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Speech and language skills in children who required neonatal intensive care. I. Spontaneous speech at 6.5 years of age.

Spontaneous speech at age 6.5 years was studied separately in a follow-up of speech and language skills in a regional cohort of 284 children requiring neonatal intensive care and in 40 controls. Eight aspects of spontaneous speech were evaluated in a conversation: A1, information; A2, speech motor function; A3, sound pattern; A4, word finding; A5, word selection; A6, grammar; A7, interaction; and A8, motivation. The children were grouped by gestational age. Most children had well developed spontaneous speech. The different groups showed very few differences in types of deviations in spontaneous speech. All groups differed from the controls in speech motor function and formal language (A2-A6), but only one child, born at <32 weeks, had a pronounced deviation in one of these aspects. Obvious deviations in one or more aspects of spontaneous speech were more common among children born at 28-31 weeks and in those born fullterm (> or =37 weeks) than among extremely preterm children born at 23-27 weeks.

Age Factors↗

Speech recognition with the nucleus 24 SPEAK, ACE, and CIS speech coding strategies in newly implanted adults.

OBJECTIVE: The objective of this study was to determine whether 1) the SPEAK, ACE or CIS speech coding strategy was associated with significantly better speech recognition for individual subjects implanted with the Nucleus CI24M internal device who used the SPrint speech processor, and 2) whether a subject's preferred strategy for use in everyday life provided the best speech recognition. DESIGN: Twelve postlinguistically deaf, newly implanted adults participated. Initial preference for the three strategies was obtained with paired-comparison testing on the first day of implant stimulation with seven of eight U.S. subjects. During the first 12 wk, all subjects used each strategy alone for 4 wk to give them experience with the strategy and to identify preferred speech processor program parameters and settings that would be used in subsequent testing. For the next 6 wk, subjects used one strategy at a time for 2-wk intervals in the same order they had for the first 12 wk. At the end of each 2-wk interval, speech recognition testing was conducted with all three strategies. At the end of the 6 wk, all three strategies were placed on each subject's processor, and subjects were asked to compare listening with these three programs in as many situations as possible for the next 2 wk. When they returned, subjects responded to a questionnaire asking about their preferred strategy and responded to two lists of medial consonants using each of the three strategies. The U.S. subjects also responded to two lists of medial vowels with the three strategies. RESULTS: Six of the 12 subjects in the present study had significantly higher CUNY sentence scores with the ACE strategy than with one or both of the other strategies; one of the 12 subjects had a significantly higher score with SPEAK than with ACE. In contrast, only two subjects had significantly higher CNC word and phoneme scores with one or two strategies than with the third strategy. One subject had a significantly higher vowel score with the SPEAK strategy than with the CIS strategy; and no subjects had significantly higher consonant scores with any strategy. Seven of 12 subjects preferred the ACE strategy, three preferred the SPEAK strategy, and two preferred the CIS strategy. Subjects' responses on a questionnaire agreed closely with strategy preference from comparisons made in everyday life. There was a strong relation between the preferred strategy and scores on CUNY sentences but not for the other speech tests. For all subjects, except one, the preferred strategy was the one with the highest CUNY sentence score or was a strategy with a CUNY score not significantly lower than the highest score. CONCLUSIONS: Despite differences in research design, there was remarkably close agreement in the pattern of group mean scores for the three strategies for CNC words and CUNY sentences in noise between the present study and the Conversion study (Arndt, Staller, Arcaroli, Hines, & Ebinger, Reference Note 1). In addition, essentially the same percentage of subjects preferred each strategy. For both studies, the strategy with which subjects had the highest score on the CUNY sentences in noise evaluation was strongly related to the preferred strategy; this relation was not strong for CNC words, CNC phonemes, vowels or consonants (Skinner, Arndt, & Staller, 2002). These results must be considered within the following context. For each strategy, programming parameters preferred for use in everyday life were determined before speech recognition was evaluated. In addition, implant recipients had experience listening with all three strategies in many situations in everyday life before choosing a preferred strategy. Finally, 11 of the 12 subjects strongly preferred one of the three strategies. Given the results and research design, it is recommended that clinicians fit each strategy sequentially starting with the ACE strategy so that the preferred programming parameters are determined for each strategy before recipients compare pairs of strategies. The goal is to provide the best opportunity for individuals to hear in everyday life within a clinically acceptable time period (e.g., 6 wk).

Acoustic Stimulation↗

Simulation of the effects of loudness recruitment and threshold elevation on the intelligibility of speech in quiet and in a background of speech.

These experiments simulated the threshold elevation and loudness recruitment associated with three different types of cochlear hearing loss: Moderate flat (condition R2), severe flat (condition R3), and moderate-to-severe sloping (condition RX). This was done to allow an examination of the effects of these factors on the intelligibility of speech, in isolation from other factors that are normally associated with cochlear hearing loss, such as reduced frequency selectivity. The simulation was performed by splitting the input signal into 13 frequency bands, and processing the envelope in each band so as to create loudness sensations in a normal ear that would resemble those produced in an impaired ear with recruitment. The bands were then recombined. All tests were performed using subjects with normal hearing. For speech in quiet, simulation of hearing loss produced a reduction in the ability to understand low-level speech. However, speech at sufficiently high levels was highly intelligible in all conditions. Linear amplification according to the National Acoustic Laboratory (NAL) prescription gave high intelligibility for speech at normal conversational levels. For speech presented at a fixed input level of 65 dB SPL, against a background of a single competing talker, simulation of hearing loss produced substantial decrements in performance. The speech-to-background ratios in conditions R2 and RX had to be 11-13 dB higher than in the control condition (unprocessed stimuli) to achieve similar levels of performance. Linear amplification according to the NAL prescription improved performance markedly for the conditions simulating flat losses, but was less effective for the condition simulating a sloping loss. This indicates that threshold elevation combined with recruitment produces a loss of intelligibility for speech in the presence of a single competing talker that is only partly compensated by linear amplification of the type typically used in hearing aids.

Acoustic Stimulation↗

Speech intelligibility during respirator wear: influences of respirator speech diaphragm size and background noise.

This study assessed the effect of respirator speech device size on speech intelligibility and the impact of background noise on respirator communications effectiveness. Thirty-five subjects completed modified rhyme test (MRT) speech intelligibility testing procedures with and without a respirator under background noises of 40, 60, and 80 dBA. Respirator wear conditions included the use of one unmodified and three mechanical speech diaphragms modified to reduce the surface area of the vibrating inner membrane available for sound transmission. Average MRT scores decreased linearly as background noise levels increased for all conditions. Lower MRT scores were observed for all respirator speech diaphragm conditions compared to the nonrespirator condition within each noise category. Average MRT scores differed significantly between the unmodified speech diaphragm and one with a 70% reduced surface area with a 40-dBA background noise. However, MRT scores were similar between the modified and unmodified diaphragms at both the 60- and 80-dBA noise levels. These findings provide evidence that alternate designs of mechanical-type respirator speech devices can be achieved without further degradation of speech sound transmission.

Adult↗

Comprehension of time-compressed speech: effects of age and speech complexity.

The periodic sampling method of time compression is characterized by periodic removal of segments of speech according to predetermined compression rate (CR) and discard interval length (DIL). Fifteen middle-aged (42-54 years old) and 15 older (60-69 years old) adults participated in the study that assessed the combined effects of CR and DIL on the comprehension of time-compressed speech by aging adults. Three CRs (30, 45, and 60%), seven DILs (35 through 155 msec), and two types of speech materials were used. The subject's task was to report associations among the items mentioned in a time-compressed passage. In all cases, performance of the subjects deteriorated with increasing CR and DIL. The older adults were affected more by CR and DIL values than middle-aged adults. The difference in sentence complexity between the two speech materials affected both groups equally. In general, the results of the study indicated that (a) time-compressed speech differentiates between speech comprehension by middle-aged and older adults and (b) the effects of CR and DIL became more independent with increasing age of the listener and increasing complexity of the speech material. Reported results support the concept that time-compressed speech may be an effective signal in clinical assessment of adults whose auditory complaints are not explained by their peripheral hearing losses.

Adult↗

Detection of errors during speech production: a review of speech monitoring models.

In this paper three theories of speech monitoring are evaluated. The perception-based approach proposes that the same mechanism employed in understanding other-produced language, the speech comprehension system, is also used to monitor one's own speech production. A conceptual, an inner, and an auditory loop convey information to a central, conscious monitor which scrutinizes the adequacy of the ongoing speech flow. In this model, only the end-products in the speech production sequences, the preverbal (propositional) message, the phonetic plan, and the auditory results, are verified. The production-based account assumes multiple local, autonomous monitoring devices, which can look inside formulation components. Moreover, these devices might be tuned to various signals from the actual speech motor execution, e.g. efferent, tactile, and proprioceptive feedback. Finally, node structure theory views error detection as a natural outflow of the activation patterns in the node system for speech production. Errors result in prolonged activation of uncommitted nodes, which in turn may incite error awareness. The approaches differ on the points of consciousness, volition and control, the number of monitoring channels, and their speed, flexibility, and capacity, and whether they can account for concurrent language comprehension disorders. From the empirical evidence presently available, it is argued for a central perception-based monitor, potentially augmented with a few automatic, production-based error detection devices.

Humans↗

Connected speech processes in developmental speech impairment: observations from an electropalatographic perspective.

This paper uses a combination of perceptual and electropalatographic (EPG) analysis to explore the presence and characteristics of connected speech processes in the speech output of five older children with developmental speech impairments. Each of the children is shown to use some processes typical of normal speech production but also to use a range of more unusual processes at word junctures, with both inter- and intra-speaker variability apparent in the data. The findings suggest that the traditional focus on single word production in the assessment of developmental speech disorders needs to be modified to allow more extensive consideration of speech production in spontaneous speech.

Adolescent↗

Impairments of speech production and speech perception in aphasia.

The basis of speech production and speech perception deficits in aphasia relates to implementation and access rather than to the underlying representation or knowledge base of the sound structure of language. Speech production deficits occur on the phonological level in which the incorrect phonological form of the word is selected but is implemented correctly, and the phonetic level in which the correct sound segments are selected but articulatory implementation is impaired. Phonological deficits emerge regardless of lesion site, whereas phonetic deficits have a specific localized neuroanatomical substrate. Phonetic deficits are not linguistic but affect particular articulatory movements. Speech perception impairments emerge in nearly all aphasic patients, suggesting that the neural basis for speech perception is broadly distributed in the language hemisphere. The impairment reflects the misperception of phonetic features rather than a deficit in the auditory processing of speech and emerges particularly as the sound properties of speech contact the lexicon.

Aphasia↗

A statistical causal model for the assessment of dysarthric speech and the utility of computer-based speech recognition.

The evaluation of the degree of speech impairment and the utility of computer recognition of impaired speech are separately and independently performed. Particular attention is paid to the question concerning whether or not there is a relationship between naive listeners' subjective judgements of impaired speech and the performance of a laboratory version of a speech recognition system. It is a difficult task to relate a speech impairment rating with speech recognition accuracy. Towards this end, a statistical causal model is proposed. This model is very appealing in its structure to support inference, and thus can be applied to perform various assessments such as the success of automatic recognition of dysarthric speech. The application of this model is illustrated with a case study of a dysarthric speaker compared against a normal speaker serving as a control.

Adult↗

Speech transmission index from running speech: a neural network approach.

Speech transmission index (STI) is an important objective parameter concerning speech intelligibility for sound transmission channels. It is normally measured with specific test signals to ensure high accuracy and good repeatability. Measurement with running speech was previously proposed, but accuracy is compromised and hence applications limited. A new approach that uses artificial neural networks to accurately extract the STI from received running speech is developed in this paper. Neural networks are trained on a large set of transmitted speech examples with prior knowledge of the transmission channels' STIs. The networks perform complicated nonlinear function mappings and spectral feature memorization to enable accurate objective parameter extraction from transmitted speech. Validations via simulations demonstrate the feasibility of this new method on a one-net-one-speech extract basis. In this case, accuracy is comparable with normal measurement methods. This provides an alternative to standard measurement techniques, and it is intended that the neural network method can facilitate occupied room acoustic measurements.

Humans↗

The potential role of speech production models in automatic speech recognition.

This paper investigates the issues that are associated with applying speech production models to automatic speech recognition (ASR). Here the applicability of articulatory representations to ASR is considered independently of the role of articulatory representations in speech perception. While the question of whether it is necessary or even possible for human listeners to recover the state of the articulators during the process of perceiving speech is an important one, it is not considered here. Hence, the authors refrain from posing completely new paradigms for ASR which more closely parallel the relationship between speech production and human speech understanding. Instead, work aimed at integrating speech production models into existing ASR formalisms is described.

Humans↗

Fractal dimensions of speech sounds: computation and application to automatic speech recognition.

The dynamics of airflow during speech production may often result in some small or large degree of turbulence. In this paper, the geometry of speech turbulence as reflected in the fragmentation of the time signal is quantified by using fractal models. An efficient algorithm for estimating the short-time fractal dimension of speech signals based on multiscale morphological filtering is described, and its potential for speech segmentation and phonetic classification discussed. Also reported are experimental results on using the short-time fractal dimension of speech signals at multiple scales as additional features in an automatic speech-recognition system using hidden Markov models, which provide a modest improvement in speech-recognition performance.

Databases as Topic↗

Speech and language therapy interventions for children with primary speech and language delay or disorder.

BACKGROUND: It is thought that approximately 6% of children have speech and language difficulties of which the majority will not have any other significant developmental difficulties. Whilst most children's difficulties resolve, children whose difficulties persist into primary school may have long-term problems concerning literacy, socialisation, behaviour and school attainment. OBJECTIVES: To examine the effectiveness of speech and language interventions for children with primary speech and language delay/disorder. SEARCH STRATEGY: The following databases were searched: The Cochrane Controlled Trials Register (Cochrane Library, CENTRAL: 2002/3), CINAHL (1982 - July 2002), EMBASE (1980 - Sept Week 4 2002), ERIC (1965 - 2002), MEDLINE (1966 - Sept Week 3 2002), PsycINFO (1872 - 2002/10 Week 2), The National Research Register (2002/3). In addition to this references were taken from reviews of the literature and reference lists from articles. SELECTION CRITERIA: The review considered randomised controlled trials of speech and language therapy interventions for children or adolescents with primary speech and language delay/disorder. DATA COLLECTION AND ANALYSIS: Titles and abstracts were identified and assessed for relevance, before the full text version was obtained of all potentially relevant articles. The data were categorised depending on the nature of the control group and considered in terms of the effects of intervention on expressive and receptive phonology, syntax and vocabulary. The outcomes used in the analysis were dependent on the focus of the study with only the primary effects of therapy being considered in this review. MAIN RESULTS: The results of twenty-five studies were used in the meta-analysis. The results suggest that speech and language therapy is effective for children with phonological (SMD=0.44, 95%CI: 0.01,0.86) or vocabulary difficulties (SMD=0.89, 95%CI: 0.21,1.56), but that there is less evidence that interventions are effective for children with receptive difficulties (SMD=-0.04, 95%CI: -0.64,0.56). Mixed findings were found concerning the effectiveness of expressive syntax interventions (n=233; SMD=1.02, 95%CI: 0.04-2.01). No significant differences were shown between clinician administered intervention and intervention implemented by trained parents, and studies did not show a difference between the effects of group and individual interventions (SMD=0.01, 95%CI: -0.26,1.17). The use of normal language peers in therapy was shown to have a positive effect on therapy outcome (SMD=2.29, 95%CI: 1.11,3.48). REVIEWER'S CONCLUSIONS: The review shows that overall there is a positive effect of speech and language therapy interventions for children with expressive phonological and expressive vocabulary difficulties. The evidence for expressive syntax difficulties is more mixed, and there is a need for further research to investigate intervention for receptive language difficulties. There is a large degree of heterogeneity in the results, and the sources of this need to be investigated.

Adolescent↗

Hearing lips and seeing voices: how cortical areas supporting speech production mediate audiovisual speech perception.

Observing a speaker's mouth profoundly influences speech perception. For example, listeners perceive an "illusory" "ta" when the video of a face producing /ka/ is dubbed onto an audio /pa/. Here, we show how cortical areas supporting speech production mediate this illusory percept and audiovisual (AV) speech perception more generally. Specifically, cortical activity during AV speech perception occurs in many of the same areas that are active during speech production. We find that different perceptions of the same syllable and the perception of different syllables are associated with different distributions of activity in frontal motor areas involved in speech production. Activity patterns in these frontal motor areas resulting from the illusory "ta" percept are more similar to the activity patterns evoked by AV(/ta/) than they are to patterns evoked by AV(/pa/) or AV(/ka/). In contrast to the activity in frontal motor areas, stimulus-evoked activity for the illusory "ta" in auditory and somatosensory areas and visual areas initially resembles activity evoked by AV(/pa/) and AV(/ka/), respectively. Ultimately, though, activity in these regions comes to resemble activity evoked by AV(/ta/). Together, these results suggest that AV speech elicits in the listener a motor plan for the production of the phoneme that the speaker might have been attempting to produce, and that feedback in the form of efference copy from the motor system ultimately influences the phonetic interpretation.

Auditory Perception↗

Cochlear implantation in children deafened by cytomegalovirus: speech perception and speech intelligibility outcomes.

BACKGROUND: Concerns have been expressed with regard to suitability for cochlear implantation of children deafened by cytomegalovirus because of possible coexisting central disorders/learning difficulties. The aim of the current study was to assess speech perception and intelligibility of speech produced by children deafened by cytomegalovirus and compare their progress with that of congenitally deaf children after cochlear implantation. METHODS: The study assessed 16 implanted children who were deafened by cytomegalovirus, using the Iowa Closed Sentence Test and Speech Intelligibility Rating. The results were compared with those of a group of 131 children who had undergone implantation who were congenitally deaf but did not have cytomegalovirus as the cause of deafness. The mean age at implantation was 3.9 years for the cytomegalovirus group (median, 3.5 years) and 4.1 years (median, 4 years) for the congenitally deaf children. They all received the Nucleus multichannel cochlear implant system. The follow-up period ranged from 1 to 5 years after implantation for both groups. RESULTS: After cochlear implantation, the intelligibility of speech produced by children deafened by cytomegalovirus had a wide range, varying from unintelligible speech to connected speech intelligible to all listeners. Relative to the median score for the control group at the last evaluation interval, 3 of the 16 children with cytomegalovirus (19%) performed better, 8 children (50%) performed more poorly, and 5 (31%) performed the same. The difference between the two groups was not statistically significant (p > 0.05). With regard to speech perception Iowa Sentence Test (Level B), relative to the median score for the control group at the last evaluation interval, 5 of the 16 children with cytomegalovirus (31%) performed better, 3 children (19%) performed more poorly, and 8 (50%) performed the same. The difference between the two groups was not statistically significant (p > 0.05). With regard to Level A and relative to the median score for the control group at the last evaluation interval, 1 of the 16 children with cytomegalovirus (6%) performed better, 6 children (38%) performed more poorly, and 9 (56%) performed the same. The difference between the two groups was statistically significant (p = 0.04). CONCLUSION: The results of the current study showed that cytomegalovirus alone, as a cause of deafness, is not a contraindication for cochlear implantation. Parents should be informed about the wide range of linguistic outcomes after implantation and that these children may need more specific or intensive rehabilitation. Although additional problems are common and outcomes may, on average, be poorer, cochlear implantation can provide useful auditory input to these children. Further research is needed to identify factors associated with cytomegalovirus that may influence the outcomes.

Case-Control Studies↗

Can all schizophrenic speech be discriminated from normal speech?

The study addressed whether the speech of non-speech disordered as well as speech disordered schizophrenics is discriminable from normal speech. An analysis, using a clinician's acumen to detect, not as is usually the case to specify, showed that schizophrenic speech (including that of non-speech disordered schizophrenics) can be accurately discriminated. This suggests that the speech of all schizophrenics does indeed differ from that of normals, but in as yet unspecified ways.

Humans↗

The effects of hearing loss on the contribution of high- and low-frequency speech information to speech understanding.

The speech understanding of persons with "flat" hearing loss (HI) was compared to a normal-hearing (NH) control group to examine how hearing loss affects the contribution of speech information in various frequency regions. Speech understanding in noise was assessed at multiple low- and high-pass filter cutoff frequencies. Noise levels were chosen to ensure that the noise, rather than quiet thresholds, determined audibility. The performance of HI subjects was compared to a NH group listening at the same signal-to-noise ratio and a comparable presentation level. Although absolute speech scores for the HI group were reduced, performance improvements as the speech and noise bandwidth increased were comparable between groups. These data suggest that the presence of hearing loss results in a uniform, rather than frequency-specific, deficit in the contribution of speech information. Measures of auditory thresholds in noise and speech intelligibility index (SII) calculations were also performed. These data suggest that differences in performance between the HI and NH groups are due primarily to audibility differences between groups. Measures of auditory thresholds in noise showed the "effective masking spectrum" of the noise was greater for the HI than the NH subjects.

Adult↗

Analysis of speech-based Speech Transmission Index methods with implications for nonlinear operations.

The Speech Transmission Index (STI) is a physical metric that is well correlated with the intelligibility of speech degraded by additive noise and reverberation. The traditional STI uses modulated noise as a probe signal and is valid for assessing degradations that result from linear operations on the speech signal. Researchers have attempted to extend the STI to predict the intelligibility of nonlinearly processed speech by proposing variations that use speech as a probe signal. This work considers four previously proposed speech-based STI methods and four novel methods, studied under conditions of additive noise, reverberation, and two nonlinear operations (envelope thresholding and spectral subtraction). Analyzing intermediate metrics in the STI calculation reveals why some methods fail for nonlinear operations. Results indicate that none of the previously proposed methods is adequate for all of the conditions considered, while four proposed methods produce qualitatively reasonable results and warrant further study. The discussion considers the relevance of this work to predicting the intelligibility of cochlear-implant processed speech.

Auditory Threshold↗