender. This pattern of performance is consistent with the lemma model in which access to lexical syntax is required before access to phonological form can take place.