Monthly Archives: April 2008
Few studies consider the appropriate measurements for assessing drug clinical trials that enroll children, say University of Liverpool researchers who reviewed 9,000 pediatric clinical trials conducted since 1950.
They also found that few studies have involved parents, and none have involved children in the process to select which measurements to use in assessing clinical trials.
Effects of activation of the efferent system on psychophysical tuning curves as a function of signal frequency
from Hearing Research
It has been shown that electrical stimulation of the efferent auditory system can influence neural tuning curves in animals. Here, we examined a psychophysical analog of this effect in humans. All of the 19 normally hearing subjects showed a reduction in the amplitude of otoacoustic emissions in one ear when contralateral broadband noise was presented, indicating a functioning efferent system. Psychophysical tuning curves (PTCs) were measured in simultaneous masking in the absence and presence of contralateral stimulation (CS). The CS was a continuous narrowband noise centered at the signal frequency and presented at a level of 50 or 60 dB SL. The CS had no consistent effect on the masker level at the tips of the PTCs. For the two highest signal frequencies (2000 and 4000 Hz), the CS reduced the masker level required for threshold on both the low- and high-frequency sides of the PTCs, and the sharpness of tuning, as measured by Q10, decreased significantly. For the two lowest signal frequencies (500 and 1000 Hz), the masker level required for threshold on the low-frequency sides of the PTCs increased with CS, and the Q10 values increased significantly. The general pattern of the results was consistent with that observed for electrical stimulation of the efferent system in animals.
Background: Individuals with agrammatism show selective deficits in functional categories. The tree-pruning hypothesis (TPH; Friedmann & Grodzinsky, 1997) suggests that this results from inability to project certain nodes in the syntactic tree. On this account, higher nodes in the tree are more vulnerable than lower ones. Other theories, however, suggest that functional category impairments can be explained in the context of a morphological deficit (e.g., Arabatzi & Edwards, 2002; Penke, 2003; Thompson, Fix, & Gitelman, 2002).
Aims: This study examined production of complementisers, tense, and agreement morphology in four English-speaking agrammatic participants to test the hierarchical nature of functional category deficits. The consistency of verb inflection errors was also tested under conditions examining a minimal set versus a full array of English inflected forms.
Materials & Procedures: In Experiment 1 participants were asked to produce sentences by using a complementiser (i.e., whether, that, and if), a tense (-ed), or agreement marker (-s), in structured sentence elicitation tasks. In Experiment 2 the participants’ production of both finite and non-finite verb inflection forms was examined.
Outcome & Results: All participants produced complex sentences successfully using a complementiser, indicating intact projection to the Complementiser Phrase (CP). As for tense and agreement – structures within the Inflection Phrase (IP) – the agrammatic speakers were impaired in both categories and they showed higher scores in non-finite vs finite verb conditions. Further, their errors were dominated by substitutions, rather than omissions, with various non-target morphemes.
Conclusions: Our agrammatic participants’ deficits are morphological, rather than syntactic. The participants were able to project to the uppermost structure, CP. They showed the ability to project verb inflection and to implement inflectional rules in their grammar. However, instantiation of grammatical markers sometimes failed to operate, resulting in incorrect inflectional forms. These findings suggest that within the domain of functional categories, IP- and CP-level deficits may result from disruption of differing underlying mechanisms and, therefore, they may require separate treatment strategies.
The authors wish to thank our laboratory members, including Michael W. Dickey, Janet O’Connor, and JungWon (Janet) Choy for their helpful comments and assistance with data collection. Our special thanks go to the agrammatic aphasic patients who participated in this study, and to The National Institutes of Health (NIH) grant DC-01948-13 (C. K. Thompson) for supporting this research.
Two-stage hearing screening, with a first stage of automated otoacoustic emissions (AOAE) followed by automated auditory brainstem response (AABR), is the protocol of choice for the early detection of congenital and early-onset hearing loss (PCEHL) in a number of developed countries. However, this protocol would miss children with auditory neuropathy/auditory dys-synchrony (AN/AD). The aim of the study was to ascertain the characteristics of infants with AN/AD profile in a developing country and identify predictors of this condition in a primary care, non-hospital-based setting. Case-control analysis of the sociodemographic and medical profile of 11 infants with normal outer hair cell function, but confirmed with PCEHL, were compared to 64 infants with normal hair cell function and no PCEHL. The infants with AN/AD profile were further compared with 45 infants with PCEHL who failed transient evoked otoacoustic emissions (TEOAE). Independent predictors were determined from univariate and multiple logistic regression analyses. Factors associated with AN/AD profile in the univariate analysis were male sex (OR, 9.39: 95% CI 1.14-77.74) and hyperbilirubinaemia requiring exchange blood transfusion (OR, 5.63: CI 1.06-129.85). About 64% of the infants with AN/AD profile had a history of hyperbilirubinaemia and 54.5% were hospitalized in the first month of life for a serious illness. No independent factor was predictive of AN/AD from multiple logistic regression analysis. Infants with AN/AD profile were significantly more likely to have a history of hyperbilirubinaemia (OR, 14.00: CI 3.00-165.34) and be hospitalized in the first month of life (OR, 7.80: CI 1.80-33.77) than infants with PCEHL who failed TEOAE. There is no prognostic/selective tool for the early detection of infants with AN/AD profile in non-hospital-based settings in developing countries. AABR screening of infants with normal outer hair cells, who have a history of hyperbilirubinaemia with or without exchange blood transfusion, is recommended as far as practicable, where a two-stage TEOAE/AABR protocol is implemented.
No abstract available.
Self-disclosure of stuttering at the beginning of interactions may improve listeners’ perceptions of people who stutter
No abstract available.
from the American Journal of Otolaryngology
The current guidelines of the American Academy of Otolaryngology—Head and Neck Surgery entrust the diagnosis of Ménière disease (MD) only to the clinical presentation and the pure tone audiometry. However, most otolaryngologists request a widened instrumental evaluation of the patients suspected of MD. The effective reliability of the further instrumental support for the diagnosis of MD is still debated in the literature because of nonstandardized procedures and sometimes incoherence among authors. New and more sophisticated diagnostic tests have been developed both in audiovestibology and in imaging in the last few years. A review of the recent literature on this controversial subject is provided.
from Brain and Language
Most existing models of language production and speech motor control do not explicitly address how language requirements affect speech motor functions, as these domains are usually treated as separate and independent from one another. This investigation compared lip movements during bilabial closure between five individuals with mild aphasia and five age and gender-matched control speakers when the linguistic characteristics of the stimuli were varied by increasing the number of syllables. Upper and lower lip movement data were collected for mono-, bi- and tri-syllabic nonword sequences using an AG 100 EMMA system. Each task was performed under both normal and fast rate conditions. Single articulator kinematic parameters (peak velocity, amplitude, duration, and cyclic spatio-temporal index) were measured to characterize lip movements. Results revealed that compared to control speakers, individuals with aphasia showed significantly longer movement duration and lower movement stability for longer items (bi- and tri-syllables). Moreover, utterance length affected the lip kinematics, in that the monosyllables had smaller peak velocities, smaller amplitudes and shorter durations compared to bi- and trisyllables, and movement stability was lowest for the trisyllables. In addition, the rate-induced changes (smaller amplitude and shorter duration with increased rate) were most prominent for the short items (i.e., monosyllables). These findings provide further support for the notion that linguistic changes have an impact on the characteristics of speech movements, and that individuals with aphasia are more affected by such changes than control speakers.
Background: A primary feature of acquired apraxia of speech (AOS) is a slow speech rate associated with lengthened sound segments and intersegment durations (McNeil, Robin, & Schmidt, 1997). This disturbance in speech production timing has been the focus of a limited number of treatment studies designed to manipulate rate and/or rhythm of speech production with speakers with mild AOS.
Aims: The purpose of this investigation was to study the effects of rate control treatment on sound production accuracy and utterance durations of multisyllabic words, phrases, and sentences in a speaker with mild AOS and aphasia.
Methods & Procedures: An individual with mild AOS and aphasia was trained to produce multisyllabic words and phrases using a combination of metronomic rate control and hand tapping. The speaker was trained to produce one syllable per beat of the metronome in conjunction with hand tapping. Feedback was only provided for accuracy of hand tapping and/or syllable production to the beat of the metronome. No feedback was given regarding the accuracy of sound production. Initially, the speaker’s rate of production was reduced, but was then systematically increased. A multiple baseline design was used to examine the acquisition, response generalisation, and maintenance effects of treatment.
Outcomes & Results: Findings revealed an increase in sound production accuracy for trained four-syllable words and some improvement in sound production accuracy for treated phrases and untrained four-syllable words. There was only a slight reduction in total utterance duration for treated items versus untreated items. There was a gradual decline in total utterance duration over time on untrained stimulus generalisation items with no consistent improvement on sound production accuracy.
Conclusions: Treatment resulted in an improvement in sound production accuracy in an individual with AOS and aphasia. Positive changes were observed for treated four-syllable words, phrases, and untrained four-syllable words, although treatment did not directly target sound production accuracy (i.e., feedback was not given regarding accuracy of productions). The study represents an initial investigation of the effects of rate control treatment specifically increasing rate of production in a speaker with mild AOS and aphasia. This type of treatment appears to have promise in terms of improving sound production accuracy and warrants further investigation.
This research was supported by Rehabilitation Research and Development, Department of Veterans Affairs. This investigation was presented as a poster at the annual Clinical Aphasiology Conference, Scottsdale, AZ, May 2007. Thanks to Joel Longhurst for his assistance with data analysis.
At the recently concluded 10th International Conference on Cochlear Implants and Other Implantable Auditory Technologies held in San Diego, California on April 10 – 12, a group of investigators from the Loyola University Chicago presented generally positive clinical results from the study of patients implanted with the Baha® bone conduction implant from Cochlear. The device is not a new one. It was cleared by the FDA in 1996 as a treatment for conductive and mixed hearing loss. (At that time, the device was made by Entific Medical Systems, which was later acquired by Cochlear.) And since 2002, the device has been approved by the FDA for the treatment of unilateral sensorineural hearing loss.
Studies of spatial perception during visual saccades have demonstrated compressions of visual space around the saccade target. Here we psychophysically investigated perception of auditory space during rapid head turns, focusing on the “perisaccadic” interval. Using separate perceptual and behavioral response measures we show that spatial compression also occurs for rapid head movements, with the auditory spatial representation compressing by up to 50%. Similar to observations in the visual system, this occurred only when spatial locations were measured by using a perceptual response; it was absent for the behavioral measure involving a nose-pointing task. These findings parallel those observed in vision during saccades and suggest that a common neural mechanism may subserve these distortions of space in each modality.
This research investigates whether children with autism learn picture, word and object relations as associative pairs or whether they understand such relations as referential. In Experiment 1, children were taught a new word (e.g. `whisk’) repeatedly paired with a novel picture. When given the picture and a previously unseen real whisk and asked to indicate a whisk, children with autism, unlike typically developing peers matched on receptive language, associated the word with the picture rather than the object. Subsequent experiments respectively confirmed that neither a bias for selecting pictures nor perseverative responding accounted for these results. Taken together, these results suggest that children with autism with cognitive difficulties are learning picture—word and picture—object relations via an associative mechanism and have difficulty understanding the symbolic nature of pictures.
Is There an Increased Familial Prevalence of Psychopathology in Children With Nonverbal Learning Disorders?
The cognitive and behavioral symptoms of nonverbal learning disabilities (NLD) have been described by previous investigators. Nevertheless, we know far less about the potential genetic contributions that may predispose a child to have NLD. An endophenotype model was investigated in 5 samples of children ages 9 to 15 years: NLD (n = 32); reading disorders (RD; n = 59); participants with a psychiatric diagnosis but without a learning disability (n = 55); typically developing controls (n = 31); and children with velocardiofacial syndrome (VCFS), a chromosomal deletion syndrome that has been proposed as being an exemplar of NLD (VCFS + NLD; n = 20). Based on a family genetic interview, the authors’ data suggest that children with NLD, RD, or a psychiatric diagnosis have a higher prevalence rate of attention-deficit/hyperactivity disorder (ADHD) and substance abuse/dependence. Psychiatric controls and children with NLD—but not children with RD— showed higher prevalence rates of familial bipolar disorder.
Long-term outcomes for individuals who use augmentative and alternative communication: Part I – what is a “good” outcome?
Over the past 20 years, there have been many advances in the field of augmentative and alternative communication (AAC). Despite these advances, there are no data on the long-term outcomes of AAC interventions. This study evaluated the long-term outcomes for a group of seven young men (ages 19 – 23 years) who had used AAC systems for at least 15 years and were part of the first generation to have received AAC services since they were in preschool. Outcomes were measured in the following domains: (a) receptive language; (b) reading comprehension; (c) communicative interaction; (d) linguistic complexity; (e) functional communication; (f) educational and vocational achievement; (g) self-determination; and (h) quality of life. The outcomes for the group were diverse, with individual variations across all measures. Evaluation of the data raised many issues surrounding the challenges of outcomes measurement; these are discussed with suggestions for future research.
Pediatric cochlear implantation has been demonstrated to be effective for children as well as cost effective for society. One of Healthy People 2010 goals is to increase the number of people who are deaf or significantly hard of hearing to begin to use a cochlear implant system. NIDCDs Healthy Hearing Progress Reports from 1999 reported that only 2 out of every 1000 adults who are deaf or hard of hearing received a cochlear implant. There were two main objectives for this study: (1) to estimate the number of children between the ages of 12 months and 6 years of age with severe to profound bilateral hearing loss who could benefit from a cochlear implant and (2) to determine if the number of children projected to be candidates received this medical care.
Using the 2000 US Census Data from children 12 months to 6 years, the number of children with severe to profound bilateral hearing loss was calculated. Children who would be considered “neurologically devastated” and the children with absent eighth nerves were excluded from the calculations.
Based on the total population of slightly over 231 million, 15,219 children presented with severe to profound hearing loss. Taking into account some exclusions, 12,816 children would be considered cochlear implant candidates. Based on the number of children who were implanted in 2000, approximately 55% of the projected number of candidates received a cochlear implant.
Even though the estimates do not reflect a direct measure of actual candidates in the targeted age groups, the population who could benefit from this technology is still being significantly underserved in the United States. With a continued shortage of qualified personnel to serve these children, insufficient reimbursement rates, and disparities in implantation rates based on ethnicity and socioeconomic status, the question remains can we truly meet the needs of these children?