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Biomedical subjects

G D Riley

Publications and source records attributed to G D Riley.

7 recordsLinked to original sources
PubMed2005

Towards performance control on the Grid.

Advances in computational Grid technologies are enabling the development of simulations of complex biological and physical systems. Such simulations can be assembled from separate components--separately deployable computation units of well-defined functionality. Such an assemblage can represent an application composed of interacting simulations or might comprise multiple instances of a simulation executing together, each running with different simulation parameters. However, such assemblages need the ability to cope with heterogeneous and dynamically changing execution environments, particularly where such changes can affect performance. This paper describes the design and implementation of a prototype performance control system (PerCo), which is capable of monitoring the progress of simulations and redeploying them so as to optimize performance. The ability to control performance by redeployment is demonstrated using an assemblage of lattice Boltzmann simulations running with and without control policies. The cost of using PerCo is evaluated and it is shown that PerCo is able to reduce overall execution time.

Benchmarking↗
PubMed2000

Acoustic duration changes associated with two types of treatment for children who stutter.

The purpose of this study was (a) to examine in young children the effects of Speech Motor Training (SMT) on selected temporal acoustic durations considered to be related to speech motor programming, (b) to compare the speech motor effects of that treatment with those of a treatment of childhood stuttering that did not directly incorporate speech motor control training (Extended Length of Utterance [ELU]), and (c) to examine the relation of acoustic duration changes to reduction of stuttering. Twelve children who stutter were recorded while repeating syllable sets /see text/ and /see text/ before and after SMT (n = 6) or ELU treatment (n = 6). Children who did not stutter served as matched reference groups. The syllables beginning with /p/ and /t/ were used as tokens for the acoustic measurement. Five measures served as indicators of temporal aspects of speech motor performance: vowel duration, stop gap duration, voice onset time, stop gap/vowel duration ratio, and total token duration. Results indicated that following SMT there was a significant increase in vowel duration and some reduction in stop gap duration that resulted in significantly reduced stop gap/vowel duration ratios. These acoustic effects were consistent across most participants. The ELU treatment reduced stuttering more than the SMT, but was not accompanied by significant effects on the selected temporal acoustic measures. These findings are compared with previous findings of increased vowel durations associated with fluency enhancement and stuttering treatment. We speculate that the increased vowel durations allow more time for speech motor planning and that stuttering is reduced moderately as a by-product of longer vowel durations. The mechanism(s) by which ELU treatment reduces stuttering did not appear to be captured by the dependent variables measured in this study.

Child↗
PubMed2000

Risperidone for the treatment of stuttering.

A randomized, double-blind, placebo-controlled study was conducted to assess the efficacy of risperidone in the treatment of developmental stuttering in 16 adults. Eight subjects received placebo and eight received risperidone at 0.5 mg once daily at night, increased to a maximum of 2 mg/day. After 6 weeks of treatment, decreases in all measures of stuttering severity were greater in the risperidone group than in the placebo group; the between-treatment difference was significant (p < 0.05) on the most important measure, the percentage of syllables stuttered. In the risperidone group, reductions from baseline in scores for the percentage of syllables stuttered, time stuttering as a percentage of total time speaking, and overall stuttering severity were significant (p < 0.01); changes in scores on the fourth measure of stuttering, duration, were not significant. No significant decreases occurred in the placebo group. Among the eight patients in the risperidone group, five responded best to 0.5 mg/day, with stuttering recurring at higher doses. The remaining three patients responded better with increasing doses of risperidone. Risperidone was generally well tolerated. The results of this small study indicate that risperidone may be effective in the treatment of developmental stuttering. This finding needs to be confirmed in a larger trial.

Adult↗
PubMed1983

Effect of therapist expectations and need for approval on self-disclosure.

Previous therapy analogue studies of self-disclosure have treated Ss as a homogeneous group without examining possibly relevant S variables. In the present study, 68 female students identified as high or low in need for approval listened to a tape-recorded interview between a high self-disclosing therapist and a female client under one of two therapist expectation conditions: Clear expectation of high self-disclosure vs. ambiguous expectation. Ss then indicated on the Jourard Self-Disclosure Questionnaire the degrees to which they would be willing to disclose to the therapist. It was predicted that high need for approval Ss would disclose most under the clear expectation condition, while low need for approval Ss would not be affected by the therapist expectation. A significant Need Approval X Therapist expectation interaction supported this prediction. Further analysis indicated that items for the Work, Money, and Personality subsections of the disclosure questionnaire contributed most to the interaction. Implications for differential treatment of high need for approval Ss who were entering therapy were discussed.

Adult↗
PubMed1980

Motoric and linguistic variables among children who stutter: a factor analysis.

Seventy-six children who stuttered, aged 5-12, were administered tests of motor coordination, psycholinguistic abilities, and stuttering severity. A factor analysis of 19 selected variables yielded four statistically useful factors that implicate linguistic integration, oral motor ability, and auditory processing abilities as underlying components among the sample population. These components are assumed to affect a child's threshold for fluency and to permit stuttering development. Stuttering frequency or severity was not related to any of the four factors. The implications for diagnosing and treating children who stutter are discussed.

Auditory Perception↗
PubMedDate not supplied

Stuttering: neuropsychiatric features measured by content analysis of speech and the effect of risperidone on stuttering severity.

Positron-emission tomographic (PET) studies and genetic research of stuttering have recently revealed underlying cerebral neurobiologic contributing factors in this disorder. We aimed to assess whether cognitive impairment and other neuropsychiatric dimensions could be detected through computerized content analysis of short samples of speech from stutterers, and whether administration of risperidone in a double-blind placebo-controlled study could decrease the severity of stuttering, as well as any of the neuropsychiatric features of these stutterers. A group of 21 stutterers with the developmental form of stuttering, an onset before age of 6 years, aged 20 to 74 years, and who were otherwise free of major medical or psychiatric problems, initially gave a 5-minute tape-recorded speech sample in response to purposely ambiguous instructions to talk about any interesting or dramatic life experiences. Then, half of these subjects (n = 10) were randomly selected to receive 6 weeks of risperidone treatment up to 2.0 mg/d and the other half (n = 11) were administered a placebo. Both groups of subjects gave a second verbal sample after 6 weeks of treatment. Significantly elevated cognitive impairment and social alienation-personal disorganization scores, derived from the computerized content of the initial 5-minute speech samples, were found. After 6 weeks, the risperidone group improved significantly on a measure of severity of stuttering but did not improve on the percentage of time spent stuttering. The placebo group did not improve on either measure of stuttering. The psychopathological processes of subjects who received risperidone treatment, including those with elevated cognitive impairment and social alienation-personal disorganization, did not change significantly. However, stutterers who had lower scores on verbal content analysis-derived shame anxiety, guilt anxiety, or hostility inward measures improved significantly more with risperidone than stutterers with higher scores on these measures. The findings of elevated cognitive impairment and social alienation-personal disorganization scores of adult stutterers with the early developmental form of stuttering are consistent with the neurobiologic abnormalities found in PET-scan and genetic research involving stutterers. Risperidone (< or =2.0 mg/d) can reduce the severity of stuttering while not significantly affecting the magnitude of neuropsychiatric dimensions such as cognitive impairment or social alienation-personal disorganization. The less the inward shame, guilt, or hostility of the stutterers, the better the beneficial effect of risperidone on the severity of stuttering.

Adult↗