The understanding of the relationship between attention and normal language processing can provide insight into the underpinnings of language disorders. Dual-task experiments can be used to understand the allocation of attention during different stages of word production. The central bottleneck model posits that while the central (response selection) stage of any cognitive task is being carried out, the same stage of any other task cannot be simultaneously carried out. The central bottleneck model permits the testing of specific hypotheses about the attentional requirements of particular elements of competing tasks. One purpose of the current study was to determine if the process of lemma selection can be said to require central attention. A secondary aim of this study was to determine whether name agreement is a variable that can be used to index lemma selection. A preliminary study was conducted to construct a set of pictures with high and low name agreement that were balanced on important confounding variables. The main experiment was a dual-task experiment involving tone identification and picture naming. Name agreement effects were examined in the dual-task experiment. The effects were investigated in relation to the central bottleneck model, word production models, and the semantic picture-word interference effect. Low name agreement due to multiple correct names was employed. Tone identification was the primary task, while picture naming was the secondary task. Average picture naming reaction times were significantly longer for low than for high name agreement condition across levels of stimulus onset asynchrony. The results are consistent with a locus of the name agreement effect at the central, response selection stage of the central bottleneck model.

Effects of Repetition on Phonation Threshold Pressure Task Performance Christina A. Dastolfo, M.S. University of Pittsburgh, 2011 ABSTRACT Purpose: Phonation threshold pressure (PTP) is a widely used measure to evaluate vocal fold structure and function. Although concerns have been expressed about PTPs vulnerability to shifts as a function of practice, to date no study has addressed this question systematically. The present study addresses that gap at a preliminary, exploratory level. Methods: Nineteen vocally healthy women between 19-27 yrs were recruited into the study. Participants were screened for normal vocal function and self-reported normal learning abilities. Each participant performed a standard PTP task at her 80%ile pitch across 5 practice blocks on two consecutive study days under the same experimental conditions. Results: All participants improved both PTP and PTP standard deviation (SD) values from first to best block in the study, without any specific interventions. Statistical analyses confirmed participants as a group improved in average PTP performance from first to best block within and across experimental days. Individual data showed changes ranged from 0.67 5.42 cm H20 (mean = 2.42 cm H20). Improvements in SDs were also significant, ranging from 0.28-2.39 cm H20 improvement shown by individual data. Conclusions: The data suggest caution is warranted in the interpretation of PTP changes subsequent to research and clinical interventions, and provide initial estimates of changes that may occur with task repetition alone. Results from the present study provide motivation for further systematic work on repetition effects on PTP performance.

Wright et al. (2007) tested Persons with Aphasia (PWA) using three N-Back tasks featuring different types of linguistic information phonological, semantic, and syntactic -- to determine whether Verbal Working Memory (VWM) is a single, united resource. The current study tested three PWA with the same tasks, as well as an additional vision-focused task, to expand on this previous research; two groups of cognitively normal individuals were tested using the same protocol to provide a baseline for comparison. Results from the unimpaired groups indicated no effects of aging, and significant differences in performance across all types of information except phonological and visual cues. Results from PWA were inconclusive. The N-Back task, however, was found to cause misleading patterns in accuracy scores for some tests; sensitivity scores are suggested as a better measure of performance on this testing paradigm.

This study profiled auditory steady-state response amplitudes in children (i.e., six to nine years of age) and in adults (i.e., 18 to 35 years of age) over a wide range of repetition rates, specifically a range well embracing component waves of conventionally stimulated and recorded transient auditory evoked responses. Response amplitudes were measured at repetition rates from 0.75 to 80 Hz. Repetition rates of 10 Hz or less have received little attention in the context of the ASSR approach which is speculated to provide technical advantages, if not additional information, to the more traditional transient protocols, at least for some applications as follows: (1) to permit characterization of subject age-dependent amplitudes; (2) to allow an exploratory examination of the effects of repetition rate on response amplitude during natural sleep, to demonstrate if results differed from those obtained when subjects were awake, and (3) to explore the use of both the fundamental and harmonics in the characterization of the response amplitude versus the typical measure of amplitude in transient analysis. Planned comparisons were conducted to evaluate the amplitude differences observed between the age groups (i.e., children and adults) and between arousal conditions (i.e., adults awake and adults asleep) across modulation frequencies. The results of this study show that the amplitude was largest at the two lowest modulation frequencies for both adults and children. Furthermore, response amplitudes for children were significantly higher than those for adults at all modulation frequencies up to 5 Hz. Response amplitudes for adults during sleep also were significantly higher than those responses of adults while awake at 0.75 and 1.25 Hz. Good reliability overall was observed for these response measures in both adults and children. An amplitude measure defined as the harmonic sum yielded results paralleling the profile of response amplitudes as a function of repetition rate that may be extracted from the literature, although with some differences, the significance of which remains to be determined. Of pragmatic importance is that this profile could be determined without subjective wave identification and/or interpretation and thus by a method that is inherently more objective than conventional, transient AEP tests.