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At least 541 records · Page 30Linked to original sources

PubMed1997

Visually induced motion perception and visual control of postural sway in congenital nystagmus.

In congenital nystagmus (CN) the threshold for detecting motion of visual objects is increased. To determine whether this increase is due to a deterioration of visual motion signals or whether visual-vestibular interactions (which are necessary to judge object-motion in space) are also involved we examined how CN patients use visual motion signals to evaluate self-motion in perceptual and behavioral tasks. Using an optokinetic drum we measured the minimum optokinetic acceleration necessary to induced motion perception of the visual environment in CN patients. This threshold was significantly elevated in the CN patients compared with normals (20.1 deg/s2 to 3.25 deg/s2). We further addressed the question whether the elevation of this threshold is due to a deficiency in evaluating visual motion in general or to a specific modification affecting the percept of visual object-motion with respect to the inertial reference only. We thus measured the latency of visually induced self-motion perception, which was found to be very similar or even slightly smaller (1.7 +/- 0.7 s) compared with normals (2.2 +/- 1.7 s). Moreover, subjects with CN were found to use vision quite efficiently for the visual stabilization of posture (Romberg quotient 2.0 +/- 1.16), even if they did not reach the level of normals (Romberg quotient 3.7 +/- 1.1). The results indicate that CN affects the estimate of object-motion in a specific and much more severe way than the estimate of self-motion. The minimal effect of CN on self-motion perception can be explained by the low pass characteristics of the optokinetic input to self-motion perception. The specific deficiency in detecting object-motion indicates that adaptation to CN occurs on the level of visual--vestibular interactions for the perception of visual object-motion and not on the level of visual motion signals.

Adolescent↗

PubMed2003

[Asthma patients' perception of dyspnea during acute bronchoconstriction].

The aim of this study was to analyze variations in the perception of acute bronchial obstruction among asthmatics in our practice and to try to define the variables that influence inter-individual differences. We studied 153 asthmatics in stable condition, using a Borg scale to measure dyspnea perceived during a histamine bronchial challenge test. To study individual perception we analyzed both absolute magnitude of perception of dyspnea on the Borg scale when forced expiratory volume in 1 second (FEV1) fell 20% (perception score 20-PS20) and the mathematical difference between PS20 and baseline dyspnea (change in Borg, CB). The results were as follows. 1) The factors that affected PS20 according to multiple linear regression were anxiety, baseline dyspnea and the provocative concentration required to produce a 20% fall in FEV1 (PC20). 2) Within each level of asthma severity, there were differences in dyspnea perception when FEV1 fell 20% (analysis of variance of repeated measures), such that patients with mild asthma and no bronchial obstruction perceived more change in dyspnea. 3) CB during the bronchial challenge test distinguished four ways of perceiving dyspnea: 15% were dysperceivers, 13% were hypoperceivers, 48% were normoperceivers and 24% were hyperperceivers. 4) Hypoperceivers and dysperceivers were at greater risk of severe exacerbation whereas hyperperceivers requested unnecessary medical consultations. 5) Subjects with poorer quality of life were usually dysperceivers; hyperperceivers were the second most common type among those with poorer quality of life. In conclusion, a large percentage of asthmatics do not appropriately perceive acute bronchial obstruction, and the simplest way to evaluate their perception is to calculate the change in dyspnea (on a Borg scale) during the bronchial challenge test. The manner of perceiving dyspnea can not be predicted beforehand, yet it has a significant impact on the use of medical resources and patient quality of life, among other aspects.

Acute Disease↗

PubMed1997

Perception of flight information from EFIS displays.

A pilot's perception of variables presented on the Electronic Flight Instrument System, EFIS, was investigated. A stimulus response technique was used to determine the accuracy and speed of the perception process. By varying the exposure time of the stimuli, it is shown that the perception of a variable's magnitude is faster and more accurate than the perception of the first derivative or rate of that variable. Results of experiments on roll and pitch attitude perception, the influence of scale division, and the perception of the indicated airspeed, are shown.

Aerospace Medicine↗

PubMed2000

Increased perception of dyspnea by inhalation of short acting beta2 agonist in patients with asthma of varying severity.

BACKGROUND: Poor perception of dyspnea in asthma may lead to a delay in starting appropriate treatment which is probably one of the factors contributing to death from asthma. OBJECTIVE: This study was carried out to determine whether impaired perception of dyspnea in patients with asthma of varying severity can be corrected by inhalation of short acting beta2 agonist treatment. METHODS: We enrolled 20 patients with asthma of varying severity. Forced expiratory volume in one second (FEV1) was measured before and 10 minutes after two puffs of salbutamol administered by metered dose inhaler. Perception of dyspnea was scored on the Borg scale during breathing through an inspiratory muscle trainer. RESULTS: After inhalation of short acting beta2 agonist treatment, the baseline Borg score was decreased significantly from 2.20 +/- 0.32 to 1.80 +/- 0.31 (P < .01). The Borg score during breathing with the highest resistance, on the contrary, was increased significantly from 6.25 +/- 0.35 to 6.90 +/- 0.35 after inhalation of short acting beta2 agonist treatment (P < .01). Highest resistance-induced score difference from the baseline value (highest resistance-load score) was increased significantly from 4.10 +/- 0.46 to 5.25 +/- 0.42 (P < .01). There was no relationship between the change of Borg score from baseline value at each resistive load and the % change of FEV1 after inhalation of short acting beta2 agonist treatment. CONCLUSION: These studies demonstrate that inhalation of short acting beta2 agonist treatment decrease dyspnea, but increase perception of dyspnea induced by a resistive load in patients with asthma, and the mechanism of the increased perception may not be related to the increased airflow rate. It may be due to some local or central effects of bronchodilator drug on perception of asthma.

Administration, Inhalation↗

PubMed2003

The significance of A-delta and C fibres for the perception of synthetic heat.

Synthetic heat is a perception of strong, but not painful, heat arising when skin is stimulated by an alternating pattern of adjacent cold and warmth. This study examines the contribution of different classes of nerve fibres to this perception. In 40 subjects changes in synthetic heat and thermal perceptions were studied during a 30-min ischaemic nerve block in one reaction time, and one threshold determination task. Synthetic heat stimuli were described as hot or warm, but not as painful, and were preceded by a transient cold. Reaction times for synthetic heat stimuli did not differ from those for cold stimuli. Thresholds for synthetic heat and thermal stimuli were similar. During A fibre nerve block the perception of synthetic heat lost the cold component whereas the frequency of hot and warm descriptors did not change. The perception of cold stimuli changed, such that pure cold was replaced by dysaesthetic descriptors. Reaction times and thresholds for thermal and synthetic heat stimuli increased equally during the nerve block. It is concluded that the perception of synthetic heat most likely arises from the fusion of signals dependent on unmyelinated low threshold cold and warm receptors. It is not dependent on A-delta cold fibres, and a contribution of nociceptors is quite unlikely. The possibility of a psychological contribution at the perceptual level is discussed.

Adult↗

PubMed2003

Attention-deficit/hyperactivity disordered boys' relationships with their mothers and fathers: child, mother, and father perceptions.

Self-perceptions of parent-child relationship quality were examined for 142 boys with attention-deficit/hyperactivity disorder (ADHD) and 55 control boys. Parent perceptions were examined as well. Mothers and fathers of ADHD boys perceived their relationships with their children more negatively than mothers and fathers of control boys. Interestingly, despite these differences in parental perceptions, ADHD boys did not differ from control boys in their perceptions of their relationships with their parents. Further, when ADHD boys' perceptions were compared directly to those of their parents, ADHD boys' reports were positively enhanced relative to those of control parent-child dyads. Together, these results may be viewed as providing support for a positive illusory bias in the social self-perceptions of ADHD children.

Adult↗

PubMed1998

Distorted perceptions in dyadic interactions of aggressive and nonaggressive boys: effects of prior expectations, context, and boys' age.

This study examined distorted self- and peer perceptions in aggressive and nonaggressive boys at preadolescent and early adolescent age levels. Subjects completed semantic differential ratings of themselves and of their peer partners following two brief dyadic discussion tasks with competitive inductions and a game-playing task with a cooperative induction. Subjects also rated their expectations for self- and peer behavior prior to the two competitive interaction tasks. Research assistants later rated videotapes of the interactions. Aggressive boys had more distorted perceptions of dyadic behavior as they overperceived aggression in their partners and underperceived their own aggressiveness. These distorted perceptions of aggression carried over for aggressive boys into the third interaction task with a cooperative induction, indicating these boys' difficulty in modulating these perceptions when the overt demand for conflict is no longer present in the situation. Results also indicated that aggressive boys' perceptions of their own behavior after the first interaction task is substantially affected by their prior expectations, in comparison to nonaggressive boys who rely more on their actual behavior to form their perceptions.

Adolescent↗

PubMed2002

Aggression and threat perception abnormalities in children with learning and behavior problems.

The current study investigated the connection between aggression and the perception of threat in a group of children with learning and behavior problems (N = 103). Aggression was assessed by means of the aggressive behavior subscales of the Child Behavior Checklist (CBCL), Teacher Report Form (TRF), and Youth Self-Report (YSR). Perception of threat was measured by studying children's reactions to a series of stories depicting ambiguous social situations. Results demonstrated small but significant correlations between self-reported aggression (as indexed by the YSR) and threat perception abnormalities. That is, high levels of aggression were associated with a high frequency of threat perception, high ratings of threat, high levels of negative feelings and cognitions, and an early detection of threat. Furthermore, no substantial connections emerged between children's level of aggression as rated by parents (CBCL) and teachers (TRF) and threat perception indices. Finally, regression analyses revealed that in particular YSR social problems was a better predictor of most threat perception abnormalities than YSR aggressive behavior. Implications of these findings are briefly discussed.

Adolescent↗

PubMed2003

The function of stereotypes in visual perception.

Human vision is a product of both physiological and cultural dispositions. This cultural study investigates the role of cultural dispositions in visual perception. In particular, the study focuses on the role of stereotypes, which are involved in recognition. I propose that stereotypes are essential for basic functions of perception and human perception. However, stereotypes also introduce significant limitations on human experience. The fact that stereotypes are abstract simplifications of realities is not the limiting factor, since scientific and cultural progress continually refines stereotypes. The very principle of the stereotype appears to introduce the limitation, because the process of forming stereotypes requires both temporal and functional fragmentations of the continuum of our perception. This fragmentation can be a cause of sensory overload, a postmodern condition that generates cultural, perceptual and behavioral problems. To address this problem, I propose a cultural modification to our modality of perception. The modification shifts the emphasis of our perception from the recognition of stereotypes to the recognition of flows, processes and durations. References to the work of Henri Bergson and Martin Heidegger provide the philosophical basis for this modification and several empirical and experimental examples illustrate such modifications in practice.

Culture↗

PubMed1998

Gender differences in risk perception: theoretical and methodological perspectives.

A substantial body of risk research indicates that women and men differ in their perceptions of risk. This paper discusses how they differ and why. A review of a number of existing empirical studies of risk perception points at several problems, regarding what gender differences are found in such studies, and how these differences are accounted for. Firstly, quantitative approaches, which have so far dominated risk research, and qualitative approaches give different, sometimes even contradictory images of women's and men's perceptions of risk. Secondly, the gender differences that appear are often left unexplained, and even when explanations are suggested, these are seldom related to gender research and gender theory in any systematic way. This paper argues that a coherent, theoretically informed gender perspective on risk is needed to improve the understanding of women's and men's risk perceptions. An analysis of social theories of gender points out some relations and distinctions which should be considered in such a perspective. It is argued that gender structures, reflected in gendered ideology and gendered practice, give rise to systematic gender differences in the perception of risk. These gender differences may be of different kinds, and their investigation requires the use of qualitative as well as quantitative methods. In conclusion, the arguments about gender and risk perception are brought together in a theoretical model which might serve as a starting point for further research.

Female↗

PubMed1996

Agreement and accuracy in children's interpersonal perceptions: a social relations analysis.

Agreement and accuracy in children's interpersonal perceptions during middle childhood were studied in the school environment. Sociocultural and ecological theories led to the prediction that, in middle childhood, peers' interpersonal perceptions would show high levels of agreement with those of teachers and would be accurate. A social relations analysis of data from a 3-year, cross-sequential study revealed that throughout middle childhood, peer perceptions of cognitive ability, observable behavior and characteristics, popularity, and affect correlated reliably with teacher perceptions. In addition, peer and teacher perceptions of targets' cognitive ability correlated with standardized test scores. Self-other agreement lagged behind teacher-peer agreement. The conceptual and statistical advantages of the social relations analysis of children's interpersonal perceptions were also considered.

Aptitude↗

PubMed1996

Perceptions of baby talk, frequency of receiving baby talk, and self-esteem among community and nursing home residents.

Community-living seniors (n = 113) and nursing home residents (n = 43) provided their impressions of baby-talk and neutral-talk scenarios and completed measures of functional health, need for succorance, and self-esteem. Two orthogonal dimensions were found in perceptions of baby talk: Warmth and Superiority. The personality trait of need for succorance was consistently associated with perceptions of warmth in baby talk, whereas functional health, age, and institutionalization were associated with perceptions of superiority. Significant interactions were found between perceptions of baby talk and frequency of receiving baby talk in the prediction of self-esteem, providing suggestive evidence for previously expressed concerns about potentially harmful effects of receiving baby talk on self-esteem among seniors who have negative perceptions of baby talk. However, older persons with positive perceptions of baby talk reported higher self-esteem when they frequently received baby talk, in accordance with person-environment theory. The self-esteem interaction for men occurred on the Superiority dimension, whereas the interaction for women occurred on the Warmth dimension.

Activities of Daily Living↗

PubMed1992

Eye movements and scene perception.

Research on eye movements and scene perception is reviewed. Following an initial discussion of some basic facts about eye movements and perception, the following topics are discussed: (I) the span of effective vision during scene perception, (2) the role of eye movements in scene perception, (3) integration of information across saccades, (4) scene context, object identification and eye movements, and (5) the control of eye movements. The relationship of eye movements during reading to eye movements during scene perception is considered. A preliminary model of eye movement control in scene perception is described and directions for future research are suggested.

Attention↗

PubMed2000

Care giver perception of children's obesity-related health risk: a study of African American families.

OBJECTIVE: To examine care giver perception of children's weight-related health risk in African American families. RESEARCH METHODS AND PROCEDURES: One-hundred and eleven families (representing 48 boys and 63 girls) screened for participation in a diabetes prevention study participated. Care givers completed a health awareness questionnaire that assessed their perception of the child's weight, eating habits, appearance, exercise habits, and health risk. The care givers also reported each subject's family history of obesity, diabetes, and other chronic diseases. After a physical examination, height and weight were used to compute an age- and sex-adjusted body mass index for each child. RESULTS: Despite the fact that a substantial number of children were obese (57%) and super-obese (12%), only 44% of the care givers perceived the child's weight to be a potential health problem. Regression analysis showed that 21% of the variance in parental perception of obesity-related health risk could be predicted by child age, body mass index, perception of frame size, and perception of exercise habits. DISCUSSION: A number of reasons for the apparent minimization of child health risk are discussed, including cultural differences in the acceptance of a large body habitus, lack of knowledge about the connection between childhood obesity and future health risk, and an optimistic bias in the perception of personal health risk.

Adult↗

PubMed2004

The impact of the perception of treatment choice on satisfaction with treatment, experienced chemotherapy burden and current quality of life.

Previous research has shown that involving patients in the decision-making process may improve their quality of life (QoL). Our purposes were to assess: (1) whether early-stage breast cancer patients perceived that they had treatment choice with regard to adjuvant chemotherapy, (2) what reasons patients provide for their perception of having had no choice of treatment and (3) whether the perception of treatment choice is related to satisfaction with the assigned treatment, experienced chemotherapy burden and current QoL. A total of 448 patients, treated between 1998 and 2003, filled in the questionnaire (response rate: 62%). Patients who indicated that they had not perceived a choice regarding chemotherapy could tick off one or more reasons out of 10 reasons, or provide their own reason(s). Quality of life was measured on a Visual Analogue Scale, by means of the EuroQol, and by means of the Hospital Anxiety and Depression Scale. Of the 405 patients who had answered the question on treatment choice, 316 patients (78%) had perceived no choice. The most frequently indicated reason for lack of choice was: "I follow the doctor's advice." We found no differences in the levels of satisfaction with assigned treatment and in how much of a burden they found chemotherapy between patients who perceived a choice of treatment and those who did not. In general, the perception of choice seemed to have no impact on QoL. However, we found an interaction effect, which indicated that the impact of perception of treatment choice on QoL was dependent upon whether the patient had been treated with chemotherapy or not. Within the group of patients who had not been treated with chemotherapy, the perception of having had a choice was related to lower current QoL. In cases when the decision to be treated or not has potential consequences for the chance of survival, patients' QoL may not be improved by the perception of having had a choice of treatment.

Adult↗

PubMed2000

Ethnic differences in perceptions of body size in middle-aged European, Maori and Pacific people living in New Zealand.

OBJECTIVES: The aim of this study was to compare perceptions of body size in European, Maori and Pacific Islands people with measured body mass index (BMI), waist-to-hip ratio and change in BMI since age 21 y. Socio-demographic factors that influenced perceptions of body size were also investigated. DESIGN: Cross-sectional survey. METHODS: Participants were 5554 workers, aged > or =40 y, recruited from companies in New Zealand during 1988-1990. RESULTS: Prevalences of BMI>25 kg/m2 were: Europeans, 64.7% men, 47.2% women; Maori, 93.2% men, 80.6% women; and Pacific Islanders, 94.1% men, 92.9% women. Similarly, prevalences of BMI >30 kg/m2 were: Europeans, 14.4% men, 14.6% women; Maori, 55.0% men, 41.9% women; and Pacific Islanders, 55.1% men, 71.7% women. At each perception of body size category, Maori and Pacific Islands men and women had a higher BMI than European men and women, respectively. BMI increased with increasing perception of body size in all gender and ethnic groups. Since age 21, increases in BMI were highest in Pacific Islands people and increased with increasing perceptions of body size category in all ethnic and gender groups. BMI adjusted odds (95% CI) of being in a lower perception category for body size were 1.70 (1.38-2.12) in Maori and 8.99 (7.30-11.09) in Pacific people compared to Europeans, 1.27 (1.13-1.42) times higher for people with no tertiary education, 1.41 (1.25-1.59) times higher in people with low socioeconomic status, and 0.94 (0.92- 0.95) for change in BMI since age 21. CONCLUSION: Nutritional programs aimed at reducing levels of obesity should be ethnic-specific, addressing food and health in the context of their culture, and also take into account the socioeconomic status of the group. On the population level, obesity reduction programs may be more beneficial if they are aimed at the maintenance of weight at age 21.

Adult↗

PubMed2004

Separating contributions of hearing, lexical knowledge, and speech production to speech-perception scores in children with hearing impairments.

Open-set word and sentence speech-perception test scores are commonly used as a measure of hearing abilities in children and adults using cochlear implants and/or hearing aids. These tests are usually presented auditorily with a verbal response. In the case of children, scores are typically lower and more variable than for adults with hearing impairments using similar devices. It is difficult to interpret children's speech-perception scores without considering the effects of lexical knowledge and speech-production abilities on their responses. This study postulated a simple mathematical model to describe the effects of hearing, lexical knowledge, and speech production on the perception test scores for monosyllabic words by children with impaired hearing. Thirty-three primary-school children with impaired hearing, fitted with hearing aids and/or cochlear implants, were evaluated using speech-perception, reading-aloud, speech-production, and language measures. These various measures were incorporated in the mathematical model, which revealed that performance in an open-set word-perception test in the auditory-alone mode is strongly dependent on residual hearing levels, lexical knowledge, and speech-production abilities. Further applications of the model provided an estimate of the effect of each component on the overall speech-perception score for each child.

Adolescent↗

PubMed2005

Categorical perception of speech by children with specific language impairments.

Previous research has suggested that children with specific language impairments (SLI) have deficits in basic speech perception abilities, and this may be an underlying source of their linguistic deficits. These findings have come from studies in which perception of synthetic versions of meaningless syllables was typically examined in tasks with high memory demands. In this study, 20 children with SLI (mean age = 9 years, 3 months) and 20 age-matched peers participated in a categorical perception task. Children identified and discriminated digitally edited versions of naturally spoken real words in tasks designed to minimize memory requirements. Both groups exhibited all hallmarks of categorical perception: a sharp labeling function, discontinuous discrimination performance, and discrimination predicted from identification. There were no group differences for identification data, but children with SLI showed lower peak discrimination values. Children with SLI still discriminated phonemically contrastive pairs at levels significantly better than chance, with discrimination of same-label pairs at chance. These data suggest that children with SLI perceive natural speech tokens comparably to age-matched controls when listening to words under conditions that minimize memory load. Further, poor performance on speech perception tasks may not be due to a speech perception deficit, but rather to a consequence of task demands.

Child↗