Speech perception benefits of internet versus conventional telephony for hearing-impaired individuals

Telephone communication is a challenge for many hearing-impaired individuals. One important technical reason for this difficulty is the restricted frequency range (0.3-3.4 kHz) of conventional landline telephones. Internet telephony (voice over Internet protocol [VoIP]) is transmitted with a larger frequency range (0.1-8 kHz) and therefore includes more frequencies relevant to speech perception. According to a recently published, laboratory-based study, the theoretical advantage of ideal VoIP conditions over conventional telephone quality has translated into improved speech perception by hearing-impaired individuals. However, the speech perception benefits of nonideal VoIP network conditions, which may occur in daily life, have not been explored. VoIP use cannot be recommended to hearing-impaired individuals before its potential under more realistic conditions has been examined.

Medication errors in a swiss cardiovascular surgery department: a cross-sectional study based on a novel medication error report method

The purpose of this study was (1) to determine frequency and type of medication errors (MEs), (2) to assess the number of MEs prevented by registered nurses, (3) to assess the consequences of ME for patients, and (4) to compare the number of MEs reported by a newly developed medication error self-reporting tool to the number reported by the traditional incident reporting system. We conducted a cross-sectional study on ME in the Cardiovascular Surgery Department of Bern University Hospital in Switzerland. Eligible registered nurses (n = 119) involving in the medication process were included. Data on ME were collected using an investigator-developed medication error self reporting tool (MESRT) that asked about the occurrence and characteristics of ME. Registered nurses were instructed to complete a MESRT at the end of each shift even if there was no ME. All MESRTs were completed anonymously. During the one-month study period, a total of 987 MESRTs were returned. Of the 987 completed MESRTs, 288 (29%) indicated that there had been an ME. Registered nurses reported preventing 49 (5%) MEs. Overall, eight (2.8%) MEs had patient consequences. The high response rate suggests that this new method may be a very effective approach to detect, report, and describe ME in hospitals.

Visual Speech Segmentation: Using Facial Cues to Locate Word Boundaries in Continuous Speech

Speech is typically a multimodal phenomenon, yet few studies have focused on the exclusive contributions of visual cues to language acquisition. To address this gap, we investigated whether visual prosodic information can facilitate speech segmentation. Previous research has demonstrated that language learners can use lexical stress and pitch cues to segment speech and that learners can extract this information from talking faces. Thus, we created an artificial speech stream that contained minimal segmentation cues and paired it with two synchronous facial displays in which visual prosody was either informative or uninformative for identifying word boundaries. Across three familiarisation conditions (audio stream alone, facial streams alone, and paired audiovisual), learning occurred only when the facial displays were informative to word boundaries, suggesting that facial cues can help learners solve the early challenges of language acquisition.

End-tidal CO(2). An important parameter for a correct interpretation in functional brain studies using speech tasks

The aim was to investigate the effect of different speech tasks, i.e. recitation of prose (PR), alliteration (AR) and hexameter (HR) verses and a control task (mental arithmetic (MA) with voicing of the result on end-tidal CO2 (PETCO2), cerebral hemodynamics and oxygenation. CO2 levels in the blood are known to strongly affect cerebral blood flow. Speech changes breathing pattern and may affect CO2 levels. Measurements were performed on 24 healthy adult volunteers during the performance of the 4 tasks. Tissue oxygen saturation (StO2) and absolute concentrations of oxyhemoglobin ([O2Hb]), deoxyhemoglobin ([HHb]) and total hemoglobin ([tHb]) were measured by functional near-infrared spectroscopy (fNIRS) and PETCO2 by a gas analyzer. Statistical analysis was applied to the difference between baseline before the task, 2 recitation and 5 baseline periods after the task. The 2 brain hemispheres and 4 tasks were tested separately. A significant decrease in PETCO2 was found during all 4 tasks with the smallest decrease during the MA task. During the recitation tasks (PR, AR and HR) a statistically significant (p < 0.05) decrease occurred for StO2 during PR and AR in the right prefrontal cortex (PFC) and during AR and HR in the left PFC. [O2Hb] decreased significantly during PR, AR and HR in both hemispheres. [HHb] increased significantly during the AR task in the right PFC. [tHb] decreased significantly during HR in the right PFC and during PR, AR and HR in the left PFC. During the MA task, StO2 increased and [HHb] decreased significantly during the MA task. We conclude that changes in breathing (hyperventilation) during the tasks led to lower CO2 pressure in the blood (hypocapnia), predominantly responsible for the measured changes in cerebral hemodynamics and oxygenation. In conclusion, our findings demonstrate that PETCO2 should be monitored during functional brain studies investigating speech using neuroimaging modalities, such as fNIRS, fMRI to ensure a correct interpretation of changes in hemodynamics and oxygenation.

Differentiation in Male and Female Speech Styles

From the moment of their birth, a person's life is determined by their sex. Ms. Goroshko wants to know why this difference is so striking, why society is so concerned to sustain it, and how it is able to persist even when certain national or behavioural stereotypes are erased between people. She is convinced of the existence of not only social, but biological differences between men and women, and set herself the task, in a manuscript totalling 126 pages, written in Ukrainian and including extensive illustrations, of analysing these distinctions as they are manifested in language. She points out that, even before 1900, certain stylistic differences between the ways that men and women speak had been noted. Since then it has become possible, for instance in the case of Japanese, to point to examples of male and female sub-languages. In general, one can single out the following characteristics. Males tend to write with less fluency, to refer to events in a verb-phrase, to be time-oriented, to involve themselves more in their references to events, to locate events in their personal sphere of activity, and to refer less to others. Therefore, concludes Ms Goroshko, the male is shown to be more active, more ego-involved in what he does, and less concerned about others. Women, in contrast, were more fluent, referred to events in a noun-phrase, were less time-oriented, tended to be less involved in their event-references, locate events within their interactive community and refer more to others. They spent much more time discussing personal and domestic subjects, relationship problems, family, health and reproductive matters, weight, food and clothing, men, and other women. As regards discourse strategies, Ms Goroshko notes the following. Men more often begin a conversation, they make more utterances, these utterances are longer, they make more assertions, speak less carefully, generally determine the topic of conversation, speak more impersonally, use more vulgar expressions, and use fewer diminutives and more imperatives. Women's speech strategies, apart from being the opposite of those enumerated above, also contain more euphemisms, polite forms, apologies, laughter and crying. All of the above leads Ms. Goroshko to conclude that the differences between male and female speech forms are more striking than the similarities. Furthermore she is convinced that the biological divergence between the sexes is what generates the verbal divergence, and that social factors can only intensify or diminish the differentiation in verbal behaviour established by the sex of a person. Bearing all this in mind, Ms Goroshko set out to construct a grammar of male and female styles of speaking within Russian. One of her most important research tools was a certain type of free association test. She took a list comprising twelve stimuli (to love, to have, to speak, to fuck, a man, a woman, a child, the sky, a prayer, green, beautiful) and gave it to a group of participants specially selected, according to a preliminary psychological testing, for the high levels of masculinity or femininity they displayed. Preliminary responses revealed that the female reactions were more diverse than the male ones, there were more sentences and word combinations in the female reactions, men gave more negative responses to the stimulus and sometimes didn't want to react at all, women reacted more to adjectives and men to nouns, and that, surprisingly, women coloured more negatively their reactions to the words man, to love and a child (Ms. Goroshko is inclined to attribute this to the present economic situation in Russia). Another test performed by Ms. Goroshko was the so-called "defective text" developed by A.A. Brudny. All participants were distributed with packets of complete sentences, which had been taken from a text and then mixed at random. The task was to reconstruct the original text. There were three types of test, the first descriptive, the second narrative, and the third logical. Ms. Goroshko created computer programmes to analyse the results. She found that none of the reconstructed texts was coincident with the original, differing both from the original text and amongst themselves and that there were many more disparities in the male than the female texts. In the descriptive and logical texts the differences manifested themselves more clearly in the male texts, and in the narrative texts in the female texts. The widest dispersal of values was observed at the outset, while the female text ending was practically coincident with the original (in contrast to the male ending). The greatest differences in text reconstruction for both males and females were registered in the middle of the texts. Women, Ms. Goroshko claims, were more sensitive to the semantic structure of the texts, since they assembled the narrative text much more accurately than the other two, while the men assembled more accurately the logical text. Texts written by women were assembled more accurately by women and texts by men by men. On the basis of computer analysis, Ms. Goroshko found that female speech was substantially more emotional. It was expressed by various means, hyperbole, metaphor, comparisons, epithets, ways of enumeration, and with the aid of interjections, rhetorical questions, exclamations. The level of literacy was higher for female speech, and there were fewer mistakes in grammar and spelling in female texts. The last stage of Ms Goroshko's research concerned the social stereotypes of beliefs about men and women in Russian society today. A large number of respondents were asked questions such as "What merits must a woman possess?", "What are male vices and virtues?", etc. After statistical manipulation, an image of modern man and woman, as it exists in the minds of modern Russian men and women, emerged. Ms. Goroshko believes that her findings are significant not only within the field of linguistics. She has already successfully worked on anonymous texts and been able to decide on the sex of the author and consequently believes that in the future her research may even be of benefit to forensic science.

Phonetic Aspects of Speech Communication

Nadeina set out to develop methods of speech development in Russian as a mother tongue, focusing on improving diction, training in voice quality control, intonation control, the removal of dialect, and speech etiquette. She began with training in the receptive skills of language, i.e. reading and listening, since the interpretation of someone else's language plays an important role in language production. Her studies of students' reading speed of students showed that it varies between 40 and 120 words per minute, which is normally considered very slow. She discovered a strong correlation between speed of reading and speaking skills: the slower a person reads the worse is their ability to speak and has designed exercises to improve reading skills. Nadeina also believes that listening to other people's speech is very important, both to analyse its content and in some cases as an example, so listening skills need to be developed. Many people have poor pronunciation habits acquired as children. On the basis of speech samples from young Russians (male and female, aged 17-22), Nadeina analysed the commonest speech faults - nasalisation, hesitation and hemming at the end of sense-groups, etc. Using a group of twenty listeners, she looked for a correlation between how voice quality is perceived and certain voice quality parameters, e.g. pitch range, tremulousness, fluency, whispering, harshness, sonority, tension and audible breath. She found that the less non-linguistic segment variations in speech appeared, the more attractive the speech was rated. The results are included in a textbook aimed at helping people to improve their oral skills and to communicate ideas to an audience. She believes this will assist Russian officials in their attempts to communicate their ideas to different social spheres, and also foreigners learning Russian.

[Verification of normative values for the Swiss version of the Freiburg speech intelligibility test.]

BACKGROUND AND OBJECTIVE: In the Swiss version of the Freiburg speech intelligibility test five test words from the original German recording which are rarely used in Switzerland have been exchanged. Furthermore, differences in the transfer functions between headphone and loudspeaker presentation are not taken into account during calibration. New settings for the levels of the individual test words in the recommended recording and small changes in calibration procedures led us to make a verification of the currently used normative values.PATIENTS AND METHODS: Speech intelligibility was measured in 20 subjects with normal hearing using monosyllabic words and numbers via headphones and loudspeakers.RESULTS: On average, 50% speech intelligibility was reached at levels which were 7.5 dB lower under free-field conditions than for headphone presentation. The average difference between numbers and monosyllabic words was found to be 9.6 dB, which is considerably lower than the 14 dB of the current normative curves.CONCLUSIONS: There is a good agreement between our measurements and the normative values for tests using monosyllabic words and headphones, but not for numbers or free-field measurements.

ASSOCIATON TESTS THAT ACCOMMODATE GENOTYPING ERRORS

High-throughput SNP arrays provide estimates of genotypes for up to one million loci, often used in genome-wide association studies. While these estimates are typically very accurate, genotyping errors do occur, which can influence in particular the most extreme test statistics and p-values. Estimates for the genotype uncertainties are also available, although typically ignored. In this manuscript, we develop a framework to incorporate these genotype uncertainties in case-control studies for any genetic model. We verify that using the assumption of a “local alternative” in the score test is very reasonable for effect sizes typically seen in SNP association studies, and show that the power of the score test is simply a function of the correlation of the genotype probabilities with the true genotypes. We demonstrate that the power to detect a true association can be substantially increased for difficult to call genotypes, resulting in improved inference in association studies.

Affective and linguistic processing of speech prosody: DC potential studies

Speech melody or prosody subserves linguistic, emotional, and pragmatic functions in speech communication. Prosodic perception is based on the decoding of acoustic cues with a predominant function of frequency-related information perceived as speaker's pitch. Evaluation of prosodic meaning is a cognitive function implemented in cortical and subcortical networks that generate continuously updated affective or linguistic speaker impressions. Various brain-imaging methods allow delineation of neural structures involved in prosody processing. In contrast to functional magnetic resonance imaging techniques, DC (direct current, slow) components of the EEG directly measure cortical activation without temporal delay. Activation patterns obtained with this method are highly task specific and intraindividually reproducible. Studies presented here investigated the topography of prosodic stimulus processing in dependence on acoustic stimulus structure and linguistic or affective task demands, respectively. Data obtained from measuring DC potentials demonstrated that the right hemisphere has a predominant role in processing emotions from the tone of voice, irrespective of emotional valence. However, right hemisphere involvement is modulated by diverse speech and language-related conditions that are associated with a left hemisphere participation in prosody processing. The degree of left hemisphere involvement depends on several factors such as (i) articulatory demands on the perceiver of prosody (possibly, also the poser), (ii) a relative left hemisphere specialization in processing temporal cues mediating prosodic meaning, and (iii) the propensity of prosody to act on the segment level in order to modulate word or sentence meaning. The specific role of top-down effects in terms of either linguistically or affectively oriented attention on lateralization of stimulus processing is not clear and requires further investigations.

Cholesky Residuals for Assessing Normal Errors in a Linear Model with Correlated Outcomes: Technical Report

Despite the widespread popularity of linear models for correlated outcomes (e.g. linear mixed models and time series models), distribution diagnostic methodology remains relatively underdeveloped in this context. In this paper we present an easy-to-implement approach that lends itself to graphical displays of model fit. Our approach involves multiplying the estimated margional residual vector by the Cholesky decomposition of the inverse of the estimated margional variance matrix. The resulting "rotated" residuals are used to construct an empirical cumulative distribution function and pointwise standard errors. The theoretical framework, including conditions and asymptotic properties, involves technical details that are motivated by Lange and Ryan (1989), Pierce (1982), and Randles (1982). Our method appears to work well in a variety of circumstances, including models having independent units of sampling (clustered data) and models for which all observations are correlated (e.g., a single time series). Our methods can produce satisfactory results even for models that do not satisfy all of the technical conditions stated in our theory.

Underestimation of Standard Errors in Multi-Site Time Series Studies

Multi-site time series studies of air pollution and mortality and morbidity have figured prominently in the literature as comprehensive approaches for estimating acute effects of air pollution on health. Hierarchical models are generally used to combine site-specific information and estimate pooled air pollution effects taking into account both within-site statistical uncertainty, and across-site heterogeneity. Within a site, characteristics of time series data of air pollution and health (small pollution effects, missing data, highly correlated predictors, non linear confounding etc.) make modelling all sources of uncertainty challenging. One potential consequence is underestimation of the statistical variance of the site-specific effects to be combined. In this paper we investigate the impact of variance underestimation on the pooled relative rate estimate. We focus on two-stage normal-normal hierarchical models and on under- estimation of the statistical variance at the first stage. By mathematical considerations and simulation studies, we found that variance underestimation does not affect the pooled estimate substantially. However, some sensitivity of the pooled estimate to variance underestimation is observed when the number of sites is small and underestimation is severe. These simulation results are applicable to any two-stage normal-normal hierarchical model for combining information of site-specific results, and they can be easily extended to more general hierarchical formulations. We also examined the impact of variance underestimation on the national average relative rate estimate from the National Morbidity Mortality Air Pollution Study and we found that variance underestimation as much as 40% has little effect on the national average.

LEARNING FROM NEAR MISSES IN MEDICATION ERRORS: A BAYESIAN APPROACH

Medical errors originating in health care facilities are a significant source of preventable morbidity, mortality, and healthcare costs. Voluntary error report systems that collect information on the causes and contributing factors of medi- cal errors regardless of the resulting harm may be useful for developing effective harm prevention strategies. Some patient safety experts question the utility of data from errors that did not lead to harm to the patient, also called near misses. A near miss (a.k.a. close call) is an unplanned event that did not result in injury to the patient. Only a fortunate break in the chain of events prevented injury. We use data from a large voluntary reporting system of 836,174 medication errors from 1999 to 2005 to provide evidence that the causes and contributing factors of errors that result in harm are similar to the causes and contributing factors of near misses. We develop Bayesian hierarchical models for estimating the log odds of selecting a given cause (or contributing factor) of error given harm has occurred and the log odds of selecting the same cause given that harm did not occur. The posterior distribution of the correlation between these two vectors of log-odds is used as a measure of the evidence supporting the use of data from near misses and their causes and contributing factors to prevent medical errors. In addition, we identify the causes and contributing factors that have the highest or lowest log-odds ratio of harm versus no harm. These causes and contributing factors should also be a focus in the design of prevention strategies. This paper provides important evidence on the utility of data from near misses, which constitute the vast majority of errors in our data.