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At least 811 records · Page 45Linked to original sources
PubMed1998

Experiential cognitive therapy in anorexia nervosa.

The paper details the characteristics of Experiential Cognitive Therapy (ECT), a relatively short-term, integrated, patient-oriented approach that focuses on individual discovery. Its novelty is the use of Virtual Reality, a new technology that could play an important role in clinical psychology, since it enables ECT to address both body experience disturbances and motivation for change, two key topics in the treatment of anorexia nervosa. All the phases of ECT are described with reference to an actual clinical case: a 22-year-old female anorectic patient.

Adult↗
PubMed2001

Coupling of posture and gait: mode locking and parametric excitation.

We investigate the temporal coordination of human gait and posture and infer the nature of their coupling. Participants viewed a sinusoidally oscillating visual display which induced medial-lateral postural sway during treadmill walking, while display frequency was varied (0.075-1.025 Hz). First, postural responses exhibited the usual low-pass characteristic but with an additional resonance peak near the preferred stride frequency, although shifted downward by 0.12 Hz; this provides evidence of a coupling from gait to posture. Second, the step cycle adapted to mode lock with the visual driver and postural sway, as well as displaying instances of intermittency (slipping in and out of phase) and quasiperiodicity (phase wandering); this provides evidence of a coupling from posture to gait. We observed a spectrum of integer mode locks, including a large 1:1 trapping region about the stride frequency and superharmonic entrainment (stride frequency > driver frequency) at lower driver frequencies. A coupled-oscillator model that incorporates a novel parametric coupling from posture to the gait "stiffness" term reproduces these features of the data, including the resonance peak shift. Biological coordination patterns may thus emerge naturally as properties of a system of appropriately coupled oscillators.

Adult↗
PubMed1997

[Pro-psychotic change of binocular depth inversion by sleep deprivation].

Binocular depth inversion represents an illusion of visual perception. Such inversion does not occur in all cases, especially when objects with a higher degree of familiarity (e.g. photographs of faces) are displayed. Cognitive factors are assumed to override the binocular disparity cues of stereopsis. We tested the hypothesis that during sleep deprivation the human CNS is unable to correct the implausible perceptual information. Measurements of binocular depth inversion in perception of 3D objects were taken in sleep-deprived medical staff and healthy volunteers. The binocular depth inversion scores were highly elevated in the sleep-deprived group in comparison to the healthy volunteers. The data demonstrate a strong impairment of binocular depth inversion after sleep deprivation and support the view that sleep deprivation may be accompanied by a disorganisation of the interaction between sensory input and generation of perceptual hypotheses.

Adult↗
PubMed2005

The inversion effect on gaze perception reflects processing of component information.

When faces are turned upside-down they are much more difficult to recognize than other objects. This "face inversion effect" has often been explained in terms of configural processing, which is impaired when faces are rotated away from the upright. Here we report a "gaze inversion effect" and discuss whether it is related to configural face processing of the whole face. Observers reported the gaze locations of photographed upright or inverted faces. When whole faces were presented, we found an inversion effect both for constant errors and observer sensitivity. These results were closely replicated when only the eyes were visible. Together, our findings suggest that gaze processing is largely based on component-based information from the eye region. Processing this information is orientation-sensitive and does not seem to rely on configural processing of the whole face.

Adult↗
PubMed1999

Viewer-centered and body-centered frames of reference in direct visuomotor transformations.

It has been hypothesized that the end-point position of reaching may be specified in an egocentric frame of reference. In most previous studies, however, reaching was toward a memorized target, rather than an actual target. Thus, the role played by sensorimotor transformation could not be disassociated from the role played by storage in short-term memory. In the present study the direct process of sensorimotor transformation was investigated in reaching toward continuously visible targets that need not be stored in memory. A virtual reality system was used to present visual targets in different three-dimensional (3D) locations in two different tasks, one with visual feedback of the hand and arm position (Seen Hand) and the other without such feedback (Unseen Hand). In the Seen Hand task, the axes of maximum variability and of maximum contraction converge toward the mid-point between the eyes. In the Unseen Hand task only the maximum contraction correlates with the sight-line and the axes of maximum variability are not viewer-centered but rotate anti-clockwise around the body and the effector arm during the move from the right to the left workspace. The bulk of findings from these and previous experiments support the hypothesis of a two-stage process, with a gradual transformation from viewer-centered to body-centered and arm-centered coordinates. Retinal, extra-retinal and arm-related signals appear to be progressively combined in superior and inferior parietal areas, giving rise to egocentric representations of the end-point position of reaching.

Adult↗
PubMed2003

The effect of discordant sensory information in graphic production: two distinct subject groups.

The present study investigated the underlying processes used to cope with discordant sensory information induced in a mirror-drawing task. Two experiments were carried out in which adults copied simple geometrical figures made up of either horizontal and vertical segments or oblique segments meeting at a right angle in both a normal and a mirror condition. Experiment 1 identified individual differences in relation to preferred graphic movement directions; some subjects preserved the visual directions that occurred in normal drawing by reversing the direction of drawing movements (perceived-direction group), while others preserved normal drawing directions that produced reversed visual directions (performed-direction group). Experiment 2 was performed to elucidate whether these two distinct behaviors resulted from different strategies used to cope with visuo-proprioceptive discordances. The main results showed that preference for the perceived directions led to longer pauses, slower movement velocity, greater movement dysfluency, and greater spatial orientation accuracy. By contrast, longer reaction time and greater angular accuracy characterized performance in the performed-direction group. These results were interpreted as indicating that two distinct information-processing strategies can be used when resolving sensory discordance in graphic production.

Adolescent↗
PubMed2000

The missing fundamental phenomenon in temporal vision.

Subjective flicker rates were measured for compound waveforms consisting of five harmonics without a fundamental component. It was found that observers perceived a rate at the fundamental frequency, although energy at this frequency was not included in the signals. In auditory pitch sensation this is called the missing fundamental phenomenon, and an analogous finding is known to occur in spatial vision. Moreover, observers perceived the flicker rates at the fundamental frequency even in the random-phase conditions, in which the period of the fundamental component is unclear in the real waveforms. The results indicate that the perceived flicker rates are not detected from the temporal waveforms per se. One possible mechanism for extracting such a periodicity in the signal is an auto-correlation function to the real temporal waveforms.

Adult↗
PubMed2002

Effects of delayed auditory feedback on timing of music performance.

Three experiments examined effects of delayed auditory feedback (DAF) on music performance as a function of the temporal location of feedback onsets within produced inter-onset intervals (IOIs). In Experiment 1, pianists performed isochronous melodies at two production rates with different amounts of DAF. Timing variability decreased for DAF amounts that caused feedback onsets to occur halfway through IOIs (binary subdivisions) in a 500-ms, but not 600-ms, IOI rate condition. In Experiment 2, pianists performed melodies with DAF delays and chose a preferred rate. Performers chose slower rates for larger delays; preferred rates approximated twice the amount of DAF. Experiment 3 tested the possibility that subjects deliberately conceptualized subdivisions in Experiments 1 and 2. Performers were given (1) no instructions, (2) instructions to mentally subdivide produced events in two, or (3) instructions to mentally subdivide produced events in three, in different blocks. Instructions to subdivide reduced timing variability for larger feedback delays. These experiments indicate that DAF disruption is reduced by subdividing instructions and sometimes by coincidences of feedback onsets with subdivisions of produced intervals. Such facilitation may reflect the use of hierarchical cognitive plans in production.

Auditory Perception↗
PubMed2002

The role of practice and automaticity in temporal and nontemporal dual-task performance.

Research on time and attention shows that a nontemporal task may interfere with a concurrent timing task by making time judgments shorter, more variable, and/or more inaccurate compared to timing-only conditions. Brown (1998, Psychological Research, 61, 71-81) counteracted the interference effect by giving subjects automaticity training on a nontemporal task to reduce the amount of processing resources the task required. Such practice attenuated interference in timing. Two new experiments were designed to replicate and extend the previous findings. Subjects generated a series of 5-s temporal productions under single-task (timing only) and dual-task (timing plus nontemporal task) conditions. The nontemporal tasks were pursuit rotor tracking (Experiment 1), and mirror-reversed reading (Experiment 2). We employed a pretest-practice-posttest paradigm, with the practice sessions devoted to performance of the nontemporal task. Pretest-posttest comparisons showed that practice reduced interference in timing in both experiments. Dual-task probe trials were given during the practice sessions to trace the time course of the improvement in timing. The results showed that interference in timing was reduced with even small amounts of practice. The findings support the idea that timing is very sensitive to changes in the allocation of attentional resources.

Adolescent↗
PubMed2001

Olanzapine in children and adolescents with chronic anorexia nervosa. A study of five cases.

Psychopathology in severely anorexic patients often seems to be of compulsive and delusional quality rendering therapeutic approaches extremely difficult. With conventional therapeutic regimes failing, administration of the novel antipsychotic olanzapine induced remarkable improvement in five cases reported here. Paranoid ideation concerning body image or weight gain decreased and sedative effects helped to reduce inner tensions and phobia with respect to food intake. Olanzapine, therefore, might represent an important therapeutic tool in anorexic patients who present the following characteristics: long-term history of anorexia nervosa mostly with several hospitalisations, missing perception of their severe state of illness, refusal of therapy, delusional quality of anorexic thinking, risk of discontinuation of therapy with life-threatening consequences.

Adolescent↗
PubMed2005

Time estimation in good and poor sleepers.

Time estimation was examined in 148 older good and poor sleepers in analogue and naturalistic sleep settings. On analogue tasks, both "empty" time and time listening to an audiobook were overestimated by both good and poor sleepers. There were no differences between groups. "Empty" time was experienced as "dragging." In the sleep setting, most poor sleepers underestimated nocturnal sleep and overestimated awake times related to their own sleep problem: sleep onset vs. sleep maintenance insomnia. Good sleepers did the opposite. Severity of sleep problem and size of time estimation errors were unrelated. Greater night-to-night wake time variability was experienced by poor than by good sleepers. Psychological adjustment was unrelated to time estimations and to magnification or minimization of sleep problems. The results suggest that for poor sleepers who magnify their sleep problem, self-monitoring can be of benefit by demonstrating that the sleep problem is not as severe as believed.

Adaptation, Psychological↗
PubMed2005

How does distraction work in the management of pain?

Engaging in thoughts or activities that distract attention from pain is one of the most commonly used and highly endorsed strategies for controlling pain. The process of distraction appears to involve competition for attention between a highly salient sensation (pain) and consciously directed focus on some other information processing activity. In this article, the evidence for distraction from pain is examined and the qualities of pain, the distractor, and some individual difference variables that have been shown influence the effectiveness of distraction are described. There has been little examination of the use of distraction in chronic pain, but some ancillary evidence suggests that it should be used with caution.

Adaptation, Psychological↗