bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multisite Study to Examine the Efficacy of the Otoacoustic Emission/Automated Auditory Brainstem Response Newborn Hearing Screening Protocol
Authors: Johnson Jean L. , White Karl R. , Widen Judith E. , Gravel Judith S. , Vohr Betty R. , James Michele , Kennalley Teresa , Maxon Antonia B. , Spivak Lynn , Sullivan-Mahoney Maureen , Weirather Yusnita , Meyer Sally
Published: April 2006

Purpose:
This article is the 1st in a series of 4 articles on a recently completed multistate study of newborn hearing screening.

Method:
The study examined the efficacy of the 2-stage otoacoustic emission/automated auditory brainstem response (OAE/A-ABR) protocol for identifying hearing loss in newborns.

Results:
The study found that the 2-stage OAE/A-ABR protocol did miss a significant number of babies who exhibited a permanent hearing loss by 1 year of age. Three subsequent articles will describe the research design and results in detail, discuss the behavioral assessment of infants, and summarize the implications of the study for policy, practice, and research.
Phonetic Inventory Development in Young Cochlear Implant Users 6 Years Postoperation
Authors: Blamey Peter J. , Barry Johanna G. , Jacq Pascale
Published: April 2006

Increases in the phonetic inventories of a group of 9 children in the fifth and sixth years of experience with a cochlear implant are reported, extending a previous 4-year study (T. A. Serry & P. J. Blamey, 1999). Thirty-six out of 44 phones in Australian English reached the criterion of 50% correct in the conversational samples of 5 or more children. This level of performance corresponds to intelligible, but not completely natural, speech. The rate of improvement in the sixth year was slow, indicating a probable plateau in performance. The 8 phones that did not attain the 50% criterion in 5 or more children were /I, , , t, s, z, , θ/. Potential reasons for the slow development or nondevelopment of these phones include very low frequency of occurrence for /I, , / and the perceptual and articulatory characteristics of /t, s, z, , θ/. /t/ is also subject to a high degree of allophonic variation in the fluent speech of normally hearing speakers, probably accounting for much of the variability in its articulation in the conversational samples.
The Effects of Contextualization on Fluency in Three Groups of Children
Authors: Trautman Lisa Scott , Healey E. Charles , Norris Janet A.
Published: April 2006

This study investigated the effects of contextualization on fluency in 12 school-age children who stutter (CWS), 11 children with language impairment (CLI), and 12 children with normally developing fluency skills (CNF). Participants in the study were between the ages of 8 and 12 years and were matched for age and sex. Four discourse samples were elicited by asking participants to (a) generate two scripts related to cooking and (b) retell two stories. Having objects or pictures immediately available contextualized a cooking task and a retelling task; another set of cooking and retelling tasks were decontextualized. Moments of disfluency were identified and coded for three primary categories of disfluency: stutteringtype, normal-type, and mazing. For CWS, a significant reduction in frequency of stuttering was noted in the contextualized script generation, and mazing occurred at a significantly higher frequency than did stuttering-type or normal-type disfluencies across the four tasks. For all three groups, both decontextualized conditions produced greater frequencies of normal-type disfluency and mazing. In addition, narrative retelling tasks yielded higher frequencies of disfluency than did the two cooking scripts.
Influence of Mothers’ Slower Speech on Their Children’s Speech Rate
Authors: Guitar Barry , Marchinkoski Lisa
Published: April 2006

This study investigated the effects on children’s speech rate when their mothers talked more slowly. Six mothers and their normally speaking 3-year-olds (3 girls and 3 boys) were studied using single-subject A-B-A-B designs. Conversational speech rates of mothers were reduced by approximately half in the experimental (B) conditions. Five of the six children appeared to reduce their speech rates when their mothers spoke more slowly. This was confirmed by paired
t
tests (
p
< .05) that showed significant decreases in the 5 children’s speech rate over the two B conditions. These findings suggest that when mothers substantially decrease their speech rates in a controlled situation, their children also decrease their speech rates. Clinical implications are discussed.
Effects of CIC Hearing Aids on Auditory Localization by Listeners With Normal Hearing
Authors: D'Angelo William R. , Bolia Robert S. , Mishler Pamela J. , Morris Linda J.
Published: April 2006

An experiment was conducted to determine the effects of completely-in-the-canal (CIC) hearing aids on auditory localization performance. Six normal-hearing listeners localized a 750-ms broadband noise from loudspeakers ranging in azimuth from –180° to +180° and in elevation from –75° to +90°. Independent variables included the presence or absence of the hearing aid and the elevation of the source. Dependent measures included azimuth error, elevation error, and the percentage of trials resulting in a front-back confusion. The findings indicate a statistically significant decrement in localization acuity, both in azimuth and elevation, occasioned by the wearing of CIC hearing aids. However, the magni-tude of this decrement was small compared to those typically caused by other ear-canal occlusions, such as earplugs, and would probably not engender mislocalization of real-world sounds.
Characteristics of Speech Disfluency and Stuttering Behaviors in 3- and 4-Year-Old Children
Authors: Pellowski Mark W. , Conture Edward G.
Published: April 2006

The purpose of this investigation was to quantitatively and qualitatively characterize speech disfluencies exhibited by 3- and 4-year-old children who do (CWS,
N
= 36) and do not (CWNS,
N
=36) stutter. Five measures of speech disfluency (e.g., percentage of total, other, and stuttering-like disfluencies, mean number of repetition units, and weighted SLD measure) were used in attempts to differentiate CWS from CWNS. Similar measures of stuttering (e.g., percentage of stutteringlike disfluencies consisting of disrhythmic phonations) were used to characterize speech disfluencies in 3- and 4-year-old CWS in relation to time since stuttering onset (TSO). It was hypothesized that such measures of speech disfluency should significantly differ between CWS and CWNS, as well as 3- versus 4-year-old CWS in relation to TSO. Results indicated that 4 out of the 5 dependent measures significantly differed between CWS and CWNS, and within the CWS group there was a significant relationship between TSO and the percentage of stuttering-like disfluencies when the effects of chronological age were partialled out of the regression analyses. Furthermore, 4-year-old CWS exhibited a moderate correlation between TSO and the percentage of stuttering-like disfluencies consisting of disrhythmic phonations, whereas 3-year-old CWS exhibited no such relationship between these two variables. Findings were taken to suggest that certain measures of speech disfluency appreciably differentiate CWS from CWNS and that 4-year-old CWS exhibit changes in nonreiterative forms of stuttering as a function of time since stuttering onset.
Muscle, Adipose, and Connective Tissue Variations in Intrinsic Musculature of the Adult Human Tongue
Authors: Miller Jeri L. , Watkin Kenneth L. , Chen Moy Fong
Published: April 2006

The purpose of this investigation was to identify the composition and organization of lingual tissues underlying the histostructural and biomechanical functions of the adult human tongue. The small-scale structures of three intrinsic muscle regions, their principal cells, structural complexities, and differences in underlying tissue composition were compared to other skeletal muscle systems and the results discussed in relation to lingual morphology. Analysis of pixel color distributions determined the percent area concentration of each stained tissue component. Results indicated that muscle content increased from anterior to posterior (p< .0001). Greater adipose (p= .005) and connective tissue (p< .002) concentrations occurred in anterior regions. Dense collagen sheaths and elastic fibers found anteriorly occurred with less magnitude in medial and posterior sites. The unique elastin, collagen, and adipose connective tissue distributions found in intrinsic sampling sites are discussed in terms of understanding lingual biomechanics in both normal and pathologic states.
Narrative Content as Described by Individuals With Down Syndrome and Typically Developing Children
Authors: Miles Sally , Chapman Robin S.
Published: April 2006

Narratives of the wordless picture story,
Frog, Where Are You?
, by 33 individuals with Down syndrome and typically developing children (33 matched for mental age, 33 for syntax comprehension, 33 for mean length of utterance) were analyzed for expression of plot line, story theme, and the protagonists' misadventures in the story. Despite their restricted expressive syntax and vocabulary, the group with Down syndrome expressed more plot line and thematic content and more of one of the protagonists' misadventures than the MLU controls; they most resembled the syntax comprehension control participants. We conclude that the group with Down syndrome had a conceptual understanding of the picture story similar to that of the TACL-R group and a strategy for expressing that understanding despite expressive lexical and syntactic limitations; this resulted in the expression of more narrative content than formal measures of expressive language would predict. We propose that the higher syntactic comprehension skills of the group with Down syndrome, combined with their experience with story content (listening to stories), may have contributed to their developing higher-level story schemas than would be expected given their MLUs.
Biological Mechanisms Underlying Voice Changes Due to Dehydration
Authors: Verdolini Katherine , Min Young , Titze Ingo R. , Lemke Jon , Brown Kice , Mersbergen Miriam van , Jiang Jack , Fisher Kim
Published: April 2006

Four vocally untrained healthy adults, 2 men and 2 women, completed the study. A double-blind placebo-controlled approach was used to administer three treatments to each participant on separate days. Drugs treatments involved a single 60-mg dose of a diuretic, Lasix (LA), on one day, and a single 50-mg dose of an oral antihistamine, diphenhydramine hydrochloride (DH), on another day. A third day involved the administration of a placebo, sugar pills (SP). Critical posttreatment measures were weight (kg), which estimated systemic dehydration, saliva viscosity (centipoise), which estimated secretion dehydration, and phona-tion threshold pressure (PTP, in cm H
2
O), at high pitches, which indicated pulmonary drive for phonation. The central experimental question was: Does systemic dehydration, or secretory dehydration, or both, mediate increases in PTP that are known to occur following dehydration treatments? The results showed that LA induced systemic dehydration, as shown by a decrease in total body mass of about 1%. Weight losses were seen during a 1- to 4-hour block following drug administration and persisted for at least 8 hours thereafter. PTPs also increased in that condition, about 23% relative to baseline, but only several hours after whole-body dehydration was initially seen (5–12 hours after drug administration). In contrast, no evidence was seen that DH accomplished either secretory dehydration or PTP shifts. The results indicate that systemic dehydration can mediate PTP increases. The influence of secretory dehydration on PTP is unclear.
Lexical and Talker Effects on Word Recognition Among Native and Non-Native Listeners With Normal and Impaired Hearing
Authors: Takayanagi Sumiko , Dirks Donald D. , Moshfegh Anahita
Published: April 2006

Evidence suggests that word recognition depends on numerous talker-, listener-, and stimulus-related characteristics. The current study examined the effects of talker variability and lexical difficulty on spoken-word recognition among four groups of listeners: native listeners with normal hearing or hearing impairment (moderate sensorineural hearing loss) and non-native listeners with normal hearing or hearing impairment. The ability of listeners to accommodate trial-totrial variations in talkers' voice was assessed by comparing recognition scores for a single-talker condition to those obtained in a multiple-talker condition. Lexical difficulty was assessed by comparing word-recognition performance between lexically ‘easy’ and ‘hard’ words as determined by frequency of occurrence in language and the structural characteristics of similarity neighborhoods formalized in the Neighborhood Activation Model. An up-down adaptive procedure was used to determine the sound pressure level for 50% performance. Non-native listeners in both normal-hearing and hearing-impaired groups required greater intensity for equal intelligibility than the native normal-hearing and hearingimpaired listeners. Results, however, showed significant effects of talker variability and lexical difficulty for the four groups. Structural equation modeling demonstrated that an audibility factor accounts for 2–3 times more variance in performance than does a linguistic-familiarity factor. However, the linguistic-familiarity factor is also essential to the model fit. The results demonstrated effects of talker variability and lexical difficulty on word recognition for both native and nonnative listeners with normal or impaired hearing. The results indicate that linguistic and indexical factors should be considered in the development of speech-recognition tests.
Sustaining a Constant Effort by the Tongue and Hand
Authors: Solomon Nancy Pearl , Drager Kathryn D. R. , Luschei Erich S.
Published: April 2006

A constant-effort task was used previously as a potential assessment technique for fatigue. Participants sustained submaximal target effort levels with the tongue and hand against soft air-filled bulbs. For 80% of all trials, pressure decreased exponentially to a positive asymptote. In addition, pressure decreased faster when the muscles were fatigued than when they were rested. This study attempted to replicate the previous findings with new participants and to extend the findings to include surface electromyographic (EMG) data. Pressure and surface EMG signals were collected simultaneously while 10 neurologically normal young adults performed the constant-effort task at 50% of maximum pressure with the tongue and the hand. Eighty-one percent of the pressure data were modeled by a negative exponential equation with a nonzero asymptote. Seventy-three percent of the corresponding EMG data also fit this mathematical model. The pressure signals decayed more slowly than the corresponding EMG signals, particularly for the hand. After participants fatigued the tongue and hand with repeated brief maximal voluntary contractions, the time constants were reduced (rate of decay increased) for the tongue but not the hand. These results corroborate the previous finding that the time constant, determined from an exponential curve-fitting procedure, is a replicable measure. Furthermore, the reduction in the time constant after inducing acute fatigue in the tongue was replicated, although this same relationship was not replicated for the hand. The EMG data suggest that decreases in neuromuscular drive, including increased early adaptation, motor unit derecruitment, and motor unit desynchronization, contributed to the decrease in pressure during the constant effort task, especially after acute fatigue was induced. These observations support the hypothesis that the task reflects, at least in part, central fatigue processes.
Grammatical Morpheme Production in 4-Year-Old Children
Authors: Balason Denise V. , Dollaghan Christine A.
Published: April 2006

Despite the importance of grammatical morpheme (GM) production for both clinical decision-making and theoretical accounts of child language impairment, evidence concerning developmental expectations for GM use is inadequate. We studied grammatical morpheme production in 15-minute spontaneous language samples from a large (
N
=100), sociodemographically diverse group of 4-year-olds. Substantial variability was observed in both the frequency of obligatory contexts (OCs) and in the percentage of correct usage of GMs. For only one morpheme did all 100 samples contain the minimum number of 3 OCs; for only 7 of the 14 GMs was an adequate number of OCs found in at least half of the 100 samples. Although mean percentages of production from samples with 3 or more OCs were high (> 85%), fewer than 25% of participants contributed to the ‘group’ means for 6 of the 14 GMs. Results from the present investigation indicate a need for caution in interpreting information on GM production derived from samples of this nature from children at this age; the validity of using such data to identify deficits in inflectional morphology for either clinical or research purposes appears questionable.
The Effect of Pacing Strategies on the Variability of Speech Movement Sequences in Dysarthria
Authors: McHenry Monica A.
Published: April 2006

There are many potential sources of variability in speech production, particularly in individuals with dysarthria. The degree and time course of stabilization of the speech production system during recovery from a neurological insult is not constant across individuals. Another source of variability in speech production is speaking rate. Although individuals with no neurological impairments typically show increased variability at reduced speaking rates, this phenomenon has not been explored extensively in individuals with dysarthria. Because rate control strategies are commonly used in dysarthria treatment, it is of clinical importance to know if individuals with dysarthria produce less variable speech with rate reduction. Six individuals with mild dysarthria, 6 with moderate-to-severe dysarthria, and 6 matched normal controls repeated an utterance in four speaking rate conditions: habitual, fast, breaks between words, and stretched. Data were analyzed using the spatiotemporal index (STI), a composite measure of spatial and temporal variability across token repetitions. The normal controls consistently demonstrated the least variability, regardless of rate condition. Both groups with dysarthria were the least variable in the stretched condition and the most variable in the fast condition. The STI values of the group with moderate-to-severe dysarthria were significantly different from both the individuals with mild dysarthria and the normal controls. There were no significant differences between the group with mild dysarthria and the normal controls. In general, slowing the speaking rate in individuals with dysarthria reduces spatiotemporal variability; however, the effect of reduced spatiotemporal variability on intelligibility requires further investigation.
Talker Separation and Sequential Stream Segregation in Listeners With Hearing Loss
Authors: Mackersie Carol L.
Published: April 2006

The purpose of this paper was to examine the relations between the ability to separate simultaneous sentences spoken by talkers of different gender and the ability to separate pitch patterns in a sequential stream segregation task. Simultaneous sentence pairs consisting of 1 sentence spoken by a male talker and 1 sentence spoken by a female talker were presented to 11 listeners with sensorineural hearing loss. Listeners were asked to repeat both sentences and were scored on the number of words repeated correctly. Separate scores were obtained for the male and female sentences. Sequential stream segregation was then measured using series of tones consisting of a fixed frequency (A) and a varying frequency tone (B). Tone series were presented in an ABA_ABA_... pattern starting at a varying frequency either below (ascending pattern) or above (descending pattern) the frequency of the fixed 1000 Hz tone. Fusion thresholds, defined as the frequency separation at which listeners could no longer perceptually separate the tones A and B, were obtained for both ascending and descending patterns. There was no significant difference between ascending and descending fusion thresholds based on the group data, but substantial individual differences were observed. Speech recognition scores for the male talker were strongly related to ascending fusion thresholds, but not descending thresholds. In contrast, speech recognition scores for the female talker were strongly related to the descending thresholds, but not the ascending thresholds. For both the male and female talkers, better recognition scores were associated with lower (nearer to normal) fusion thresholds. Results suggest that the importance of streaming in the perceptual separation of talkers may depend on the nature of the information provided by the changing pitch stream.
The Effects of Taste and Consistency on Swallow Physiology in Younger and Older Healthy Individuals
Authors: Ding Ruiying , Logemann Jeri A. , Larson Charles R. , Rademaker Alfred W.
Published: April 2006

Recent studies done on healthy older individuals have demonstrated elevated taste thresholds for sweet, sour, and salty taste. At suprathreshold levels, such individuals have also shown less ability to discriminate between different intensities of the same tastant. This study was designed to provide information on swallow timing and muscle contraction intensity variables in healthy older people during swallowing of liquid and cottage cheese consistencies in 3 taste conditions (sweet, salty, and sour). Taste and consistency were incorporated in the design of this study to determine not only the effect of taste and consistency independently, but also the effects of taste and consistency in combination. Surface electromyography (EMG) at 3 sites—the orbicularis oris inferior region, submental muscle region, and infrahyoid muscle region—were included in the study.

Results revealed that the start of submental muscle activation was significantly later in older participants than in younger participants. The 3 taste conditions had higher EMG levels and shorter activation times than the no-taste condition, although different taste conditions and different muscle sites were affected differently. With thicker consistency, substantially increased EMG amplitude and duration were noted for all three sites. A more pronounced effect of taste was manifested as earlier submental or infrahyoid muscle activation when the three tastants were added to a thicker consistency. Interaction of taste, consistency, and age was also noted for onset time at the submental and infrahyoid sites.
A Method for Examining Productivity of Grammatical Morphology in Children With and Without Specific Language Impairment
Authors: Miller Carol A. , Deevy Patricia
Published: April 2006

Children with specific language impairment (SLI) show inconsistent use of grammatical morphology. Children who are developing language typically also show a period during which they produce grammatical morphemes inconsistently. Various theories claim that both young typically developing children and children with SLI achieve correct production through memorization of some inflected forms (M. Gopnik, 1997; M. Tomasello, 2000a, 2000b). Adapting a method introduced by C. Miller and L. Leonard (1998), the authors investigated the use of present tense third singular -sby 24 typically developing preschoolers and 36 preschoolers with SLI. Each group was divided into 2 mean length of utterance (MLU) levels. Group and individual data provided little evidence that memorization could explain the correct productions of the third singular morpheme for either children with SLI or typically developing children, and there was no difference between children with higher and lower MLUs.
Taxometric Analyses of Specific Language Impairment in 3- and 4-Year-Old Children
Authors: Dollaghan Christine A.
Published: April 2006

Specific language impairment (SLI), like many diagnostic labels for complex behavioral conditions, is often assumed to define a category of children who differ not only in degree but also in kind from children developing language normally. Although this assumption has important implications for theoretical models and clinical approaches, its validity has not been tested. In this study, distributions of language scores from children at ages 3 (
N
= 620) and 4 (
N
= 623) years were analyzed using a taxometric procedure known as "mean above minus below a cut" (MAMBAC; P. E. Meehl & L. J. Yonce, 1994). Language scores were distributed dimensionally at both ages, failing to support the hypothesis of a qualitatively distinct group corresponding to children with SLI.
Word Learning by Preschoolers With Specific Language Impairment
Authors: Gray Shelley
Published: April 2006

Twenty preschoolers with specific language impairment (SLI) and 20 age matches with normal language (NL) participated in a study to determine whether phonological memory or semantic knowledge predicted word-learning success. Poor learners’ performance was analyzed to investigate whether phonology or semantics contributed more to word-learning difficulty. Results suggest that existing lexical knowledge, as measured by the Peabody Picture Vocabulary Test (PPVT-III), and fast-mapping ability hold promise for identifying poor word learners, but individual PPVT-III scores must be compared with SLI group scores. Poor word learners comprehended most new words and showed sufficient semantic knowledge of their referents to draw them but had difficulty producing the words. Findings indicated that both semantics and phonology contribute to word-learning difficulty, with word production presenting the biggest hindrance to success.
Effects of Neurosurgical Management of Parkinson's Disease on Speech Characteristics and Oromotor Function
Authors: Farrell Anna , Theodoros Deborah , Ward Elizabeth , Hall Bruce , Silburn Peter
Published: April 2006

The present study examined the effects of neurosurgical management of Parkinson’s disease (PD), including the procedures of pallidotomy, thalamotomy, and deep-brain stimulation (DBS) on perceptual speech characteristics, speech intelligibility, and oromotor function in a group of 22 participants with PD. The surgical participant group was compared with a group of 25 non-neurologically impaired individuals matched for age and sex. In addition, the study investigated 16 participants with PD who did not undergo neurosurgical management to control for disease progression. Results revealed that neurosurgical intervention did not significantly change the surgical participants’ perceptual speech dimensions or oromotor function despite significant postoperative improvements in ratings of general motor function and disease severity. Reasons why neurosurgical intervention resulted in dissimilar outcomes with respect to participants’ perceptual speech dimensions and general motor function are proposed.
Open Source Software for Experiment Design and Control
Authors: Hillenbrand James M. , Gayvert Robert T.
Published: April 2006

The purpose of this paper is to describe a software package that can be used for performing such routine tasks as controlling listening experiments (e.g., simple labeling, discrimination, sentence intelligibility, and magnitude estimation), recording responses and response latencies, analyzing and plotting the results of those experiments, displaying instructions, and making scripted audio-recordings. The software runs under Windows and is controlled by creating text files that allow the experimenter to specify key features of the experiment such as the stimuli that are to be presented, the randomization scheme, interstimulus and intertrial intervals, the format of the output file, and the layout of response alternatives on the screen. Although the software was developed primarily with speech-perception and psychoacoustics research in mind, it has uses in other areas as well, such as written or auditory word recognition, written or auditory sentence processing, and visual perception.
Double-Vowel Perception in Listeners With Cochlear Hearing Loss
Authors: Arehart Kathryn Hoberg , Rossi-Katz Jessica , Swensson-Prutsman Julie
Published: April 2006

This study presents 2 experiments investigating whether listeners with cochlear hearing loss (hearing impaired; HI) and listeners with normal hearing (NH) show differential susceptibility to masking in double-vowel identification. Experiment 1 addressed how double-vowel perception changes as a function of differences in fundamental frequency (ΔF
0
) of 0 and 2 semitones and the relative amplitudes of the constituent vowels (target-to-masker ratios: –10, –5, 0, 5, 10 dB). When ΔF
0
is 0 semitones, listeners in the HI group often perceive the presence of only 1 vowel, whereas listeners in the NH group generally perceive the presence of 2 vowels. In both groups, ΔF
0
benefits target-vowel identification, with the greatest benefit occurring when the target-to-masker ratio is –10 dB. When identification rates of specific vowels (in
d
') were rank ordered, different patterns of vowel dominance were found between the NH and HI groups. In Experiment 2, the effects of ΔF
0
(0 to 4 semitones) were compared for monaural and dichotic presentation of double vowels. Both groups show significant dichotic benefit. In addition, individual listeners in the HI group showed trends toward greater dichotic benefit. In both experiments, identification of competing vowels was significantly worse in HI listeners. The results of this study support the idea that increased susceptibility to masking is a primary factor underlying the degraded double-vowel perception in listeners with hearing loss.
Speech Interactions With Linguistic, Cognitive, and Visuomotor Tasks
Authors: Dromey Christopher , Bates Emily
Published: April 2006

Lip movements were examined across several repetitive speaking conditions (speech alone and speaking concurrently with a linguistic, cognitive, or visuomotor challenge task) in 20 young adults. Performance in these nonspeech activities was also compared between isolated tasks and concurrent speech conditions. Linguistic challenges resulted in increased spatiotemporal variability of lip displacement across repetitions. Motor challenges led to more rapid speech with smaller lip displacement. These qualitatively different changes suggest that different aspects of attention are required for linguistic versus manual visuomotor activity. Vocal intensity increased for all concurrent task conditions compared with speech alone, suggesting increased effort compared to the control condition. Scores for linguistic performance decreased when utterance repetition occurred concurrently with the syntactic challenge. These findings reveal that speech motor activity can influence linguistic performance as well as be influenced by it. Although these data come from healthy speakers, they suggest that clinicians working with disordered speakers should not overlook the potential interactions among the demands of language formulation, cognitive activity, and speech motor performance.
Forced-Choice Analysis of Segmental Production by Chinese-Accented English Speakers
Authors: Rogers Catherine L. , Dalby Jonathan
Published: April 2006

This study describes the development of a minimal-pairs word list targeting phoneme contrasts that pose difficulty for Mandarin Chinese-speaking learners of English as a second language. The target phoneme inventory was compiled from analysis of phonetic transcriptions of about 800 mono- and polysyllabic English words with examples of all the vowels, diphthongs, and syllable onsets and codas of the language. The Mandarin-specific minimal-pairs list derived from the phonetic transcription analyses contains 190 items. Tape recordings were made of 8 Mandarin speakers reading a randomized version of target items from the minimal-pairs list and a set of 20 sentences. Listeners who were native American English speakers judged the words in a forced-choice task and wrote down what they understood of the sentences. Correlations between listener responses on the forced-choice task and the sentence intelligibility scores showed differences in the strength of the relationship with sentence intelligibility across categories of minimal-pairs contrasts. Multiple regression analysis found listener responses on the minimal-pairs task to account for approximately 76% of the variance in speakers' sentence intelligibility scores, showing that performance on the minimal pairs of the probe list does predict connected speech intelligibility. Analyses of individual contrasts indicate target phonemes most often misperceived by native listeners.
Probed Serial Recall in Williams Syndrome
Authors: Brock Jon , McCormack Teresa , Boucher Jill
Published: April 2006

Williams syndrome is a genetic disorder that, it has been claimed, results in an unusual pattern of linguistic strengths and weaknesses. The current study investigated the hypothesis that there is a reduced influence of lexical knowledge on phonological short-term memory in Williams syndrome. Fourteen children with Williams syndrome and 2 vocabulary-matched control groups, 20 typically developing children and 13 children with learning difficulties, were tested on 2 probed serial-recall tasks. On the basis of previous findings, it was predicted that children with Williams syndrome would demonstrate (a) a reduced effect of lexicality on the recall of list items, (b) relatively poorer recall of list items compared with recall of serial order, and (c) a reduced tendency to produce lexicalization errors in the recall of nonwords. In fact, none of these predictions were supported. Alternative explanations for previous findings and implications for accounts of language development in Williams syndrome are discussed.
Adaptation of a Pocket PC for Use as a Wearable Voice Dosimeter
Authors: Popolo Peter S. , Švec Jan G. , Titze Ingo R.
Published: April 2006

This article deals with the adaptation of a commercially available Pocket PC for use as a voice dosimeter, a wearable device that measures the vocal dose of teachers or other individuals on the job, at home, and elsewhere during the course of an entire day. An engineering approach for designing a voice dosimeter is described, and design data are presented. Technical issues include transducer selection, dynamic range, frequency response, memory requirements, power requirements, attachment, cables, connections, and data collection. Advantages and disadvantages of the design are discussed.
Roles of Initiation and Responsiveness in Access and Participation for Children With Specific Language Impairment
Authors: Liiva Colleen A. , Cleave Patricia L.
Published: April 2006

This study compared the abilities of children with specific language impairment (SLI;
n
=10) and typically developing (TD) children (
n
=13) to access and participate in an ongoing interaction between two unfamiliar peer partners. Results revealed that all children in the study accessed by either making an unprompted initiation toward their peers (access initiation) or by responding to a question or play invitation directed toward them (access response). However, 4 children with SLI were unsuccessful in achieving successful access initiation during the 10-min play period. Children with SLI required a longer period of time to achieve access initiation. Following access, children with SLI were addressed significantly less by their play partners, participated in less group play, and engaged in more individual play and onlooking behavior. Among the SLI group, language levels were negatively related to the time children required to achieve their first successful access and first access initiation. Expressive language levels were positively related to the percentage of utterances children produced postaccess and the percentage of utterances they were addressed postaccess by their play partners. Differences in receptive skills among SLI children were less strongly related to the time they required in achieving their first access and were unrelated to their ability to participate in the interaction.
Polymer bilayer structure via inkjet printing
Authors: Xia Yajun , Friend Richard H.
Published: April 2006

We report the formation of a polymer bilayer structure by inkjet printing poly(9,9′-dioctylfluorene-co-benzothiadiazole) (F8BT) from p-xylene solution onto a poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine (TFB) thin film. Despite the compatibility of both polymers with the same organic solvent, a TFB layer under the later-deposited F8BT was directly observed through fluorescence microscopy. Micro-Raman spectroscopy reveals that this bottom layer is ∼10nm thick for a film made by inkjet printing F8BT onto a TFB film of ∼20nm thickness. The bilayer structure leads to enhanced efficiency for light-emitting diodes in comparison with devices made from spin-coated TFB:F8BT blend films.
Resonantly enhanced femtosecond second-harmonic generation and nonlinear luminescence in GaN film grown on sapphire
Authors: Yang Hui , Xu S. J. , Li Q. , Zhang Jie
Published: April 2006

At room temperature, by using a tunable broadband femtosecond laser as excitation source we observed second-harmonic generation (SHG) and nonlinear photoluminescence (NPL) in GaN film grown on sapphire simultaneously or individually. In addition to the observation of the resonance effect of the nonlinear response when the SHG is tuned to coincide with the near-band-edge emission, we carefully measured dependence of the SHG and NPL signals on polarization of the excitation light. The results reveal that the reabsorption of the SHG photons with energies higher than the fundamental gap of GaN significantly contributes to generation of the efficient NPL signal.
Domain architecture and structure of the bacterial cell division protein DivIB
Authors: Robson Scott A. , King Glenn F.
Published: April 2006

Bacterial cytokinesis requires the coordinated assembly of a complex of proteins, collectively known as the divisome, at the incipient division site. DivIB/FtsQ is a conserved component of the divisome in bacteria with cell walls, suggesting that it plays a role in synthesis and/or remodeling of septal peptidoglycan. We demonstrate that the extracytoplasmic region of DivIB comprises three discrete domains that we designate α, β, and γ from the N to C terminus. The α-domain is proximal to the cytoplasmic membrane and coincident with the polypeptide transport-associated domain that was proposed previously to function as a molecular chaperone. The β-domain has a unique 3D fold, with no eukaryotic counterpart, and we show that it interconverts between two discrete conformations via cis–trans isomerization of a Tyr–Pro peptide bond. We propose that this isomerization might modulate protein–protein interactions of the flanking α- and γ-domains. The C-terminal γ-domain is unstructured in the absence of other divisomal proteins, but we show that it is critical for DivIB function.
Antibody Response to Influenza Vaccination in Nursing Home Residents and Healthcare Workers During Four Successive Seasons in Niigata, Japan
Authors: Sato Mizuho , Saito Reiko , Tanabe Naohito , Nishikawa Makoto , Sasaki Asami , Gejyo Fumitake , Suzuki Hiroshi
Published: April 2006

Objective:

To evaluate the antibody response to influenza vaccines in nursing home residents and healthcare workers (HCWs) and its relation to residents' functional and chronic disease status during four successive seasons.

Design:

Before-after study.

Setting:

Nine nursing homes during the 1998-1999 season and two during the 1999-2000, 2000-2001, and 2001-2002 seasons.

Participants:

Two hundred fifty-nine residents and 79 HCWs during the 1998-1999 season; 180 and 71, respectively, during the 1999-2000 season; 162 and 71, respectively, during the 2000-2001 season; and 153 and 79, respectively, during the 2001-2002 season.

Results:

Multivariate analysis indicated that the mean fold increase in the geometric mean titers (GMTs) of hemagglutination inhibition (HI) antibodies and the response rate (the proportion of vaccinées resulting in a significant, at least fourfold increase in antibody titer) were good and no significant differences occurred for almost all strains in both residents and HCWs. The GMTs of HI antibodies and the protection rate (the proportion of participants with HI antibody titers & 40) were increased in both residents and HCWs, but were significantly lower for almost all strains in residents than in HCWs. Furthermore, multivariate analysis indicated that subdivision of residents into three groups by level of daily activities and into four groups according to underlying diseases revealed only minor differences in immune responses.

Conclusions:

Antibody responses to the influenza vaccine were lower in residents than in HCWs. However, residents showed similar antibody responses regardless of their level of daily activity or underlying diseases.
Multiple gene genealogical analyses suggest divergence and recent clonal dispersal in the opportunistic human pathogen Candida guilliermondii
Authors: Lan Lisa , Xu Jianping
Published: April 2006

Candida guilliermondii is a haploid opportunistic pathogen accounting for about 2 % of human blood yeast infections. Recent analyses using multilocus enzyme electrophoresis and karyotyping suggest that strains from human sources traditionally designated C. guilliermondii in fact include at least two species, C. guilliermondii and Candida fermentati. However, the patterns of molecular variation within and between these two species remain largely unknown. In this study, DNA fragments were sequenced from five genes for each of 37 strains collected from Canada, China, the Philippines and Tanzania. The analyses identified significant sequence differences between C. guilliermondii and C. fermentati. The five gene genealogies showed no apparent incongruence, suggesting a predominantly clonal reproductive structure for both species in nature. Indeed, two large clones of C. guilliermondii were identified, with one from Ontario, Canada, and the other from China. Interestingly, the results indicate that strains currently designated C. guilliermondii may contain additional divergent lineages. On the practical side, the results revealed several diagnostic molecular markers that can be used in clinical microbiology laboratories to distinguish C. guilliermondii and C. fermentati. The multiple gene genealogical analyses conducted here revealed significant divergence and clonal dispersal in this important pathogenic yeast complex.
An activated Ras protein alters cell adhesion by dephosphorylating Dictyostelium DdCAD-1
Authors: Secko David M. , Siu Chi-Hung , Spiegelman George B. , Weeks Gerald
Published: April 2006

RasG-regulated signal transduction has been linked to a variety of growth-specific processes and appears to also play a role in the early development ofDictyostelium discoideum. In an attempt to uncover some of the molecular components involved in Ras-mediated signalling, several proteins have been described previously, including the cell adhesion molecule DdCAD-1, whose phosphorylation state was affected by the expression of the constitutively activated RasG, RasG(G12T). Here it has been shown that acadAnull strain lacks the phosphoproteins that were tentatively identified as DdCAD-1, confirming its previous designation. Further investigation revealed that cells expressing RasG(G12T) exhibited increased cell–cell cohesion, concomitant with reduced levels of DdCAD-1 phosphorylation. This increased cohesion was DdCAD-1-dependent and was correlated with increased localization of DdCAD-1 at the cell surface. DdCAD-1 phosphorylation was also found to decrease duringDictyosteliumaggregation. These results revealed a possible role for protein phosphorylation in regulating DdCAD-1-mediated cell adhesion during early development. In addition, the levels of DdCAD-1 protein were substantially reduced in arasGnull cell line. These results indicate that RasG affects both the expression and dephosphorylation of DdCAD-1 during early development.
Transcription factor NNR from Paracoccus denitrificans is a sensor of both nitric oxide and oxygen: isolation of nnr* alleles encoding effector-independent proteins and evidence for a haem-based sensing mechanism
Authors: Lee Yi-Ying , Shearer Neil , Spiro Stephen
Published: April 2006

The nitrite reductase and nitric oxide reductase regulator (NNR) fromParacoccus denitrificansactivates transcription in response to nitric oxide (NO). The mechanism of NO sensing has not been elucidated for NNR, or for any of its orthologues from the FNR/CRP family of transcriptional regulators. Using regulated expression of thennrgene inEscherichia coli, evidence has now been obtained to indicate that activation of NNR by NO does not requirede novosynthesis of the NNR polypeptide. In anaerobic cultures, NNR is inactivated slowly following removal of the source of NO. In contrast, exposure of anaerobically grown cultures to oxygen causes rapid inactivation of NNR, suggesting that the protein is inactivated directly by oxygen. By random and site-directed mutagenesis, two variants of NNR were isolated (with substitutions of arginine at position 80) that show high levels of activity in anaerobic cultures in the absence of NO. These proteins remain substantially inactive in aerobic cultures, suggesting that the substitutions uncouple the NO- and oxygen-signalling mechanisms, thus providing further evidence that NNR senses both molecules. Structural modelling suggested that Arg-80 is close to the C-helix that forms the monomer–monomer interface in other members of the FNR/CRP family and plays an important role in transducing the activating signal between the regulatory and DNA binding domains. Assays of NNR activity in a haem-deficient mutant ofE. coliprovided preliminary evidence to indicate that NNR activity is haem dependent.
A comparison of the Seeing Optical Stylet and the gum elastic bougie in simulated difficult tracheal intubation: a manikin study
Authors: Evans A. , Morris S. , Petterson J. , Hall J. E.
Published: April 2006

Management of the difficult airway is one of the major challenges that anaesthetists face. The flexible fibreoptic scope is widely available but its use requires a level of skill, training and continued practice that is not universally found in all anaesthetists, particularly trainees. The Seeing Optical Stylet is a new, semirigid fibreoptic stylet ‘scope. We compared the Seeing Optical Stylet with a gum elastic bougie in a simulated Cormack and Lehane Grade 3 laryngoscopy in a manikin. Forty‐four anaesthetists were timed while intubating the manikin's trachea with both devices. The mean (SD) time taken with the Seeing Optical Stylet was 20.8 (9.3) s and with the bougie 30 (19.8) s (p = 0.001). Oesophageal intubation occurred six times with the bougie but did not occur with the Seeing Optical Stylet (p = 0.011). We conclude that the Seeing Optical Stylet may be superior to the bougie in difficult tracheal intubation. We feel that the results of this manikin trial are sufficiently encouraging to proceed to a clinical trial in patients.
Local clinical quality monitoring for detection of excess operative deaths
Authors: Arrowsmith J. E. , Powell S. J. , Nashef S. A. M.
Published: April 2006

A monitoring system for cardiac surgery has been in use at Papworth Hospital for 10 years. We wished to determine whether this system would have detected an increase in deaths associated with a single practitioner, whether a poorly performing doctor or a serial killer such as Dr Harold Shipman, whose activites went undetected in the absence of a monitoring system for nearly a quarter of a century. Random extra deaths were artificially introduced into the practice of a surgeon and an anaesthetist in a way that broadly reproduced Shipman's pattern. The standard monitoring system was then used to analyse the hypothetical data thus generated. Using the current standard monitoring, the excess deaths would have been detected in less than 10 months. Suspicions would have been raised even earlier. Robust local quality monitoring of risk‐adjusted outcomes is possible and, in our opinion, essential.