Monthly Archives: May 2008
Temporary hearing loss influences post-stimulus time histogram and single neuron action potential estimates from human compound action potentials
An analytic compound action potential (CAP) obtained by convolving functional representations of the post-stimulus time histogram summed across auditory nerve neurons [P(t)] and a single neuron action potential [U(t)] was fit to human CAPs. The analytic CAP fit to pre- and postnoise-induced temporary hearing threshold shift (TTS) estimated in vivo P(t) and U(t) and the number of neurons contributing to the CAPs (N). The width of P(t) decreased with increasing signal level and was wider at the lowest signal level following noise exposure. P(t) latency decreased with increasing signal level and was shorter at all signal levels following noise exposure. The damping and oscillatory frequency of U(t) increased with signal level. For subjects with large amounts of TTS, U(t) had greater damping than before noise exposure particularly at low signal levels. Additionally, U(t) oscillation was lower in frequency at all click intensities following noise exposure. N increased with signal level and was smaller after noise exposure at the lowest signal level. Collectively these findings indicate that neurons contributing to the CAP during TTS are fewer in number, shorter in latency, and poorer in synchrony than before noise exposure. Moreover, estimates of single neuron action potentials may decay more rapidly and have a lower oscillatory frequency during TTS. ©2008 Acoustical Society of America
from the Guardian.co.uk
A company that claimed to offer a “miracle cure” for dyslexia has closed its UK offices, leaving staff worried about whether they will be paid and parents unsure whether their children’s treatment will be completed.
Dore, which was set up and funded by the millionaire paint entrepreneur Wynford Dore, promoted individualised exercise courses to patients to improve dyslexia symptoms such as poor reading and writing skills. Despite being promoted heavily in the media as a cure for dyslexia, the evidence base of the programme has been criticised by some scientists.
The value of a liquid alginate suspension (Gaviscon Advance) in the management of laryngopharyngeal reflux
Abstract Laryngopharyngeal reflux (LPR) refers to the backflow of stomach contents into the laryngopharynx. Increasing evidence has demonstrated that LPR is a contributing factor in some cases of hoarseness, vocal fatigue, voice breaks, cough and globus and chronic throat clearing. However, several randomised placebo-controlled trials of proton pump inhibitors in the treatment of LPR have been reported with the majority showing no significant benefit in patient symptom scores over placebo. The aim of this pilot clinical study was to investigate whether any improvement in LPR-related symptoms, using the Reflux Symptom Index (RSI), and clinical findings, using the Reflux Finding Score (RFS), could be achieved with treatment with a liquid alginate suspension compared to control (no treatment). Patients presenting with the symptoms of LPR to the Otorhinolaryngology Outpatient Department at the Queen’s Medical Centre, Nottingham, UK were considered eligible if they had an RSI of greater than 10 and an RFS greater than 5 based on a fibreoptic examination of the larynx. A total of 49 patients were randomised into the open, parallel group study; 24 patients were randomised to receive 10 ml liquid alginate suspension (Gaviscon® Advance) four times daily after meals and at bedtime, and 25 patients into the control group (no treatment). Patients were assessed pre-treatment and at 2, 4 and 6 months post treatment. Mean (SD) RSI and RFS pre-treatment scores were 23.9 (7.0) and 10.4 (3.6) for the treatment group and 24.6 (7.4) and 10.3 (3.3) for the control group, respectively. Significant differences between treatment and control were observed for RSI at the 2-month (11.2 (7.0) vs. 16.8 (6.4), P = 0.005) and 6-month (11.2 (8.1) vs. 18.3 (9.4), P = 0.008) assessments and for RFS at the 6-month (7.1 (2.8) vs. 9.5 (3.4), P = 0.005) assessment. Significant improvement in symptom scores and clinical findings were achieved with liquid alginate suspension (Gaviscon® Advance) compared to control and further evaluation for the management of patients presenting with LPR is warranted.
Studying the effects of mobile phone use on the auditory system and the central nervous system: a review of the literature and future directions
Abstract The wide spread of mobile communication since the late 1980 s raises questions about the effects of electromagnetic fields (EMFs) on the human body. Most studies have focused on the non-thermal effects of electromagnetic radiation (EMR). Low-energy EMFs seem to cause structural and functional changes in the cell membrane of different cell types, leading to abnormal cell response. Such changes within the central nervous system (CNS) and auditory system, which directly receive EMR during mobile phone use, are of particular interest. Various studies suggest that EMR directly affects neurons by reducing the neuronal reactivity, increasing the neural membrane conductivity and prolonging their refractory period. Furthermore, although it has been suggested that EMR is related with increased incidence of specific tumors and can interact with known carcinogenic agents, no conclusive evidence exists supporting its role in carcinogenesis. Therefore, no safe conclusions can be drawn regarding the potential harmful effects of mobile phone use. Experiments are underway by our laboratory to investigate possible effects of mobile phone use on the auditory system and the CNS. These along with other studies are expected to further clarify whether mobile phone use truly presents a health hazard.
from the European Journal of Plastic Surgery
Abstract The aim of the study was an evaluation of Furlow’s method in correction of velopharyngeal insufficiency. A prospective study was conducted by a speech pathologist and a plastic surgeon. Rating of hypernasality and speech intelligibility were completed prior to and after surgical intervention. Nasometric measurements were also performed before and after surgical intervention. From May 2003 through September 2006, the first author performed 44 Furlow surgeries for the treatment of velopharyngeal insufficiency in patients with cleft palate. Patients with short, repaired cleft palates but with preserved normal function of pharyngeal sphincter qualified for the operation. The surgery was performed using double-opposing Z-plasty. The method was used in 24 males and 20 females aged from 6 to 25 years (mean age, 12 years). One patient (2%) developed wound dehiscence, and two further patients (4.5%) developed maceration of the wound margins, which delayed the healing process by only several days. Very good, good, or moderate results were obtained in 41 patients (91%). Poor outcome of treatment—excessive hypernasality or poor speech quality after the operation—was still present in four patients (9%). In our opinion, Furlow’s method is a very useful treatment method in patients with velopharyngeal insufficiency especially with sagittal orientation of levator veli palatini muscles.
Purpose: A study was conducted that examined factors that lead children who stutter at around age 8 years to persist in the disorder when they reach age 12 years.
Method: Seventy-six children were verified to be stuttering at initial assessment. When they reached 12 years of age, they were classified as persistent or recovered. A range of measures was taken at the 2 age points, and measures were examined by recovery group.
Results: Although the tendency for more males than females to stutter was confirmed, the reasons for this tendency are not apparent for these speakers. Different patterns in speech were observed: Severity ratings of the recovered speakers dropped by age 12+. The severity ratings for the persistent speakers remained high at 12+, and dysfluency types tended to change from whole words to part words. Persistent and recovered speakers differed on temperamental performance at around age 8 years and performed differently on sensory and motor tasks at age 12+ years.
Conclusions: Stuttering in late childhood affects mainly males. The later a child attends clinic, the longer he or she will stutter. Speech patterns of children who persist diverge from those who recover or who are fluent. As speakers persist, there are temperamental, sensory, and motor changes.
Addressing Feeding Disorders in Children on the Autism Spectrum in School-Based Settings: Physiological and Behavioral Issues
Purpose: The purposes of this article are to define the nature of feeding difficulties in children with autism spectrum disorder (ASD), identify important components of the assessment and treatment of feeding disorders specific to this population, and delineate specific therapeutic techniques designed to improve assessment and treatment within the school setting. Method: Literature review and case example are used to define the predominant nature of the feeding difficulties that are experienced by some children on the autism spectrum. Characteristics of this complex disorder that can have an impact on feeding skill and behavior are also identified. These factors are then integrated to create assessment and intervention techniques that can be used in conjunction with traditional feeding approaches to facilitate improvements in eating in this unique population. Implications: The complex nature of ASD and its many influences on feeding skills and behavior create the need for modification to both assessment and treatment approaches. Additional research is needed to create therapeutic protocols that can be used by school-based speech-language pathologists to effectively assess and treat feeding difficulties that are commonly encountered in children with ASD.
Purpose: Language acquisition is predictive of successful reading development, but the nature of this link is poorly understood.
Method: A sample of 7,179 twin pairs was assessed on parent–report measures of syntax and vocabulary at ages 2, 3, and 4 years and on teacher assessments of reading achievement (RA) at ages 7, 9, and 10 years. These measures were used to construct latent factors of early language ability (LA) and RA in structural equation model-fitting analyses.
Results: The phenotypic correlation between LA and RA (r = .40) was primarily due to shared environmental influences that contribute to familial resemblance. These environmental influences on LA and RA overlapped substantially (rC = .62). Genetic influences made a significant but smaller contribution to the phenotypic correlation between LA and RA, and showed moderate overlap (rA = .36). There was also evidence for a direct causal influence of LA on RA.
Conclusions: The association between early language and later reading is underpinned by common environmental and genetic influences. The effects of some risk factors on RA may be mediated by language. The results provide a foundation for more fine-grained studies that examine links between specific measures of language, reading, genes, and environments.
Purpose: To examine the relation between vowel production characteristics and intelligibility.
Method: Acoustic characteristics of 10 vowels produced by 45 men and 48 women from the J. M. Hillenbrand, L. A. Getty, M. J. Clark, and K. Wheeler (1995) study were examined and compared with identification accuracy. Global (mean f0, F1, and F2; duration; and amount of formant movement) and fine-grained measures (vowel space area; mean distance among vowels; f0, F1, and F2 ranges; duration ratio between long and short vowels; and formant movement ratio between dynamic and static vowels) were used to predict identification scores. Acoustic measures of the most frequently confused pairs (/æ/–// and //–//) were compared.
Results: Global and fine-grained measures accounted for less than 1/4 of variance in identification scores: Vowel space area alone accounted for 9%–12% of variance. Differences in vowel identification were largely due to poor identification of /æ/, //, //, or //. Well-identified vowels were distinctive in formant frequencies, duration, and amount of formant movement over time.
Conclusions: Distinctiveness among neighboring vowels is more important in determining vowel intelligibility than vowel space area. Acoustic comparison of confused vowels may be more useful in studying intelligibility of normal and disordered speech than in measuring vowel space area.
The Relationship Between Listener Comprehension and Intelligibility Scores for Speakers With Dysarthria
Purpose: This study examined the relationship between listener comprehension and intelligibility scores for speakers with mild, moderate, severe, and profound dysarthria. Relationships were examined across all speakers and their listeners when severity effects were statistically controlled, within severity groups, and within individual speakers with dysarthria.
Method: Speech samples were collected from 12 speakers with dysarthria secondary to cerebral palsy. For each speaker, 12 different listeners completed 2 tasks (for a total of 144 listeners): One task involved making orthographic transcriptions, and 1 task involved answering comprehension questions. Transcriptions were scored for the number of words transcribed correctly. Responses to comprehension questions were scored on a 3-point scale according to their accuracy.
Results: Across all speakers, the Pearson product–moment correlation between comprehension and intelligibility scores was nonsignificant when the effects of severity were factored out and residual scores were examined. Within severity groups, the same relationship was significant only for the mild group. Within individual speaker groups, the relationship was nonsignificant for all but 2 speakers with dysarthria. Percentage of correct scores for listener comprehension was descriptively higher than percentage of correct intelligibility scores for all groups.
Conclusion: Findings suggest that transcription intelligibility scores do not accurately reflect listener comprehension scores. Measures of both intelligibility and listener comprehension may provide a more complete description of the information-bearing capability of dysarthric speech than either measure alone.
The Influence of Fundamental Frequency and Sound Pressure Level Range on Breathing Patterns in Female Classical Singing
Purpose: This study investigated the influence of fundamental frequency (F0) and sound pressure level (SPL) range on respiratory behavior in classical singing.
Method: Five trained female singers performed an 8-s messa di voce (a crescendo and decrescendo on one F0) across their musical F0 range. Lung volume (LV) change was estimated, and chest-wall kinematic behavior (dimensional change in ribcage [RC] and abdominal [AB] wall) was recorded using triaxial magnetometry.
Results: The direction of F0 influence on LV excursion (LVE) varied among singers, but SPL range appeared to be less important than duration to LVE. LVE was generally evenly divided between crescendo and decrescendo. Kinematic patterns differed markedly among singers, despite task consistency, and RC and AB paradoxing was widespread.
Conclusion: Each singer maintained her characteristic kinematic pattern regardless of F0 or SPL range, although these did influence aspects of RC and AB behavior. Given the essential role of breathing in classical singing, further work is needed to understand how singers develop their highly individual respiratory strategies and the principles by which each singer’s breathing strategy can be optimized.
The Argument-Structure Complexity Effect in Children With Specific Language Impairment: Evidence From the Use of Grammatical Morphemes in French
Purpose: The hypothesis that the linguistic deficit presented by children with specific language impairment (SLI) is caused by limited cognitive resources (e.g., S. Ellis Weismer & L. Hesketh, 1996) was tested against the hypothesis of a limitation in linguistic knowledge (e.g., M. L. Rice, K. Wexler, & P. Cleave, 1995).
Method: The study examined the influence of the argument-structure complexity of a target sentence on the production of grammatical morphemes in French children with SLI compared with younger children matched for grammatical level in production (GL) and children of the same chronological age (CA). A sentence production task was used where the target sentences varied in terms of argument complexity and length.
Results: The results indicated that children with SLI used articles and auxiliaries in obligatory contexts significantly less often than both the GL and CA control groups: More complex argument structures elicited the highest number of grammatical morpheme omissions; this effect was larger in children with SLI than in the GL group and was independent of the length of the sentences, which failed to show any influence on the production of grammatical morphemes.
Conclusion: These results support the hypothesis that grammatical-morpheme deficit in SLI depends at least in part on limited processing capacities.
Purpose: This study examined the types, frequencies, and distribution of speech disruptions in the spoken narratives of children with specific language impairment (SLI) and their age-matched (CA) and language-matched (LA) peers.
Method: Twenty 4th-grade children with SLI, 20 typically developing CA children, and 20 younger typically developing LA children were included in this study. Speech disruptions (i.e., silent pauses and vocal hesitations) occurring in the narratives of these children were analyzed.
Results: Children with SLI exhibited speech disruption rates that were higher than those of their age-matched peers but not higher than those of their language-matched peers. The difference in disruption rates between the SLI and CA groups was restricted to silent pauses of 500–1000 ms. Moreover, children with SLI produced more speech disruptions than their peers before phrases but not before sentences, clauses, or words.
Conclusions: These findings suggest that there is a relationship between language ability and speech disruptions. Higher disruption rates at phrase boundaries in children with SLI than in their age-matched peers reflect lexical and syntactic deficits in children with SLI.
Short-Term Word-Learning Rate in Children With Normal Hearing and Children With Hearing Loss in Limited and Extended High-Frequency Bandwidths
Purpose: This study examined children’s word learning in limited and extended high-frequency bandwidth conditions. These conditions represent typical listening environments for children with hearing loss (HL) and children with normal hearing (NH), respectively.
Method: Thirty-six children with NH and 14 children with moderate-to-severe HL served as participants. All of the children were between 8 and 10 years of age and were assigned to either the limited or the extended bandwidth conditions. Five nonsense words were paired with 5 novel pictures. Word learning was assessed in a single session, multitrial, learning paradigm lasting approximately 15 min. Learning rate was defined as the number of exposures necessary to achieve 70% correct performance.
Results: Analysis of variance revealed a significant main effect for bandwidth but not for group. A Bandwidth x Group interaction was also not observed. In this short-term learning paradigm, the children in both groups required 3 times as many exposures to learn each new word in the limited bandwidth condition compared with the extended bandwidth condition.
Conclusion: These results suggest that children with HL may benefit from extended high-frequency amplification when learning new words and for other long-term auditory processes.
Purpose: To investigate the efficacy of parent–child interaction therapy (PCIT) with young children who stutter.
Method: This is a longitudinal, multiple single-subject study. The participants were 6 children aged 3;3–4;10 [years;months] who had been stuttering for longer than 12 months. Therapy consisted of 6 sessions of clinic-based therapy and 6 weeks of home consolidation. Speech samples were videorecorded during free play with parents at home and analyzed to obtain stuttering data for each child before therapy, during therapy, and up to 12 months posttherapy.
Results: Stuttering frequency data obtained during therapy and posttherapy were compared with the frequency and variability of stuttering in the baseline phase. Four of the 6 children significantly reduced stuttering with both parents by the end of the therapy phase.
Conclusions: PCIT can reduce stuttering in preschool children with 6 sessions of clinic-based therapy and 6 weeks of parent-led, home-based therapy. The study highlights the individual response to therapy. Suggestions for future research directions are made.