The association between auditory memory span and speech rate in children from kindergarten to sixth grade

This study reexamined the association between speech rate and memory span in children from kindergarten to sixth grade (N = 152) in order to potentially account for the inconsistencies within the published literature on this topic. Some of the inconsistencies in past research may reflect the different methods adopted in assessing speech rate. In particular, repeating word triples may itself involve memory demands, contaminating the correlation between speech rate and memory span in younger children. Analyses using composite speech rate and memory span measures showed that speech rate for word triples shared variance with memory span that was independent of speech rate for single words. Moreover, speech rate for word triples was largely redundant with age in explaining additional variation in memory span once the effects of speech rate for single words were controlled. (C) 2002 Elsevier Science.

Kinematic analysis of lingual fatigue in myasthenia gravis

This study describes a preliminary examination of the viability and suitability of the physiologic technique electromagnetic articulography (EMA) in investigating lingual fatigue in myasthenia gravis (MG). A 52.9-year-old female diagnosed with MG at the age of 18 years, but who was in remission, participated in the study with a matched control subject. Changes in the duration, speed, and range of tongue-tip and tongue-back movements during repetition of /taka/ over two minutes were investigated. Results revealed that the MG subject did not exhibit significant changes in duration, maximum velocity, maximum acceleration, or the distance travelled by her tongue as measured by EMA over the task. The kinematic results were, in part, expected since the MG subject was in remission. The results, therefore, may not be representative of the majority of individuals with active MG. The examination of the current case did highlight, however, the potential advantages of EMA in providing detailed, objective information regarding lingual kinematics for future investigations of individuals with MG. It also showed that EMA may be sensitive in detecting subclinical kinematic features of fatigue in individuals who are in remission from MG. Finally, EMA led to the identification of possible physiologic factors underlying the CV transform effect, which was evident for the MG subject's syllable productions. In the past, the effect had been assumed to be a purely perceptual-based phenomenon.

Perception or synthesized voice quality in connected speech by Cantonese speakers

Perceptual voice analysis is a subjective process. However, despite reports of varying degrees of intrajudge and interjudge reliability, it is widely used in clinical voice evaluation. One of the ways to improve the reliability of this procedure is to provide judges with signals as external standards so that comparison can be made in relation to these anchor signals. The present study used a Klatt speech synthesizer to create a set of speech signals with varying degree of three different voice qualities based on a Cantonese sentence. The primary objective of the study was to determine whether different abnormal voice qualities could be synthesized using the built-in synthesis parameters using a perceptual study. The second objective was to determine the relationship between acoustic characteristics of the synthesized signals and perceptual judgment. Twenty Cantonese-speaking speech pathologists with at least three years of clinical experience in perceptual voice evaluation were asked to undertake two tasks. The first was to decide whether the voice quality of the synthesized signals was normal or not. The second was to decide whether the abnormal signals should be described as rough, breathy, or vocal fry. The results showed that signals generated with a small degree of aspiration noise were perceived as breathiness while signals with a small degree of flutter or double pulsing were perceived as roughness. When the flutter or double pulsing increased further, tremor and vocal fry, rather than roughness, were perceived. Furthermore, the amount of aspiration noise, flutter, or double pulsing required for male voice stimuli was different from that required for the female voice stimuli with a similar level of perceptual breathiness and roughness. These findings showed that changes in perceived vocal quality could be achieved by systematic modifications of synthesis parameters. This opens up the possibility of using synthesized voice signals as external standards or anchors to improve the reliability of clinical perceptual voice evaluation. (C) 2002 Acoustical Society of America.

Input-driven Language Learning

Input-driven models provide an explicit and readily testable account of language learning. Although we share Ellis's view that the statistical structure of the linguistic environment is a crucial and, until recently, relatively neglected variable in language learning, we also recognize that the approach makes three assumptions about cognition and language learning that are not universally shared. The three assumptions concern (a) the language learner as an intuitive statistician, (b) the constraints on what constitute relevant surface cues, and (c) the redescription problem faced by any system that seeks to derive abstract grammatical relations from the frequency of co-occurring surface forms and functions. These are significant assumptions that must be established if input-driven models are to gain wider acceptance. We comment on these issues and briefly describe a distributed, instance-based approach that retains the key features of the input-driven account advocated by Ellis but that also addresses shortcomings of the current approaches.

Lateralization of speech production using verbal/manual dual tasks: meta-analysis of sex differences and practice effects

The present paper reviews the findings of 30 years of verbal/manual dual task studies, the method most commonly used to assess lateralization of speech production in non-clinical samples. Meta-analysis of 64 results revealed that both the type of manual task used and the nature of practice that is given influence the size of the laterality effect. A meta-analysis of 36 results examining the effect size of sex differences in estimate,, of lateralization of speech production indicated that males appear to show, slightly larger laterality effects than females. (C) 2002 Elsevier Science Ltd. All rights reserved.

Variation in articulatory timing of three English consonants: An electropalatographic investigation

Increasingly, electropalatography (EPG) is being used in speech pathology research to identify and describe speech disorders of neurological origin. However, limited data currently exists that describes normal articulatory segment timing and the degree of variability exhibited by normal speakers when assessed with EPG. Therefore, the purpose of the current investigation was to use the Reading EPG3 system to quantify segmental timing values and examine articulatory timing variability for three English consonants. Ten normal subjects repeated ten repetitions of CV words containing the target consonants /t/, /l/, and /s/ while wearing an artificial palate. The target consonants were followed by the /i/ vowel and were contained in the carrier phrase 'I saw a __'. Mean duration of the approach, closure/constriction, and release phases of consonant articulation were calculated. In addition, inter-subject articulatory timing variability was investigated using descriptive graphs and intra-subject articulatory timing variability was investigated using a coefficient of variation. Results revealed the existence of intersubject variability for mean segment timing values. This could be attributed to individual differences in the suprasegmental features of speech and individual differences in oral cavity size and structure. No significant differences were reported for degree of intra-subject variability between the three sounds for these same phases of articulation. However, when this data set was collapsed, results revealed that the closure/constriction phase of consonant articulation exhibited significantly less intra-subject variability than both the approach and release phases. The stabilization of the tongue against the fixed structure of the hard palate during the closure phase of articulation may have reduced the levels of intra-subject variability.

Acoustic analysis of speech through a hearing aid: perceptual effects of changes with two-channel compression

Compression amplification significantly alters the acoustic speech signal in comparison to linear amplification. The central hypothesis of the present study was that the compression settings of a two-channel aid that best preserved the acoustic properties of speech compared to linear amplification would yield the best perceptual results, and that the compression settings that most altered the acoustic properties of speech compared to linear would yield significantly poorer speech perception. On the basis of initial acoustic analysis of the test stimuli recorded through a hearing aid, two different compression amplification settings were chosen for the perceptual study. Participants were 74 adults with mild to moderate sensorineural hearing impairment. Overall, the speech perception results supported the hypothesis. A further aim of the study was to determine if variation in participants' speech perception with compression amplification (compared to linear amplification) could be explained by the individual characteristics of age, degree of loss, dynamic range, temporal resolution, and frequency selectivity; however, no significant relationships were found.

Electrolytic properties and nanostructural features in the La2O3-CeO2 system

Doped ceria (CeO2) compounds are fluorite-type oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, considerable interest has been shown in applications of these materials for low or intermediate temperature operation of solid-oxide fuel cells (SOFCs). In this study, the effective index was suggested to maximize the ionic conductivity in La2O3-CeO2 based oxides. The index considers the fluorite structure, and combines the expected oxygen vacancy level with the ionic radius mismatch between host and dopant cations. Using this approach, the ionic conductivity of this system has been optimized and tested under operating conditions of SOFCs. LaxCe1-xO2-delta (x = 0.125, 0.15, 0.175, and 0.20), (LaxSr1-x)(0.175)Ce0.825O2-delta (x = 0.1, 0.2, and 0.4), and (La1-xSr0.2Bax)(0.175)Ce0.825O2-delta (x 5 0.03, 0.05, and 0.07) were prepared and characterized as the specimens with low, intermediate, and high index, respectively. The ionic conductivity was increased with increasing suggested index. The transmission electron microscopy analysis suggested that partial substitution of alkaline earth elements in place of La into Ce site contributes to a decrease of microdomain size and an improvement of conductivity. (La0.75Sr0.2Ba0.05)(0.175)Ce0.825O1.891 with high index and small microdomains exhibited the highest conductivity, wide ionic domain, and good performance in SOFCs. (C) 2003 The Electrochemical Society.

Voice and speech characteristics and vocal hygiene in novice and professional voice broadcast journalists

Knowledge of differences in voice and speech characteristics between novice and professional broadcasters is essential for effective education of broadcast journalism students. Because newsreaders rely on optimal voice production, information pertaining to vocal hygiene is also important. The first aim of this study was to compare the voice and speech characteristics of professional newsreaders, student newsreaders and control participants. The second aim was to compare the awareness and use of vocal hygiene across these groups. Professional radio newsreaders, broadcast journalism students and two matched control groups were included in the study. Each participant recorded a news bulletin and completed a questionnaire on vocal hygiene. Data analysis of the recording included objective analysis and perceptual ratings by a panel of three judges. Significant student-professional differences were found. Compared to both the students and the control groups, the professional newsreaders had greater variation in speaking fundamental frequency, a faster rate of speech, fewer pronunciation errors and higher perceptual ratings on vocal quality, emphasis, continuity, phrasing and style of newsreading. Female professional newsreaders had a higher speaking fundamental frequency than both their control participants and the student newsreaders. Comparison of vocal hygiene awareness revealed few significant differences between any of the groups.

'Iron lung': Distinctive bronchoscopic features of acute iron tablet aspiration

Three confirmed cases of acute iron tablet-induced necrosis due to a fulminant chemical burn injury to the tracheobronchial tree as a result of accidental inhalation and/or aspiration of iron tablets are described. Although histological confirmation has been relied upon for diagnosis, the distinctive bronchoscopic features may allow prompt recognition and treatment by bronchoscopists to prevent this potentially fatal condition.