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J Au-Yeung

Publications and source records attributed to J Au-Yeung.

5 recordsLinked to original sources
PubMed1999

Exchange of stuttering from function words to content words with age.

Dysfluencies on function words in the speech of people who stutter mainly occur when function words precede, rather than follow, content words (Au-Yeung, Howell, & Pilgrim, 1998). It is hypothesized that such function word dysfluencies occur when the plan for the subsequent content word is not ready for execution. Repetition and hesitation on the function words buys time to complete the plan for the content word. Stuttering arises when speakers abandon the use of this delaying strategy and carry on, attempting production of the subsequent, partly prepared content word. To test these hypotheses, the relationship between dysfluency on function and content words was investigated in the spontaneous speech of 51 people who stutter and 68 people who do not stutter. These participants were subdivided into the following age groups: 2-6-year-olds, 7-9-year-olds, 10-12-year-olds, teenagers (13-18 years), and adults (20-40 years). Very few dysfluencies occurred for either fluency group on function words that occupied a position after a content word. For both fluency groups, dysfluency within each phonological word occurred predominantly on either the function word preceding the content word or on the content word itself, but not both. Fluent speakers had a higher percentage of dysfluency on initial function words than content words. Whether dysfluency occurred on initial function words or content words changed over age groups for speakers who stutter. For the 2-6-year-old speakers that stutter, there was a higher percentage of dysfluencies on initial function words than content words. In subsequent age groups, dysfluency decreased on function words and increased on content words. These data are interpreted as suggesting that fluent speakers use repetition of function words to delay production of the subsequent content words, whereas people who stutter carry on and attempt a content word on the basis of an incomplete plan.

Adolescent↗
PubMed1999

Utterance rate and linguistic properties as determinants of lexical dysfluencies in children who stutter.

Two important determinants of variation in stuttering frequency are utterance rate and the linguistic properties of the words being spoken. Little is known how these determinants interrelate. It is hypothesized that those linguistic factors that lead to change in word duration, alter utterance rate locally within an utterance that then gives rise to an increase in stuttering frequency. According to the hypothesis, utterance rate variation should occur locally within the linguistic segments in an utterance that is known to increase the likelihood of stuttering. The hypothesis is tested using length of tone unit as the linguistic factor. Three predictions are confirmed: Utterance rate varies locally within the tone units and this local variation affects stuttering frequency; stuttering frequency is positively related to the length of tone units; variations in utterance rate are correlated with tone unit length. Alternative theoretical formulations of these findings are considered.

Child↗
PubMed1998

Phonological words and stuttering on function words.

Stuttering on function words was examined in 51 people who stutter. The people who stutter were subdivided into young (2 to 6 years), middle (6 to 9 years), and older (9 to 12 years) child groups; teenagers (13 to 18 years); and adults (20 to 40 years). As reported by previous researchers, children up to about age 9 stuttered more on function words (pronouns, articles, prepositions, conjunctions, auxiliary verbs), whereas older people tended to stutter more on content words (nouns, main verbs, adverbs, adjectives). Function words in early positions in utterances, again as reported elsewhere, were more likely to be stuttered than function words at later positions in an utterance. This was most apparent for the younger groups of speakers. For the remaining analyses, utterances were segmented into phonological words on the basis of Selkirk's work (1984). Stuttering rate was higher when function words occurred in early phonological word positions than other phonological word positions whether the phonological word appeared in initial position in an utterance or not. Stuttering rate was highly dependent on whether the function word occurred before or after the single content word allowed in Selkirk's (1984) phonological words. This applied, once again, whether the phonological word was utterance-initial or not. It is argued that stuttering of function words before their content word in phonological words in young speakers is used as a delaying tactic when the forthcoming content word is not prepared for articulation.

Child↗
PubMed1996

Aggregation of rhDNase occurred during the compression of KBr pellets used for FTIR spectroscopy.

PURPOSE: To determine if a protein changes when it is compressed into a KBr pellet for FTIR spectroscopy measurement in the solid state, using recombinant human deoxyribonuclease I (rhDNase) as an example. METHODS: Lyophilized rhDNase with KBr compressed at different pressures were analyzed by FTIR spectroscopy, size exclusion HPLC and enzymatic activity assay. Different protein/KBr weight ratios and residual water contents were studied for their possible effects on aggregation. RESULTS: Depending on the pressure, a loss of enzymatic activity accompanied by an increase in soluble high molecular weight aggregates of the protein (up to approximately 15%) was demonstrated. Aggregation was reduced to less than 5% by a suitable dilution of the protein in KBr (1 in 1000). In contrast, water content variability (1-11 wt. %) did not affect aggregation. CONCLUSIONS: The findings emphasize the importance to examine for protein integrity when using the KBr method for FTIR sample preparation. Protein aggregation may be minimized by optimizing the sample preparation condition such as changing the protein/KBr weight ratio.

Bromides↗