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PubMed1987

Event-related brain potentials and the perception of a phonetic continuum.

Competing predictions concerning phoneme discrimination were tested by means of event-related potentials. In research on speech perception, one tradition stems from the physiology of the auditory system whereas another emphasizes categorical perception which involves a marked psychological component. The stimuli were the end points of the Finnish (i)-(y) continuum together with the intermediate boundary sound. Two of these stimuli were presented in each block of trials. One (the 'standard') had a high probability while the other (the 'deviant') was rare. The so-called mismatch negativity (MMN) component of the ERP in response to deviant stimuli showed a large amplitude and short latency when these two stimuli were pure vowels (i) and (y). When the boundary stimulus and one of the pure vowels comprised the stimulus pair, a smaller and more delayed MMN occurred. This result may be taken as support that the discrimination occurs at a basic physiological level. On the other hand, cognitive perception was reflected in the different latencies of the P3 component to (i) and (y). In sum, the results lend support to multilevel hybrid models in the explanation of vowel perception.

Adult↗
PubMed1996

Perception of detail and greyscale range in X-ray fluoroscopy images captured with a personal computer and frame-grabber.

OBJECTIVE: To assess the dynamic range of radiological images captured with a personal computer frame-grabbing system coupled to an X-ray fluoroscopy machine. METHODS: A 386DX-40 MHz, IBM compatible, computer with an SVGA monochrome graphics subsystem and a 387 co-processor, installed with a Screen Machine frame-grabber and controlled by a program specially written was used. Various systems were examined and the observer's perceptions of the results assessed. RESULTS: The dynamic range available to an ordinary X-ray fluoroscopy system was found to be restricted to about 750 mV. Similar measurements showed that the dynamic range was always restricted to 3/4-1/2 of the full available signal because of a high value of the dark voltage of the TV camera's target on all seven systems measured. The dynamic range of the computer-frame grabber system was found to be significantly wider than the Image Intensifier-TV camera chain but, surprisingly, it was affected by the type of file format used for image storing on disk. Clinical images from a barium meal examination as well as CT images captured after optimisation of the frame-grabber were found to contain large quantities of noise in the first two least significant bit planes making them redundant and limiting the grey levels needed for image display to less than 64. This number was also less than the 80 grey levels that could be discriminated by the human eye on the computer monitor. CONCLUSIONS: It was concluded that 6 bit digitisation would have been sufficient for image capture. The advantages of the wider dynamic range of the frame-grabber and the processing capabilities of the computer were tested for the possibility of improving the perception of detail. However, the results were negative. The limiting spatial resolution measured with a variable density bar pattern at all magnifications was about 0.4 lp/mm lower from that measured directly on the fluoroscopic screen. A detail perception test had the same result. The perception success was significantly lower with the digital images at all but the highest of the exposure rates and despite the use of image processing filters.

Artifacts↗
PubMed1996

Longitudinal stability and predictability of sexual perceptions, intentions, and behaviors among early adolescent African-Americans.

PURPOSE: To assess the stability and predictability of perceptions, intentions, and behaviors regarding intended sexual intercourse and condom use. METHODS: One hundred and nineteen African-American youth aged 9-15 years living in urban public housing provided information at baseline and 6 months later using a theory-based and culturally- and developmentally-tailored instrument assessing perceptions, intentions, and sexual behaviors. RESULTS: Over the 6-month study interval, individual behaviors, intentions, and perceptions demonstrated considerable stability. Intentions regarding sexual intercourse in the next half-year were predictive of subsequent coitus among the entire cohort and among the subset who were virgins at baseline. Youth who thought it likely that they would be sexually-active in the next 6 months were at significantly elevated risk of doing so, compared to youth who were uncertain or thought coitus unlikely. However, intentions regarding future coitus among the subset of youth who were sexually-experienced at baseline were not predictive of future coital behavior. CONCLUSIONS: These data suggest that social cognitive behavioral models that incorporate intentions and perceptions are appropriate as the theoretical basis for interventions targeting these young adolescents.

Adolescent↗
PubMed2006

Paramedics' perceptions of their role in providing pre-hospital thrombolytic treatment: qualitative study.

BACKGROUND: The majority of ambulance services in England provide pre-hospital thrombolysis, following publication of the National Service Framework for Coronary Heart Disease. A meta-analysis has confirmed the effectiveness of pre-hospital administration in terms of all-cause mortality reduction and time saved. Little is known however, about how paramedics perceive their role in thrombolytic administration. AIMS: To describe ambulance paramedics' perceptions of their role in delivering thrombolytic treatment in the pre-hospital setting. METHODS: Twenty paramedics, based in one rural ambulance service in the South West of England participated in focus group interviews. RESULTS: Five key themes emerged: Perceptions of drivers for change; duty of care; perceptions of professional image; role expansion; and preparedness for practice. CONCLUSION: Paramedics' perceptions of their role in pre-hospital thrombolysis were mixed, encompassing professional and political issues including lack of ownership of the emerging national strategy, desire for national certification and financial reward. For successful development and implementation of new strategies within the ambulance service early engagement of paramedics and other staff is essential.

Attitude of Health Personnel↗
PubMed2006

Food risk perceptions, gender, and individual differences in avoidance and approach motivation, intuitive and analytic thinking styles, and anxiety.

Risks appear to be perceived in two different ways, affectively and rationally. Finnish adult internet users were contacted via e-mail and asked to fill an internet questionnaire consisting of questions of food risks and measures of avoidance and approach motivation, analytic and intuitive information processing style, trait anxiety, and gender in order to find out (1) whether food risks are perceived two-dimensionally, (2) how individual differences in motivation, information processing, and anxiety are associated with the different dimensions of food risk perceptions, and (3) whether gender moderates these associations. The data were analyzed by factor, correlation and regression analyses. Three factors emerged: risk scariness, risk likelihood, and risks of cardiovascular disease. Personality and gender x personality interactions predicted food risk perceptions. Results showed that food risk perceptions generally form two dimensions; scariness and likelihood, but that this may depend on the nature of the risk. In addition, results imply that individuals with high avoidance motivation perceive food risks as scarier and more likely than others, and that individuals with an analytic information processing style perceive food risks as less likely than others. Trait anxiety seems to be associated with higher food risk perceptions only among men.

Adolescent↗
PubMed2004

Brain areas underlying visual mental imagery and visual perception: an fMRI study.

We used functional magnetic resonance imaging (fMRI) to assess the maximal degree of shared neural processing in visual mental imagery and visual perception. Participants either visualized or saw faint drawings of simple objects, and then judged specific aspects of the drawings (which could only be evaluated properly if they used the correct stimulus). The results document that visual imagery and visual perception draw on most of the same neural machinery. However, although the vast majority of activated voxels were activated during both conditions, the spatial overlap was neither complete nor uniform; the overlap was much more pronounced in frontal and parietal regions than in temporal and occipital regions. This finding may indicate that cognitive control processes function comparably in both imagery and perception, whereas at least some sensory processes may be engaged differently by visual imagery and perception.

Adult↗
PubMedDate not supplied

Cortical bases of speech perception: evidence from functional lesion studies.

Functional lesion studies have yielded new information about the cortical organization of speech perception in the human brain. We will review a number of recent findings, focusing on studies of speech perception that use the techniques of electrocortical mapping by cortical stimulation and hemispheric anesthetization by intracarotid amobarbital. Implications for recent developments in neuroimaging studies of speech perception will be discussed. This discussion will provide the framework for a developing model of the cortical circuitry critical for speech perception.

Amobarbital↗
PubMed2026

Molecular mechanisms underlying umami taste perception: A DIA-based proteomic analysis of Agrocybe aegerita peptides.

The mechanisms underlying the modulation of the salivary perception of umami peptides remain poorly understood. Herein, three umami peptides (DDL, DEL, and ENG) obtained from Agrocybe aegerita were used to investigate the regulatory role of saliva in umami taste perception via a combined approach involving sensory evaluation and proteomics analysis based on 4D-DIA technology. The results revealed that umami intensity peaked at 10&#xa0;s after ingestion and was accompanied by a significant increase in saliva secretion (p&#xa0;<&#xa0;0.05). Further proteomics analysis revealed that lactotransferrin and proline-rich proteins are closely associated with the sensory perception of umami peptides. Differentially expressed proteins were mainly enriched in pathways related to saliva secretion and proteasome function. This study provides new insights from the perspectives of salivary proteomics and dynamic salivary secretion, contributing to a deeper understanding of the mechanisms by which saliva regulates umami perception.

Humans↗
PubMed2004

Perceptions of nursing: confirmation, change and the student experience.

Research has identified a number of negative societal perceptions of nursing related to gendered stereotyping, subordination to doctors, low academic standards, limited career opportunities and poor pay and conditions, and importantly how these perceptions may affect levels of recruitment into nursing. Focusing specifically on nurses, research has also considered the extent to which these societal perceptions are realities in their workplaces, and the direct experiences that contribute to attrition from both nursing courses and jobs. However, to date, few research has actually bridged the above approaches and considered the perceptions that nursing students hold as they first enter their education and how these change, or are confirmed, as a result of their experiences. In this context, the current study uses a combined questionnaire (n = 650), interview (n = 30) and focus group (n = 7) methodology to investigate the experiences of students based at two British Universities. The findings suggest that many students were surprised, yet not overwhelmed, by the high academic standards required of them and came to recognize and value the tremendous knowledge, skills set and responsibilities of nurses as they acquired them. However, their experiences reinforced both society's and their own image of an underpaid, overworked profession that lacks respect and has low morale. The findings support media initiatives that emphasize nurses' skills in order to influence public opinion. They also support a range of subtle changes in nurse education at the institutional level to make student life easier. Nevertheless, it is acknowledged that these may have a limited impact unless pay and conditions are adequately addressed at the national level.

Attitude of Health Personnel↗
PubMed2005

Speech perception with the ACE and the SPEAK speech coding strategies for children implanted with the Nucleus cochlear implant.

OBJECTIVE: The aim of this study is to determine whether implanted children using the ACE speech coding strategy demonstrate superior performances compared to implanted children using the SPEAK speech coding strategy over time. METHODS: Cochlear implanted children with prelinguistic sensorineural bilateral deafness of profound degree, using either the ACE or SPEAK coding strategy, were evaluated and compared. Both groups of children used one of the speech coding strategies continuously from the initial programming session and for a period of 2 years post-switch-on. One group comprised children who were retrospectively implanted and had received the SPEAK speech coding strategy (n=32) and the second group consisted of prospectively implanted children who received the ACE speech coding strategy (n=26). Both populations were homogenous as far as age of implantation, degree of hearing loss, anatomy of the cochlea, depth of electrode insertion, and educational and rehabilitative support provided. Children were assessed at 6, 12 and 24 months post switch-on via pure-tone audiometry and for speech perception tests. Children using the ACE speech coding strategy were additionally evaluated using the MAIS and MUSS language scales. RESULTS: Satisfactory benefits in speech perception were demonstrated by both groups of implanted children. No significant difference between the mean pure tone thresholds was observed postoperatively between the groups. Two years post switch-on the group using the ACE speech coding strategy demonstrated superior results for vowel discrimination in comparison to children using the SPEAK coding strategy. No significant difference was observed between the groups for performance on discrimination of syllable patterns (ESP) or for disyllablic word recognition tests. Additionally, the group of ACE users demonstrated maximum performance on MAIS and MUSS scales, 2 years post switch-on. CONCLUSIONS: The results clearly demonstrate significant benefit of cochlear implantation in prelinguistically deafened children for speech perception ability when using either the SPEAK or ACE speech coding strategies. Children using the ACE speech coding strategy demonstrate more rapid progress in improved speech perception ability initially, however 2 years post switch-on, no significant difference in performance on open-set speech recognition tests can be noted irrespective of the strategy in use.

Audiometry, Pure-Tone↗
PubMed2005

Speech perception of children using Nucleus, Clarion or Med-El cochlear implants.

OBJECTIVE: The purpose of this study was to present speech perception achievements of implanted children using commercially available cochlear implant devices: Nucleus, Clarion or Med-El. STUDY DESIGN: A retrospective analysis. METHODS: Speech perception data of 96 hearing-impaired children: 27 with Clarion, 49 with Nucleus and 20 with Med-El were collected. Speech tests included the Hebrew Infant Toddlers Meaningful Auditory Integration Scale (HIT-MAIS) for the infants, the Hebrew Early Speech Perception (HESP) closed-set word-identification test and Hebrew Arthur Boothroyd (HAB) open-set one-syllable word recognition test were used for the older children. RESULTS: I HIT-MAIS: (1) Infants showed similar rate of progress, regardless of device. (2) Children implanted under two years of age reached performance within normal development on this test. II HAB: (1) Most children achieved open set results with mean HAB between 40 and 50%, within 1-1.5 years post implantation. (2) Linear regression analyses revealed no statistical differences between the Clarion the Nucleus and the Med-El devices on the mean final measurement of this test. (3) Age of implantation and mode of communication were significant covariate variables: (a) the younger the child is implanted the better the results and (b) oral communication prior to implantation results in better performance than sign language. CONCLUSIONS: There are no apparent differences in speech perception performance between implant devices when considering background variables. The data have important implications on the rehabilitation process of hearing impaired children with cochlear implants in relation to device selection, age at implantation and mode of communication prior to implantation.

Adolescent↗
PubMed2005

Pain perception, obstructive imagery and phase-ordered gamma oscillations.

The neural mechanisms underlying pain perception and anti-nociceptive effects of mental imagery are not well understood. Using a measure of phase-ordered beta and gamma EEG oscillations in response to painful electric stimulation, we recently found that somatosensory event-related phase-ordered gamma oscillations (38-42 Hz), elicited by the onset of painful stimuli over Cz scalp site, were linearly related to pain perception. In the present study, 38 subjects were engaged in a painful stimulus detection task using an oddball paradigm. This task was performed under a condition in which subjects were required simply to count the number of target stimuli (pain condition) and under another condition in which subjects were required to produce an obstructive mental imagery of painful stimulus perception (obstructive imagery). Only EEG responses to standard stimuli were analyzed in this study. Correlation analysis of sweeps for each individual revealed brief intervals of phase ordering of EEG patterns in the beta and gamma bands. The frequencies of interest were the beta1 (26-30 Hz), beta2 (30-34 Hz), gamma1 (34-38 Hz), gamma2 (38-42 Hz) and gamma3 (42-46 Hz) bands. Obstructive imagery treatment, compared to pain condition, significantly reduced pain perception. This reduction was paralleled by significant decreases of evoked phase-ordered gamma2 and gamma3 patterns over Cz scalp site. Phase-ordered oscillations at Cz scalp site, for both gamma2 and gamma3 bands, significantly predicted pain ratings during pain condition. Phase-ordered oscillation scores, obtained for these gamma bands over parietal and frontal scalp sites, resulted the best predictor of pain ratings during obstructive imagery. This study provides evidence for the role of gamma oscillations in the subjective experience of pain. Further, it has provided support for the view that pain reduction during obstructive mental imagery is the product of an inhibitory process involving frontal and parietal cortical regions.

Adult↗
PubMed2006

Perception and education of unilateral weightbearing amongst health care professionals.

Studies have shown that healthy individuals cannot accurately judge the degree of weightbearing through one lower extremity [Bohannon R, Waters G, Cooper J. Perception of unilateral lower extremity weightbearing during bilateral upright stance. Percept Mot Skills 69;1989:875-80]. This study of 40 healthcare professionals assessed a simple education process to see if this perception could be improved. Weightbearing was assessed before and after the education process, a familiarisation exercise with a set of bathroom scales. The education process had no significant effect on individual's perception of weightbearing, nor was there any difference between members of the multi-disciplinary team. As an important aspect of patient care, further work is necessary to identify an accurate and reproducible method of quantifying weightbearing.

Education, Continuing↗
PubMed2006

What you don't know can hurt you: perceptions of sex-partner concurrency and partner-reported behavior.

BACKGROUND: The objectives of this study were as follows: (1) to determine the extent of agreement between adolescents' perceptions of sex-partner concurrency (having a partner who has other overlapping sexual partnerships) and their partners' self-reported concurrency, and (2) to identify the relationship-level factors associated with agreement. METHODS: Adolescents ages 14 to 19 years, along with their main sex partners, were recruited from a primary care clinic and a public sexually transmitted disease clinic and interviewed separately about their own concurrency status and their perception of their partner's concurrency status. Information from both participants and their partners were included in this analysis (N = 90 couples). RESULTS: This sample consisted of African-American, sexually experienced heterosexual couples. For males and females who perceived their partner not to have other partners, 16% and 37% of their sex partners reported having other partners, respectively. Of males and females who perceived their partner to have other partners, 80% and 39% of their sex partners reported not having other partners, respectively. Multivariate logistic regression revealed that adolescents who had been with their partners for more than 6 months and considered themselves more emotionally close were nearly twice as likely to agree on concurrency. CONCLUSIONS: Among adolescent couples, agreement between perceptions of sex-partner concurrency and partner-reported behavior was low. To the extent that partner self-reports are accurate, individuals who presume that they are in a mutually monogamous relationship often underestimate their own sexually transmitted disease risk. To appropriately tailor risk reduction messages, prevention efforts need to consider adolescents' perceptions of concurrent sex partners.

Adolescent↗
PubMed2005

A difference in perception of quality of life in chronically ill children was found between parents and pediatricians.

BACKGROUND AND OBJECTIVES: Quality of life measurements can help to estimate the well-being of chronically ill patients, and disclose discrepancies in perception between physicians and patients that might otherwise interfere with the effectiveness of treatment. The objective was to investigate the differences in perception of quality of life between parents of chronically ill children and pediatricians. METHODS: A cross-sectional study was conducted in four tertiary pediatric care centers in The Netherlands. The Health Utilities Index mark 3 (HUI3) was used by 37 pediatricians and 279 parents of patients (children aged 1 to 17 years) with cystic fibrosis admitted either in daycare or for a pneumonia, or patients with newly diagnosed acute lymphoblastic leukemia, juvenile idiopathic arthritis, or asthma. RESULTS: Differences in perception of quality of life between parents and pediatricians appeared to be dependent of the disease. In patients with acute lymphoblastic leukemia (OR 7.4; [95% CI 2.88-18.97], juvenile idiopathic arthritis (4.7; [95% CI 2.00-11.22]), and asthma (2.3; [95% CI 1.13-4.69]) a difference in perception was more likely to occur than in patients with cystic fibrosis admitted in daycare. CONCLUSION: At the onset of a chronic disease, the parents of pediatric patients may be misunderstood by health care professionals, especially in subjective attributes. Assessment of quality of life may contribute to better understanding between pediatricians and parents, and thus may even enhance compliance and treatment effects.

Adolescent↗
PubMedDate not supplied

The role of early language experience in the development of speech perception and phonological processing abilities: evidence from 5-year-olds with histories of otitis media with effusion and low socioeconomic status.

UNLABELLED: This study tested the hypothesis that early language experience facilitates the development of language-specific perceptual weighting strategies believed to be critical for accessing phonetic structure. In turn, that structure allows for efficient storage and retrieval of words in verbal working memory, which is necessary for sentence comprehension. Participants were forty-nine 5-year-olds, evenly distributed among four groups: those with chronic otitis media with effusion (OME), low socio-economic status (low-SES), both conditions (both), or neither condition (control). All children participated in tasks of speech perception and phonological awareness. Children in the control and OME groups participated in additional tasks examining verbal working memory, sentence comprehension, and temporal processing. The temporal-processing task tested the hypothesis that any deficits observed on the language-related tasks could be explained by temporal-processing deficits. Children in the three experimental groups demonstrated similar results to each other, but different from the control group for speech perception and phonological awareness. Children in the OME group differed from those in the control group on tasks involving verbal working memory and sentence comprehension, but not temporal processing. Overall these results supported the major hypothesis explored, but failed to support the hypothesis that language problems are explained to any extent by temporal-processing problems. LEARNING OUTCOMES: As a result of this activity, the participant will be able to (1) Explain the relation between language experience and the development of mature speech perception strategies, phonological awareness, verbal working memory, and syntactic comprehension. (2) Name at least three populations of individuals who exhibit delays in the development of mature speech perception strategies, phonological awareness, verbal working memory, and syntactic comprehension, and explain why these delays exist for each group. (3) Point out why perceptual strategies for speech are different for different languages. (4) Describe Baddeley's model [A.D. Baddeley, The development of the concept of working memory: implications and contributions of neuropsychology, in: G. Vallar, T. Shallice (Eds.), Neuropsychological Impairments of Short-term Memory, Cambridge University Press, New York, 1990, p. 54] of verbal working memory.

Acoustic Impedance Tests↗
PubMed2004

Testing the concurrent and predictive relations among articulation accuracy, speech perception, and phoneme awareness.

The relations among articulation accuracy, speech perception, and phoneme awareness were examined in a sample of 97 typically developing children ages 48 to 66 months. Of these 97 children, 46 were assessed twice at ages 4 and 5 years. Children completed two tasks for each of the three skills, assessing these abilities for the target phoneme /r/ and the control phoneme /m/ in the word-initial position. Concurrent analyses revealed that phoneme-specific relations existed among articulation, awareness, and perception. Articulation accuracy of /r/ predicted speech perception and phoneme awareness for /r/ after controlling for age, vocabulary, letter-word knowledge, and speech perception or phoneme awareness for the control phoneme /m/. The longitudinal analyses confirmed the pattern of relations. The findings are consistent with a model whereby children's articulation accuracy affects preexisting differences in phonological representations and, consequently, affects how children perceive, discriminate, and manipulate speech sounds.

Child↗
PubMed2006

Phoneme monitoring in silent naming and perception in adults who stutter.

UNLABELLED: The present study investigated phonological encoding skills in persons who stutter (PWS). Participants were 10 PWS (M=31.8 years, S.D.=5.9) matched for age, gender, and handedness with 12 persons who do not stutter (PNS) (M=24.3 years, S.D.=4.3). The groups were compared in a phoneme monitoring task performed during silent picture naming. The phonological complexity of the target items in the task was varied such that participants monitored either compound words or noun phrases. Performance in this task was compared to phoneme monitoring performed on aurally presented target words to investigate whether any differences observed in silent naming were also evident in perception. Analysis of the response time data, in milliseconds, indicated that PWS were significantly slower as compared to PNS in phoneme monitoring during silent naming; group differences were not obtained in the perception task. The groups were also comparable in the response time to phoneme monitoring within compound words and noun phrases in both silent naming and perception. The findings suggested that PWS were slower in the encoding of segmental, phonological units during silent naming. Furthermore, absence of such differences in perception ruled out a general monitoring deficit in PWS. Findings are interpreted within the context of the psycholinguistic theories of stuttering that postulate phonological encoding and/or monitoring as a causal variable in stuttering. EDUCATIONAL OBJECTIVES: As a result of this activity, the participant should: (1) describe relevant literature on phonological encoding skills in children and adults who stutter, (2) identify paradigms that can be used to investigate phonological processing in PWS, and (3) discuss the role of phonological encoding in speech production.

Adolescent↗