882 resultados para perceptual scepticism


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The main questions addressed in this work were whether and how adaptation to suppression of visual information occurs in a free-fall paradigm, and the extent to which vision availability influences the control of landing movements. The prelanding modulation of EMG timing and amplitude of four lower-limb muscles was investigated. Participants performed six consecutive drop-landings from four different heights in two experimental conditions: with and without vision. Experimental design precluded participants from estimating the height of the drop. Since cues provided by proprioceptive and vestibular information acquired during the first trials were processed, the nervous system rapidly adapted to the lack of visual information, and hence produced a motor output (i.e., prelanding EMG modulation) similar to that observed when performing the activity with vision available.

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The hallucinogenic brew Ayahuasca, a rich source of serotonergic agonists and reuptake inhibitors, has been used for ages by Amazonian populations during religious ceremonies. Among all perceptual changes induced by Ayahuasca, the most remarkable are vivid seeings. During such seeings, users report potent imagery. Using functional magnetic resonance imaging during a closed-eyes imagery task, we found that Ayahuasca produces a robust increase in the activation of several occipital, temporal, and frontal areas. In the primary visual area, the effect was comparable in magnitude to the activation levels of natural image with the eyes open. Importantly, this effect was specifically correlated with the occurrence of individual perceptual changes measured by psychiatric scales. The activity of cortical areas BA30 and BA37, known to be involved with episodic memory and the processing of contextual associations, was also potentiated by Ayahuasca intake during imagery. Finally, we detected a positive modulation by Ayahuasca of BA 10, a frontal area involved with intentional prospective imagination, working memory and the processing of information from internal sources. Therefore, our results indicate that Ayahuasca seeings stem from the activation of an extensive network generally involved with vision, memory, and intention. By boosting the intensity of recalled images to the same level of natural image, Ayahuasca lends a status of reality to inner experiences. It is therefore understandable why Ayahuasca was culturally selected over many centuries by rain forest shamans to facilitate mystical revelations of visual nature. Hum Brain Mapp, 2012. (c) 2011 Wiley Periodicals, Inc.

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Studies of subjective time have adopted different methods to understand different processes of time perception. Four sculptures, with implied movement ranked as 1.5-, 3.0-, 4.5-, and 6.0-point stimuli on the Body Movement Ranking Scale, were randomly presented to 42 university students untrained in visual arts and ballet. Participants were allowed to observe the images for any length of time (exploration time) and, immediately after each image was observed, recorded the duration as they perceived it. The results of temporal ratio (exploration time/time estimation) showed that exploration time of images also affected perception of time, i.e., the subjective time for sculptures representing implied movement were overestimated.\

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Arthritis may affect the larynx and produce symptoms such as hoarseness and vocal fatigue. Objective: This paper aimed to evaluate the laryngeal manifestations of rheumatoid arthritis. Methods: This is prospective study assessed 27 patients with rheumatoid arthritis with the aid of videolaryngostroboscopy, auditory-perceptual analysis of the speech using the GIRBAS scale, acoustic analysis and the Voice Handicap Index questionnaire. Results: Nineteen patients had laryngeal complaints, the main ones being intermittent dysphonia and sensation of a foreign body in the throat. The most frequent laryngoscopical finding was overlapping arytenoids. Three patients had low pitch, nine patients had mild dysphonia and roughness. Median acoustic measures were: F0, 198.39 Hz; Jitter, 0.815; Shimmer, 4.915; and NHR, 0.144. Regarding the Voice Handicap Index, the median score was zero in all domains. There was a statistically significant correlation between voice complaints and the domains of this index. Functional classes were significantly correlated to: overlapping arytenoids (p = 0.001), PPQ (p = 0.0257), Shimmer (p = 0.0295), APQ (p = 0.0195), and the VHI physical (p = 0.0227) and total domains (p = 0.0425). Conclusion: Laryngeal complaints were reported by 70.4% of the patients and laryngoscopical alterations were observed in 48% of the subjects. Voice acoustic evaluation and self-perception were altered.

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This study compared intermanual performance asymmetry between adults and children of different ages in timing components of an aiming task. Participants manipulated a computer mouse with either hand, aiming to rapidly reach targets of different widths with a pointer on a monitor. Results showed longer deceleration movements with the left hand in children, leading to increased intermanual performance asymmetry when aiming at narrower targets. Increased intermanual performance asymmetry in children is conceptualized to derive from planning to minimize trajectory variability when controlling the nondominant hand.

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Efficiency in front-crawl stroke has been inferred primarily by means of the analysis of arm actions, specifically, stroke frequency and stroke length. The objective of the present study was to investigate whether swimming efficiency could be better assessed in children still learning the front-crawl stroke by analyzing the movement pattern as a whole. Forty-two children enrolled in private swimming programs volunteered to participate in the study. The task consisted of swimming 30 m as fast as possible. Three experts analyzed the movement pattern of the participants using a checklist. Both stroke frequency and stroke length were calculated. The correlation coefficients between the time taken to swim and both the stroke frequency and stroke length were not significant, but the total and components of the checklist scores were. Results indicate that the swimming efficiency of children learning the front-crawl stroke can be better assessed by analyzing their whole movement pattern.

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The study examined how children of different ages integrate fundamental movement skills, such as running and throwing, and whether their developmental status was related to the combination of these skills. Thirty children were divided into three groups (G1 = 6-year-olds, G2 = 9-year-olds, and G3 = 12-year-olds) and filmed performing three tasks: running, overarm throwing, and the combined task. Patterns were identified and described, and the efficiency of integration was calculated (distance differences of the ball thrown in two tasks, overarm throwing and combined task). Differences in integration were related to age: the 6-year-olds were less efficient in combining the two skills than the 9- and 12-year-olds. These differences may be indicative of a phase of integrating fundamental movement skills in the developmental sequence. This developmental status, particularly throwing, seems to be related to the competence to integrate skills, which suggests that fundamental movement skills may be developmental modules.

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OBJECTIVE: To analyze the association between noise levels present in preschool institutions and vocal disorders among educators. METHODS: Cross-sectional study conducted in 2009 with 28 teachers from three preschool institutions located in the city of Sao Paulo (Southeastern Brazil). Sound pressure levels were measured according to Brazilian Technical Standards Association, with the use of a sound level meter. The averages were classified according to the levels of comfort, discomfort, and auditory damage proposed by the Pan American Health Organization. The educators underwent voice evaluation: self-assessment with visual analogue scale, auditory perceptual evaluation using the GRBAS scale, and acoustic analysis utilizing the Praat program. To analyze the association between noise and voice evaluation, descriptive statistics and the chi-square test were employed, with significance of 10% due to sample size. RESULTS: The teachers' age ranged between 21 and 56 years. The noise average was 72.7 dB, considered as damage 2. The professionals' vocal self-assessment ranked an average of 5.1 on the scale, being considered as moderate alteration. In the auditory-perceptual assessment, 74% presented vocal alteration, especially hoarseness; of these, 52% were considered mild alterations. In the acoustic assessment the majority presented fundamental frequency below the expected level. Averages for jitter, shimmer and harmonic-noise ratio showed alterations. An association between the presence of noise between the harmonics and vocal disorders was observed. CONCLUSIONS: There is an association between presence of noise between the harmonics and vocal alteration, with high noise levels. Although most teachers presented mild voice alteration, the self-evaluation showed moderate alteration, probably due to the difficulty in projection.

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Purpose. To use a randomized design to evaluate the effectiveness of voice training programs for telemarketers via multidimensional analysis. Methods. Forty-eight telemarketers were randomly assigned to two groups: voice training group (n = 14) who underwent training over an 8-week period and a nontraining control group (n = 34). Before and after training, recordings of the sustained vowel /epsilon/ and connected were collected for acoustic and perceptual analyses. Results. Based on pre- and posttraining comparisons, the voice training group presented with a significant reduction in percent jitter (P = 0.044). No other significant differences were observed, and inter-rater reliability varied from poor to fair. Conclusions. These findings suggest that voice training improved a single acoustic dimension, but do not change perceptual dimension of telemarketers' voices.

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Introduction: The literature suggests that individuals with history of cleft lip and palate who present with midfacial growth deficiency are at higher risk of presenting lisping. The relationship between distortions during production of linguoalveolar fricative sounds and the severity of malocclusion, however, has not been established for the population with cleft. Objective: To study the association between lisping and dental arch relationship. Methodology: Speech samples and dental arch casts were obtained from 106 children with operated unilateral cleft lip and palate (UCLP) during the stage of mixed dentition and before orthodontic treatment. Videotaped productions of the phrase/u saci saiw sedu/were rated by speech-language pathologists for the identification of lisping during [s]. Dental arch casts were rated by orthodontists using the Goslon Yardstick and the Five-Year Index to establish dental arch relationship. Results: Multiple logistic regression showed no significant association between lisping and dento-occlusal index (p = .802) and age (p = .662). Substantial interjudge agreement during auditory-perceptual ratings was found (kappa = .63). Almost perfect agreement was found between orthodontists while establishing the dental arch relationship (kappa = .81). Discussion: This study failed to reveal an association between lisping and dental arch relationship in children with operated UCLP. Multiple variables may play a role in determining occurrence of lisping, warranting further investigation.

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Objectives. To evaluate whether the overall dysphonia grade, roughness, breathiness, asthenia, and strain (GRBAS) scale, and the Consensus Auditory Perceptual Evaluation-Voice (CAPE-V) scale show the same reliability and consensus when applied to the same vocal sample at different times. Study Design. Observational cross-sectional study. Methods. Sixty subjects had their voices recorded according to the tasks proposed in the CAPE-V scale. Vowels /a/ and /i/ were sustained between 3 and 5 seconds. Reproduction of six sentences and spontaneous speech from the request "Tell me about your voice" were analyzed. For the analysis of the GRBAS scale, the sustained vowel and reading tasks of the sentences was used. Auditory-perceptual voice analyses were conducted by three expert speech therapists with more than 5 years of experience and familiar with both the scales. Results. A strong correlation was observed in the intrajudge consensus analysis, both for the GRBAS scale as well as for CAPE-V, with intraclass coefficient values ranging from 0.923 to 0.985. A high degree of correlation between the general GRBAS and CAPE-V grades (coefficient = 0.842) was observed, with similarities in the grades of dysphonia distribution in both scales. The evaluators indicated a mild difficulty in applying the GRBAS scale and low to mild difficulty in applying the CAPE-V scale. The three evaluators agreed when indicating the GRBAS scale as the fastest and the CAPE-V scale as the most sensitive, especially for detecting small changes in voice. Conclusions. The two scales are reliable and are indicated for use in analyzing voice quality.

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Objective: to compare acoustic and perceptual parameters regarding the voice of cochlear implanted children, with normal hearing children. Method: this is a cross-sectional, quantitative and qualitative study. Methods: Thirty six cochlear implanted children aged between 3y and 3 m to 5y and 9 m and 25 children with normal hearing, aged between 3y and 11 m and 6y and 6 m, participated in this study. The recordings and the acoustics analysis of the sustained vowel/a/and spontaneous speech were performed using the PRAAT program. The parameters analyzed for the sustained vowel were the mean of the fundamental frequency, jitter, shimmer and harmonic-to-noise ratio (HNR). For the spontaneous speech, the minimum and maximum frequencies and the number of semitones were extracted. The perceptual analysis of the speech material was analyzed using visual-analogical scales of 100 points, composing the aspects related to the overall severity of the vocal deviation, roughness, breathiness, strain, pitch, loudness and resonance deviation, and instability. This last parameter was only analyzed for the sustained vowel. Results: The results demonstrated that the majority of the vocal parameters analyzed in the samples of the implanted children disclosed values similar to those obtained by the group of children with normal hearing. Conclusion: implanted children who participate in a (re) habilitation and follow-up program, can present vocal characteristics similar to those vocal characteristics of children with normal hearing. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

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Objective: Parameters to distinguish normal from deviant voices in early childhood have not been established. The current study sought to auditorily and acoustically characterize voices of children, and to study the relationship between vocal behavior reported by teachers and the presence of vocal aberrations. Methods: One hundred children between four and 6 years and 11 months, who attended early childhood educational institutions, were included. The sample comprised 50 children with normal voices (NVG) and 50 with deviant voices (DVG) matched by gender and age. All participants were submitted to auditory and acoustic analysis of vocal quality and had their vocal behaviors assessed by teachers through a specific protocol. Results: DVG had a higher incidence of breathiness (p < 0.001) and roughness (p < 0.001), but not vocal strain (p = 0.546), which was similar in both groups. The average F-0 was lower in the DVG and a higher noise component was observed in this group as well. Regarding the protocol used "Aspects Related to Phonotrauma - Children's Protocol", higher means were observed for children from DVG in all analyzed aspects and also on the overall means (DVG = 2.15; NVG = 1.12, p < 0.001). In NVG, a higher incidence of vocal behavior without alterations or with discrete alterations was observed, whereas a higher incidence of moderate, severe or extreme alterations of vocal behavior was observed in DVG. Conclusions: Perceptual assessment of voice, vocal acoustic parameters (F-0, noise and GNE), and aspects related to vocal trauma and vocal behavior differentiated the groups of children with normal voice and deviant voice. (C) 2012 Elsevier Ireland Ltd. All rights reserved.

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The analysis of spatial relations among objects in an image is an important vision problem that involves both shape analysis and structural pattern recognition. In this paper, we propose a new approach to characterize the spatial relation along, an important feature of spatial configurations in space that has been overlooked in the literature up to now. We propose a mathematical definition of the degree to which an object A is along an object B, based on the region between A and B and a degree of elongatedness of this region. In order to better fit the perceptual meaning of the relation, distance information is included as well. In order to cover a more wide range of potential applications, both the crisp and fuzzy cases are considered. In the crisp case, the objects are represented in terms of 2D regions or ID contours, and the definition of the alongness between them is derived from a visibility notion and from the region between the objects. However, the computational complexity of this approach leads us to the proposition of a new model to calculate the between region using the convex hull of the contours. On the fuzzy side, the region-based approach is extended. Experimental results obtained using synthetic shapes and brain structures in medical imaging corroborate the proposed model and the derived measures of alongness, thus showing that they agree with the common sense. (C) 2011 Elsevier Ltd. All rights reserved.

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CONTEXT AND OBJECTIVE: Children and adolescents who live in situations of social vulnerability present a series of health problems. Nonetheless, affirmations that sensory and cognitive abnormalities are present are a matter of controversy. The aim of this study was to investigate aspects to auditory processing, through applying the brainstem auditory evoked potential (BAEP) and behavioral auditory processing tests to children living on the streets, and comparison with a control group. DESIGN AND SETTING: Cross-sectional study in the Laboratory of Auditory Processing, School of Medicine, Universidade de São Paulo. METHODS: The auditory processing tests were applied to a group of 27 individuals, subdivided into 11 children (7 to 10 years old) and 16 adolescents (11 to 16 years old), of both sexes, in situations of social vulnerability, compared with an age-matched control group of 10 children and 11 adolescents without complaints. The BAEP test was also applied to investigate the integrity of the auditory pathway. RESULTS: For both children and adolescents, there were significant differences between the study and control groups in most of the tests applied, with significantly worse performance in the study group, except in the pediatric speech intelligibility test. Only one child had an abnormal result in the BAEP test. CONCLUSIONS: The results showed that the study group (children and adolescents) presented poor performance in the behavioral auditory processing tests, despite their unaltered auditory brainstem pathways, as shown by their normal results in the BAEP test.