Propositional Idea Density in written descriptions of health: Potential clinical applications

In order to assess the effect of word finding difficulties for the spontaneous discourse of people with aphasia, a number of different measures of informativeness have been developed for clinical application (Doyle, Goda, & Spencer, 1995; Nicholas & Brookshire, 1993; Oelschlaeger & Thorne, 1999; Wright, Silverman, & Newhoff, 2003). The main challenges for the assessment of discourse (written or spoken) relate to issues of validity and reliability (AUTHOR DELETED). There is a need for valid and authentic sampling which is personally relevant to individuals and additionally, able to be repeated for the same individual on successive occasions, and comparable to other individuals. The use of a consistent elicitation task that could be widely used for adult populations would be beneficial to both allow comparisons of the same individual over time and also across individuals

Refrigerated storage and cryopreservation of hormonally induced sperm in the threatened frog, Litoria aurea

As sperm cryopreservation and other assisted reproductive technologies (ARTs) advance in common amphibian species, focus on applying non-lethal sperm collection methods to the conservation and genetic management of threatened species is imperative. The goal of this study was to examine the application of logistically practical ART protocols in a threatened frog (Litoria aurea). First, we tested the efficacy of various concentrations of human chorionic gonadotropin (hCG) (20, 40 IU/g bodyweight) and Gonadotropin releasing hormone antagonist (0.25 µg/g and 0.5 µg/g body weight GnRH-a) on the induction of spermatozoa. Using the samples obtained from the previous trials, we tested the effect of cold storage and cryopreservation protocols on long-term refrigerated storage and post-thaw sperm recovery. Our major findings include: (1) high quality sperm were induced with 20 and 40 IU/g bodyweight of (hCG); (2) proportions of live, motile sperm post-thaw, were recovered at higher levels than previously reported for L. aurea (&gt;50%) when preserved with 15% v/v DMSO and 1% w/v sucrose; and (3) spermic urine stored at 5 °C retained motility for up to 14 days. Our findings demonstrate that the protocols developed in this study allowed for successful induction and recovery of high-quality spermatozoa from a threatened Australian anuran, L. aurea, providing a prime example of how ARTs can contribute to the conservation of rare and threatened species.</p

Propositional Idea Density: Computerized analysis to determine effects of presence and severity of aphasia

This paper presents research that aimed to extend the available analyses of informativeness of aphasic discourse. A ‘proposition’ can be defined as a linguistic relation and its associated arguments (Kintsch & Keenan, 1973; Turner & Greene, 1977), and has been used as an index of informativeness in research on language and aging. The proportion of propositions in a text (Propositional Idea Density – PD) has been found to be a sensitive index of age-associated cognitive impairment and dementia (Riley, Snowdon, Desrosiers, & Markesbery, 2005). The research on PD has primarily used manual analysis methods, noting high training needs for raters to ensure adequate inter-coder and intra-coder reliability, as has also been found in analyses of informativeness in the field of aphasia (Nicholas & Brookshire, 1993; Oelschlaeger & Thorne, 1999; Yorkston & Beukelman, 1980). The development of a computer program, Computerized Propositional Idea Density Rater known as CPIDR (Brown, Snodgrass, & Covington, 2007; Brown, Snodgrass, Kemper, Herman, & Covington, 2008) has made the process of calculating PD accessible to untrained individuals. The benefits of a computer-based program are further seen in reliability, with 100% consistency when re-counting a single sample, and inter-rater reliability of 97% when compared to manual calculations which is more reliable than most human coders (Brown, et al., 2008). The present research made use of this computerised analysis of PD to investigate the effects of aphasia on informativeness. It was hypothesised that information content, as measured by PD, would be significantly reduced in the oral discourse of people with aphasia when compared to non-aphasic controls, and that PD would decrease with increasing aphasia severity as determined by Western Aphasia Battery - Aphasia Quotient (Kertesz, 2006)

The safety of Stockholm Birth Centre study: a critical review

This paper critically appraised the validity and generalizability of the safety of the Stockholm Birth Center care study to determine if it can be relied on to answer the question, “Is primiparous labor and birth in a birth center as safe for babies as standard medical care?” The retrospective cohort study is summarized, and statistical and methodological aspects are evaluated. Errors that were identified include selection bias and two forms of performance bias, both involving the independent variable. Nondefinition and lack of control of the independent variable and minor statistical errors were also noted. More serious concerns relate to the validity of an intention-to-treat analysis. Some methodological problems reduced validity of the study and ability to generalize the findings to other birth centers. Birth center care is a desirable and established birth option. A more useful approach to improving maternity care provision could involve comparing multiple birth center sites with each other to find best practice so that it can be analyzed and duplicated. (BIRTH 32:2 June 2005

Crop yield components - photoassimilate supply- or utilisation limited-organ development?

Yield potential is the genome-encoded capacity of a crop species to generate yield in an optimal growth environment. Ninety per cent of plant biomass is derived from the photosynthetic reduction of carbon dioxide to organic carbon (photoassimilates - primarily sucrose). Thus, development of yield components (organ numbers and individual organ masses) can be limited by photoassimilate supply (photosynthesis arranged in series with phloem transport) or by their inherent capacity to utilise imported photoassimilates for growth or storage. To this end, photoassimilate supply/utilisation of crop yield has been quantitatively re-evaluated using published responses of yield components to elevated carbon dioxide concentrations across a selection of key crop species including cereal and pulse grains, fleshy fruits, tubers and sugar storing stems and tap roots. The analysis demonstrates that development of harvested organ numbers is strongly limited by photoassimilate supply. Vegetative branching and, to a lesser extent, flower/pod/fleshy fruit abortion, are the major yield components contributing to sensitivity of organ numbers to photoassimilate supply. In contrast, harvested organ size is partially dependent (eudicots), or completely independent (cereals), of photoassimilate supply. Processes limiting photoassimilate utilisation by harvested organs include membrane transport of soluble sugars and their allocation into polymeric storage products

Changes in the length of speeches in the plays of William Shakespeare and his contemporaries: A mixed models approach.

Since 2007 a number of investigators have compiled statistics on the length in words of speeches in plays by William Shakespeare and his contemporaries, focusing on a change to shorter speeches around 1600. In this article we take account of several potentially confounding factors in the variation of speech lengths in these works and present a model of this variation in the period 1538-1642 through Linear Mixed Models. We confirm that the mode of speech lengths in English plays changed from nine words to four words around 1600, and that Shakespeare's plays fit this wider pattern closely. We establish for the first time: that this change is independent of authorship, dramatic genre, theatrical company, and the proportion of verse in a play's dialogue; that the chosen time span can be segmented into pre-1597 plays (with high modes), 1597-1602 plays (with mixed high and low modes), and post-1602 plays (with low modes); that some additional secondary modes are evident in speech lengths, at 16 and 24 words, suggesting that the length of a standard blank verse line (around 8 words) is an underlying unit in speech length; and that the general change to short speeches also holds true when the data is viewed through the perspective of the median and the mean. The change in speech lengths is part of a collective drift in the plays towards liveliness and verisimilitude and is evidence of a hitherto hidden constraint on the playwrights: whether or not they were aware of the fact, playwrights as a group were conforming to a structure for the distribution of speech lengths peculiar to the era they were writing in. The authors hope that the full modelling of this variation in the article will help bring this change to the attention of scholars of Shakespeare and his contemporaries

Language and ageing - exploring propositional density in written language - stability over time

This study investigated the stability of propositional density (PD) in written texts, as this aspect of language shows promise as an indicator and as a predictor of language decline with ageing. This descriptive longitudinal study analysed written texts obtained from the Australian Longitudinal Study of Women's Health in which participants were invited to respond to an open-ended question about their health. The 635 texts used for this study were taken from 127 middle-aged women who responded to this question on each of the five surveys conducted at 3-year intervals over a 16-year period. The study made use of an automated PD rater (CPIDR-3) for the analysis. PD was found to be a stable measure over time when comparing the grouped data, but there was between- and within-subject variation over time. Further research is needed to explore the valid use of this measure in research into language and ageing

Assessment of reliable change using 95% credible intervals for the differences in proportions: a statistical analysis for case study methodology

Purpose: Case study methodology studying change is often used in the field of speech-language pathology but can be criticised for not being statistically robust. Yet, with the heterogeneous nature of many communication disorders, case studies allow clinicians and researchers to closely observe and report on change. Such information is valuable and can further inform large-scale experimental designs. In this research note a statistical analysis for case study data is outlined that employs a modification to the Reliable Change Index (Jacobson & Truax, 1991). The relationship between reliable change and clinical significance is discussed. Example data are used to guide the reader through the use and application of this analysis. Method: The authors detail a method of analysis that is suitable for assessing change in measures with binary categorical outcomes. The analysis is illustrated using data from one individual, measured pre- and post-treatment for stuttering. Conclusion: The application of this approach to assess change in categorical, binary data has potential application in speech-language pathology. It enables clinicians and researchers to analyse results from case studies for their statistical and clinical significance. This new method addresses a gap in the research design literature, i.e., the lack of analysis methods for non-continuous data (such as counts, rates, proportions of events) that may be used in case study designs

Propositional idea density in women's written language over the lifespan: computerized analysis

The informativeness of written language, as measured by Propositional Idea Density (PD), has been shown to be a sensitive predictive index of language decline with age and dementia in previous research. The present study investigated the influence of age and education on the written language of three large cohorts of women from the general community, born between 1973 and 1978, 1946-51 and 1921-26. Written texts were obtained from the Australian Longitudinal Study on Women's Health in which participants were invited to respond to an open-ended question about their health. The informativeness of written comments of 10 words or more (90% of the total number of comments) was analyzed using the Computerized Propositional Idea Density Rater 3 (CPIDR-3). Over 2.5 million words used in 37,705 written responses from 19,512 respondents were analyzed. Based on a linear mixed model approach to statistical analysis with adjustment for several factors including number of comments per respondent and number of words per comment, a small but statistically significant effect of age was identified for the older cohort with mean age 78 years. The mean PD per word for this cohort was lower than the younger and mid-aged cohorts with mean age 27 and 53 years respectively, with mean reduction in PD 95% confidence interval (CI) of .006 (.003, .008) and .009 (.008, .011) respectively. This suggests that PD for this population of women was relatively more stable over the adult lifespan than has been reported previously even in late old age. There was no statistically significant effect of education level. Computerized analyses were found to greatly facilitate the study of informativeness of this large corpus of written language. Directions for further research are discussed in relation to the need for extended investigation of the variability of the measure for potential application to the identification of acquired language pathologies