PubMed Health⌕ Search

Biomedical subjects

Paul Fletcher

Publications and source records attributed to Paul Fletcher.

10 recordsLinked to original sources
PubMed2006

Nonword repetition and sentence repetition as clinical markers of specific language impairment: the case of Cantonese.

PURPOSE: Recent research suggests that nonword repetition (NWR) and sentence repetition (SR) tasks can be used to discriminate between children with SLI and their typically developing age-matched (TDAM) and younger (TDY) peers. METHOD: Fourteen Cantonese-speaking children with SLI and 30 of their TDAM and TDY peers were compared on NWR and SR tasks. NWR of IN nonwords (CV combinations attested in the language) and OUT nonwords (CV combinations unattested in the language) were compared. SR performance was compared using 4 different scoring methods. RESULTS: The SLI group did not score significantly lower than the TDAM group on the test of NWR (overall results were TDAM = SLI > TDY). There were nonsignificant group differences on IN syllables but not on OUT syllables. The results do not suggest a limitation in phonological working memory in Cantonese-speaking children with SLI. The SR task discriminated between children and their TDAM peers but not between children with SLI and their TDY peers matched for mean length of utterance. CONCLUSIONS: SR but not NWR discriminates between children with SLI and their TDAM peers. Poorer NWR for English-speaking children with SLI might be attributable to weaker use of the redintegration strategy in word repetition. Further cross-linguistic investigations of processing strategies are required.

Analysis of Variance↗
PubMed2005

The expression of aspect in Cantonese-speaking children with specific language impairment.

Previous studies of verb morphology in children with specific language impairment (SLI) have been limited in the main to tense and agreement morphemes. Cantonese, which, like other Chinese languages, has no grammatical tense, presents an opportunity to investigate potential difficulties for children with SLI in other areas of verb morphology, via scrutiny of elements of its aspectual system. The performance of 3 groups of children (n = 15 in each group)--preschoolers with SLI, typically developing same-age peers, and younger, typically developing peers--was compared in procedures designed to elicit aspect forms. The children with SLI were less likely to produce both perfective and imperfective aspect markers. It is suggested that reasons for these findings are to be found in the sparse morphology of Cantonese and in the nonobligatory nature of these forms.

Analysis of Variance↗
PubMed2004

Utterance length and lexical diversity in Cantonese-speaking children with and without specific language impairment.

Two studies of children's conversational language abilities are reported. In the first, mean length of utterance (MLU) and lexical diversity (D) were examined in a group of typically developing Cantonese-speaking children in Hong Kong. Regression analyses indicated a significant linear relationship between MLU and age (R = .44) and a significant curvilinear relationship between D and age (R = .73) in children age 27-68 months. MLU and D were moderately correlated with each other (r = .23); however, the two measures showed no statistical relationship when the effect of age was partialled out. In a second study, the utterances of Chinese children with specific language impairment (SLI) were found to be significantly shorter and less lexically diverse than typically developing children matched for age but similar to children matched for comprehension level. Discriminant analyses revealed that the combination of age, MLU, and D could be used to accurately differentiate children with SLI from both age-matched and language-matched children. Based on these findings, we hypothesize that these measures can be used jointly as a marker of SLI in Cantonese-speaking children.

Age Factors↗
PubMed2004

Questions without movement: A study of Cantonese-speaking children with and without specific language impairment.

English-speaking children with specific language impairment (SLI) appear to have special difficulty in the use of who-object questions (e.g., Who is the girl chasing?). It has been argued that problems related to grammatical movement may be responsible for this difficulty. However, it is also possible that the lower frequency of who-object questions relative to who-subject questions also plays a role. In this study, the use of who-object and who-subject questions by children with SLI who were acquiring Cantonese as their 1 st language was examined. In Cantonese, the surface form of who-object questions (e.g., hung4zai2 sek3 bin1go3? [Bear kiss who?]) reflects the same subject, verb, object order typically used for declarative sentences, and a movement account provides no basis for expecting special difficulties with such questions. As in English, however, Cantonese who-object questions occur less frequently than do who-subject questions. A comparison of preschoolers with SLI, typically developing same-age peers, and younger, typically developing peers revealed that the children with SLI were less accurate in using who-object questions than either of the other participant groups yet showed no differences from these groups in the use of who-subject questions (e.g., bin1go3 sek3 zyu1zyu1? [Who kiss Piglet?]). The implications of these findings for current accounts of SLI are discussed, and the idea that input frequency and animacy may play a larger role than is often assumed is suggested.

Analysis of Variance↗
PubMed2003

Distinct brain regions associated with syllable and phoneme.

The syllable and the phoneme are two important units in the phonological structure of speech sounds. In the brain mapping literature, it remains unsolved as to whether there are separate brain regions mediating the processing of syllables and phonemes. Using functional magnetic resonance imaging (fMRI), we investigated the neural substrate of these phonological units with Chinese subjects. Results revealed that the left middle frontal cortex contributes to syllabic processing, whereas the left inferior prefrontal gyri contributes to phonemic processing. This pattern of findings offers compelling evidence for distinct cortical areas relevant to the representation of syllables and phonemes.

Adult↗
PubMed2003

Practice and difficulty evoke anatomically and pharmacologically dissociable brain activation dynamics.

Brain activation is adaptive to task difficulty and practice. We used functional MRI to map brain systems activated by an object-location learning task in 24 healthy elderly volunteers each scanned following placebo and two of four active drugs studied. We distinguished a fronto-striatal system adaptive to difficulty from a posterior system adaptive to practice. Fronto-striatal response to increased cognitive load was significantly attenuated by scopolamine, sulpiride and methylphenidate; practice effects were not modulated by these drugs but were enhanced by diazepam. We also found enhancement by methylphenidate, and attenuation by sulpiride, of load response in premotor, cingulate and parietal regions comprising a spatial attention network. Difficulty and practice evoke anatomically and pharmacologically dissociable brain activation dynamics, which are probably mediated by different neurotransmitter systems in humans.

Adrenergic Uptake Inhibitors↗
PubMed2003

Vertical distance from the crest of bone to the height of the interproximal papilla between adjacent implants.

BACKGROUND: As patient demand increases for more natural restorations in the esthetic zone, clinicians must have the highest level of skill and knowledge to maintain or reform the interdental papilla between teeth, between implants and teeth, and between adjacent implants. To date, there are no reports that have measured the distance from the contact point to the bony crest between implants. One reason for this may be the fact that, with two adjacent implants, the contact point of the crown can be established at any distance from the gingival margin according to the restorative dentist's specifications. Therefore, in this study, the height of the soft tissue to the crest of bone was measured between two adjacent implants independent of the location of the contact point. The purpose of this study was to determine the range and average height of tissue between two adjacent implants. METHODS: A total of 136 interimplant papillary heights were examined in 33 patients by eight different examiners in five private dental offices. After administration of appropriate local anesthesia, a standardized periodontal probe was placed vertically from the height of the papilla to the crest of bone. The measurements were rounded off to the nearest millimeter. RESULTS: The mean height of papillary tissue between two adjacent implants was 3.4 mm, with a range of 1 mm to 7 mm. CONCLUSIONS: Clinicians should proceed with great caution when placing two implants adjacent to each other in the esthetic zone. In most cases, only 2, 3, or 4 mm of soft tissue height (average 3.4 mm) can be expected to form over the interimplant crest of bone. These results showed that modification of treatment plans may be necessary when esthetics are critical for success.

Dental Implantation, Endosseous↗
PubMedDate not supplied

The interface between phonetic and lexical abilities in early Cantonese language development.

Data from the Cantonese Communicative Development Inventory (CCDI) is used to review the phonological preferences of younger (16-22 months) and older (23-30 month) groups of children in the lexical items they are reported to be able to say. Analogous results to those found for English emerge from the Cantonese data: the younger group display selectivity in the initial consonants of words they say, and their preferences accord with developmental tendencies in Cantonese phonology. From children whose scores fell below the tenth percentile of the CCDI, a subset were followed up 1 year later and their linguistic progress evaluated. Only a proportion of these children were below still below the tenth percentile for vocabulary at follow-up. Their lexical immaturities were accompanied by limited phonetic abilities. The implications of the findings are discussed.

Age Factors↗