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At least 973 records · Page 54Linked to original sources

PubMed1994

Motion perception in optic neuropathy.

We tested motion perception in 15 eyes of 13 patients with optic neuropathy. Eleven of the eyes had optic neuritis. The motion perception paradigm tested subjects' ability to discriminate the direction of a global coherent motion signal amid varying levels of background noise. The results showed defective motion processing in eight of the 15 eyes. This defect was not due to low visibility (poor spatial resolution), since 11 of the 15 eyes had Snellen acuities of 20/20 or better. Neither was impaired motion perception due to decreased luminance sensitivity, since attenuating the display signal by 2.1 log units (0.6 units more than the worst relative afferent pupillary defect in any patient) in five normal eyes had no effect. Motion perception and critical flicker fusion were independent of each other. Given proposals that both depend exclusively on the same M, or transient, channel, we had not predicted this double dissociation between flicker and motion perception.

Adult↗

PubMed2006

Social perception of speech in individuals with oropharyngeal reconstruction.

Oral cancer affects approximately 5% of the Canadian population every year. One option for treatment of oropharyngeal cancer includes resection of the diseased tissue with primary reconstruction of the defect using a microvascular free flap, followed by post-operative adjuvant radiation therapy. The aim of reconstructive surgery is to maintain functional speech and swallowing. While the literature provides support for the maintenance of speech intelligibility following reconstructive procedures, certain aspects of resonance may be altered when the palatal structures are involved. Little is known about the effect of such alterations on the perception of speakers who have been treated with microvascular free flap reconstruction. Social perception is a process in which we infer attributes of others, with the speech signal playing an integral part in attribution. The purpose of this study was to explore the social perceptions formed about speakers both before and after surgery for oropharyngeal cancer. The results of this study revealed that positive perceptions of speakers significantly diminished as a result of surgery and negative perceptions increased. Certain variables, such as degree of resection of the soft palate and base of tongue, and sex of the speaker, had influence on the results. This research suggests that intelligibility measurements of speech, although useful, do not provide a complete indication of the social impact of reconstructive surgery on patients with oropharyngeal resections.

Adult↗

PubMed2003

Zolpidem-induced distortion in visual perception.

OBJECTIVE: To describe a patient who developed visual perception distortion after a single dose of zolpidem. CASE SUMMARY: A 50-year-old Asian woman had been prescribed conjugated estrogen 1 tablet daily for hormone replacement therapy and tricalcium phosphate twice daily for osteoporosis. One day, she took zolpidem 10 mg for insomnia as well as acetaminophen 500 mg for headache at bedtime and began to have visual perception distortion (e.g., the shapes of objects were twisted, houses were crooked) within 20 minutes, lasting for approximately 30 minutes, and then her vision returned to normal. She only partially recalled the event. She had never taken zolpidem before, and she had not had any such disturbances in the past. DISCUSSION: There have been 21 case reports of zolpidem-related psychotic symptoms in the literature; however, the exact mechanism by which zolpidem may cause visual perception changes is undetermined. Many factors have been correlated with zolpidem-induced visual experiences, such as pharmacokinetic factors, gender, age, and hypoalbuminemia. This patient shared certain similarities such as gender, dosage, and time of onset and duration of adverse reactions. CONCLUSIONS: An objective causality assessment revealed that the zolpidem-induced visual perception distortion in this patient was probable. Clinicians should be aware of the potential for visual perception distortion, as this is an uncommon adverse effect.

Female↗

PubMed2005

Relationships between risk-taking behaviour and subsequent risk perceptions.

Research has suggested that engagement in patterns of risk-taking behaviour might have a negative influence on the processing of risk information. However, risk-takers display higher risk perceptions than non-risk takers. This paradox might be resolved by removing the confounding effect of risk takers' increased exposure to risk. A longitudinal survey was administered to 255 motorists to examine the extent to which Time 1 (T1) self-reported speeding behaviour predicted exposure-free measures of Time 2 (T2) risk perceptions. Hierarchical regression analyses, controlling for demographics and T1 risk perceptions, showed that T1 speeding, and T1 to T2 speeding changes, both inversely predicted T2 risk perceptions. This suggests that successive increments in risk-taking behaviour will lead to progressively lower increases in personal risk perception. Possible foundations and implications of this effect are discussed.

Adult↗

PubMed2005

Terror threat perception and its consequences in contemporary Britain.

The terrorist attacks of 9/11, and subsequent terrorist acts around the world, have alerted social psychologists to the need to examine the antecedents and consequences of terrorist threat perception. In these two studies, we examined the predictive power of demographic factors (age, gender, location), individual values and normative influences on threat perception and the consequences of this perception for behavioural change and close relationships. In Study 1 (N = 100), gender, benevolence values and normative influences were all correlates of threat perception, whilst sense of personal threat was correlated with increased contact with friends and family. In Study 2 (N = 240) age, gender, location, and the values of openness to change and hedonism, all predicted threat perception, which, in turn, predicted behavioural change and relationship contact. Such findings point to the important role social psychologists should play in understanding responses to these new terrorist threats.

Adaptation, Psychological↗

PubMed1994

Perception scoring of induced bronchoconstriction as an index of awareness of asthma symptoms.

Perception of asthma symptoms shows a wide interindividual variability. Poor perception of airflow obstruction may lead to undertreatment of asthma. We reviewed the possibility of using a simple test to detect poor perceivers of bronchoconstriction as part of the investigation of asthmat. We studied 150 consecutive subjects referred for assessment of airway responsiveness. All had a histamine PC20 within the asthmatic range (< 16 mg/ml) and a fall in FEV1 of < 20 percent after saline inhalation. On histamine challenge, before each FEV1 measurement, perception of dyspnea was assessed on a modified Borg scale. A perception score of breathlessness at 20 percent fall in FEV1 (PS20) was obtained by interpolation of the two last points on the perception/fall in FEV1 curve. It was concluded that in a hyperreactive population, PS20 (1) showed a normal distribution pattern; (2) was similar in both genders; and (3) increased with age due to high postcontrol saline inhalation scores. Hypoperceivers or hyperperceivers were similar for age, sex, baseline FEV1, and PC20. The PS20 determination may be a useful additional parameter to obtain during provocation tests to assess perception of symptoms associated with bronchoconstriction. Its correlation with clinical outcome remains, however, to be determined.

Adolescent↗

PubMed1998

Influence of beclomethasone and salmeterol on the perception of methacholine-induced bronchoconstriction.

BACKGROUND: Patient evaluation of asthma severity and medication needs is mostly based on respiratory symptoms and may be influenced by changes in perception of bronchoconstriction-induced sensations. However, the influence of asthma medication on the ability to perceive symptoms is still to be documented. This study evaluated the effects of short-term and regular use of salmeterol on the perception of methacholine-induced bronchoconstriction (MIB) in subjects with mild asthma, using inhaled salbutamol on an "as required" basis (n=15), and in subjects with moderate asthma, using daily inhaled beclomethasone (mean daily dose, 640 microg; n=15) in addition to salbutamol to control their asthma. METHODS: Methacholine challenges (MC) were performed at entry into the study, and then before, 1, and 12 h following inhalation of 50 microg of salmeterol or a placebo, after a 15-day baseline period; and after 4 weeks of twice daily use of those treatments. The measurements were then repeated with the alternate treatment after a 15-day washout period. Finally, a last MC was performed after another 15-day washout period. For each MC, the perception score of bronchoconstriction-associated breathlessness at 20% fall in FEV1 (PS20) was evaluated on a modified Borg scale from 0 to 10. RESULTS: Subjects using regular beclomethasone had a higher baseline PS20 than those using only salbutamol (means: 3.06 0.06 and 2.01+/-0.07, p=0.0001). Short- and long-term use of salmeterol did not change significantly the PS20 compared with placebo (p>0.05) in either group (with or without corticosteroid). Although there were some intraindividual variations, mean PS20 did not vary significantly throughout the study. CONCLUSION: These observations show that the perception of bronchoconstriction-associated breathlessness is not influenced by regular use of salmeterol. Patients using inhaled corticosteroids show a greater perception of MIB.

Administration, Inhalation↗

PubMed1986

The dentist-patient relationship: mutual perceptions and behaviors.

The relationship between patients' characteristics and dentists' perceptions as well as the associations between these dimensions and specific dentist behaviors as perceived by patients are explored. Dentist perceptions of patient sophistication and anxiety were related to several patient characteristics, but perceptions of patient likability were unrelated to patient personal and social characteristics. Perceptions of patient likability were associated with more specific dentist behaviors than were other dentist perceptions noted by patients. The results suggest that dentists' views are influenced primarily by those patient characteristics manifested during treatment. In general, dentists like patients who are dentally sophisticated and not anxious.

Adolescent↗

PubMed2004

Effect of patient socioeconomic status on perceptions of first- and second-year medical students.

BACKGROUND: Physician decision-making and perceptions of patients are affected by a patient's socioeconomic status (SES). We sought to determine if the perceptions of first- and second-year medical students are similarly affected. We also wanted to determine whether a student's own SES affects his or her perceptions of patients from a low or high SES background. METHODS: Two similar videos of a physician-patient interview were created. One video featured a patient of apparently high SES and the other featured a patient of apparently low SES. Differences in SES were portrayed by means of clothing, accessories and dialogue. First- and second-year medical students at the University of Western Ontario were recruited to view 1 of the videos and to answer a questionnaire using a 5-point Likert scale. RESULTS: Responses were obtained from 205 (89%) of the 231 medical students invited to participate. Respondents' perceptions of the low SES and high SES patients were significantly different in the following respects. The low SES patient was perceived to be less compliant in taking medications and less likely to return for follow-up visits; was perceived to have a lower level of social support, poorer overall health and a worse prognosis; and was perceived to be more adversely affected in his occupational duties by illness (p < 0.05). Furthermore, second-year students who watched the video with the low SES patient were less inclined to want that patient in their practice than second-year students who watched the video with the high SES patient (p = 0.032). One hundred and six students (52%) were categorized as having high SES and 37 (18%) as having low SES (the remaining students were categorized as having mid-level SES). Among students who watched the video with the low SES patient, the level of agreement with the statement "This person is the kind of patient I would like to have in my practice" was greater among low SES students than among high SES students (p = 0.012). INTERPRETATION: First- and second-year medical students have negative perceptions of low SES patients on several dimensions.

Adult↗

PubMed2003

Effect of voice onset time (VOT), stop burst and vowel on the perception of voicing in Hebrew stops: preliminary results.

Very few studies investigated systematically the acoustic cues for the perception of voicing stops in Hebrew. Voicing is characterized by several parameters of which the voice onset time (VOT) was found to be the primary cue for its perception. There are, however, other known acoustic cues to voicing such as transition to the first formant (F1) and the initial burst. The purpose of the present study was to measure the relative weighting of these various acoustic cues in the perception of Hebrew voicing, using the conflicting cues paradigm. Thirteen adults with normal hearing participated in this study. Stimuli consisted of one pair of meaningful words that differ in the voicing of the initial stop. Four different continua were constructed from the pair of natural stimuli. The first two consisted of the voiced burst combined with the vowel that was truncated from the consonant-vowel combination (where the consonant was voiced or voiceless). The remaining two continua consisted of the voiceless burst combined with the same truncated vowels. For each stimulus, a VOT continuum was created varying from -40 to +40 ms in 10 ms segments. Subjects were tested using a two alternative forced choice labeling procedure. The percent of responses to each stimulus of each VOT continuum (/b-p/) was calculated for each individual and combination. The results show that each acoustic cue contributed to the perception of initial voicing in Hebrew: (1) When the stimulus was constructed from the voiced cues, positive VOT values were needed for the voice/voiceless distinction; (2) when the stimulus was constructed from the voiceless cues, negative VOT values were needed for the voicing distinction; and (3) when the stimulus was constructed from voiced and voiceless cues, intermediate VOT values were needed for the voicing distinction. These results provide initial information regarding the relative effect of the acoustic cues in the perception of Hebrew stop voicing.

Acoustic Stimulation↗

PubMed1986

The effect of alcohol on self-evaluation and perception of negative interpersonal feedback.

Recent theories of alcohol use and misuse assume that alcohol alters cognitive-perceptual mediating processes that indirectly reduce emotional distress. One view is that alcohol enhances perceptions of control and power. Alternatively, it has been suggested that alcohol is used to reduce self-awareness, perceptions of negative feedback and negative self-evaluations. The purpose of this study was to test these two hypotheses. Forty men, all college students, participated in the study and were randomly assigned to the four conditions in a 2 X 2 balanced placebo design. Subjects interacted with a woman confederate at two points in the procedure: first under positive feedback conditions and then, after beverage consumption, under negative feedback conditions. Both sequences were videotaped and eventually viewed by the subjects. Before and after each interaction period and after the videotape procedure, subjects completed rating forms which assessed their self-perceptions. Whereas perceptions of control and power were diminished when subjects were sober, the ratings of intoxicated subjects remained stable after they received negative interpersonal feedback. Alcohol impaired the perception of negative feedback and reduced negative evaluations of the videotaped sequences.

Adult↗

PubMed2005

[Comparative study of the perception of urban noise].

OBJECTIVE: To comparatively analyze the perception of daily urban noise between residents of an acoustically and a non-acoustically controlled area. METHODS: Two urban areas were selected through objective assessments of equivalent sound levels and defined as a non-acoustically and an acoustically controlled area. A random sample of each area was selected and a questionnaire was applied to its residents. Statistical indicators of urban noise perception were generated through factorial multivariate analysis. RESULTS: The average sound level (Leq) found in the downtown district (a non-acoustically controlled area) was 72.9 dB(A) and in the acoustically controlled area was 53.3 dB(A). Three statistical indicators were generated through factorial multivariate analysis: temporary perception, perception of atypical noises and sources and disturbances. CONCLUSIONS: Residents of the acoustically controlled area reported increased noise level. The sound level in the downtown district has remained practically constant and much above the standards established by local law. The generated indicators are useful parameters to characterize the perception to continuous noise exposure in the population.

Environmental Exposure↗

PubMed2006

[Risk perception related to work in a rural community of Rio de Janeiro State, Brazil: pesticides, health, and environment].

The present study applies the risk perception analytical methodology based on rapid surveys. It took place in the micro-basin of the São Lourenço Creek in Nova Friburgo, Rio de Janeiro State, Brazil. The methodological approach was based on participatory observation, semi-structured interviews with 24 key informants selected among local farmers (N = 120), and evaluation of local work processes. Field data analysis revealed some issues related to the risk perception profile in the study population, including the development of defensive strategies to deal with work hazards, the importance of communication in developing workers' risk perceptions, the subjective responses to potentially hazardous situations, and the role of individual risk perception as a determinant of human exposure to pesticides. The results evoked the importance of systematically incorporating risk perception analyses into intervention strategies, especially in educational risk communication campaigns.

Adult↗

PubMed1977

Physiognomic form perception: mature or immature?

The hypothesis that physiognomic perception, rather than being an immature mode, characterizing, in particular, children, primitives, and schizophrenics, is, instead, a basic mode, was tested. Children of both Eastern and Western parentage in Grades 3, 5, 6, and 11 were given the Physiognomic Form Perception Test, an instrument specially developed for testing physiognimic perception. No decrease with age in such perception was noted. Although there was a tendency for scores to increase with age for girls of Eastern origin, in general the scores do not increase with age. Physiognomic perception is apparently not acquired. Sex differences were not significant.

Adolescent↗

PubMed1999

Change in role perception, role conflict, and psychological health of working mothers.

A model of the interrelationship among Change in Role Perception, Role Conflict, and Psychological Health of working mothers is introduced. The model posits that Change in Role Perception after the birth of children influences Psychological Health directly or indirectly through Role Conflict. The model was tested with a sample of 192 employed mothers (aged 26-45 years) with at least one child under 11 years of age and who lived in either Melbourne or Canberra, Australia. As expected, scores on Role Conflict predicted all four measures of Psychological Health (Anxiety, Self-esteem, Uptight, and Worn Out). Change in scores on Role Perception predicted Self-esteem and Worn Out. Geographic location predicted scores for Uptight and Worn Out and Occupational Type predicted scores for Worn Out, perhaps due to perceived social support. There are theoretical reasons for maintaining the model's structure. Refinement of methodology, measurement of Change in Role Perception, and possible adoption of a longitudinal approach is recommended. It is concluded that measuring experienced role conflict and change in role perception should be taken into account in any consideration of women's psychological health.

Adult↗

PubMed2001

Postcoincidence trajectory duration affects motion event perception.

In a two-dimensional display, identical visual targets moving toward and across each other with equal, constant speed can be perceived either to reverse their motion directions at the coincidence point (bouncing percept) or to stream through one another (streaming percept). Although there is a strong tendency to perceive the streaming percept, various factors have been reported to induce the bouncing percept, such as a sound or a visual flash at the moment of the visual target coincidence. By changing duration of the postcoincidence trajectory (PCT), we investigated how long it would take for such bounce-inducing factors to be maximally effective after the visual coincidence. With bounce-inducing factors, the percentage of the bouncing percept did not reach its maximal level immediately after the coincidence but increased as a function of PCT duration up to 150-200 msec. The results clearly reject the possibility of the cognitive-bias hypothesis about the bounce-inducing effect and suggest rather that the bounce-inducing factors have to interact with the PCT for some period after the coincidence to be maximally effective.

Adult↗

PubMed1992

On the perception of shape from shading.

The extraction of three-dimensional shape from shading is one of the most perceptually compelling, yet poorly understood, aspects of visual perception. In this paper, we report several new experiments on the manner in which the perception of shape from shading interacts with other visual processes such as perceptual grouping, preattentive search ("pop-out"), and motion perception. Our specific findings are as follows: (1) The extraction of shape from shading information incorporates at least two "assumptions" or constraints--first, that there is a single light source illuminating the whole scene, and second, that the light is shining from "above" in relation to retinal coordinates. (2) Tokens defined by shading can serve as a basis for perceptual grouping and segregation. (3) Reaction time for detecting a single convex shape does not increase with the number of items in the display. This "pop-out" effect must be based on shading rather than on differences in luminance polarity, since neither left-right differences nor step changes in luminance resulted in pop-out. (4) When the subjects were experienced, there were no search asymmetries for convex as opposed to concave tokens, but when the subjects were naive, cavities were much easier to detect than convex shapes. (5) The extraction of shape from shading can also provide an input to motion perception. And finally, (6) the assumption of "overhead illumination" that leads to perceptual grouping depends primarily on retinal rather than on "phenomenal" or gravitational coordinates. Taken collectively, these findings imply that the extraction of shape from shading is an "early" visual process that occurs prior to perceptual grouping, motion perception, and vestibular (as well as "cognitive") correction for head tilt. Hence, there may be neural elements very early in visual processing that are specialized for the extraction of shape from shading.

Attention↗

PubMed2001

Tactile illusion perception in patients with central pain.

OBJECTIVE: To evaluate lemniscal pathways in patients with central pain (CP) by use of a novel tactile illusion (TI)-producing technique. PATIENTS AND METHODS: Somatosensory (SS) and TI testing was performed on the unaffected and affected wrists of 27 patients with unilateral central nervous system injury and unilateral CP. Data on TI testing-naive control subjects were used to adjust for a learning effect. RESULTS: Testing in CP patients with cervical and brainstem injuries revealed predominantly unchanged or decreased SS perception on the affected side compared with the unaffected side. The majority of cervical- and brainstem-injured subjects with CP had improved TI performance on the affected side compared with the unaffected side. All the thalamic-injured and most of the suprathalamic-injured CP patients had altered SS testing with either decreased or increased SS perception noted. In these same CP patients the majority had reduced TI perception on the affected side compared with the unaffected side. Unexpectedly, perseveration of numbers was noted in patients with Dejerine-Roussy syndrome, and expanded TI testing was performed to better define this observation. CONCLUSION: Cervical spinal cord-injured CP patients may have improved TI perception, whereas the majority of patients with supraspinal injuries and CP have reduced SS and TI perception. A unique sensory phenomenon of TI perseveration was observed in some patients with Dejerine-Roussy syndrome.

Adult↗