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Biomedical subjects

Peter Howell

Publications and source records attributed to Peter Howell.

14 recordsLinked to original sources
PubMed2006

Anxiety in speakers who persist and recover from stuttering.

PURPOSE: The study was designed to see whether young children and adolescents who persist in their stutter (N=18) show differences in trait and/or state anxiety compared with people who recover from their stutter (N=17) and fluent control speakers (N=19). METHOD: A fluent control group, a group of speakers who have been documented as stuttering in the past but do not stutter now and a group of speakers (also with a documented history of stuttering) who persist in their stuttering participated, all aged 10-17 years. The State-Trait Anxiety Inventory for Children was administered. RESULTS: There were no differences between persistent, recovered and control groups with regard to trait anxiety. The persistent group had higher state anxiety than controls and the recovered group for three out of four speaking situations. CONCLUSION: The findings are interpreted as showing that anxiety levels in certain affective states appear to be associated with the speaking problem. LEARNING OUTCOMES: A reader should be able to appreciate the difference between state and trait anxiety understand views about how the role anxiety has on stuttering has changed over time appreciate different views about how anxiety affects speakers who persist and recover from stuttering see why longitudinal work is needed to study these issues.

Adaptation, Psychological↗
PubMed2006

Signs of developmental stuttering up to age eight and at 12 plus.

Clinicians who are familiar with the general DSM-IV-TR scheme may want to know how to identify whether a child does, or (equally importantly) does not, stutter and what differences there are in the presenting signs for children of different ages. This article reviews and discusses topics in the research literature that have a bearing on these questions. The review compared language, social-environmental and host factors of children who stutter across two age groups (up to age eight and 12 plus). Dysfluency types mainly involved repetition of one or more whole function words up to age eight whereas at age 12 plus, dysfluency on parts of content words often occurred. Twin studies showed that environmental and host factors were split roughly 30/70 for both ages. Though the disorder is genetically transmitted, the mode of transmission is not known at present. At the earlier age, there were few clearcut socio-environmental influences. There were, however, some suggestions of sensory (high incidence of otitis media with effusion) and motor differences (high proportion of left-handed individuals in the stuttering group relative to norms) compared to control speakers. At age 12 plus, socio-environmental influences (like state anxiety) occurred in the children who persist, but were not evident in the children who recover from the disorder. Brain scans at the older age show some replicable abnormality in the areas connecting motor and sensory areas in speakers who stutter. The topics considered in the discussion return to the question of how to identify whether a child does or does not stutter. The review identifies extra details that might be considered to improve the classification of stuttering (e.g. sensory and motor assessments). Also, some age-dependent factors and processes are identified (such as change in dysfluency type with age). Knowing the distinguishing features of the disorder allows it to be contrasted with other disorders which show superficially similar features. Two or more disorders can co-occur for two reasons: comorbidity, where the child has two identifiable disorders (e.g. a child with Down Syndrome whose speech has been properly assessed and classed as stuttering). Ambiguous classifications, where an individual suffering from one disorder meets the criteria for one or more other disorders. One way DSM-IV-TR deals with the latter is by giving certain classification axes priority over others. The grounds for such superordinacy seem circular as the main role for allowing this appears to be to avoid such ambiguities.

Age of Onset↗
PubMed2006

Auditory abilities of speakers who persisted, or recovered, from stuttering.

OBJECTIVE: The purpose of this study was to see whether participants who persist in their stutter have poorer sensitivity in a backward masking task compared to those participants who recover from their stutter. DESIGN: The auditory sensitivity of 30 children who stutter was tested on absolute threshold, simultaneous masking, backward masking with a broadband and with a notched noise masker. The participants had been seen and diagnosed as stuttering at least 1 year before their 12th birthday. The participants were assessed again at age 12 plus to establish whether their stutter had persisted or recovered. Persistence or recovery was based on participant's, parent's and researcher's assessment and Riley's [Riley, G. D. (1994). Stuttering severity instrument for children and adults (3rd ed.). Austin, TX: Pro-Ed.] Stuttering Severity Instrument-3. Based on this assessment, 12 speakers had persisted and 18 had recovered from stuttering. RESULTS: Thresholds differed significantly between persistent and recovered groups for the broadband backward-masked stimulus (thresholds being higher for the persistent group). CONCLUSIONS: Backward masking performance at teenage is one factor that distinguishes speakers who persist in their stutter from those who recover. Education objectives: Readers of this article should: (1) explain why auditory factors have been implicated in stuttering; (2) summarise the work that has examined whether peripheral, and/or central, hearing are problems in stuttering; (3) explain how the hearing ability of persistent and recovered stutterers may differ; (4) discuss how hearing disorders have been implicated in other language disorders.

Adolescent↗
PubMed2006

Strength of British English accents in altered listening conditions.

This work is concerned with the processing or representational level at which accent forms learned early in life can change and with whether alteration to a speaker's auditory environment can elicit an original accent. In Experiment 1, recordings were made of an equal number of (1) speakers living in the home counties (HC) of Britain (around the London conurbation) who claimed to have retained the accent of the region that they originally had come from, (2) speakers who stated that they had lost their regional accent and acquired an HC accent, and (3) native HC speakers. They read two texts in a normal listening environment. Listeners rated the similarity in accent between each of these texts and all the other texts. The results showed that in the normal listening conditions, the speakers who had lost their accent were rated as being more similar to HC English speakers than to those speakers from the same region who had retained their accent. In Experiment 2, recordings of the same speakers under frequency-shifted and delayed auditory feedback, as well as the normal listening conditions used earlier, were rated in order to see whether the manipulations of listening environment would elicit the speaker's original accent. Listeners rated similarity of accent in a sample of speech recorded under normal listening against a sample read by another speaker in one of the altered listening conditions. When listening condition was altered, the speakers who had lost their original accent were rated as more similar to those who had retained their accent. It is concluded that accent differences can be elicited by altering listening environment because the speech systems of speakers who have lost their accent are more vulnerable than those of speakers who have not changed their original accent.

Adult↗
PubMed2004

Predicting stuttering from phonetic complexity in German.

UNLABELLED: This study investigated how phonetic complexity affects stuttering rate in German and how this changes developmentally. Phonetic difficulty was assessed using Jakielski's index [Motor Organization in the Acquisition of Consonant Clusters, Dissertation/Ph.D. Thesis, University of Texas Austin, 1998] of phonetic complexity (IPC) in which words are scored on eight different characteristics. Stuttering rate was not related to IPC score for German function words, as previously shown for Spanish and English. Significant correlations between stuttering rate and IPC score were found for content words for children over the age of six and adults. It was also found that German content words have a higher mean IPC sum compared to their English counterparts. There was a bigger difference in IPC score between fluent and stuttered words in German than in English. Factor 5 (word shape) influenced stuttering rates in both German age groups. This has also been found for Spanish but does not apply to English. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) describe a method to measure phonetic complexity and how this affects stuttering rates for words of different grammatical classes; (2) explain why this method is suitable for different languages and age groups; (3) detect which phonetic characteristics have most impact on different age groups in English and German; (4) assess possible theoretical reasons for these findings.

Adolescent↗
PubMed2004

Development of auditory sensitivity in children who stutter and fluent children.

OBJECTIVE: The purpose of this study was to establish whether there are any differential changes in auditory sensitivity over ages in a variety of peripheral and central auditory tasks between participants who stutter and participants who do not stutter. DESIGN: The auditory sensitivity of 37 participants who stutter and 44 participants who do not stutter, ages between 8 and 19 yr, assigned to three age categories, were obtained in five listening conditions: Pure tone threshold, simultaneous masking, backward masking, notched backward masking, and simple dichotic (simultaneous) masking. RESULTS: Across all listening conditions and both talker groups, thresholds decreased over age. The thresholds of participants who do not stutter decreased for simultaneous, backward, and notched backward masking conditions over the 8- to 19-year age range. Analysis of each condition only showed significant improvement over age groups for backward masking for the participants who stutter. CONCLUSIONS: These results indicate that auditory sensitivity for sounds in noise continues to develop through to teenage, and a different pattern of auditory development exists for the participants who stutter compared with participants who do not stutter.

Adolescent↗
PubMed2003

Persistence of memory in drop breakup: the breakdown of universality.

A low-viscosity drop breaking apart inside a viscous fluid is encountered when air bubbles, entrained in thick syrup or honey, rise and break apart. Experiments, simulations, and theory show that the breakup under conditions in which the interior viscosity can be neglected produces an exceptional form of singularity. In contrast to previous studies of drop breakup, universality is violated so that the final shape at breakup retains an imprint of the initial and boundary conditions. A finite interior viscosity, no matter how small, cuts off this form of singularity and produces an unexpectedly long and slender thread. If exterior viscosity is large enough, however, the cutoff does not occur because the minimum drop radius reaches subatomic dimensions first.

Journal Article↗
PubMed2003

Predicting stuttering from linguistic factors for German speakers in two age groups.

UNLABELLED: Brown's factors [J. Speech Disorders 10 (1945) 181] predict the likely loci of disfluency in English-speaking adults who stutter. A word is more likely to be stuttered for these speakers if it is a content word, starts with a consonant, is positioned at the beginning of a sentence, and if it is a long word. These same factors were examined in native German-speaking children and adults who stutter. Speech data of 15 German adults and 17 children were coded according to Brown's factors. For the adult group, it was predicted that words starting with consonants would not lead to as much of an increase in disfluencies compared with English samples, because of cross-linguistic differences in syllable onset properties. It was predicted that stuttering would be more likely in later sentence positions in German because in German the verb is usually near the end of a sentence. There were no obvious reasons to expect differences on the two remaining factors, content words and word length. With children, it was hypothesised that Brown's factors that specify level of linguistic difficulty would not be such a good predictor of stuttering rate. Specifically, it was predicted that the difference in stuttering rate between function and content words would be lower in children. For the adults both word type (content/function) and word length increased stuttering rate significantly, whereas changes in stuttering rate for the other two factors were non-significant. It was also found that when word difficulty (based on a combined measure of all factors) increased, stuttering rate rose. With children, only the word-length factor was significant, and stuttering rate was not governed to the same extent by overall word difficulty. Conclusions are drawn as to the effect of linguistic and motor influences on stuttering. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to describe: (1) how linguistic factors affect stuttering rates in German; (2) the different patterns of adults and children who stutter and how language might influence this pattern; and (3) how to interpret these findings in light of a current theory of fluency failure.

Adolescent↗
PubMed2003

Exchange of disfluency with age from function words to content words in spanish speakers who stutter.

The main purpose of the present study was to examine whether the developmental change in loci of disfluency from mainly function words to mainly content words, observed for English speakers who stutter (P. Howell, J. Au-Yeung, & S. Sackin, 1999), also occurs for comparable Spanish speakers who stutter. The participants were divided into 5 age groups. There were 7 participants in Group 1, from 3 to 5 years old; 11 in Group 2, from 6 to 9 years old; 10 in Group 3, from 10 to 11 years old; 9 in Group 4, from 12 to 16 years old; and 9 in Group 5, from 20 to 68 years old. Across all groups, 36 of the 46 participants were male. The study method involved segmenting speech into phonological words (PWs) that consist of an obligatory content word with optional function words that precede and follow it. The initial function words in the PWs were examined to establish whether they have a higher disfluency rate than the final ones (J. Au-Yeung, P. Howell, & L. Pilgrim, 1998). Disfluency on function words in a PW was higher when the word occurred before a content word rather than after a content word for all age groups. Disfluencies on function and content words were then examined to determine whether they change over age groups in the same way as for English speakers who stutter (Howell et al., 1999). The rate of disfluency on function words was higher than that on content words, particularly in the youngest speakers. Function word disfluency rate dropped off and content word disfluency rate increased across age groups. These patterns are similar to those reported for English. Possible explanations for these similarities across the two languages are discussed.

Adolescent↗
PubMed2003

Speech perception in rats: use of duration and rise time cues in labeling of affricate/fricative sounds.

The voiceless affricate/fricative contrast has played an important role in developing auditory theories of speech perception. This type of theory draws some of its support from experimental data on animals. However, nothing is known about differential responding of affricate/fricative continua by animals. In the current study, the ability of hooded rats to "label" an affricate/fricative continuum was tested. Transfer (without retraining) to analogous nonspeech continua was also tested. The nonspeech continua were chosen so that if transfer occurred, it would indicate whether the animals had learned to use rise time or duration cues to differentiate affricates from fricatives. The data from 9 of 10 rats indicated that rats can discriminate between these cues and do so in a similar manner to human subjects. The data from 9 of 10 rats also demonstrated that the rise time of the stimulus was the basis of the discrimination; the remaining rat appeared to use duration.

Animals↗
PubMed2002

Non-word reading, lexical retrieval and stuttering: comments on Packman, Onslow, Coombes and Goodwin (2001).

A recent study by Packman, Onslow, Coombes and Goodwin (2001) employed a non-word-reading paradigm to test the contribution of the lexical retrieval process to stuttering. They consider that, with this material, the lexical retrieval process could not contribute to stuttering and that either anxiety and/or the motor demand of reading are the governing factors. This paper will discuss possible processes underlying non-word reading and it argues that the conclusion arrived at by Packman et al. does not stand up to close scrutiny. In their introduction, the authors acknowledge that the lexicalization process involves retrieval and encoding of words. In a non-word-reading task, the word retrieval component is eliminated. The possibility that the encoding component of the lexicalization process leads to stuttering is, however, completely ignored by the authors when they attribute stuttering to motor demands. As theories put forward by Postma and Kolk (the Covert Repair Hypothesis, 1993) and Howell and Au-Yeung (the EXPLAN theory, 2002) argue heavily for the role of the phonological encoding processes in stuttering, Packman et al.'s work does not evaluate such theories. Theoretical issues aside, Packman et al.'s arguments about reading rate and stuttering rate based on reading time is also questionable.

Humans↗
PubMed2002

Sociodynamic relationships between children who stutter and their non-stuttering classmates.

BACKGROUND: Previous research has indicated that children who stutter are more likely to be bullied and to hold a lower social position than their peers who do not stutter. However, the majority of this research has used data from respondents who were in the educational system more than 20 years ago. The current policy on integration of children with severe disabilities into mainstream education and the increased awareness of bullying in schools would indicate that attitudes toward children who stutter might have changed in the intervening period. METHOD: The study uses a sociometric scale (adapted from Coie, Dodge, & Coppotelli, 1982) to assess children who stutter in classroom groups with fluent peers. The peer relationships between 16 children who stutter and their classmates (403 children in total) were examined. RESULTS: Children who stutter were rejected significantly more often than were their peers and were significantly less likely to be popular. When compared to children who do not stutter, the children who stutter were less likely to be nominated as 'leaders' and were more likely to be nominated to the 'bullied' and 'seeks help' categories. CONCLUSIONS: The changes in integration policy and the implementation of anti-bullying policies in many schools appear to have made little impact on the social status of children who stutter. The incidence of bullying and rejection reported in this study has implications for schools and clinicians.

Adolescent↗
PubMed2002

Timing interference to speech in altered listening conditions.

A theory is outlined that explains the disruption that occurs when auditory feedback is altered. The key part of the theory is that the number of, and relationship between, inputs to a timekeeper, operative during speech control, affects speech performance. The effects of alteration to auditory feedback depend on the extra input provided to the timekeeper. Different disruption is predicted for auditory feedback that is out of synchrony with other speech activity (e.g., delayed auditory feedback, DAF) compared with synchronous forms of altered feedback (e.g., frequency shifted feedback, FSF). Stimulus manipulations that can be made synchronously with speech are predicted to cause equivalent disruption to the synchronous form of altered feedback. Three experiments are reported. In all of them, subjects repeated a syllable at a fixed rate (Wing and Kristofferson, 1973). Overall timing variance was decomposed into the variance of a timekeeper (Cv) and the variance of a motor process (Mv). Experiment 1 validated Wing and Kristofferson's method for estimating Cv in a speech task by showing that only this variance component increased when subjects repeated syllables at different rates. Experiment 2 showed DAF increased Cv compared with when no altered sound occurred (experiment 1) and compared with FSF. In experiment 3, sections of the subject's output sequence were increased in amplitude. Subjects just heard this sound in one condition and made a duration decision about it in a second condition. When no response was made, results were like those with FSF. When a response was made, Cv increased at longer repetition periods. The findings that the principal effect of DAF, a duration decision and repetition period is on Cv whereas synchronous alterations that do not require a decision (amplitude increased sections where no response was made and FSF) do not affect Cv, support the hypothesis that the timekeeping process is affected by synchronized and asynchronized inputs in different ways.

Adult↗