No description available.

The purpose of this study was to examine the effects of multi-modal stimulation (differing amounts of light and vocal stimulation) on preterm infants' behavioral and state organization. Specifically, we looked at the effects that supplemental vocal stimulation (taped female voice) had when varied in amount of exposure (three times a day versus once a day) and when provided in different lighting conditions ("typical illumination" versus "decreased illumination"). Forty infants were placed in one of four groups: Standard Illumination/High Voice (SIHV), Standard Illumination /Low Voice (SILV), Decreased Illumination/High Voice (DIHV) and Decreased Illumination/Low Voice (DILV). Infants receiving standard illumination were exposed to the vocal stimulus in standard NICU lighting conditions (approximately 20 lux), whereas infants in the "low" lighting conditions were exposed to the stimulus in darkened conditions (approximately 3 lux). Infants receiving high vocal stimulation listened to a taped female voice three times a day, whereas infants receiving low vocal stimulation were exposed to the voice only once a day. Each infant received 10 minutes of exposure per session over five consecutive days. Infants were videotaped in their incubator for 10 minutes before, during, and after the stimulus exposure (total of 30 minutes) for each day. The videotapes were then scored on the infant's frequency of stress related behaviors and self-regulatory behaviors before, during, and after the stimulus for each day. Results indicated that both lighting levels and vocal stimulation altered preterm infants' stress and self-regulatory behaviors, and that these effects were dependent on both the day and the stimulus condition the infant was in. In addition, the vocal stimulation and lighting levels had an effect on the states that infants exhibited during and after the presentation of stimulation. These results suggest that the occurrence of different types and amounts of stimulation have an effect on behavioral organization of the preterm infant, and these effects are highly dependent on both history and context in which this stimulation is presented / Ph. D.

Several studies have found that adult caretakers usually hyperarticulate to infants by modifying their voice in ways that promote and sustain infants' attention. This articulation when engaging in infant directed speech (IDS) can result in "clear speech" by the expansion of the vowel space area. The degree of speech clarity produced by caregivers appears to provide advantages for young language learners to promote lexical perception and learning. However few studies have ever examined whether infants are able to perceive the difference between hyperarticulation and normal speech. In this study, 7-to 12-month-olds' (n=17) speech discrimination when hearing hyperarticulated and non-hyperarticulated words in mothers' natural speech production was examined. The degree of speech clarity was determined by the relations of the first (F1) and second formant frequencies (F2) of the vowel. The result showed that there was no discrimination between listening to hyperarticulated and non-hyperarticulated words, indicating that the benefit accrued by exposure to clear speech may require no selective attention on the part of the infant. Thus the advantages of hyperarticulation might be related to other characteristics. / Master of Science

Speech perception plays an important role in how infants begin to produce speech. This study aims to understand how changes in infant selective attention to various parts of talking faces guides their understanding of speech and subsequent production. In this study, we tracked infant (4-12 months of age) and adult gaze patterns to determine where on a face they attend, when hearing and seeing the face speak in either their native (English) or a non-native language (Spanish). We also tracked infant selective attention to moving-silent and silent-static faces, to determine if this would result in different patterns of attention. The findings suggest that there are two shifts in infant attention. The first shift occurs between four and eight months of age, with infants shifting their eyes to the mouth of the talking face. The second shift occurs around twelve months of age, when infants begin to return their gaze back to the eye region when hearing and seeing their native language, but continue to attend to the mouth region when hearing and seeing the non-native language. Overall, the results of this study suggest that changes in selective attention to talking faces guides the development of speech production and is dependent on early language experience. / by Amy H. Tift. / Thesis (M.A.)--Florida Atlantic University, 2012. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.

From syllables to fluent speech, it is important for infants to quickly learn and decipher linguistic information. To do this, infants must not only use their auditory perception but also their visual perception to understand speech and language as a multisensory coherent event. Previous research by Lewkowicz and Hansen-Tift (2012) demonstrated that infants shift their allocation of visual attention from the eyes to the mouth of the speaker's face throughout development as they become interested in speech production. This project examined how infants, from 4-14-months of age, allocate their visual attention to increasingly complex speech tasks. In Experiment 1, infants were presented with upright and inverted faces vocalizing syllables and the results demonstrated that in response to the upright faces, 4-month-old infants attended to the eyes and 8- and 10-month-olds attended equally to the eyes and mouth. In response to the inverted face presentation, both the 4- and 10-month-olds attended equally to the eyes and mouth but the 8-month olds attended to the eyes. In Experiment 2, infants were presented with a phoneme matching task (Patterson & Werker, 1999, 2002, 2003) and the results demonstrated that the 4-month-old infants successfully matched the voice to the corresponding face, but that older infants did not. Measures of their selective attention to this task showed that the 4-month-old infants attended more to the eyes of the faces during the task, not attending to the redundant speech information at the mouth, but older infants attended equally to the eyes and mouth, although they did not match the voice to the face. Experiment 3 presented infants with a fluent speech matching task (Lewkowicz et al., 2015) which demonstrated that although the infants (12-14-months) did not systematically match the voice to the corresponding face, the infants attended more to the mouth region, which would have provided them with the neces sary redundant information. Overall, these studies demonstrate that there are developmental changes in how infants distribute their visual attention to faces as they learn about speech and that the complexity of the speech is a critical factor in how they allocate their visual attention. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

published_or_final_version / Applied Statistics / Master / Master of Social Sciences

The objective of this randomized, double-blind, placebo-controlled trial was to determine whether glucose enhanced memory for a repeated auditory stimulus in human newborns. Infants consumed water or glucose (2-g/kg) solution. Memory test phases were: Orientation (turning towards the stimulus); Habituation (not turning towards), indicating familiarity; Delay (100 seconds); Spontaneous Recovery (stimulus representation: not turning towards indicates remembering, while turning towards indicates forgetting), and Novelty (turning towards a different word confirms wakefulness). Decreased head-turning towards during Spontaneous Recovery indicates enhanced memory. Blood glucose levels were measured after testing. / "Glucose" infants had higher blood glucose levels than "water" infants (p < 0.001). "Glucose" infants had significantly decreased turns towards during Spontaneous Recovery compared to "water" infants (p = 0.008), indicating memory enhancement. / Therefore, glucose specifically enhances memory for a repeated auditory stimulus in newborn humans. Elevating blood glucose levels by approximately 2 mmol/L appears to be sufficient for memory enhancement in healthy newborns.

A take-home milk supplementation programme consisting of 2 kg dry powdered milk offered monthly for 12 months to children 6--24 months of age in participating primary health care clinics was evaluated by assessing weight changes in supplemented and control children. Growth charts of supplemented (n = 362) and control (n = 410) children were summarized by the intercept and slope from the regression of individual weight measurements on age. The 2 groups were stratified by gender, ethnicity (Indo-Guyanese and Afro-Guyanese), and age intervals 0--6, 6--24, and 24--30 months which corresponded to pre, during, and post supplementation periods, respectively. Supplemented Indo-Guyanese girls gained significantly (p < 0.001) more weight than their controls: the difference being approximately 40 grams per month. No other differences were observed in the other gender/ethnic groups. Contextual information collected in a sub-sample of 60 mothers/caregivers of beneficiaries revealed that the supplement was mainly consumed with porridge, and tended to be shared more in the Afro-Guyanese than in Indo-Guyanese households. Over 90% of the beneficiaries were satisfied with the programme and wanted it to continue while 74% stated that it was of financial benefit. For future programmes, the use of locally produced infant cereal was recommended.

Infants with hearing loss (HL) are being diagnosed and fitted with amplification earlier than ever before. In order to acquire speech and language abilities that are on par with their normal-hearing (NH) peers, hearing-impaired (HI) infants require amplification that provides appropriate exposure to the sounds of their native language. To date, no research has addressed this issue and thus, there is a need to examine the type of amplification that is most suitable for infants during the early stages of language acquisition. In this thesis, three different amplification types were compared: one that preserves the natural spectral shape of speech (unmodified speech); a second that emphasises high-frequency speech information (positive spectral tilt); and a third that emphasises low-frequency information (negative spectral tilt). NH infants were tested to examine how each of these amplification types affects speech perception and to explore whether infants at different stages of language acquisition find modified spectral tilt a help or hindrance in perceiving native-language speech contrasts. A visual habituation (VH) procedure was used to test 288 6- and 9-month-old NH infants on their ability to discriminate the high-frequency fricative contrast /f/- /s/; the mid-frequency approximant contrast /l/-/r/; and the low-frequency vowel contrast /5/-/N/ under modified spectral tilt conditions. For each speech contrast, 96 infants were tested in one of three conditions: (a) unmodified spectral tilt (n = 32); (b) with a positive 6 dB/octave spectral tilt (n = 32); or (c) with a negative 6 dB/octave spectral tilt (n = 32). The results showed that both 6- and 9-month-olds discriminated the three speech contrasts in the unmodified condition. However, when the contrasts were spectrally modified, a consistent developmental trend emerged. Six-month-olds’ discrimination performance improved when the spectral tilt modification amplified the relevant frequency information. That is, for the consonant contrasts (fricatives /f/-/s/ and approximants /l/-/r/) 6-month-olds performed best when high-frequency information was emphasised, whereas for the vowel contrast (/5/-/N/) the best discrimination performance was found when low-frequency information was enhanced. Nine-month-olds, on the other hand, showed no evidence of discriminating any of the contrasts when spectral tilt was modified. For all three contrasts, the older infants’ best discrimination performance was in the unmodified spectral tilt condition. The findings reflect the early stages of linguistic development. Six-month olds, whose acoustically driven speech perception operates in a language-general mode, demonstrated a broad-based ability to discriminate speech sounds. They not only accommodated speech with positive or negative spectral tilt, but a facilitation effect was observed when relevant frequency information was amplified. In contrast, 9-month-olds, whose perception is linguistically driven, found that spectral tilt modifications hinder speech perception. It seems that because older infants are attuning to native phonemic categories, their attention is constrained to native language spectral profiles only. Thus, even those spectral tilt modifications that should have been beneficial for perception were eschewed by 9-month-olds because they were incompatible with the older infants���� narrow focus on spectrally intact native speech sounds. Only NH infants were tested in this study, so it is not possible draw firm conclusions about amplification schemes until HI infants are tested too. Nevertheless, the results have a number of implications for infants with HL. The demonstration that spectral tilt modifications interfere with older NH infants’ speech perception suggests that future research should investigate whether HI infants also show this developmental pattern. That is, do HI infants progressively attune to the native language, and if so, does this affect their perception of spectrally modified speech sounds? Moreover, if HI infants are to attune to the native language and acquire speech and language in the same way as their NH peers, then the research reported here suggests that, throughout infancy, HI infants will need access to amplified speech that maintains the spectral shape of natural speech. Thus, the current research demonstrates, for the first time, a developmental difference in the way that infants perceive spectrally modified speech, one that is closely linked to the infant’s stage of native-language attunement. This research provides a solid foundation on which to conduct further research with HI infants and offers preliminary suggestions with regard to amplification and intervention to ensure that HI infants have the opportunity to emulate the native-language attunement process and subsequently achieve language development outcomes comparable with their NH peers. / Doctor of Philosophy (PhD)

Thesis (M.A.)--University of North Carolina Wilmington, 2009. / Title from PDF title page (January 12, 2010) Includes bibliographical references (p. 56-58)