Single Word Repetition Research Articles

Comparing Speech Production Errors of 3 to 5 Year Old Bengali Children with Cleft Lip and/or Palate in Two Contexts: Word Naming And Sentence Repetition

Research suggests various standardized assessment tools to collect and analyze the speech of the individual with cleft lip and/or palate (CLP). Despite the importance of developing an assessment framework for the growing CLP population, documentation on Bengali cleft speech is limited. This study aims to investigate the phonetic differences that happen in the speech sound production of 3 to 5-year-old Bengali-speaking CLP children in two different contexts: single word and sentence repetition. It also aims to evaluate the effects of these two speech assessment tools in those children’s phonological evaluation to identify the proper evaluation for CLP individuals. In total, 12 Bengali-speaking CLP children from 3 to 5 years old participated in each test. Thus, data has been collected from a sample of 24 with 79-word stimuli. Two types of speech materials were used: single-word naming and sentence repetition tasks. The samples were analyzed using narrow phonetic transcription for targeted speech items. The percentage of consonants correct (PCC), percentage of correct places (PCP), percentage of correct manners (PCM), as well as phonological simplification processes (PSP) were assessed from the samples. Results showed a range of word structures and place-manner features produced by CLP children in both tasks. Also, the PCC, PCP, PCM, and PSP results were considerably less accurate in the sentence repetition task, suggesting that the task may provide a more accurate assessment of the CLP population. Social Science Review, Vol. 40(2), December 2023 Page: 205-224

Degeneracy in the neurological model of auditory speech repetition

Both classic and contemporary models of auditory word repetition involve at least four left hemisphere regions: primary auditory cortex for processing sounds; pSTS (within Wernicke’s area) for processing auditory images of speech; pOp (within Broca’s area) for processing motor images of speech; and primary motor cortex for overt speech articulation. Previous functional-MRI (fMRI) studies confirm that auditory repetition activates these regions, in addition to many others. Crucially, however, contemporary models do not specify how regions interact and drive each other during auditory repetition. Here, we used dynamic causal modelling, to test the functional interplay among the four core brain regions during single auditory word and pseudoword repetition. Our analysis is grounded in the principle of degeneracy—i.e., many-to-one structure-function relationships—where multiple neural pathways can execute the same function. Contrary to expectation, we found that, for both word and pseudoword repetition, (i) the effective connectivity between pSTS and pOp was predominantly bidirectional and inhibitory; (ii) activity in the motor cortex could be driven by either pSTS or pOp; and (iii) the latter varied both within and between individuals. These results suggest that different neural pathways can support auditory speech repetition. This degeneracy may explain resilience to functional loss after brain damage.

Investigating Verbal Repetition in Persian-speaking Patients with the Semantic Variant of Primary Progressive Aphasia Compared to Healthy Individuals

Introduction: Language deficit is regarded as one of the most important hallmarks of primary progressive aphasia. This study aims to analyze the nature of verbal repetition ability in a group of patients suffering from the semantic variant of primary progressive aphasia and investigate their cognitive capability.
 Materials and Methods: In this cross-sectional study, 12 patients of the semantic variant of primary progressive aphasia and 12 healthy individuals accomplished a set of tasks, including naming, word comprehension, digit span, repetition of multisyllabic single words, monosyllabic word span under similar or dissimilar phonological conditions, and sentence repetition
 Results: The patients exhibited some degree of impairment with diverse patterns in each task, although the accomplishment of the sentence repetition task was the most challenging activity for the primary progressive aphasic patients of the semantic variant. However, the healthy individuals performed well in all tasks.
 Conclusion: The recognition of the quantity and quality of the cognitive deficit in the semantic variant of primary progressive aphasics can illuminate the nature of this disease and contribute to a better diagnosis of this disease. Furthermore, it can assist speech therapists and neuropsychologist to recruit appropriate therapies and employ better techniques for the diagnosis and cure of these patients.

Single Word Repetition Predicts Long-Term Outcome of Aphasia Caused by an Ischemic Stroke

Purpose: Better understanding of clinical predictors of aphasia outcome is of the utmost importance, in patients’ rehabilitation planning, expectation management, and further physiopathology understanding.We aimed to identify clinical predictors of long-term poststroke aphasia's outcome. Methods: We conducted a prospective longitudinal observation study of patients with left-Middle Cerebral Artery stroke with aphasia. Patients were evaluated at baseline, day 7 and 6 months with National Institutes of Health Stroke Scale (NIHSS) and Aphasia Rapid Test Other demographic variables and vascular risk factors were collected. A linear regression was performed to identify best predictors of aphasia at 6 months. Findings: We included 113 patients with a left hemisphere stroke, with 81 reaching the final evaluation. Aphasia Handicap Score at 6 months was predicted by baseline total NIHSS (β = .077, 95%CI = [.026, .127]. P = .004), infarct volume on CT-scan (β = .009, 95%CI = [.003, .015]. P = .003), single word repetition at baseline (β = .188, 95%CI = [.040, .335]. P = .013), and infection during hospitalization (β = .759, 95%CI = [.263, 1.255]. P = .003). Conclusions: Aphasia's outcome in patients with stroke is predicted by a single word repetition task at baseline. Infection during hospitalization has a negative impact on aphasia's outcome at 6 months.

When does lexical availability influence phonology? Evidence from Jargon reading and repetition

ABSTRACTJargon aphasia is a language disorder characterised by phonological and nonword error. Errors are thought to arise when target segments are insufficiently activated, allowing non-target or recently used phonology to intrude. Words which are more frequent and familiar reside with greater degrees of activation and therefore should be less susceptible to error. The current study tested this hypothesis in a group of 10 people with Jargon aphasia using single word repetition and reading aloud. Each task had two lexicality conditions, one high and one low lexical availability word set. Measures of nonword quantity, phonological accuracy and perseveration were used in group and case series analyses. Results demonstrated that fewer nonwords were produced when lexical availability was greater. However, lexicality effects on phonological accuracy and perseveration were only observed in repetition in a sub-group of moderately impaired individuals, demonstrating that lexical information does not consistently influence phonological processing in Jargon aphasia.

Individual differences in verbal short-term memory and reading aloud: Semantic compensation for weak phonological processing across tasks.

According to contemporary accounts, linguistic behavior reflects the interaction of distinct representations supporting word meaning and phonology. However, there is controversy about the extent to which this interaction occurs within task-specific systems, specialized for reading and short-term memory (STM), as opposed to between components that support the full range of linguistic tasks. We examined whether individual differences in the efficiency of phonological processing would relate to the application of lexical-semantic knowledge to support verbal STM, single word reading and repetition. In a sample of 83 participants, we related nonword performance in each task (as a marker of phonological capacity in the absence of meaning) to the effects of word imageability (a lexical-semantic variable). We found stronger reliance on lexical-semantic knowledge in participants with weaker phonological processing. This relationship held across tasks, suggesting that lexical-semantic processing can compensate for phonological weakness which would otherwise give rise to poor performance. Our results are consistent with separable yet interacting primary systems for phonology and semantics, with lexical-semantic knowledge supporting pattern completion within the phonological system in a similar way across STM and reading tasks. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Allophony in English Language Learners: The Case of Tap in English and Spanish.

Purpose The objective of this study was to examine tap production by English language learners (ELLs) in kindergarten whose 1st language is Spanish. The conflicting status of tap in Spanish and English could present challenges for allophonic learning in 2nd language for ELLs. Prior research has evaluated acquisition of other allophone pairs, but none has focused exclusively on tap. Method Thirty ELLs, 30 English monolinguals, and 29 Spanish monolinguals participated in the study. Participants completed a single-word repetition task in which numerous opportunities to produce tap were provided. Productions were phonetically transcribed and analyzed. Results The great majority of taps were pronounced correctly in both languages. The allophonic status of tap in English and phonemic status in Spanish suggest ELLs could experience negative transfer in learning; however, this was not observed. A significant interaction indicated more t/d substitutions in English and more semivowel/liquid substitutions in Spanish, contradicting the expectation of negative transfer. ELLs were also significantly more accurate at producing tap in Spanish than English. Conclusion Findings suggest that, at early kindergarten, ELL children rapidly adapted to English patterns of tap production even though Spanish and English conflict in phonemic/allophonic status of tap. This study was preliminary, and further investigation is warranted.

Aphasia in Progressive Supranuclear Palsy: As Severe as Progressive Non-Fluent Aphasia.

Adynamic speech is characteristic of progressive supranuclear palsy (PSP), but higher language deficits have been reported inconsistently, in the context of clinical and pathological overlaps with progressive non-fluent aphasia (PNFA). The present study tested two hypotheses: 1) PSP and PNFA display impaired single word repetition, object naming, semantic knowledge, and syntactic comprehension; and 2) PSP have reduced speed on timed cognitive tasks. Structured clinical and neuropsychological assessments of language were performed on patients with clinically defined PSP and PNFA. Language was tested using the Sydney Language Battery (SYDBAT) and the Test of Reception of Grammar (TROG). In total, 144 participants were studied (PSP 22, PNFA 29, and Control 93). PSP patients had prominent eye movement abnormalities, parkinsonism, and falls. All 4 PSP patients who underwent postmortem examination had 4-Repeat tauopathy, with PSP pathology in 3. The frequency and severity of impairment on the SYDBAT (naming, word comprehension, semantic association), and TROG (syntactic comprehension) did not differ between PSP and PNFA, but PSP were significantly slower on timed non-language cognitive tests. Tested formally, aphasia may be seen in PSP, with a severity similar to that seen in PNFA.

The priming of basic combinatory responses in MEG

Priming has been a powerful tool for the study of human memory and especially the memory representations relevant for language. However, although it is well established that lexical access can be primed, we do not know exactly what types of computations can be primed above the word level. This work took a neurobiological approach and assessed the ways in which the complex representation of a minimal combinatory phrase, such as red boat, can be primed, as evidenced by the spatiotemporal profiles of magnetoencephalography (MEG) signals. Specifically, we built upon recent progress on the neural signatures of phrasal composition and tested whether the brain activities implicated for the basic combination of two words could be primed. In two experiments, MEG was recorded during a picture naming task where the prime trials were designed to replicate previously reported combinatory effects and the target trials to test whether those combinatory effects could be primed. The manipulation of the primes was successful in eliciting larger activity for adjective-noun combinations than single nouns in left anterior temporal and ventromedial prefrontal cortices, replicating prior MEG studies on parallel contrasts. Priming of similarly timed activity was observed during target trials in anterior temporal cortex, but only when the prime and target shared an adjective. No priming in temporal cortex was observed for single word repetition and two control tasks showed that the priming effect was not elicited if the prime pictures were simply viewed but not named. In sum, this work provides evidence that very basic combinatory operations can be primed, with the necessity for some lexical overlap between prime and target suggesting combinatory conceptual, as opposed to syntactic processing. Both our combinatory and priming effects were early, onsetting between 100 and 150ms after picture onset and thus are likely to reflect the very earliest planning stages of a combinatory message. Thus our findings suggest that at the earliest stages of combinatory planning in production, a combinatory memory representation is formed that affects the planning of a relevantly similar combination on a subsequent trial.

Common and divergent neural correlates of anomia in amnestic and logopenic presentations of Alzheimer's disease

The majority of logopenic variant primary progressive aphasia (lv-PPA) cases harbour Alzheimer pathology, suggesting that lv-PPA constitutes an atypical presentation of Alzheimer's disease (AD). However, even if caused by Alzheimer pathology, the clinical manifestations of lv-PPA differ from those observed in the typical or amnestic AD presentation: in lv-PPA, aphasia is the main feature while amnestic AD is characterised by impaired episodic memory. Anomia or impaired naming, however, is present in both AD presentations. Whether these presentations share anatomical and mechanistic processes of anomia has not been fully investigated. Accordingly, we studied naming performance and its relationship with regions of brain atrophy in 23 amnestic AD and 22 lv-PPA cases with presumed underlying Alzheimer pathology. Both AD groups displayed some degree of anomia and impaired word comprehension but these were particularly severe in lv-PPA and accompanied by a range of linguistic deficits, comprising phonological substitutions, superordinate semantic paraphasias and abnormal single-word repetition. Analysis of cortical thickness revealed that anomia was correlated with thinning in left superior temporal gyrus in both groups. In amnestic AD, however, anomia was also associated with thinning in right inferior temporal regions. Single-word comprehension (SWC), by contrast, was associated with cortical thinning involving bilateral fusiform gyri in both groups. These findings suggest that anomia in both amnestic AD and lv-PPA results from the involvement at multiple steps of word processing, in particular, semantic and lexical retrieval; in addition lv-PPA patients display a more marked involvement of phonological processing.

Effects of semantic context on access to words of low imageability in deep-phonological dysphasia: a treatment case study

ABSTRACTBackground: Deep dysphasia is a relatively rare subcategory of aphasia, characterised by word repetition impairment and a profound auditory-verbal short-term memory (STM) limitation. Repetition of words is better than nonwords (lexicality effect) and better for high-image than low-image words (imageability effect). Another related language impairment profile is phonological dysphasia, which includes all of the characteristics of deep dysphasia except for the occurrence of semantic errors in single word repetition. The overlap in symptoms of deep and phonological dysphasia has led to the hypothesis that they share the same root cause, impaired maintenance of activated representation of words, but that they differ in severity of that impairment, with deep dysphasia being more severe.Aims: We report a single-subject multiple baseline, multiple probe treatment study of a person who presented with a pattern of repetition that was consistent with the continuum of deep-phonological dysphasia: imageability and lexicality effects in repetition of single and multiple words and semantic errors in repetition of multiple-word utterances. The aim of this treatment study was to improve access to and repetition of low-imageability words by embedding them in modifier-noun phrases that enhanced their imageability.Methods & Procedures: The treatment involved repetition of abstract noun pairs. We created modifier-abstract noun phrases that increased the semantic and syntactic cohesiveness of the words in the pair. For example, the phrases “long distance” and “social exclusion” were developed to improve repetition of the abstract pair “distance-exclusion”. The goal of this manipulation was to increase the probability of accessing lexical and semantic representations of abstract words in repetition by enriching their semantic -syntactic context. We predicted that this increase in accessibility would be maintained when the words were repeated as pairs, but without the contextual phrase.Outcomes & Results: Treatment outcomes indicated that increasing the semantic and syntactic cohesiveness of low-imageability and low-frequency words later improved this participant’s ability to repeat those words when presented in isolation.Conclusions: This treatment approach to improving access to abstract word pairs for repetition was successful for our participant with phonological dysphasia. The approach exemplifies the potential value in manipulating linguistic characteristics of stimuli in ways that improve access between phonological and lexical-semantic levels of representation. Additionally, this study demonstrates how principles of a cognitive model of word processing can be used to guide treatment of word processing impairments in aphasia.

The peri-Sylvian cortical network underlying single word repetition revealed by electrocortical stimulation and direct neural recordings

Verbal repetition requires the coordination of auditory, memory, linguistic, and motor systems. To date, the basic dynamics of neural information processing in this deceptively simple behavior are largely unknown. Here, we examined the neural processes underlying verbal repetition using focal interruption (electrocortical stimulation) in 58 patients undergoing awake craniotomies, and neurophysiological recordings (electrocorticography) in 8 patients while they performed a single word repetition task. Electrocortical stimulation revealed that sub-components of the left peri-Sylvian network involved in single word repetition could be differentially interrupted, producing transient perceptual deficits, paraphasic errors, or speech arrest. Electrocorticography revealed the detailed spatio-temporal dynamics of cortical activation, involving a highly-ordered, but overlapping temporal progression of cortical high gamma (75–150Hz) activity throughout the peri-Sylvian cortex. We observed functionally distinct serial and parallel cortical processing corresponding to successive stages of general auditory processing (posterior superior temporal gyrus), speech-specific auditory processing (middle and posterior superior temporal gyrus), working memory (inferior frontal cortex), and motor articulation (sensorimotor cortex). Together, these methods reveal the dynamics of coordinated activity across peri-Sylvian cortex during verbal repetition.

Heterogeneous Language Profiles in Patients with Primary Progressive Aphasia due to Alzheimer's Disease.

The logopenic variant of Primary Progressive Aphasia (lvPPA) is associated with underlying Alzheimer's disease (AD) pathology and characterized by impaired single word retrieval and repetition of phrases and sentences. We set out to study whether logopenic aphasia is indeed the prototypic language profile in PPA patients with biomarker evidence of underlying AD pathology and to correlate language profiles with cortical atrophy patterns on MRI. Inclusion criteria: (I) clinical diagnosis of PPA; (II) CSF profile and/or PiB-PET scan indicative for amyloid pathology; (III) availability of expert language evaluation. Based on language evaluation, patients were classified as lvPPA (fulfilling lvPPA core criteria), lvPPA extended (fulfilling core criteria plus other language disturbances), or PPA unclassifiable (not fulfilling lvPPA core criteria). Cortical atrophy patterns on MRI were visually rated and quantitative measurements of cortical thickness were performed using FreeSurfer. We included 22 patients (age 67±7 years, 50% female, MMSE 21±6). 41% were classified as lvPPA, 36% as lvPPA extended with additional deficits in language comprehension and/or confrontation naming, and 23% as PPA unclassifiable. By both qualitative and quantitative measurements, patients with lvPPA showed mild global cortical atrophy on MRI, whereas patients with lvPPA extended showed more focal cortical atrophy, predominantly at the left tempo-parietal side. For PPA unclassifiable, qualitative measurements revealed a heterogeneous atrophy pattern. Although most patients fulfilled the lvPPA criteria, we found that their language profiles were heterogeneous. The clinical and radiological spectrum of PPA due to underlying AD pathology is broader than pure lvPPA.

Is the logopenic-variant of primary progressive aphasia a unitary disorder?

Logopenic progressive aphasia is one of the clinical presentations of primary progressive aphasia and formally defined by the co-occurrence of impaired naming and sentence repetition. Impaired naming is attributed to failure of lexical retrieval, which is a multi-staged process subserved by anatomically segregated brain regions. By dissecting the neurocognitive processes involved in impaired naming, we aimed to disentangle the clinical and neuroanatomical heterogeneity of this syndrome. Twenty-one individuals (66.7% females, age range 53–83 years) who fulfilled diagnostic criteria for logopenic variant and had at least two clinical and language assessments, 1 year apart, were recruited and matched for age, sex distribution and level of education with a healthy control sample (n = 18). All participants underwent a structural brain scan at the first visit and surface-wise statistical analysis using Freesurfer. Seventeen participants with logopenic variant underwent amyloid imaging, with 14 demonstrating high amyloid retention. Based on their performance on single-word comprehension, repetition and confrontation naming, three subgroups of logopenic cases with distinctive linguistic profiles and distribution of atrophy were identified. The first subgroup (n = 10) demonstrated pure anomia and left-sided atrophy in the posterior inferior parietal lobule and lateral temporal cortex. The second subgroup (n = 6), presented additional mild deficits in single-word comprehension, and also exhibited bilateral thinning of the fusiform gyri. The third subgroup (n = 5) showed additional impaired single-word repetition, and cortical thinning focused on the left superior temporal gyrus. The subgroups differed in the proportion of cases with high amyloid retention and in the rate of decline of naming performance over time, suggesting that neurodegeneration spreads differentially throughout regions subserving word processing. In line with previous reports, these results confirm the extensive damage to the language network and, in part, explain the clinical heterogeneity observed across logopenic cases.

Swedish Test of Intelligibility for Children (STI-CH) – Validity and reliability of a computer-mediated single word intelligibility test for children

The aim of this study was twofold: first, to describe a new Swedish intelligibility test (Swedish Test of Intelligibility for Children, STI-CH) and second to evaluate its validity and reliability. STI-CH is based on the repetition of single words. Ten children with a speech-sound disorder (4:6–8:3 years of age, mean = 6.0 years) and 10 children with typical speech and language development (4:8–7:4 years of age, mean = 5.9 years) were included. Twenty speech-language pathology students served as listeners. Intra-judge reliability was high (r > 0.92), as was the intra-class correlation of inter-judge reliability (0.97). In terms of validity, there was a significant difference in STI-CH scores between the two groups, and the scores correlated statistically significantly with the Percentage of Consonants Correct (r = 0.94) and with intelligibility in spontaneous speech (r = 0.85). To sum up, the results indicate that STI-CH could be an option for the assessment of intelligibility in Swedish-speaking children, and that the principles used in the development of the test could be of use in the design of intelligibility tests in languages other than Swedish.

Verbal Repetition in Primary Progressive Aphasia and Alzheimer's Disease

We aimed to explore the nature of verbal repetition deficits and infer the cognitive systems involved in primary progressive aphasia (PPA) and Alzheimer's disease (AD). A total of 63 patients (13 semantic variant (sv-PPA), 17 nonfluent/agrammatic variant (nfv-PPA), 10 logopenic variant (lv-PPA), 23 AD) and 13 matched healthy controls completed a battery of tests that included naming, word comprehension, digit span, repetition of multisyllabic single words, monosyllabic word span presented under similar and dissimilar phonological conditions, and sentence repetition. All patient groups displayed some level of impairment, however, specific patterns emerged in each variant. Participants with sv-PPA were the least impaired, showing marginal difficulties exclusively for sentence repetition, whereas those with lv-PPA had the worst overall performance. Cases with nfv-PPA showed compromised repetition of multisyllabic and phonologically similar words. The deficit in cases with AD was confined to span tasks. These distinctive patterns of language impairments can assist in the differential diagnosis of PPA variants and point toward the vulnerability of specific cognitive systems in each syndrome.

The effects of initiation, termination and inhibition impairments on speech rate in a case of progressive nonfluent aphasia with progressive apraxia of speech with frontotemporal degeneration

Recent research into nonfluent forms of primary progressive aphasia and progressive apraxia of speech has highlighted the importance of speech rate as a diagnostic feature. We describe detailed investigation and comparison of speech rate (latencies and utterance length in single word/nonword production and speech rate in connected speech) on a range of experimental tasks in a man with progressive speech deterioration of 10 years duration from Pick's Disease. C.S. had a progressive nonfluent aphasia (PNFA) together with progressive apraxia of speech (pAOS) with an absence of significant interlectual, phonological or semantic impairment. C.S. showed increased latencies but reduced word length compared to matched controls on single word and nonword repetition and reading, an absence of a syllabic length effect in either single word/nonword tasks or connected speech tasks. Further investigation suggested that underlying his speech production impairments were problems with speech initiation, termination and inhibition. Most impairments worsened with progression over a 12-month period. Results provide support for the view that progressive apraxia of speech presents differently to apraxia of speech following stroke and, especially at advanced stages, involves deterioration in more central and supportive cognitive processes.

Primary progressive aphasia with parkinsonism

A 65-year-old man presented with word-finding difficulty and gait disturbance. His speech was nonfluent with word retrieval impairment and difficulties with sentence repetition. Other cognitive domains were intact initially. He developed asymmetrical bradykinesia, rigidity and a rest tremor. Over the following 8 years, his speech production impairment slowly deteriorated with the development of a motor speech disorder, anomia, impaired repetition of single words as well as sentences, and impaired comprehension of initially sentences then single words. His parkinsonian syndrome also deteriorated with limited response to levodopa. Serial brain MRI revealed progressive asymmetric perisylvian atrophy. He died after a disease duration of 12 years. The clinical syndrome is discussed by an expert, the pathology is described, and important clinical points from the case are highlighted. © 2013 Movement Disorder Society

Patterns of longitudinal brain atrophy in the logopenic variant of primary progressive aphasia

The logopenic variant of primary progressive aphasia (PPA) is characterised by impaired sentence repetition and word retrieval difficulties. Post mortem studies, amyloid imaging and CSF tau/Aβ measurements suggest Alzheimer’s disease (AD) pathology as the underlying cause. Relatively little is known about patterns of progression in patients with the logopenic variant of PPA. 21 patients (3 with post mortem confirmation of AD and 5 with positive amyloid PIB-PET scans) were studied with longitudinal T1-weighted MR imaging (mean interscan interval 1.2years) using volumetric analysis and voxel-based morphometry (VBM). Baseline imaging showed asymmetrical (left greater than right) involvement of the posterior superior temporal and inferior parietal lobes as well as posterior cingulate and medial temporal lobes. The whole brain rate of volume loss was 2.0% per year with a greater rate of left hemisphere atrophy (2.3%/year) than right hemisphere (1.6%/year). Longitudinal VBM analysis showed increasing involvement of other areas in the left hemisphere (temporal, parietal, frontal and caudate) and atrophy of areas in the right hemisphere that had been involved earlier in the disease in the left hemisphere, particularly posterior cingulate/precuneus. With disease progression there was worsening of anomia, sentence repetition and sentence comprehension but consistent with the spread of imaging changes also deficits in single word comprehension, single word repetition and verbal memory. This study shows that the logopenic variant of PPA remains an asymmetrical disease, with spread through the left hemisphere language network but also involvement to a lesser degree of regions in the right hemisphere that mirror the earlier left hemisphere changes.

Synthesized Speech Intelligibility and Early Preschool-Age Children: Comparing Accuracy for Single-Word Repetition With Repeated Exposure

This investigation examined the effect of repeated exposure to novel and repeated spoken words in typical environments on the intelligibility of 2 synthesized voices and human recorded speech in preschools. Eighteen preschoolers listened to and repeated single words presented in human-recorded speech, DECtalk Paul, and AT&T Voice Michael during 5 experimental sessions. Stimuli consisted of repeated and novel words presented in each speech output condition during each session. Sessions took place in the presence of typically occurring noise in classroom or home settings. There was a significant main effect for voice as participants accurately identified significantly more words in the human-recorded speech and AT&T Voice than in the DECtalk speech output condition. When averaged across speech output conditions, children increased their accuracy as they participated in additional sessions. There was a statistically significant interaction between session and voice. DECtalk had a slightly larger effect of session than did AT&T Voice and human-recorded speech.