SEARCH · PubMed Health

Results for “Perception”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13Linked to original sources

PubMed1999

The cerebral haemodynamics of music perception. A transcranial Doppler sonography study.

The perception of music has been investigated by several neurophysiological and neuroimaging methods. Results from these studies suggest a right hemisphere dominance for non-musicians and a possible left hemisphere dominance for musicians. However, inconsistent results have been obtained, and not all variables have been controlled by the different methods. We performed a study with functional transcranial Doppler sonography (fTCD) of the middle cerebral artery to evaluate changes in cerebral blood flow velocity (CBFV) during different periods of music perception. Twenty-four healthy right-handed subjects were enrolled and examined during rest and during listening to periods of music with predominant language, rhythm and harmony content. The gender, musical experience and mode of listening of the subjects were chosen as independent factors; the type of music was included as the variable in repeated measurements. We observed a significant increase of CBFV in the right hemisphere in non-musicians during harmony perception but not during rhythm perception; this effect was more pronounced in females. Language perception was lateralized to the left hemisphere in all subject groups. Musicians showed increased CBFV values in the left hemisphere which were independent of the type of stimulus, and background listeners showed increased CBFV values during harmony perception in the right hemisphere which were independent of their musical experience. The time taken to reach the peak of CBFV was significantly longer in non-musicians when compared with musicians during rhythm and harmony perception. Pulse rates were significantly decreased in non-musicians during harmony perception, probably due to a specific relaxation effect in this subgroup. The resistance index did not show any significant differences, suggesting only regional changes of small resistance vessels but not of large arteries. Our fTCD study confirms previous findings of right hemisphere lateralization for harmony perception in non-musicians. In addition, we showed that this effect is more pronounced in female subjects and in background listeners and that the lateralization is delayed in non-musicians compared with musicians for the perception of rhythm and harmony stimuli. Our data suggest that musicians and non-musicians have different strategies to lateralize musical stimuli, with a delayed but marked right hemisphere lateralization during harmony perception in non-musicians and an attentive mode of listening contributing to a left hemisphere lateralization in musicians.

Adult↗

PubMed2002

Speech perception and cortical event related potentials in children with auditory neuropathy.

OBJECTIVES: 1) To investigate the unaided and aided speech perception abilities of children with auditory neuropathy (AN) and to compare their performance to children with sensorineural hearing loss. 2) To establish whether cortical event related potentials (ERPs) could be recorded in children with AN, and to determine the relationship between the presence of these responses and speech perception. DESIGN: Unaided and aided speech perception assessments (PBK words), and cortical-ERP testing was carried out in a group of 18 children with AN. Data also were obtained from a cohort of age and hearing level matched children with sensorineural hearing loss. RESULTS: The speech perception performance of the 15 children with AN able to complete a PBK-word assessment, fell into two distinct categories. The children either showed no open-set speech perception ability (7/15 cases), or performance levels similar to their sensorineural counterparts (8/15 cases). Approximately 50% of children with AN showed ERPs of normal latency, amplitude and morphology. In all cases, response presence (at normal latencies) was consistent with reasonable speech perception ability, and response absence was consistent with negligible speech perception. CONCLUSIONS: In approximately 50% of children with auditory neuropathy, the provision of amplification results in significant open-set speech perception improvements. The results confirm the previously published reports that speech perception ability cannot be reliably estimated from the behavioral audiogram in children with AN. Obligatory ERP test results may offer a means of predicting perceptual skills in newly diagnosed youngsters as the presence of ERPs (with age-appropriate latency and morphology) was correlated with significant open set speech perception abilities and amplification benefit. The absence of the ERP in contrast, indicated profound hearing disability evidenced by profound hearing loss and/or extremely poor speech perception.

Adolescent↗

PubMed2000

Age differences in depressive symptoms, antisocial behavior, and negative perceptions of family, school, and peers among adolescents.

OBJECTIVES: To examine age differences among adolescents in the perceptions of family, school, and peers and their relationship with depressive and antisocial symptoms. METHOD: The sample consisted of 11,516 adolescents, aged 12 to 18 years, coming from a large representative community sample from 212 randomly selected schools in the Netherlands. In the period between October 1992 and January 1993, subjects filled out a self-report questionnaire on perceptions of family, school, and peer group environment; depressive symptoms; and antisocial behavior. Multivariate analyses of variance were performed to analyze age differences in the perceptions of family, school, and peers. Relationships with depressive and antisocial symptoms were studied by means of multiple regression analyses. RESULTS: Significant age differences were found for all 3 social support systems, with negative perceptions of family increasing with age, negative perceptions of peers decreasing with age, and negative perceptions of school remaining fairly stable after an initial increase at age 13. Independent of age, negative perceptions of the family had the-strongest relationship with depressive symptoms and antisocial behavior. In addition, depressive symptoms had a stronger independent relationship with negative perceptions of peers than with negative perceptions of school, while antisocial behavior had a stronger relationship with negative perceptions of school. No remarkable interaction effects between the 3 social support systems were found. CONCLUSIONS: Although age differences existed in the reporting of negative perceptions of family, school, and peers, the strong relationship with dysfunctioning in adolescence invariantly held true throughout the school years of adolescence.

Adolescent↗

PubMed2004

Examining localized patterns of air quality perception in Texas: a spatial and statistical analysis.

Environmental and human health issues associated with outdoor air pollution, such as ozone, sulfur dioxide, and other pollutants in metropolitan regions, are an area of growing concern for both policy officials and the general public. Increasing attention from the news media, new health data, and public debate over the effectiveness of clean air regulations have raised the importance of air quality in the public consciousness. While public perceptions of air quality have been studied thoroughly dating back to the 1960s, little empirical research has been conducted to explain the spatial aspects of these perceptions, particularly at the local level. Although recent studies suggest characteristics of local setting are important in shaping perceptions of air quality, the roles of proximity, neighborhood characteristics, and location have not been clarified. This study seeks to improve understanding of the major factors shaping public perceptions of air quality by examining the spatial pattern of local risk perception, the role of socioeconomic characteristics in forming these perceptions, and the relationship between perceived and scientifically measured air pollution. First, we map the spatial pattern of local air quality perceptions using Geographic Information Systems (GIS) across the Dallas and Houston metropolitan areas. Next, we explain these perceptions through local contextual factors using both bivariate correlations and multivariate regression analysis. Results indicate that perceptions of air quality in the study areas are not significantly correlated with air quality based on readings of air monitoring stations. Instead, perceptions appear to be influenced by setting (urban vs. rural), state identification, access to information, and socioeconomic characteristics such as age, race, and political identification. We discuss the implications of the findings and provide direction on how further research can provide a deeper understanding of the local contextual factors influencing public perceptions.

Air Pollutants↗

PubMed2005

Delusional mood and delusional perception -- a phenomenological analysis.

In the initial stages of schizophrenia, the environment as perceived by the patient changes into a puzzling, mysterious and stage-like scenery. At the same time, objects or persons may gain an overwhelming physiognomic expression and may even fuse with the patient's body. The paper explains these different alterations using Husserl's concept of intentional perception on the one hand, and Merleau-Ponty's concept of embodied perception on the other hand. The first may also be understood as describing the intersubjective constitution of reality through common concepts which structure intentional perception. The latter points to the embodiment of the perceiving subject and uncovers our intimate connection with the world mediated by the lived body. Thus, in each perception, an active, intentional or 'gnostic' component and a bodily, 'pathic' component work together. On this basis, the alteration of schizophrenic perception in delusional mood may be described as a paralysis of intentionality, or of the 'gnostic' component of perception. The synthetic and sense-bestowing processes effective in perception are seriously disturbed. On the other hand, as a result of the disturbance of intentional perception, physiognomic and expressive properties are set free within the perceptual field. The 'pathic' component of perception becomes independent. Thus, the intersubjective constitution of reality is replaced by idiosyncratic meanings and qualities of perception, leading finally into delusional perception.

Adult↗

PubMed1999

Analysis of the perception of and reactivity to pain and heat in patients with wallenberg syndrome and severe spinothalamic tract dysfunction.

BACKGROUND: The aim of the study was to assess the consequences of severe spinothalamic tract lesions resulting from lateral medullary infarct and to show that a specific pain perception can be elicited by strong thermal stimulation. CASE DESCRIPTIONS: Both patients examined presented with severe thermoalgic dissociation of the limbs contralateral to the lesion, with normal discriminative somatosensory perception and motor strength. They reported pain perception when touching very warm (>50 degrees C to 60 degrees C) objects and a brisk, occasionally uncontrolled withdrawal reaction of the arm and hand under the same conditions, without any perception of the heat nature of the stimulus. Warm stimulation, <45 degrees C, elicited no thermal perception or discrimination. Pain perception could be elicited in both patients by increasing the temperature, with a reproducible threshold of 47 degrees C to 49 degrees C. Pain always occurred after a prolonged delay of 8 to 10 seconds in response to threshold heat, and was described as deep and osseous, and clearly different from that perceived on the nonaffected side. The delay was much shorter when the temperature was increased by 4 degrees C to 5 degrees C. Cold stimulation elicited similar pain perception in one patient. Analysis of subjective perception of laser stimulation showed a much higher pain threshold on the affected hand. There were no laser-evoked potentials on this side, which suggested major spinothalamic injury. Assessment of the RIII noxious reflex revealed persistent response withdrawal reactions, with an increased threshold on the affected side, and partial consciousness of the noxious nature of the stimulus. CONCLUSIONS: To our knowledge, this is the first description of the appearance of pain perception of high temperatures in patients with severe spinothalamic injury who are suffering from a complete loss of temperature perception. This implies that noxious thermal stimulation can still be perceived via extra spinothalamic pathways (which are slow and multisynaptic), such as the spinoreticulothalamic tract. Patients with Wallenberg syndrome should be informed and made aware of their residual perception of and reactions to noxious stimulation.

Central Nervous System Diseases↗

PubMed2002

Patients' perceptions of intensive case management.

OBJECTIVE: The authors examined patients' perceptions of their case management care and the factors that influenced those perceptions. METHODS: A nine-item patients' perceptions questionnaire was administered to 225 patients with severe psychosis who were enrolled in a randomized controlled trial evaluating the efficacy of intensive versus standard case management. RESULTS: Factor analysis of the responses to the perceptions questionnaire revealed two principal components: quality of care received (including relationship and contact with the case manager) and overall perception of case management. Patients had a better overall perception of intensive case management compared with standard case management, but no significant differences were noted in perceived quality of care. Patients with female case managers had more positive perceptions of the quality of the care they received than those with male case managers. Several clinical and social variables were strongly associated with perceived quality of care but less so with overall perception of case management. CONCLUSIONS: Patients' general perceptions of intensive case management seemed more favorable than patients' general perceptions of standard case management, but no difference was noted in their perceptions of quality of care.

Adult↗

PubMed2005

Patients' perceptions regarding oral anticoagulation therapy and its effect on quality of life.

OBJECTIVE: Anticoagulation clinics have improved the time spent within therapeutic range and decreased hemorrhagic complications and costs in chronic oral anticoagulation. Whether these benefits correlate to patients' quality of life (QOL) remains to be determined. The impact of patients' perceptions about anticoagulation on QOL has not been evaluated. The objective of this study was to evaluate prospectively patients' perceptions and quality of life in patients chronically anticoagulated. RESEARCH DESIGN AND METHODS: A cross-sectional study was designed to investigate the prevalence of positive and negative perceptions about oral anticoagulation therapy (OAT) and to identify vulnerable groups. Patients anonymously completed the SF-36 survey and a questionnaire that focused on patients' perceptions of protection from thrombotic complications or fear of haemorrhage due to the anticoagulation. We related those perceptions to the General Health SF-36 score, to the patient's characteristics, the absolute bleeding risk (i.e. intended International Normalized Ratio [INR]), duration of therapy and medical attention. RESULTS: One thousand patients were included and 905 questionnaires evaluated. Most patients felt protected and better since the beginning of therapy (71.5% and 61.5%, respectively). Patient characteristics associated with negative perceptions were; female sex (Odds Ratio [OR] 1.58, 95% Confidence Interval [CI] 1.06-2.36, p = 0.01); patients with less than 1 year of therapy (OR 2.16, 95% CI 1.34-3.48, p = 0.006); those not satisfied with medical attention (OR 2.86, 95% CI 1.53-5.18, p = 0.0001); and those that modified their lifestyle (OR 2.75, 95% CI 1.49-4.91, p = 0.0002). Patients with a lower bleeding risk (INR 2.0-3.0) had more negative perceptions than those with a higher risk. Patients with negative perceptions achieved the lowest score in the SF-36 survey. Haemorrhages did not affect patients' perception or QOL. CONCLUSIONS: Patients' perceptions correlated with QOL. We were able to identify patient characteristics associated with poor QOL and thus the group of patients whose negative perceptions most warranted special attention from their clinicians.

Administration, Oral↗

PubMed2006

Cochlear implant-mediated perception of music.

PURPOSE OF REVIEW: This paper examines and consolidates recent advances in cochlear implant sound processing from the perspective of music perception, which is increasingly viewed as one of the most difficult of all listening conditions. RECENT FINDINGS: Music is an essentially abstract, complex form of sound composed of multiple layers of sounds that vary in temporal presentation, frequency distribution, and harmonic content. As a result, music perception is perhaps the most challenging aspect of implant-mediated listening. Thus far, implant performance has shown poor performance overall during perception of musical pitches, melodies, and timbre while perception of rhythm is relatively good. Recent advances in implant sound processing strategies, particularly the use of current distribution along adjacent electrodes, have promising early results in terms of improving the number of pitch percepts available to cochlear implant listeners. SUMMARY: Music perception poses auditory challenges that can exceed those of language perception during cochlear implant-mediated listening. These challenges should be emphasized to patients prior to implantation. Although rhythm perception via cochlear implants is reasonably good using simple test paradigms, significant work remains to improve critically important aspects of music perception, including melody and timbre. New implant processing strategies are encouraging and should lead to improved music perception in the near future.

Auditory Perception↗

PubMed2006

The association between levels of cortisol secretion and fear perception in patients with remitted depression predicts recurrence.

This study examines the association between cortisol secretion and fear perception in remitted patients to identify mechanisms underlying risk for recurrence of depression. We hypothesized that the stronger the association between cortisol secretion and fear perception in persons with remitted depression, the more recurrence would be experienced. We also investigated whether high levels of cortisol and fear perception per se predict more recurrence. These effects were assumed to be stronger in women than in men. In a prospective design, we investigated 77 outpatients with remitted depression and related the association between their 24-hour urinary free cortisol secretion and fear perception (from ambiguous faces and from vocal expressions) to recurrence of depression within 2 years. We applied Cox regression models, partial correlations, and Fisher z tests. In 21 patients, depression recurred. Irrespective the channel of perception (eye or ear), the interaction between fear perception and cortisol secretion was significantly related to recurrence of depression. Patients high or low on both variables are more at risk. This increased risk was also reflected by a significant association between cortisol secretion and facial fear perception, but only among subjects who experienced recurrence. A trend in the same direction was found for vocal fear perception. Fear perception and cortisol secretion per se did not predict recurrence. No gender differences were found. The association between cortisol secretion and fear perception (probably indicative for altered fear circuits in the brain) constitutes a mechanism underlying risk for recurrence of depression.

Adult↗

PubMed1993

Perception of horizontal head and trunk rotation: modification of neck input following loss of vestibular function.

Chronic loss of vestibular function modifies the role of neck afferents in human perception of self-motion. We characterized this change by comparing the self-motion perception of patients with chronic vestibular loss (Ps) to that of normal subjects (Ns). Stimuli consisted of sinusoidal horizontal rotations (0.025-0.4 Hz) of the trunk relative to the head (neck stimulation) and/or of the head in space (vestibular stimulation). Perception of head rotation relative to the trunk, of trunk rotation in space, or of head rotation in space was assessed in terms of gain and phase (veridical perception, G = 1 and phi = 0 degree) as well as detection threshold using a pointing procedure. (1) Perception of head rotation relative to the trunk (neck proprioception). Ps' detection threshold of head-to-trunk rotation was normal (i.e. similar to that of Ns) across all frequencies tested. Also, with peak angular velocities above 5 degrees/s, the gain of their perception was approximately normal. When peak velocity was decreased below this value, however, either by lowering stimulus frequency with peak displacement kept constant (+/- 8 degrees) or by decreasing peak displacement at constant frequency (0.05 Hz), the gain increased above unity, unlike in Ns. In contrast, the phase remained normal (approximately 0 degree). (2) Perception of trunk rotation in space. Ps perceived their trunks as stationary during neck stimulation and all vestibular-neck combinations at medium to low frequencies. At 0.4 Hz, however, Ps consistently perceived the trunk rotation, conceivably due to somatosensory self-motion cues arising from high body acceleration. In contrast, Ns perceive a trunk-in-space rotation with the neck stimulation and most of the stimulus combinations across the whole frequency range tested. Ns perceived their trunks as stationary only during head rotation on the stationary trunk (presumed to reflect a mutual cancellation of neck and vestibular signals). (3) Perception of head rotation in space. In Ps, unlike Ns, this perception always resembled that of head rotation relative to the trunk. (4) When Ps were presented with a visual or somatosensory space reference (not motion cues), their perception of trunk and head rotation in space became approximately normal. (5) We suggest that there are basically two changes in the neck-induced self-motion perception associated with chronic vestibular loss. First, neck proprioception shows a non-linear gain that overemphasizes low stimulus velocities, for unknown reasons.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1996

Diabetic sensory neuropathy effect on ankle joint movement perception.

OBJECTIVE: To determine if diabetic subjects with lower extremity cutaneous sensory neuropathy also have a loss of ankle joint movement perception. The strength of association between measurements of ankle joint movement perception and measures of cutaneous sensory function was also investigated. DESIGN: Diabetic subjects with and without sensory neuropathy and individuals without diabetes participated in this study. SETTING: All subjects were community-living individuals. PARTICIPANTS: Fifty-one subjects, ages 40 to 68. Seventeen of the 34 subjects with diabetes had significant distal sensory neuropathy as determined by cutaneous perception of mechanical vibration. All individuals without diabetes were volunteers from the community. Most subjects with diabetes were recruited through direct referral from their physicians. INTERVENTIONS: Ankle joint movement perception threshold (JMPT) was assessed using a device designed for this study. Cutaneous sensory function under both halluces was measured for vibration perception using a vibrometer and for touch-pressure perception using Semmes-Weinstein monofilaments. MAIN OUTCOME MEASURES: Ankle JMPTs (degrees) were compared to measurements of cutaneous vibration perception (volts) and touch-pressure perception (monofilaments force ratings). RESULTS: Diabetic subjects with cutaneous sensory neuropathy demonstrated a significant loss of ankle movement perception (p < .01). Correlation between JMPT and cutaneous sensory tests ranged from Spearman's rank r = .43 to .67. CONCLUSIONS: Although individuals with cutaneous sensory loss secondary to diabetic neuropathy also demonstrated loss of movement perception at the ankle, the relatively low explained variance between the two types of assessment (18% to 45%) indicates that the severity of ankle joint movement perception deficits cannot be directly implied from cutaneous sensory tests.

Adult↗

PubMedDate not supplied

Interpersonal perception: a theory and method for studying pharmacists' and patients' views of pharmaceutical care.

OBJECTIVES: To identify the congruency between pharmacists' and their patients' perceptions of the benefits of services a pharmacist would provide if practicing according to the pharmaceutical care model, and to characterize the relationship between the congruency of their perceptions and the extent to which each reports that such services are provided. DESIGN: This study employed the interpersonal perception method, a communication theory and tool through which two people's perceptions are compared to assess their agreement with and understanding of one another regarding a particular issue. SETTING AND PARTICIPANTS: Six independent community pharmacies participated in a written survey of perceptions of pharmaceutical care. Questionnaires were distributed to 100 adult patients from each store. Pharmacists completed a self-report of the pharmaceutical care services provided to their patients; patients were asked whether they received such services. MAIN OUTCOME MEASURES: Pharmacists' and patients' perceptions of pharmaceutical care; pharmacists' and patients' reports of pharmaceutical care activities. RESULTS: Pharmacists and patients were found to disagree on the potential benefits of pharmaceutical care services. Pharmacists tended not to understand their patients' perceptions. The differences were not found to be related to the level of pharmaceutical care reportedly provided. CONCLUSION: The extent to which pharmacists' and patients' perceptions serve as barriers to the provision of pharmaceutical care is yet unknown. This study shows that differences in these perceptions exist and may perpetuate both patients' traditional perceptions of dispensing activities in the community pharmacy and pharmacists' perceptions of lack of patient interest in pharmaceutical care.

Adolescent↗

PubMed1998

How does the intervention of cardiac surgery affect the self-perception of children with congenital heart disease?

BACKGROUND: There is little published information about the self-perceptions of children with chronic physical diseases and the ways in which self-perceptions might change as a result of treatment. An innovative measure of self-perception is described, suitable for use by children of widely varying ages as well as by parents. METHODS: The instrument used assessed eight constructs contributing to self-perception, and also measured differences between perceptions of actual and ideal self. Children (n = 31; age 5-15 years) with congenital heart disease (CHD) were assessed prior to surgery and 1 year post-operatively. Comparisons were made with children before and 1 year after bone marrow transplantation (BMT), and with healthy children. RESULTS: There were no differences between the groups in ideal self-perceptions, but the CHD children rated themselves as weaker, more frightened and more ill than the healthy group. Given the differences in symptomatology and illness experience of children with cyanotic and acyanotic lesions, surprisingly few differences emerged in the self-perceptions of these two groups, although differences were found among younger and older children assessed separately. Significant improvements were found in self-perceptions of the CHD and BMT groups following treatment, and at follow-up, no significant differences remained between the CHD and healthy groups. In the latter, self-perception was largely unchanged between the two assessments. CONCLUSIONS: Assessment of self-perception should be an integral part of the assessment of health outcomes in childhood illness. The study demonstrated the significant improvement in self-perception following surgery for CHD. The results also support the validity, reliability and sensitivity to change of the assessment measure.

Adolescent↗

PubMed1999

Patients' perceptions of medical urgency: does deprivation matter?

BACKGROUND: Consultation behaviour is recognized as having numerous determinants, but patients' perceptions of medical urgency have been neglected as a variable of potential importance. OBJECTIVES: We aimed to describe the variation in patients' perceptions of medical urgency, and to investigate the influence of socio-economic deprivation on such perceptions. We also aimed to investigate the association between patients' perceptions of urgency and their perception of doctor availability. METHODS: We carried out a questionnaire survey (incorporating 10 clinical vignettes) of patients attending one of 17 participating practices during a 1-week study period. A medical urgency score was calculated for each patient, and compared for patients sharing similar characteristics. The setting was West Lothian, Scotland. RESULTS: Patients' perceptions of medical urgency as measured by the urgency score were normally distributed amongst a sample of 4999 patients attending their GP. Whilst socio-economic deprivation was a significant determinant of perceptions of medical urgency, the effect was small and can probably be discounted as an important variable determining such perceptions. An association was observed between patients' perceptions of doctor availability following a non-urgent consultation request and a heightened sense of medical urgency. CONCLUSIONS: Further work is required to explain the differences in the population with regard to perceptions of medical urgency, and to examine the association between patients' perceptions of the seriousness of symptoms and the urgency of consultation requests.

Adolescent↗

PubMed1997

Odour perception in chronic renal disease.

BACKGROUND: The sense of smell plays an important role in the quality of life. Many studies have shown a declining odour perception in the elderly, as well as in subjects in poor health or nutritional state. Considering the high prevalence of poor nutritional state in renal disease and the importance of odour perception in nutrition and health, the relationship between renal function, nutritional state, and odour perception is explored in this study. METHODS: A total of 101 patients with chronic renal failure participated in the study. Thirty-eight haemodialysis patients (mean age = 64.3 years) were evaluated both before and after dialysis. Sixteen patients on peritoneal dialysis treatment (mean age = 64.0 years), 28 transplanted patients (mean age = 53.5 years, mean creatinine clearance = 64.0 ml/min) and 19 patients with varying degrees of renal insufficiency were also included (mean age = 63.7 years, mean creatinine clearance = 29.5 ml/min). Patients with cognitive deficits or upper respiratory airway diseases were excluded. A validated objective procedure was used to measure odour perception, by determining the detection threshold for isoamyl acetate (banana odour) as the lowest detectable odour concentration. RESULTS: Healthy control persons had significantly lower odour thresholds compared to patients on peritoneal (P = 0.001) and haemodialysis (P = 0.002). No significant difference was observed in odour perception between patients on peritoneal and haemodialysis (P = 0.779) and for patients on haemodialysis before and after a dialysis session. Transplanted patients had significantly better odour perception compared to matched patients on dialysis (P < 0.001). Odour perception of transplanted patients and matched healthy control persons was similar (P = 0.81). In patients with varying degrees of renal insufficiency, including healthy controls and transplanted patients, a significant positive correlation was found between odour perception and creatinine clearance (P = 0.02). A significant negative correlation was found between odour perception and serum concentration of urea (P < 0.001), serum phosphorus (P = 0.022) and protein catabolic rate (P < 0.05). Other parameters measuring nutritional status (albumin, BMI) were not correlated with odour perception. CONCLUSION: Our results show that the ability to smell is severely impaired in patients with chronic renal failure and is related to the degree of renal impairment and the degree of accumulation of uraemic toxins. After renal transplantation, patients have a normal odour perception, indicating the capacity of the olfactory system to recover once the concentration of uraemic toxins remains below a critical threshold. Acute removal of uraemic toxins by dialysis does not correct olfactory disturbances, suggesting a long lasting effect of uraemia on olfactory function.

Adult↗

PubMed1996

Medical students' and private family physicians' perceptions of family practice.

BACKGROUND: Many studies have attempted to determine what factors influence medical students' career selections. This study determined students' perceptions of family practice, examined what variables influenced these perceptions, and measured whether medical students' perceptions were similar to or different from those of practicing family physicians. METHODS: The two populations studied were students sampled at an Ohio medical school over the first 3 years of their training and a random sample of Ohio family physicians. Each subject was asked to complete a questionnaire that asked about perceptions of family practice and demographic information. RESULTS: A total of 719 (69%) students and 295 (59%) family physicians responded to the survey. Sixty-seven percent of the physician responders were actively involved in medical student teaching. More than 94% of the students had exposure to family physicians during their preclinical education. Students' perceptions were different than physicians' perceptions about lifestyle issues, patient care, and practice characteristics; over time, these approached the physicians' perceptions. However, the perceptions of family physicians and students about professional issues were similar. DISCUSSION: Medical students and family physicians have different perceptions about family practice. Students' perceptions become similar to physicians' perceptions as they progress through the educational system, while, at the same time, their interest in family practice declines.

Attitude↗

PubMed2002

Object motion perception is shaped by the motor control mechanism of ocular pursuit.

It is still a matter of debate whether the control of smooth pursuit eye movements involves an internal drive signal from object motion perception. We measured human target velocity and target position perceptions and compared them with the presumed pursuit control mechanism (model simulations). We presented normal subjects (Ns) and vestibular loss patients (Ps) with visual target motion in space. Concurrently, a visual background was presented, which was kept stationary or was moved with or against the target (five combinations). The motion stimuli consisted of smoothed ramp displacements with different dominant frequencies and peak velocities (0.05, 0.2, 0.8 Hz; 0.2-25.6 degrees /s). Subjects always pursued the target with their eyes. In a first experiment they gave verbal magnitude estimates of perceived target velocity in space and of self-motion in space. The target velocity estimates of both Ns and Ps tended to saturate at 0.8 Hz and with peak velocities >3 degrees /s. Below these ranges the velocity estimates showed a pronounced modulation in relation to the relative target-to-background motion ('background effect'; for example, 'background with'-motion decreased and 'against'-motion increased perceived target velocity). Pronounced only in Ps and not in Ns, there was an additional modulation in relation to the relative head-to-background motion, which co-varied with an illusion of self-motion in space (circular vection, CV) in Ps. In a second experiment, subjects performed retrospective reproduction of perceived target start and end positions with the same stimuli. Perceived end position was essentially veridical in both Ns and Ps (apart from a small constant offset). Reproduced start position showed an almost negligible background effect in Ns. In contrast, it showed a pronounced modulation in Ps, which again was related to CV. The results were compared with simulations of a model that we have recently presented for velocity control of eye pursuit. We found that the main features of target velocity perception (in terms of dynamics and modulation by background) closely correspond to those of the internal drive signal for target pursuit, compatible with the notion of a common source of both the perception and the drive signal. In contrast, the eye pursuit movement is almost free of the background effect. As an explanation, we postulate that the target-to-background component in the target pursuit drive signal largely neutralises the background-to-eye retinal slip signal (optokinetic reflex signal) that feeds into the eye premotor mechanism as a competitor of the target retinal slip signal. An extension of the model allowed us to simulate also the findings of the target position perception. It is assumed to be represented in a perceptual channel that is distinct from the velocity perception, building on an efference copy of the essentially accurate eye position. We hold that other visuomotor behaviour, such as target reaching with the hand, builds mainly on this target position percept and therefore is not contaminated by the background effect in the velocity percept. Generally, the coincidence of an erroneous velocity percept and an almost perfect eye pursuit movement during background motion is discussed as an instructive example of an action-perception dissociation. This dissociation cannot be taken to indicate that the two functions are internally represented in separate brain control systems, but rather reflects the intimate coupling between both functions.

Adult↗