Examining inhibition during spoken word production in aphasia

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BayesCTDesign: An R Package for Bayesian Trial Design Using Historical Control Data

This article introduces the R package BayesCTDesign for two-arm randomized Bayesian trial design using historical control data when available, and simple two-arm randomized Bayesian trial design when historical control data is not available. The package BayesCTDesign, which is available from the Comprehensive R Archive Network, has two simulation functions, historic_sim() and simple_sim() for studying trial characteristics under user-defined scenarios, and two methods print() and plot() for displaying summaries of the simulated trial characteristics. The package BayesCTDesign works with two-arm trials with equal sample sizes per arm. The package BayesCTDesign allows a user to study Gaussian, Poisson, Bernoulli, Weibull, lognormal, and piecewise exponential outcomes. Power for two-sided hypothesis tests at a user-defined α is estimated via simulation using a test within each simulation replication that involves comparing a 95% credible interval for the outcome specific treatment effect measure to the null case value. If the 95% credible interval excludes the null case value, then the null hypothesis is rejected, else the null hypothesis is accepted. In the article, the idea of including historical control data in a Bayesian analysis is reviewed, the estimation process of BayesCTDesign is explained, and the user interface is described. Finally, the BayesCTDesign is illustrated via several examples

Volcanism of the Late Silurian Eastport Formation of the Coastal Volcanic Belt, Passamaquoddy Bay, New Brunswick: GAC–MAC Halifax 2022 Pre-Meeting Field Trip

This field trip is an excursion through the exquisite, nearly pristine exposures of a Silurian, felsic-dominated bimodal volcanic and sedimentary sequence exposed in the Passamaquoddy Bay area of southwestern, New Brunswick (Eastport Formation). These rocks form the northwest extension of the Coastal Volcanic Belt that extends from southwestern New Brunswick to the southern coast of Maine. The sequence is significant because it is part of a large bimodal igneous province with evidence for supervolcano-scale eruptions that began to form during the close of the Salinic Orogeny (about 424 Ma), and continued into the Acadian Orogeny (421–400 Ma). The geochemical characteristic of the rocks can be explained by extension related volcanism but the specific drivers of the extension are uncertain. The Passamaquoddy Bay sequence is 4 km thick and comprises four cycles of basaltic-rhyolitic volcanism. Basaltic volcanism typically precedes rhyolitic volcanism in Cycles 1–3. Cycle 4 represents the waning stages of volcanism and is dominated by peritidal sediments and basaltic volcanics. A spectrum of eruptive and emplacement mechanisms is represented ranging from the Hawaiian and Strombolian-type volcanism of the basaltic flows and pyroclastic scoria deposits, to highly explosive sub-Plinian to Plinian rhyolitic pyroclastic eruptions forming pyroclastic density currents (PDC) and high grade rheomorphic ignimbrites. During this field trip we will examine key exposures illustrating this spectrum of eruptive and emplacement processes, and their diagnostic characteristics, along with evidence for the interaction between mafic and felsic magmas and a variety of peperitic breccias formed as a result of emplacement of flows on wet peritidal sediments. The constraints the depositional setting and voluminous bimodal volcanism places on tectonic models will also be considered.Cette sortie sur le terrain est une excursion à travers les magnifiques affleurements pratiquement non altérés d'une séquence volcanique et sédimentaire bimodale silurienne à dominance felsique exposée dans la région de la baie de Passamaquoddy, au sud-ouest du Nouveau-Brunswick (Formation d'Eastport). Ces roches forment le prolongement nord-ouest de la Ceinture volcanique côtière qui s'étend du sud-ouest du Nouveau-Brunswick à la côte sud du Maine. La séquence est importante car elle fait partie d'une grande province ignée bimodale comprenant des preuves de super éruptions volcaniques qui ont commencé à se former à la fin de l'orogenèse salinique (environ 424 Ma) et se sont poursuivies pendant l'orogenèse acadienne (421–400 Ma). La caractéristique géochimique des roches peut être expliquée par le volcanisme lié à l'extension, mais les facteurs spécifiques de l'extension sont incertains. La séquence de la baie de Passamaquoddy a une épaisseur de 4 km et comprend quatre cycles de volcanisme basaltique-rhyolitique. Le volcanisme basaltique précède généralement le volcanisme rhyolitique dans les cycles 1–3. Le cycle 4 représente les stades décroissants du volcanisme et est dominé par des sédiments péritidaux et des roches volcaniques basaltiques. Une variété de mécanismes éruptifs et de mises en place est représentée, allant du volcanisme de type hawaïen et strombolien des coulées basaltiques et des dépôts de scories pyroclastiques, aux éruptions pyroclastiques rhyolitiques hautement explosives sous-pliniennes à pliniennes formant des courants de densité pyroclastiques et des ignimbrites rhéomorphes à haute teneur. Au cours de cette visite sur le terrain, nous examinerons les affleurements clés illustrant cette gamme de processus éruptifs et de mises en place, et leurs caractéristiques diagnostiques, ainsi que les preuves de l'interaction entre les magmas mafiques et felsiques et une variété de brèches pépéritiques formées à la suite de la mise en place de coulées sur des sédiments péritidaux humides. Les contraintes que le contexte de dépôt et le vaste volcanisme bimodal imposent aux modèles tectoniques seront également examinées

Rule-based treatment for acquired phonological dyslexia

In the context of a multiple-baseline design, this study demonstrated the positive effects of behavioural treatment using grapheme to phoneme correspondence rules to treat a patient with phonological dyslexia 17 years after stroke onset. Treatment used repeated exposure to real and nonsense word stimuli embodying the regularities of two grapheme to phoneme correspondence rules (GPCR) with hierarchical cueing and knowledge of results. Results revealed a pattern of performance that increased beyond baseline variability and coincided in time with the institution of treatment. Generalization of these treatment effects occurred to words requiring knowledge of other GPCR and to an independent processing based reading measure

Developing a standardized measure of short-term memory and syntactic complexity: results from subtests of the CRTT-R

Short-term memory (STM) effects have shown to be distinguishable from other working memory components supporting complex computations/central executive functions. To develop a measure capable of assessing the effects of STM and linguistic computations on sentence processing,  effects of syntactic complexity and padding were investigated with the Computerized Revised Token Test –Revised in individuals with aphasia and control participants.  Off-line measures revealed clear effects of both factors.  The expected interaction of complexity and padding  and overadditive effects for individuals with aphasia were not found. An effect of complexity on word errors in passive sentences for individuals was shown

Varieties of linguistic complexity in a standardized assessment of language performance

This study examined the comprehension of linguistically complex sentences among unimpaired adults and adults with aphasia. Participants completed a self-paced reading version of the Computerized Revised Token Test (CRTT-R) containing passive sentences, sentences with adverbial clauses, and sentences with discontinuous adjective-noun dependencies. Off-line measures revealed clear effects of linguistic complexity for passive and discontinuous-dependency sentences, with more complex sentences eliciting lower scores for impaired and aphasic groups, but not for sentences with adverbial clauses. In contrast, on-line measures revealed the opposite pattern: less complex sentences elicited slower reading times. Off-line measures appear more sensitive to linguistic complexity in this task

Automatic activation, interference and facilitation effects in persons with aphasia and normal adult controls on experimental CRTT-R-Stroop tasks

The current study investigated the effects of several color word congruent and incongruent “Stroop” tasks, within the context of a reading comprehension test (CRTT-R-wf-Stroop), in persons with aphasia (PWA) (N=25) and normal adults (NA) (N=29). Reading times, percentage of correct responses and CRTT-R-wf scores were examined for the color words. Both groups demonstrated significant vigilance and interference effects on RT ratios reflecting costs in sustained attention, interference/suppression effects and attentional switching. Both groups showed a facilitation effect on the CRTT-R-wf score. Unlike the NA, the PWA showed no attentional effects for the number of correct response on the color adjectives

Effects of visually augmented kinematic feedback with constant practice for the treatment of apraxia of speech: A single subject experiment

There is established efficacy for the treatment for apraxia of speech (AOS); however, the number of efficacious treatments is few and each is in need of replication. This single-subject multiple-baseline across-behaviors experimental study assessed the effects of on-line visual kinematic and clinician supplied auditory perceptual feedback on the acquisition, generalization and maintenance of speech production in a person with mild-to-moderate severity AOS. Intervention yielded immediate acquisition of nine sequentially treated behaviors and generalization to numerous untreated targets within and outside of the phoneme classes. Differential acquisition effects were realized for the frequency (50% versus 100%) of feedback administratio

Effects of training multiple form classes on acquisition, generalization and maintenance of word retrieval in a single subject

A study by McNeil et nl. reported no generalization effects in two individuals with aphasia following application of a word finding treatment in which subjects were trained sequentially on lexical items arranged by form class. The present investigation examined, in one of the two subjects from the original study, whether training on lexical items from a variety of form classes concurrently would result in greater response generalization than was observed previously in this subject. Results replicated earlier findings with positive acquisition and maintenance effects and little evidence of generalization to untrained items within or across form classes

Predictors of slowed reading times in persons with aphasia and control participants

Online sentence-level reading and listening times are sensitive measures of lexical access, parsing, syntactic and semantic integration processes (e.g., Rayner et al, 2004; Trueswell et al, 1993). Studies linking online to offline performance in syntactic processing have shown that persons with aphasia (PWA) show normal or near-to-normal parsing processes on sentences that are comprehended correctly (Caplan & Waters, 2003; Caplan et al., 2007, Dickey & Thompson, 2009). However, their reading times are usually slower than those of control participants even on correct items (e.g., Sung et al, 2011; Chenery et al, 1990), suggesting generally slowed reading in this group