Effectiveness of taping and bracing in balance

Taping and bracing are thought to be effective methods in restricting the ankle's joint motion and assisting prevention of injuries. Research evidence suggests that taping and bracing enhance both the mechanical support and the proprioception of the ankle. However, there is little research concerning the influence of taping and bracing on sport performance. Research has mainly examined tasks with demands on the frontal plane. Therefore, the present study examined the effect of taping and bracing on the performance of a task with demands on the frontal plane. A sample of 30 physical education students (Mage=21.9 yr.) performed a balance task requiring estimation of balance and both right and left deviations. The subjects performed the balance task on four different conditions, with tape, with Swede-O (a lace-up, boot style stabilizer), with Aircast (an inflatable cast), and without any stabilizer. There were no significant differences among the conditions. These findings indicate that taping and bracing do not have negative effects on balance in the frontal plane. This study created concerns regarding the appropriate stabilizer for different tasks, bilateral coordination after the application of a stabilizer, and the influence of psychological factors on prevention of injury.     

Age-related EMG variables during maximum voluntary contraction

We studied the neuromuscular adaptation that occurs with aging by comparing changes in surface electromyography (EMG) variables from the tibialis anterior muscle in 12 young (21.4 +/- 1.7 yr. old) and 13 older subjects (70.8 +/- 3.1 yr. old). EMG variables such as the muscle fiber conduction velocity, median frequency, and averaged rectified value were calculated during maximum voluntary contraction for 5-sec. isometric contractions. The dorsiflexion force, muscle fiber conduction velocity, median frequency, and average rectified value during maximum voluntary contraction were significantly smaller in the older than in the younger group (p < .05). These results suggested that the neuromuscular system in older subjects is affected by the selective atrophy of fast twitch fibers and differences in motor unit firing statistics. Our results suggest the utility of applying the EMG observed during maximum voluntary contraction to the noninvasive evaluation of neuromuscular function in elderly persons.     

Color of computer display frame in work performance, mood, and physiological response

The effects of the color of a personal computer screen on work performance, psychological mood, and autonomic response were investigated. 24 subjects were asked to perform visual tasks presented on the computer display. Three types of computer monitor, which were colored red, blue, or beige, were employed to present visual cognitive tasks. The mood measure, the Japanese Stress Arousal Check List, and heart rate measurement were administered before and after work on each color of computer monitor. Analysis of a low-demand task (Exp. 1) showed that the red computer monitor reduced visual task performance compared to that with the blue, while the blue monitor decreased visual task performance on a high-demand task (Exp. 2). The color of the monitor did not affect mood or heart rate. Based on these findings, the effect of the color of environmental cues on work was discussed.     

Using the PAI with an eating disordered population: scale characteristics,factor structure,and differences among diagnostic groups

Psychometric properties of the Personality Assessment Inventory (PAI; Morey 1991) within an eating disordered sample seeking treatment (N = 238) and differences among eating disorder diagnostic groups on the PAI were examined. The PAI showed acceptable alpha coefficients, item-total correlations, and interitem correlations. The factor structure was similar to that reported by Morey (1991), with the addition of another factor related to interpersonal coolness and distance. Those with binge eating disorder (BED) reported fewer problems and less distress in general compared to other eating disordered groups. The BED and bulimia nervosa groups were different from the anorexia nervosa groups in frequency of matching on two PAI clusters. Use of the PAI with an eating disordered population and its utility in understanding eating disorder diagnostic groups is supported.     

On the complexity of classical guitar playing: functional adaptations to task constraints

The authors performed a behavioral study of the complexity of left-hand finger movements in classical guitar playing. Six professional guitarists played movement sequences in a fixed tempo. Left-hand finger movements were recorded in 3 dimensions, and the guitar sound was recorded synchronously. Assuming that performers prefer to avoid extreme joint angles when moving, the authors hypothesized 3 complexity factors. The results showed differential effects of the complexity factors on the performance measures and on participants' judgments of complexity. The results demonstrated that keeping the joints in the middle of their range is an important principle in guitar playing, and players exploit the available tolerance in timing and placement of the left-hand fingers to control the acoustic output variability.     

Processing of temporal duration information in working memory after frontodorsal tumour excisions

This study aimed to test the hypothesis that impairments of temporal duration processing after frontal lobe lesions reflect deficits in executive monitoring functions rather than a domain-specific deficit in the maintenance of duration information in working memory. Patients with frontodorsal lesions, clinical controls with post-central lesions, and healthy controls performed recognition and classification tasks, which should allow for testing maintenance and monitoring functions, respectively. Results showed mild non-selective impairments of the frontal patients on both temporal and spatial recognition tasks, but a marked selective degradation on temporal classification while performance on spatial classification was unimpaired. This suggests that maintenance of duration information in working memory after frontal lesions is basically preserved but that, depending on executive task characteristics, there is a specific deficit in the strategic organization of this type of information.     

The man who executed "imagined" movements: evidence for dissociable components of the body schema

We examined the nature of representations underlying motor imagery and execution in a patient (CW) with bilateral parietal lesions. When imagining hand movements, CW executed the imagined motor act but was unaware of the movements. These movements were significantly more accurate than volitional movements for the left but not right hand. CW also exhibited preserved motor imagery for the left but not right hand. Consistent with previous accounts, these findings suggest that motor imagery may normally involve the inhibition of movements. CW's unawareness of movements during motor imagery may reflect inattention or misattribution of the unexpected sensory feedback. Furthermore, in line with current models of motor control, motor imagery may depend on the integrity of a "forward model" derived from motor outflow information to generate a prediction of the consequences of a motor command. Such predictions appear to be preserved for imagery of left but not right hand movements in CW. Action may additionally depend on precise updating of effector position derived from the comparison of predicted and actual sensory information. We propose that CW's impaired volitional movements may be attributable to the degradation of such an updating mechanism.     

Division of the corpus callosum into subregions

Various attempts have been made to subdivide the corpus callosum (CC) into anatomically and functionally distinct subareas. A promising current approach is the use of factor analytic techniques in conjunction with traced MRI images. The traced images are divided into 99 percentile slices, where the widths of the percentile slices are used as variables that are entered into the analysis (Denenberg, Kertesz & Cowell, 1991). Studies that use this technique agree broadly between 6 and 7 factors, but available factor solutions contain inconsistencies and large gaps, which arise when many of the percentile slices do not load appreciably on any of the factors. The present study uses a larger number of brains (N = 184), all normalized, and some methodological refinements in the analysis of the traced MRI images of the CC. A stable 7 factor solution was found, and the factor structure for males and females was very similar.     

The pursuit of Leonardo's constraint

Leonardo da Vinci (1452-1519) identified two stimulus situations that cannot be painted faithfully on a canvas: (a) when two objects are located in the same direction with respect to the painter's head, and (b) when parts of a surface are visible to one eye, but occluded from the other eye. He analysed these situations in terms of rays being emitted from the two eyes and, aside from the origin of the rays, the projective geometry he used was correct. His analyses showed that what can be seen from two vantage points cannot be represented on a canvas, because a 'correct' painting must be created from a single 'station point'. He was struck by the consequence of this fact that the depth seen on a canvas cannot match that of viewing the scene with two eyes. Subsequent visual scientists focused on Leonardo's observation about the lack of vivid depth in a picture. We argue that a complete understanding of what we see in the two stimulus situations requires consideration of visual direction in addition to visual depth. More specifically, we argue that the visual directions of the two objects, (a) above, and the visual direction of the monocular areas, (b) above, are dependent upon the constraint that two opaque objects cannot be represented in the same direction. Demonstrations that readers can perform, and that support this argument, are provided on the Perception website at http://www.perceptionweb.com/perc0102/ono.html.