Garden-Path Effects and Recovery in Aphasia

How people resolve and recover from syntactic ambiguity has been a central research topic in the psycholinguistic literature on sentence comprehension. It has attracted less attention in the literature on communicative impairments. However, there is increasing evidence that brain damage can affect how adults understand syntactically ambiguous sentences, both for right-hemisphere brain damage (e.g., Schneiderman & Saddy, 1988) and left-hemisphere damage (e.g., Novick, Trueswell & Thompson-Schill, 2005). Understanding how persons with aphasia (PWA) comprehend syntactically ambiguous sentences is therefore important to evaluating their communicative function, specifically their sentence comprehension ability. Syntactically ambiguous sentences are often referred to as garden-path sentences (Bever, 1970). These sentences lead comprehenders “down the garden path”: they cause readers or listeners to briefly misinterpret an ambiguous word or phrase, initially misanalyzing its syntactic role in the sentence. Subsequent information then indicates that this initial interpretation was incorrect, forcing comprehenders to reinterpret the sentence. This garden-path effect has been consistently found in healthy young and older adults (Christianson, et al., 2001, 2006; Ferreira & Henderson, 1991; Frazier & Rayner, 1982). Syntactic ambiguity resolution may be particularly strongly affected by reduced cognitive function such as reduced working memory (WM), common in healthy aging (e.g., Christianson, et al., 2006; Kemper et al., 2004). Kemper and colleagues (2004) found that older adults showed larger garden-path effects than younger adults, spending longer reading and re-reading garden-path sentences, and that these age-related differences were mediated by WM. This finding provides evidence of the importance of WM in resolving syntactic ambiguities. Christianson, et al. (2006) found that older adults’ comprehension question accuracy for garden-path sentences was correlated with their WM span. This finding provides evidence of the role of WM in successful recovery from a garden path. However, there has been little research on whether PWA also exhibit garden-path effects in their real-time comprehension of syntactically ambiguous sentences, or how successfully they recover from such garden paths. PWA have also been argued to have reduced WM capacity which contributes to their sentence comprehension deficits (e.g., Miyake, Carpenter & Just, 1994). WM is likely involved in the reanalysis of garden-path sentences (Kemper, et al., 2004), since reanalysis requires performing operations on structures held in memory. This study therefore examined the comprehension of garden-path sentences in PWA, and tested how their on-line garden-path effects and their off-line garden-path recovery were predicted by WM and short-term memory (STM)

Verb Argument Structure Encoding during Verb Naming and Sentence Production in Normal and Agrammatic Aphasic Speakers: An Eyetracking Study

Verbs with more complex argument structures are more impaired than those with less complex argument structures in agrammatic aphasia. However, the source of this deficit is unclear. The current study examined the production of two- and three-argument verbs in verb naming (VN) and sentence production (SP) conditions using eyetracking in twelve normal controls and one agrammatic aphasic speaker. For both control and aphasic participants, three-argument verbs elicited longer speech onset latency than two-argument verbs. Eye movement patterns from both groups provided evidence of incremental encoding of argument structure, suggesting that considerable capacity for argument structure encoding remains intact in agrammatism

The on-line comprehension of wh- movement structures in agrammatic Broca’s aphasia: Evidence from eyetracking

Dickey & Thompson (2004) present evidence that individuals with agrammatic Broca’s aphasia retain significant on-line gap-filling capacity, which improves in response to linguistically-motivated treatment (TUF; Thompson 2001). This paper presents data from an eyetracking study following up this result. Twelve agrammatic aphasic individuals’ and eight control participants’ eyes were tracked while they listened to stories ending with comprehension probes involving wh- movement (wh- object questions, object clefts). Aphasic participants’ responses to probes demonstrated impaired comprehension of wh- movement structures. However, their eye-movements indicated intact automatic processing of the movement sentences, even for wh- questions which they failed to comprehend

Highly purified human-derived follicle-stimulating hormone (Bravelle®) has equivalent efficacy to follitropin-beta (Follistim ®) in infertile women undergoing in vitro fertilization

BACKGROUND: These data compare the efficacy and safety of highly purified human-derived follicle-stimulating hormone (Bravelle(R)) and recombinant follitropin-β (Follistim(R)) in women undergoing in vitro fertilization. METHODS: This report describes the pooled data from two, nearly identical, randomized, controlled, parallel-group, multicenter studies conducted in a total of 19 academic and private IVF-ET centers in the United States. Infertile premenopausal women underwent pituitary down-regulation using leuprolide acetate followed by a maximum of 12 days of subcutaneous Bravelle(R) (n = 120) or Follistim(R) (n = 118), followed by administration of human chorionic gonadotropin, oocyte retrieval and embryo transfer. The primary efficacy measure was the mean number of oocytes retrieved; secondary efficacy measures included the total dose and duration of gonadotropin treatment; peak serum estradion levels; embryo transfer and implantation rates; chemical, clinical and continuing pregnancies; and live birth rates. All adverse events were recorded and injection site pain was recorded daily using a patient, self-assessment diary. RESULTS: Similar efficacy responses were observed for all outcome parameters in the two treatment groups. Although patients receiving Bravelle(R) consistently reported a greater number of chemical, clinical and continuing pregnancies, as well as an increased rate of live birth, the data did not attain statistical significance (P > 0.05). The overall incidence of adverse events was similar in both groups, but compared to Follistim(R), injections of Bravelle(R) were reported by patients to be significantly less painful (P < 0.001). CONCLUSIONS: Bravelle(R) and Follistim(R) had comparable efficacy in controlled ovarian hyperstimulation in women undergoing IVF-ET. There were no differences in the nature or number of adverse events between the treatment groups although Bravelle(R) injections were reported to be significantly less painful

The Gradient Expansion for the Free-Energy of a Clean Superconductor

We describe a novel method for obtaining the gradient expansion for the free energy of a clean BCS superconductor. We present explicit results up to fourth order in the gradients of the order parameter.Comment: 33 pages, Late

Description of an Intensive Residential Aphasia Treatment Program: Rationale, Clinical Processes, and Outcomes

Purpose: The purpose of this article is to describe the rationale, clinical processes, and outcomes of an intensive comprehensive aphasia program (ICAP). Method: Seventy-three community-dwelling adults with aphasia completed a residentially based ICAP. Participants received 5 hr of daily 1:1 evidence-based cognitivelinguistically oriented aphasia therapy, supplemented with weekly socially oriented and therapeutic group activities over a 23-day treatment course. Standardized measures of aphasia severity and communicative functioning were obtained at baseline, program entry, program exit, and follow-up. Results were analyzed using a Bayesian latent growth curve model with 2 factors representing (a) the initial level and (b) change over time, respectively, for each outcome measure. Results: Model parameter estimates showed reliable improvement on all outcome measures between the initial and final assessments. Improvement during the treatment interval was greater than change observed across the baseline interval, and gains were maintained at follow-up on all measures. Conclusions: The rationale, clinical processes, and outcomes of a residentially based ICAP have been described. ICAPs differ with respect to treatments delivered, dosing parameters, and outcomes measured. Specifying the defining components of complex interventions, establishing their feasibility, and describing their outcomes are necessary to guide the development of controlled clinical trials

Subthalamic Nucleus and Sensorimotor Cortex Activity During Speech Production

The sensorimotor cortex is somatotopically organized to represent the vocal tract articulators such as lips, tongue, larynx, and jaw. How speech and articulatory features are encoded at the subcortical level, however, remains largely unknown. We analyzed LFP recordings from the subthalamic nucleus (STN) and simultaneous electrocorticography recordings from the sensorimotor cortex of 11 human subjects (1 female) with Parkinson´s disease during implantation of deep-brain stimulation (DBS) electrodes while they read aloud three-phoneme words. The initial phonemes involved either articulation primarily with the tongue (coronal consonants) or the lips (labial consonants). We observed significant increases in high-gamma (60?150 Hz) power in both the STN and the sensorimotor cortex that began before speech onset and persisted for the duration of speech articulation. As expected from previous reports, in the sensorimotor cortex, the primary articulators involved in the production of the initial consonants were topographically represented by high-gamma activity. We found that STN high-gamma activity also demonstrated specificity for the primary articulator, although no clear topography was observed. In general, subthalamic high-gamma activity varied along the ventral?dorsal trajectory of the electrodes, with greater high-gamma power recorded in the dorsal locations of the STN. Interestingly, the majority of significant articulator-discriminative activity in the STN occurred before that in sensorimotor cortex. These results demonstrate that articulator-specific speech information is contained within high-gamma activity of the STN, but with different spatial and temporal organization compared with similar information encoded in the sensorimotor cortex.Fil: Chrabaszcz, Anna. University of Pittsburgh; Estados UnidosFil: Neumann, Wolf Julian. Universität zu Berlin; AlemaniaFil: Stretcu, Otilia. University of Pittsburgh; Estados UnidosFil: Lipski, Witold J.. University of Pittsburgh; Estados UnidosFil: Dastolfo Hromack, Christina A.. University of Pittsburgh; Estados UnidosFil: Bush, Alan. University of Pittsburgh; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Física de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Física de Buenos Aires; ArgentinaFil: Wang, Dengyu. Tsinghua University; China. University of Pittsburgh; Estados UnidosFil: Crammond, Donald J.. University of Pittsburgh; Estados UnidosFil: Shaiman, Susan. University of Pittsburgh; Estados UnidosFil: Dickey, Michael W.. University of Pittsburgh; Estados UnidosFil: Holt, Lori L.. University of Pittsburgh; Estados UnidosFil: Turner, Robert S.. University of Pittsburgh; Estados UnidosFil: Fiez, Julie A.. University of Pittsburgh; Estados UnidosFil: Richardson, R. Mark. University of Pittsburgh; Estados Unido

Polydnavirus genomes reflect their dual roles as mutualists and pathogens

AbstractSymbionts often exhibit significant reductions in genome complexity while pathogens often exhibit increased complexity through acquisition and diversification of virulence determinants. A few organisms have evolved complex life cycles in which they interact as symbionts with one host and pathogens with another. How the predicted and opposing influences of symbiosis and pathogenesis affect genome evolution in such instances, however, is unclear. The Polydnaviridae is a family of double-stranded (ds) DNA viruses associated with parasitoid wasps that parasitize other insects. Polydnaviruses (PDVs) only replicate in wasps but infect and cause severe disease in parasitized hosts. This disease is essential for survival of the parasitoid's offspring. Thus, a true mutualism exists between PDVs and wasps as viral transmission depends on parasitoid survival and parasitoid survival depends on viral infection of the wasp's host. To investigate how life cycle and ancestry affect PDVs, we compared the genomes of Campoletis sonorensis ichnovirus (CsIV) and Microplitis demolitor bracovirus (MdBV). CsIV and MdBV have no direct common ancestor, yet their encapsidated genomes share several features including segmentation, diversification of virulence genes into families, and the absence of genes required for replication. In contrast, CsIV and MdBV share few genes expressed in parasitized hosts. We conclude that the similar organizational features of PDV genomes reflect their shared life cycle but that PDVs associated with ichneumonid and braconid wasps have likely evolved different strategies to cause disease in the wasp's host and promote parasitoid survival

Free Energy of an Inhomogeneous Superconductor: a Wave Function Approach

A new method for calculating the free energy of an inhomogeneous superconductor is presented. This method is based on the quasiclassical limit (or Andreev approximation) of the Bogoliubov-de Gennes (or wave function) formulation of the theory of weakly coupled superconductors. The method is applicable to any pure bulk superconductor described by a pair potential with arbitrary spatial dependence, in the presence of supercurrents and external magnetic field. We find that both the local density of states and the free energy density of an inhomogeneous superconductor can be expressed in terms of the diagonal resolvent of the corresponding Andreev Hamiltonian, resolvent which obeys the so-called Gelfand-Dikii equation. Also, the connection between the well known Eilenberger equation for the quasiclassical Green's function and the less known Gelfand-Dikii equation for the diagonal resolvent of the Andreev Hamiltonian is established. These results are used to construct a general algorithm for calculating the (gauge invariant) gradient expansion of the free energy density of an inhomogeneous superconductor at arbitrary temperatures.Comment: REVTeX, 28 page