Monthly Archives: January 2011
Automated Analysis of Pharyngeal Pressure Data Obtained with High-Resolution Manometry
We present an algorithm developed in MATLAB that can be applied to both normal and disordered swallowing to automatically extract a wide array of measurements from the spatiotemporal plots produced by high-resolution manometry (HRM) of the pharyngeal swallow. The algorithm was developed from data from 12 normal and 3 disordered subjects swallowing 5-ml water boluses. Automated extraction was compared to manual extraction for a subset of seven normal and the three disordered subjects to evaluate algorithm accuracy. Area and line integrals, pressure wave velocity, and pressure gradients during upper esophageal sphincter opening were also measured. Automated extraction showed strong correlations with manual extraction, producing high correlation coefficients in both normal and disordered subjects for maximum velopharyngeal pressure and maximum tongue base pressure. Timing data were also strongly correlated for all variables, including velopharyngeal pressure duration, tongue base pressure duration, and total swallow duration. Preliminary descriptive data on area and line integrals are presented. Our results indicate that the algorithm can effectively extract data automatically from HRM spatiotemporal plots. The efficiency of the algorithm makes it a valuable tool to supplement clinical and research use of HRM.
from Dysphagia
NIH Grant Enables Cochlear Implant Breakthrough
Project Uses Smartphone Interface to Adjust Settings for Noisy Environments
Reduction in secondhand smoking associated with fewer cases of middle ear infection among children
Harvard School of Public Health (HSPH) researchers and colleagues from Research Institute for a Tobacco Free Society have found that a reduction in secondhand smoking in American homes was associated with fewer cases of otitis media, the scientific name for middle ear infection. The study appears on January 26, 2011, as an online first article on the website of the journal Tobacco Control.
from News-Medical.net
Novel surgery removes rare tumor, rebuilds trachea
Using a novel surgical approach, it’s possible to rebuild the trachea and preserve a patient’s voice after removing an invasive throat tumor, according to a new report from Henry Ford Hospital in Detroit.
from EurekAlert.org
Voice-saver: Light therapy for early-stage laryngeal cancer
Light, or photodynamic, therapy can help preserve the voice and vocal cord function for patients with early stage laryngeal (voice box) cancer, according to a study from Henry Ford Hospital in Detroit.
from EurekAlert.org
Language Development after Adoption
Though rare, in some cases internationally adopted children appear to be developing the necessary prerequisite skills for academic and social success but later on begin to have learning difficulty.
from ASHA Sphere
On-the-Job Hearing Loss Keeping Workers Awake
Loud workplace noise may lead to tinnitus, other problems that can affect sleep, study finds
from MedlinePlus.gov
Human auditory cortical responses to pitch and to pitch strength
Pitch is a fundamental auditory sensation, underlying both music and speech perception. This study was designed to explore pitch coding in human auditory cortex by testing whether activity in pitch-responsive regions covaries as a function of pitch salience (pitch strength). A psychophysical paradigm was used to confirm three levels of pitch salience for two different pitch-evoking stimuli. The location and magnitude of the response to these stimuli were measured using functional magnetic resonance imaging. A pitch response was found in planum temporale, close to the posterolateral border of Heschl’s gyrus. However, the response was not sensitive to pitch salience. One interpretation is that pitch-sensitive regions are maximally responsive to the presence or absence of pitch and not to pitch salience.
from NeuroReport
Literate humans sound out words during silent reading
Whether humans spontaneously sound out words in their mind during silent reading is a matter of debate. Some models of reading postulate that skilled readers access the meaning directly from print but others involve print-to-sound transcoding mechanisms. Here, we provide evidence that silent reading activates the sound form of words before accessing their meaning by comparing event-related potentials induced by highly expected words and their homophones. We found that expected words and words that sound the same but have a different orthography (homophones and pseudohomophones) reduce scalp activity to the same extent within 300 ms of presentation compared with unexpected words. This shows that phonological access during silent reading, which is critical for literacy acquisition, remains active in adulthood.
from NeuroReport
Causes of permanent childhood hearing impairment
Discussion:
The systematic review and the results of the population-based study provided little support for the generally accepted distribution of causes of PCHI.
from The Laryngoscope
Is laryngeal electromyography useful in the diagnosis and management of vocal fold paresis/paralysis?
No abstract is available for this article.
from The Laryngoscope
Sensorineural hearing loss in sickle cell disease—A prospective study from Oman
Summary/Conclusions:
The study reveals a significant incidence of sensorineural hearing loss (SNHL) in SCD patients (36.95%), although the patients were clinically asymptomatic. The hearing loss was worse in the right ears and had a female preponderance. Also, the hearing loss was more severe at the higher frequencies, 2,000–8,000 Hz in SCD patients. HbS, HbF, or low hemoglobin levels did not discriminate SCD patients with SNHL, and the role of hemoglobin F in the cochlea is still not clear. Regular audiometric assessment should therefore be recommended in SCD patients routinely.
from The Laryngoscope
Observer weighting of interaural cues in positive and negative envelope slopes of amplitude-modulated waveforms
The auditory system can encode interaural delays in highpass-filtered complex sounds by phase locking to their slowly modulating envelopes. Spectrotemporal analysis of interaurally time delayed highpass waveforms reveals the presence of a concomitant interaural level cue. The current study systematically investigated the contribution of time and concomitant level cues carried by positive and negative envelope slopes of a modified sinusoidally amplitude-modulated (SAM) high-frequency carrier. The waveforms were generated from concatenation of individual modulation cycles whose envelope peaks were extended by the desired interaural delay, allowing independent control of delays in the positive and negative modulation slopes. In experiment 1, thresholds were measured using a 2-interval forced-choice adaptive task for interaural delays in either the positive or negative modulation slopes. In a control condition, thresholds were measured for a standard SAM tone. In experiment 2, decision weights were estimated using a multiple-observation correlational method in a single-interval forced-choice task for interaural delays carried simultaneously by the positive, and independently, negative slopes of the modulation envelope. In experiment 3, decision weights were measured for groups of 3 modulation cycles at the start, middle, and end of the waveform to determine the influence of onset dominance or recency effects. Results were consistent across experiments: Thresholds were equal for the positive and negative modulation slopes. Decision weights were positive and equal for the time cue in the positive and negative envelope slopes. Weights were also larger for modulations cycles near the waveform onset. Weights estimated for the concomitant interaural level cue were positive for the positive envelope slope and negative for the negative slope, consistent with exclusive use of time cues.
from Hearing Research
Imaging electrical resonance in hair cells
The mechanosensory hair cells of many auditory receptor organs are tuned by an electrical resonance that increases their responses to stimulation over a narrow band of frequencies. The small oscillations of membrane potential characteristic of this phenomenon have previously been detectable only through intracellular electrode measurements, which are laborious and preclude analysis at the level of an entire sensory organ. We used a voltage-sensitive dye to image hair-cell electrical resonance in an intact preparation of the bullfrog’s sacculus, a receptor organ sensitive to low-frequency seismic and auditory stimuli. Imaging revealed distinct populations of hair cells whose resonant response varied with the frequency of transepithelial electrical stimulation. Most of the hair cells in the saccular epithelium in vitro were electrically tuned to stimulation at 25–50 Hz. The frequency dependence of the fluorescence signal was sensitive to pharmacological blockade of large-conductance Ca2+-sensitive K+ channels and to enzymatic digestion. At an elevated concentration of Ca2+, we observed transient fluorescence signals that probably represented action potentials. The stroboscopic imaging and analysis techniques described here present a general approach for studying subthreshold oscillations in electrically excitable cells.
from the Proceedings of the National Academy of Sciences of the United States of America
The auditory cortex mediates the perceptual effects of acoustic temporal expectation
When events occur at predictable instants, anticipation improves performance. Knowledge of event timing modulates motor circuits and thereby improves response speed. By contrast, the neuronal mechanisms that underlie changes in sensory perception resulting from expectation are not well understood. We developed a behavioral procedure for rats in which we manipulated expectations about sound timing. Valid expectations improved both the speed and the accuracy of the subjects’ performance, indicating not only improved motor preparedness but also enhanced perception. Single-neuron recordings in primary auditory cortex showed enhanced representation of sounds during periods of heightened expectation. Furthermore, we found that activity in auditory cortex was causally linked to the performance of the task and that changes in the neuronal representation of sounds predicted performance on a trial-by-trial basis. Our results indicate that changes in neuronal representation as early as primary sensory cortex mediate the perceptual advantage conferred by temporal expectation.
from Nature Neuroscience
