Comparison of speech production in upright and supine position

Speech is usually produced in an upright sitting or standing posture. Measurements and judgments of speech may be made in conditions requiring a supine position, however. These conditions include MRI recordings, and oral procedures, such as, adjustments to dental appliances, medical and surgical procedures. It is of interest, therefore, to see whether gravity has strong or systematic effects on tongue behavior. In the present study, 13 subjects repeated several words, which contained extreme consonant and vowel tongue positions, during upright and supine condition. Ultrasound imaging provided midsagittal tongue contours, in each condition, for comparison. A neck brace was used to stabilize transducer placement and the palate was used as a physiological reference to register the data sets. Results showed a significant subject effect. In supine position the tongue was more posterior than upright for seven subjects, more anterior for two subjects and varied by phoneme for four subjects. However, there was no significant phoneme effect. The direction of change and the amount of change were not directly related. Most subjects had small upright-supine differences. The largest differences, less than 3 mm on average, were in the posterior tongue.

Is the NHS research ethics committees system to be outsourced to a low-cost offshore call centre? Reflections on human research ethics after the Warner Report

The recently published Report of the AHAG on the Operation of NHS Research Ethics Committees (the Warner Report) advocates major reforms of the NHS research ethics committees system. The main implications of the proposed changes and their probable effects on the major stakeholders are described.

A test of the binaural equal-loudness-ratio hypothesis for tones

It is well known that a tone presented binaurally is louder than the same tone presented monaurally. It is less clear how this loudness ratio changes as a function of level. The present experiment was designed to directly test the Binaural Equal-Loudness-Ratio hypothesis (BELRH), which states that the loudness ratio between equal-SPL monaural and binaural tones is independent of SPL. If true, the BELRH implies that monaural and binaural loudness functions are parallel when plotted on a log scale. Cross-modality matches between string length and loudness were used to directly measure binaural and monaural loudness functions for nine normal listeners. Stimuli were 1-kHz 200-ms tones ranging in level from 5 dB SL to 100 dB SPL. A two-way ANOVA showed significant effects of level and mode (binaural or monaural) on loudness, but no interaction between the level and mode. Consequently, no significant variations were found in the binaural-to-monaural loudness ratio across the range of levels tested. This finding supports the BELRH. In addition, the present data were found to closely match loudness functions derived from binaural level differences for equal loudness using the model proposed by Whilby et al. [J. Acoust. Soc. Am. 119, 3931-3939 (2006)].

Familial isolated hyperparathyroidism is linked to a 1.7 Mb region on chromosome 2p13.3-14

BACKGROUND

Familial isolated hyperparathyroidism (FIHP) is an autosomal dominantly inherited form of primary hyperparathyroidism. Although comprising only about 1% of cases of primary hyperparathyroidism, identification and functional analysis of a causative gene for FIHP is likely to advance our understanding of parathyroid physiology and pathophysiology.

METHODS

A genome-wide screen of DNA from seven pedigrees with FIHP was undertaken in order to identify a region of genetic linkage with the disorder.

RESULTS

Multipoint linkage analysis identified a region of suggestive linkage (LOD score 2.68) on chromosome 2. Fine mapping with the addition of three other families revealed significant linkage adjacent to D2S2368 (maximum multipoint LOD score 3.43). Recombination events defined a 1.7 Mb region of linkage between D2S2368 and D2S358 in nine pedigrees. Sequencing of the two most likely candidate genes in this region, however, did not identify a gene for FIHP.

CONCLUSIONS

We conclude that a causative gene for FIHP lies within this interval on chromosome 2. This is a major step towards eventual precise identification of a gene for FIHP, likely to be a key component in the genetic regulation of calcium homeostasis.

Reaction Time to 1- and 4-kHz Tones as a Function of Sensation Level in Listeners with Normal Hearing

OBJECTIVE

Measures of reaction time (RT) near threshold have been used to indicate whether listeners with hearing losses of primarily cochlear origin experience greater loudness at elevated thresholds than at normal thresholds. These measurements have been based on the assumption that RTs near threshold are not affected by stimulus frequency in the 1- to 4-kHz range. The present study tests this hypothesis.

DESIGN

To gain an understanding of how RT is affected by frequency, RTs to 1- and 4-kHz tones were measured in 16 listeners with normal hearing across a wide range of sensation levels (SLs).

RESULTS

Statistical analyses indicate that RTs are affected by frequency in some listeners. This effect is most common at low SLs but is also present at higher SLs. Learning effects could not account for the observed differences between RTs at the two frequencies.

CONCLUSIONS

Although reaction time-especially at low levels-is affected by stimulus frequency in some listeners, the effect is not large enough to account for the differences in RTs measured in all listeners with impaired hearing in other studies.

Potential carry-over effect in the measurement of induced loudness reduction

The majority of studies on induced loudness reduction (ILR) use an experimental paradigm that results in an underestimation of the amount of ILR. Most of those studies utilize loudness matches between tones of two different frequencies (a test tone and a comparison tone) with (experimental condition) and without (baseline condition) an inducer tone at the test frequency. The change in level of the comparison tone between the baseline and experimental conditions is the amount of ILR. In those experiments, the level of the comparison tone in the baseline condition tends to be substantially higher (often about 10 dB) than in the experimental condition. Because of this level difference, exposure to the baseline condition immediately prior to the experimental condition causes unintended ILR for the comparison tone. In this study, the delay between the baseline and experimental conditions was varied and it was determined that the amount of ILR is underestimated by about 30% and the variability is increased when the experimental condition is run immediately after the baseline condition. A second experiment using a Békésy-tracking procedure showed that ILR maximizes rapidly upon exposure to an inducer and decays over the course of several minutes after the inducer is removed.

Why effective consent presupposes autonomous authorisation: a counterorthodox argument

Effective consent is indeed a legal fiction

Loudness of brief tones measured by magnitude estimation and loudness matching

McFadden [J. Acoust. Soc. Am. 57, 702-704 (1975)] questioned the accuracy and reliability of magnitude estimation for measuring loudness of tones that vary both in duration and level, whereas Stevens and Hall [Percept. Psychophys. 1, 319-327 (1966)] reported reasonable group data. To gain insight into this discrepancy, the present study compares loudness measures for 5- and 200-ms tones using magnitude estimation and equal-loudness matches from the same listeners. Results indicate that both procedures provide rapid and accurate assessments of group loudness functions for brief tones, but may not be reliable enough to reveal specific characteristics of loudness in individual listeners.

A report of a national mutation testing service for the MEN1 gene: clinical presentations and implications for mutation testing

INTRODUCTION

Mutation testing for the MEN1 gene is a useful method to diagnose and predict individuals who either have or will develop multiple endocrine neoplasia type 1 (MEN 1). Clinical selection criteria to identify patients who should be tested are needed, as mutation analysis is costly and time consuming. This study is a report of an Australian national mutation testing service for the MEN1 gene from referred patients with classical MEN 1 and various MEN 1-like conditions.

RESULTS

All 55 MEN1 mutation positive patients had a family history of hyperparathyroidism, had hyperparathyroidism with one other MEN1 related tumour, or had hyperparathyroidism with multiglandular hyperplasia at a young age. We found 42 separate mutations and six recurring mutations from unrelated families, and evidence for a founder effect in five families with the same mutation.

DISCUSSION

Our results indicate that mutations in genes other than MEN1 may cause familial isolated hyperparathyroidism and familial isolated pituitary tumours.

CONCLUSIONS

We therefore suggest that routine germline MEN1 mutation testing of all cases of "classical" MEN1, familial hyperparathyroidism, and sporadic hyperparathyroidism with one other MEN1 related condition is justified by national testing services. We do not recommend routine sequencing of the promoter region between nucleotides 1234 and 1758 (Genbank accession no. U93237) as we could not detect any sequence variations within this region in any familial or sporadic cases of MEN1 related conditions lacking a MEN1 mutation. We also suggest that testing be considered for patients <30 years old with sporadic hyperparathyroidism and multigland hyperplasia.

A test of the equal-loudness-ratio hypothesis using cross-modality matching functions

This study tests the Equal-Loudness-Ratio hypothesis [Florentine et al., J. Acoust. Soc. Am. 99, 1633-1644 (1996)], which states that the loudness ratio between equal-SPL long and short tones is independent of SPL. The amount of temporal integration (i.e., the level difference between equally loud short and long sounds) is maximal at moderate levels. Therefore, the Equal-Loudness-Ratio hypothesis predicts that the loudness function is shallower at moderate levels than at low and high levels. Equal-loudness matches and cross-modality string-length matches were used to assess the form of the loudness function for 5 and 200 ms tones at 1 kHz and the loudness ratio between them. Results from nine normal listeners show that (1) the amount of temporal integration is largest at moderate levels, in agreement with previous studies, and (2) the loudness functions are shallowest at moderate levels. For eight of the nine listeners, the loudness ratio between the 200 and 5 ms tones is approximately constant, except at low levels where it tends to increase. The average data show good agreement between the two methods, but discrepancies are apparent for some individuals. These findings support the Equal-Loudness-Ratio hypothesis, except at low levels.

A framework for structured modeling of skeletal muscle

The aim of this study is to present a detailed continuum mechanics formulation, and the corresponding algorithms, to predict the deformation of skeletal muscle at different structural levels, starting from the muscle fiber level. The model is used to investigate force production and structural changes during isometric and dynamic contractions of the cat medial gastrocnemius. From a comparison with experimental data obtained in our own laboratories, we conclude that the model faithfully predicts all of the observations pertaining to force production, fascicle length and angle of pennation under various test conditions.

Inferring basilar-membrane motion from tone-burst otoacoustic emissions and psychoacoustic measurements

The amplitude of otoacoustic emissions, which arise on the basilar membrane, is assumed to be proportional to basilar-membrane motion. It should then be possible to assess basilar-membrane motion on the basis of otoacoustic emissions. The present study provides support for this possibility by comparing basilar-membrane motion inferred from emissions to that inferred from psychoacoustic measures. Three psychoacoustic measurements believed to be associated with basilar-membrane motion were investigated: (1) pulsation threshold; (2) loudness functions derived from temporal integration; and (3) loudness functions derived from loudness matches between pure tones and multitone complexes. Results of the psychoacoustic measurements and of the tone-burst otoacoustic emissions led to very similar estimations of basilar-membrane motion. Accordingly, emissions could serve as an excellent tool--one that is objective, noninvasive, and rapid--for estimating relative basilar-membrane motion.

The effects of window delay, delinearization, and frequency on tone-burst otoacoustic emission input/output measurements

Tone-burst otoacoustic emissions (TBOAEs) are a potential tool for objectively examining cochlear activity in humans. However, their use requires knowledge of how the TBOAE input/output depends on measurement and analysis paradigms. The present experiment examined the effect of variations in response-window timing, response delinearization, and local changes in stimulus frequency on TBOAE input/output measurement. None of these experimental manipulations had a profound effect on TBOAE measurements as long as reasonable parameter choices were made. Nonetheless, judicial choice of the experimental parameters can optimize the assessment of BM I/O functions. It is concluded that the consistency of TBOAE I/O across the parameters tested makes it a viable tool to consider for examining human cochlear activity.

Genetic testing in familial isolated hyperparathyroidism: unexpected results and their implications

Familial hyperparathyroidism is not uncommon in clinical endocrine practice. It encompasses a spectrum of disorders including multiple endocrine neoplasia types 1 (MEN1) and 2A, hyperparathyroidism-jaw tumour syndrome (HPT-JT), familial hypocalciuric hypercalcaemia (FHH), and familial isolated hyperparathyroidism (FIHP). Distinguishing among the five syndromes is often difficult but has profound implications for the management of patient and family. The availability of specific genetic testing for four of the syndromes has improved diagnostic accuracy and simplified family monitoring in many cases but its current cost and limited accessibility require rationalisation of its use. No gene has yet been associated exclusively with FIHP. FIHP phenotypes have been associated with mutant MEN1 and calcium-sensing receptor (CASR) genotypes and, very recently, with mutation in the newly identified HRPT2 gene. The relative proportions of these are not yet clear. We report results of MEN1, CASR, and HRPT2 genotyping of 22 unrelated subjects with FIHP phenotypes. We found 5 (23%) with MEN1 mutations, four (18%) with CASR mutations, and none with an HRPT2 mutation. All those with mutations had multiglandular hyperparathyroidism. Of the subjects with CASR mutations, none were of the typical FHH phenotype. These findings strongly favour a recommendation for MEN1 and CASR genotyping of patients with multiglandular FIHP, irrespective of urinary calcium excretion. However, it appears that HRPT2 genotyping should be reserved for cases in which other features of the HPT-JT phenotype have occurred in the kindred. Also apparent is the need for further investigation to identify additional genes associated with FIHP.

Visible-spectroscopy study of the adsorption of alizarinate by Al-montmorillonite in aqueous suspensions and in solid state

The adsorption of the monovalent anionic dye alizarinate onto Na- and Al-montmorillonite was carried out by adding the dye into aqueous clay suspensions. Electronic spectra of aqueous suspensions and of air-dried dye-clay complexes were studied. Na-montmorillonite adsorbed only part of the added dye. With total amount of alizarinate up to 5 mmol dye per 100 g clay the adsorption of the dye takes place on the broken bonds, leading to peptization of the clay. Al-montmorillonite adsorbed alizarinate completely up to 10 mmol per 100 g clay. Above this loading there was a partition of the dye between the clay and the supernatant. The maximum adsorption for Na- and Al-clay was 4 and 25 mmol dye per 100 g clay, respectively. Absorption bands in the spectrum of Al-montmorillonite suspensions (488-504 nm) appear at longer wavelengths than in the spectrum of air-dried Al-montmorillonite (415-455 nm). Thermo-X-ray study of these clay-alizarinate complexes suggests that the organic compound was located in the interlayer space in Al-montmorillonite but was not located there in Na-montmorillonite. In Al-montmorillonite alizarinate formed a coordination complex with exchangeable Al(3+). In Na-montmorillonite it formed bonds with Al exposed on the broken-bonds sites.

Evolving therapeutic strategies for retarding progression of diabetic nephropathy--an update for 2002

During the past few years, several major intervention trials have been conducted in an attempt to determine the efficacy of specific antihypertensive agents in retarding progression of diabetic nephropathy. These studies have clearly demonstrated the importance of renin-angiotensin system blockade in attenuating progressive renal disease. The preferred initial therapy is an angiotensin-converting enzyme (ACE) inhibitor, or an angiotensin type I (AT1) receptor antagonist based on the recent 'landmark' proof-of-concept trials--the Irbesartan Type 2 Diabetic Nephropathy Trial (IDNT) and the Reduction of Endpoints in NIDDM with Angiotensin II Antagonist Losartan (RENAAL). However, these clinical trials also demonstrate that aggressive blood pressure targets are needed in patients with diabetes and hypertension. This frequently requires multiple-drug therapy with several different classes of antihypertensive agents. Data from several clinical trials, including RENAAL, suggest that calcium antagonists may be added to ACE inhibitor or AT1 receptor antagonist therapy as needed to achieve target blood pressure. Calcium antagonists could, therefore, constitute an important component of the antihypertensive regimen in the management of patients with diabetic nephropathy.

Importance of potassium in cardiovascular disease

The pivotal role of potassium (K+) in cardiovascular disease and the importance of preserving potassium balance have become clinical hot points, particularly as relates to new and emerging cardioprotective and renoprotective therapies that promote potassium retention. Although clinicians may be aware of the critical nature of this relationship, quite frequently there is some uncertainty as to the best way to monitor potassium levels in the face of a host of pathologic states and/or accompanying drug therapies that affect serum levels and/or total body potassium balance. Moreover, guidelines for monitoring of serum potassium levels are at best tentative and oftentimes are translated according to the level of concern of the respective physician. To address these uncertainties, an expert group was convened that included representatives from multiple disciplines. They attempted to reach consensus on the importance of K+ in hypertension, stroke, and arrhythmias as well as practical issues on maintaining K+ balance and avoiding K+ depletion. Because of the complexity of this topic, issues of hyperkalemia will be addressed in a forthcoming manuscript.