Compromised Speech Processing in Language Disorders

The relationship between the control of processes required for speech and language production were investigated in the context of fluency analysis of natural language samples produced by aphasic speakers. We used a new and objective approach to segmentation and fluency analysis. The procedure reveals two lognormal pause duration distributions and one lognormal speech segment duration distribution. We hypothesized that the short and long pause durations reflect articulatory gestures and cognitive processes respectively. The results can be interpreted by reference to either a modular approach to speech and language, or an integrated approach, where brain damage that impacts on the long pauses will, unless it is very minor, impact on articulatory gestures as well. The results provide support for the use of natural language analysis rather than reliance on diagnostic batteries based in the theory of modularity for clinical diagnosis of verbal communication disorders

Target definition for shipwreck hunting

The research described in the present article was implemented to define the locations of two World War II shipwrecks, the German raider Kormoran, and the Australian light cruiser HMAS Sydney. The paper describes the long and complex trail that led through inefficient oceanographic prediction to ambiguous historical prediction involving a single report and on to precise cognitive prediction based on nine reports from more than 70 survivors, a process that yielded a single target position or “mean” just 2.7NM (nautical miles) from the wreck of Kormoran. Prediction for the position of the wreck of Sydney opened with wishful thinking that she had somehow reached the coast more than 100NM away when cognitive analysis of the survivor’s reports actually provided the basis for accurate prediction in a position near to the wreck of Kormoran. In the account provided below, the focus on cognitive procedures emerged from, first, a review of a sample of the shipwreck hunts, and, second, growing awareness of the extraordinarily rich database available for this search, and the extent to which it was open to cognitive analysis. This review touches on both the trans-disciplinary and the cognitive or intra-disciplinary issues that so challenged the political entities responsible for supervising of the search for the wrecks of Kormoran and Sydney. One of the theoretical questions that emerged from these debate concerns the model of expertise advanced by Collins (2013). The decomposability of alleged forms of expertise is revealed as a fundamental problem for research projects that might or might not benefit from trans-disciplinary research. Where expertise can be decomposed for operational purposes, the traditional dividing lines between experts and novices, and fools for that matter, are much harder to discern, and require advanced and scientifically informed review

Language Production: A complex dynamic system with a chronometric footprint

In this paper we outline a new approach to the study of language production. Central to this approach is the assumption that communication takes place in a dynamic environment in which cognitive resources are deployed to achieve ‘Right-Time’ as distinct from ‘Fast-as-Possible’ solutions. This is based on the assumption that language production includes a single, integrated, interactive process that recruits and coordinates information from a variety of internal, external and interactive sources to build each speech segment. The output of this process is reflected in the longer of the two log-normal pause duration distributions observed in spontaneous speech (Kirsner, Dunn, Hird, Parkin & Clark, 2002). The methodology described here permits the inspection of temporally defined processes under natural speaking conditions. The procedures do not rely on the assumption that language is the product of independent components that can be studied under static, de-contextualised conditions. Results from aphasia, amnesia and bilingualism will be used to illustrate the new paradigm

Aphasia classification: The relationship between objective measures of spontaneous speaking samples and naive listener judgments of similarity and fluency

For an objective measure to be useful in a clinical setting it must correlate with perceptions of the speaker and what is considered “normal” (Kreiman, Gerratt, Kempster, Erman, & Berke, 1993). Perceptions of the functional communicative abilities of people with aphasia do not correlate well with changes on decontextualised linguistic measures (Wertz, 1999). In addition, the current practice of reliance on specific perceptual ratings of fluency of speech has been shown to be unreliable (Gordon, 1998; Kent, 1996,). Using a multidimensional scaling technique Kreiman, Gerratt & Precoda (1990) found that naïve and expert listeners attended to different aspects of voice when making similarity judgments. They recommended that naïve listeners become the “gold standard” for perceptual judgment tasks as their listening experiences were more homogenous. Listeners learn, through the computational analysis of connected speech, that pause duration information is an important factor in determining how spoken discourse is segmented, analyzed and interpreted, as pauses allow the listener to identify discourse structures and links between related materials (Fox Tree & Schrock, 1999). Perception of speech is achieved holistically, and values obtained for any one dimension may be highly influenced by co-occurring dimensions and the range of individual past listening experiences (Kent, 1996, 1997; Lehar, 2003). The development of a classification method derived from acoustic measures offers an objective approach to the correlates of speaking fluency. Fluency in this instance is considered a system measure rather than an isolable characteristic of spontaneous speech. The aim of this study was to explore (a) the relationship between objective pause data and naïve listeners’ similarity judgments of aphasic connected speech samples using MDS (b) the relationship between objective pause data and naïve listeners’ direct magnitude fluency estimates of aphasic connected speech samples and (c) the way listeners employ descriptors and concepts when describing aphasic speech samples

Seasonal Minimum and Maximum Solar Ultraviolet Exposure Measurements of Classroom Teachers Residing in Tropical North Queensland, Australia

The risk of keratinocyte skin cancer, malignant melanoma and ultraviolet radiation (UVR)-induced eye disease is disproportionately higher in Australia and New Zealand compared to equivalent northern hemisphere latitudes. While many teachers are aware of the importance of reinforcing sun-safety messages to students, many may not be aware of the considerable personal exposure risk while performing outdoor duties in locations experiencing high to extreme ambient-UVR year-round. Personal erythemally-effective exposure of classroom teachers in tropical Townsville (19.3o S) was measured to establish seasonal extremes in exposure behavior. Mean daily personal exposure was higher in winter (91.2 J m 2, 0.91 Standard Erythema Dose (SED)) than summer (63.3 J m-2, 0.63 SED). The range of exposures represent personal exposures that approximate current national guidelines for Australian workers at the study latitude of approximately 1.2 SED (30 J m-2 effective to the International Commission on Non-Ionizing Radiation Protection). Similar proportions of teachers spent more than 1 hour outdoors per day in winter (28.6%) and summer (23.6%) as part of their teaching duties with seasonal differences having little effect on the time of exposure. Personal exposures for teachers peaked during both seasons near school meal-break times at 11:00 am and 1:00 pm respectively