Monthly Archives: December 2010
Spatial and numerical abilities without a complete natural language
We studied the cognitive abilities of a 13-year-old deaf child, deprived of most linguistic input from late infancy, in a battery of tests designed to reveal the nature of numerical and geometrical abilities in the absence of a full linguistic system. Tests revealed widespread proficiency in basic symbolic and non-symbolic numerical computations involving the use of both exact and approximate numbers. Tests of spatial and geometrical abilities revealed an interesting patchwork of age-typical strengths and localized deficits. In particular, the child performed extremely well on navigation tasks involving geometrical or landmark information presented in isolation, but very poorly on otherwise similar tasks that required the combination of the two types of spatial information. Tests of number- and space-specific language revealed proficiency in the use of number words and deficits in the use of spatial terms. This case suggests that a full linguistic system is not necessary to reap the benefits of linguistic vocabulary on basic numerical tasks. Furthermore, it suggests that language plays an important role in the combination of mental representations of space.
from Neuropsychologia
Stress matters: Effects of anticipated lexical stress on silent reading
This paper presents findings from two eye-tracking studies designed to investigate the role of metrical prosody in silent reading. In Experiment 1, participants read stress-alternating noun–verb or noun–adjective homographs (e.g. PREsent, preSENT) embedded in limericks, such that the lexical stress of the homograph, as determined by context, either matched or mismatched the metrical pattern of the limerick. The results demonstrated a reading cost when readers encountered a mismatch between the predicted and actual stress pattern of the word. Experiment 2 demonstrated a similar cost of a mismatch in stress patterns in a context where the metrical constraint was mediated by lexical category rather than by explicit meter. Both experiments demonstrated that readers are slower to read words when their stress pattern does not conform to expectations. The data from these two eye-tracking experiments provide some of the first on-line evidence that metrical information is part of the default representation of a word during silent reading.
from the Journal of Memory and Language
Relationship between gap detection thresholds and loudness in cochlear implant users
Gap detection threshold (GDT) is a commonly used measure of temporal acuity in cochlear implant (CI) recipients. This measure, like other measures of temporal acuity, shows considerable variation across subjects and also varies across stimulation sites within subjects. The aims of this study were (1) to determine whether across-site variation in GDTs would be reduced or maintained with increased stimulation levels; (2) to determine whether across-site variation in GDTs at low stimulation levels was related to differences in loudness percepts at those same levels; and (3) to determine whether matching loudness levels could reduce across-site differences in GDTs. Thresholds and maximum comfortable loudness levels were measured in postlingually deaf adults using all available sites in their electrode arrays. All sites were then surveyed at 30% of the dynamic range (DR) to examine across-site variation. Two sites with the largest difference in GDTs were then selected and for those two sites GDTs were measured at multiple levels of the DR (10%, 30%, 50%, 70%, and 90%). Stimuli consisted of 500 ms trains of symmetric-biphasic pulses, 40 μs/phase, presented at a rate of 1000 pps using a monopolar (MP1+2) electrode configuration. To examine perceptual differences in loudness, the selected sites were loudness-matched at the same levels of the DR. Variations in GDTs and loudness patterns were observed across stimulation sites and across subjects. Variations in GDTs across sites tended to decrease with increasing stimulation levels. For the majority of the subjects, stimuli at a given level in %DR were perceived louder at sites with better GDTs than those presented at the same level in %DR at sites with poorer GDTs. These results suggest that loudness is a contributing factor to across-site variation in GDTs and that CI fittings based on more detailed loudness matching could reduce across-site variation and improve perceptual acuity.
from Hearing Research
Processing words in two languages: An event-related brain potential study of proficient bilinguals
In a previous study of native-English speaking university learners of a second language (Spanish) we observed an asymmetric pattern of ERP translation priming effects in L1 and L2 (Alvarez, Holcomb, & Grainger, 2003, Brain & Language, 87, 290–304) with larger and earlier priming on the N400 component in the L2 to L1, compared with the L1 to L2 direction. In the current study 20 native-Russian speakers who were also highly proficient in English participated in a mixed-language lexical decision task in which critical words were presented in Russian (L1) and English (L2) and repetitions of these words (within and between languages) were presented on subsequent trials. ERPs were recorded to all items allowing for comparisons of repetition effects within and between (translation) languages. The results revealed a symmetrical pattern of within-language repetition and between-language translation ERP priming effects, which in conjunction with Alvarez et al. (2003), supports the hypothesis that L2 proficiency level rather than age or order of language acquisition is responsible for the observed patterns of translation priming. The ramifications of these results for models of bilingual word processing are discussed.
from the Journal of Neurolinguistics
Validation of self-reported hearing loss using television volume
Conclusions: Television volume is a useful marker of hearing loss in situations where audiometry is unavailable, for instance in a primary care setting. However, it is not a very specific test.
from the Journal of Laryngology and Otology
Developing a schedule to identify social communication difficulties and autism spectrum disorder in young children with visual impairment
Available observational tools used in the identification of social communication difficulties and diagnosis of autism spectrum disorder (ASD) rely partly on visual behaviours and therefore may not be valid in children with visual impairment. A pilot observational instrument, the Visual Impairment and Social Communication Schedule (VISS), was developed to aid in identifying social communication difficulties and ASD in young children with visual impairment affected by congenital disorders of the peripheral visual system (disorders of the globe, retina, and anterior optic nerve). The VISS was administered to 23 consecutive children (age range 1y 9mo–6y 11mo, mean 4y 1mo [SD 1.6]; 12 males, 11 females) with visual impairment (nine with severe and 14 with profound visual impairment). Item analysis was carried out by fit of the items to the Rasch model. Validity of the VISS was explored by comparison with the Childhood Autism Rating Scale (CARS) score, and the clinical ASD diagnosis (n=9). Correlation between the VISS and CARS total scores was highly significant (Spearman’s rho=−0.89; p=0.01). Below threshold rating on the VISS (score of 35) showed good agreement with the clinical ASD diagnosis (sensitivity 89%, specificity 100%). This preliminary study shows the VISS to be a promising schedule to aid the identification of ASD in young children with visual impairment.
Does kinship terminology provide evidence for or against universal grammar?
Jones introduces an intricate machinery of kin classification that overcomes limitations of previous accounts. I question whether such a machinery is plausible. Because individuals never need to learn the entire spectrum of kin terminology, they could rely on data-driven learning. The complexity of Jones’s machinery for kin classification casts doubt on the existence of innate structures that cover the complete linguistic domain.
Acoustical Modeling of Swallowing Mechanism
In this paper, a mathematical modeling of the swallowing sound generation is presented. To evaluate the model, its application on swallowing disorder (dysphagia) diagnosis is discussed. As a starting point, a simple linear time invariant model is assumed to represent the pharyngeal wall and tissue excited by a train of impulses. The modeling is approached by two different assumptions. In one approach, it is assumed that the impulse train, representing the neural activities to trigger swallow, is the same for both groups of control and dysphagic, and it is the pharyngeal model that accounts for the difference between the two groups. On the other hand, in the second approach, it is assumed that the pharyngeal response is the same for both groups, but the neural activities to initiate the swallow are different between the two groups. The results show that the second approach complies better with the physiological characteristics of swallowing mechanism as it provides a much better discrimination between the swallowing sounds of control and dysphagic groups of this study. Though, it should be noted that our dysphagic group subjects were cerebral palsy and stroke patients. Hence, the model accounting for initiation of neural activities is reasonable to show better results.
Does speed matter? A comparison of the effectiveness of fluency and discrete trial training for teaching noun labels to children with autism
This study used an alternating-treatment design to compare the efficacy of discrete trial training (DTT) with fluency training (FT) for the acquisition, stimulus generalization, and retention of noun labels in children with autism. Four elementary-age students diagnosed with autism were taught to expressively label nouns using a DTT format and a FT format. A between-treatments comparison of the total number of nouns retained at 6 weeks post intervention was also conducted to compare retention. The results of this study showed that FT was superior to DTT in all of these areas. © 2010 Wiley Periodicals, Inc.
Maintaining SLPs as the Preferred Providers of Dysphagia Services: A Call to Action
Speech-language pathologists (SLPs) in the general medical hospital setting spend approximately half of their time providing swallowing services. Other professions, including occupational therapists (OTs) and dietitians, promote themselves as disciplines well suited to assist patients with dysphagia. Responses to a survey distributed by the American Speech-Language-Hearing-Association (ASHA) in 2007 indicated that 83% of SLPs working in hospitals believed encroachment and defining professional boundaries was a problem. The highest level of personal experience with encroachment was with occupational therapy. Effective 2009, the American Occupational Therapy Association (AOTA) began offering Specialty Certification in Feeding, Eating and Swallowing (SCFES) to OTs and OTAs who meet specific educational and clinical experience requirements. This article reviews the many reasons why SLPs are the professionals best suited for assisting patients with swallowing disorders. It provides specific strategies to assist SLPs in promoting our discipline as the providers of dysphagia services.
from Perspectives on Swallowing and Swallowing Disorders (Dysphagia)
Malnutrition: Risks & Concerns in Dysphagia Management
Malnutrition, particularly undernutrition, negatively affects health outcomes. Risk of malnutrition, often identified by a Registered Dietitian as part of a patient’s dietary assessment, increases greatly in the presence of dysphagia. Patient characteristics that may be linked to malnutrition include advanced age, medical diagnoses, level of diet tolerated, actual calorie and protein intake, need for feeding assistance, weight changes, and quality of life issues. Many older adults may be malnourished at the time of their hospital admission or become so during the course of their medical care. Poor physical condition from malnutrition could negatively impact a patient’s rehabilitation potential. This article highlights possible causes and effects of undernutrition and the importance of nutrition strategies to patient care through a case study illustration.
from Perspectives on Swallowing and Swallowing Disorders (Dysphagia)
Swallowing in the Elderly: Evidence From Fluoroscopy
An understanding of changes in swallow associated with aging, differentiated from effects of disease processes or other factors characteristic of aging, is critical to clinicians working with elderly dysphagic patients. Rapid growth in our aging population, and the prevalence of dysphagia within this group, underscore this need. The intent of this paper is to review current information regarding typical changes in aging with implications for swallowing. Particular emphasis is on evidence from fluoroscopic studies of swallow function. Objective measures of timing and displacement, and other observations, were collected for 63 normal, non-dysphagic adults under the age of 65 years, and 74 carefully-screened, non-dysphagic volunteers over the age of 65 years. Differences between the groups are discussed, with special attention to their clinical relevance and application. Information provided will hopefully serve clinicians in recognizing typical and atypical swallow in the elderly, as well as characteristics of “typical” that may increase dysphagia risk, and reduce swallowing potential, in some elderly individuals.
from Perspectives on Swallowing and Swallowing Disorders (Dysphagia)
The Impact of Prescribed Medication on Swallowing: An Overview
Dysphagia clinicians are aware that best practices guidelines recommend a medications review as part of the assessment process. This article aims to review the literature to date regarding the impact that medications may have on the physiology of swallowing. It is important to consider the side effects of all medications, not only medications listing swallowing difficulties as a known side effect. Medications that impact upon arousal, awareness, and xerostomia should also be considered as part of a comprehensive dysphagia evaluation. Speech-language pathologists should consider the pharmacist an integral dysphagia team member and a valuable resource.
from Perspectives on Swallowing and Swallowing Disorders (Dysphagia)
Ventilation, Respiration, Pulmonary Diseases, and Swallowing
The respiratory and digestive functions of the upper aerodigestive tract (UAT) are inextricably linked, taking turns performing their life-supporting functions. The SLP is responsible for the management of swallowing disorders that increase health risks to patients, and necessarily need to understand and integrate into their evaluations and interventions, how the respiratory system works in health and disease, how to examine it, and how it changes in response to various conditions. This paper reviews the basics of respiratory anatomy and pulmonary function, respiratory-swallow coordination, and common pulmonary diseases in adults and how they affect swallowing function.
from Perspectives on Swallowing and Swallowing Disorders (Dysphagia)
Diet and gender influences on processing and discrimination of speech sounds in 3- and 6-month-old infants: a developmental ERP study
Early post-natal nutrition influences later development, but there are no studies comparing brain function in healthy infants as a function of dietary intake even though the major infant diets differ significantly in nutrient composition. We studied brain responses (event-related potentials; ERPs) to speech sounds for infants who were fed either breast milk (BF), milk-based formula (MF), or soy formula (SF) during the first 6 months of life. Two syllables presented in an oddball paradigm elicited a late positive wave (P350) from temporal and frontal brain regions involved in language processes. All groups showed significantly greater response amplitudes to the infrequent syllable across sites at 3 months and frontally at 6 months, but significant discrimination at temporal sites was only observed at 6 months in BF infants. Decreases in response amplitudes from 3 to 6 months were greater for the frequently presented syllable, most prominent in BF infants, and greater in females than males. The results indicate greater syllable discrimination in BF than formula-fed infants, but whether this can be attributed to dietary influences alone remains unclear. Feeding method and background factor differences between breastfed and formula-fed infants may also contribute to the observed differences. The general absence of differences between formula-fed groups is notable and suggests that milk-based formula and soy formula equally support brain development and function during the first post-natal 6 months. Finally, the results indicate gender differences in the development of neural and temporal processes involved in sensory discrimination, and suggest that at 6 months these processes are better developed in females.
