Neurilemoma of the medial plantar nerve: a case report and literature review.

A neurilemoma is an uncommon, benign, encapsulated neoplasm whose origin is derived from the Schwann cells. Its incidence in the foot is uncommon. A review of the literature, etiology, incidence, clinical presentation, histology, differential diagnosis, and treatment are discussed. The authors present a case of a neurilemoma of the medial plantar nerve of the foot.

Mechanical treatment of plantar fasciitis. A prospective study.

A randomized, prospective study was conducted to compare the effectiveness of three individual mechanical modalities in the treatment of plantar fasciitis. Two hundred fifty-five subjects were randomly assigned to one of three treatment groups: custom-made orthoses, over-the-counter arch supports, or tension night splints. Subjects were treated for 3 months, with follow-up visits at 2, 6, and 12 weeks. No statistically significant difference was noted among treatment groups with respect to final outcomes based on first-step pain or pain felt during the day. However, there was a statistically significant difference among the three groups with respect to early patient withdrawal from the study due to continued severe pain, noncompliance, or inability to tolerate the device. Patient compliance was greatest with the use of custom-made orthoses.

Conservative treatment of plantar fasciitis. A prospective study.

A randomized, prospective study was conducted to compare the individual effectiveness of three types of conservative therapy in the treatment of plantar fasciitis. One hundred three subjects were randomly assigned to one of three treatment categories: anti-inflammatory, accommodative, or mechanical. Subjects were treated for 3 months, with follow-up visits at 2, 4, 6, and 12 weeks. For the 85 patients who completed the study, a statistically significant difference was noted between groups, with mechanical treatment with taping and orthoses proving to be more effective than either anti-inflammatory or accommodative modalities.

Valuing of identity, distribution of attention, and perceptual salience in free and rule-governed classifications.

This experiment investigated classifications of multidimensional objects to test whether (1) the valuing of identity as a classification criterion occurs early in development, (2) the distribution of attention to multiple relations increases with development, and (3) the role of separate, component relations in solving multidimensional classification problems would be manifested through measures of perceptual salience. A salience preassessment followed by free and rule-governed classification tasks were given to 4-, 7-, and 18-year-olds. Total identity, partial identity, overall similar, or overall different choices were available for classification. Results associated with both free and rule-governed classifications indicated that identity serves as a highly valued classification criterion beginning as early as 4 years of age. Results associated with salience indicated that children as young as 4 years perceive and process relations separately and that 4-year-olds show greater differential attention than older children and adults.

Perception of multidimensional stimuli: a differential-sensitivity account of cognitive processing and development.

A differential-sensitivity account of cognitive processing is described that emphasizes the development of perceptual sensitivity to object relations that are directly perceived. Four experiments are presented that investigate this account and compare it to the integrality-separability view of development and the view that younger children are nonselective in their processing of multidimensional stimuli. Results show that stimulus differences are more salient than identities (Expt. 1), younger as well as older children are highly selective in their perception and classify stimuli by separate dimensions (Expt. 2), differential sensitivity affects the perceived magnitude of stimulus differences (Expt. 3), and younger and older children perceive separate dimensions in speeded classifications (Expt. 4). The importance of considering individual patterns of responses in cognitive and developmental research is also demonstrated.

Sound localization and sensitivity to interaural time differences in human infants.

The role of interaural time differences in infants' sound localization was investigated. One experiment on free-field sound localization corroborated previous findings that the minimum audible angle changes substantially toward the end of the first half year after birth, and 3 experiments explored interaural time discrimination in that age range. The first of these 3 experiments used an adaptive psychophysical procedure, showing that infants responded appropriately in a sound lateralization task that provides a direct measure of interaural time discrimination. The other 2 experiments improved on the psychophysical procedure by taking into account the ceiling level on performance in the task. Infants aged 16, 20, and 28 weeks had thresholds in the range of 50 to 75 microsec, with no apparent age difference. These thresholds were much lower than would be predicted from studies of free-field sound localization, indicating that sensitivity to interaural time differences is not a limiting factor for the precision of sound localization in this age range. Instead, age-related changes in free-field sound localization may reflect the need to integrate across different localization cues and to calibrate the changing values of cues due to head growth.

Perception of the relative distances of nearby sound sources.

The pressure of a sound varies systematically with a listener's distance from a sound source, providing a useful cue for perceiving changes in the distance between a listener and a sound-producing object. The pressure-discrimination hypothesis predicts that thresholds for discriminating changes in distance are constrained by the underlying ability to discriminate the resulting changes in sound pressure--specifically, that the smallest discriminable change in distance should be about 5% of the reference distance. Previous studies reported thresholds of about 5% for reference distances greater than a few meters but surprisingly worse thresholds for closer reference distances. In the present study, thresholds at two close distances, 1 and 2 m, were within the 5% range predicted from the pressure-discrimination hypothesis. Moreover, thresholds were significantly worse in a control condition in which the pressure cue was removed. Results of previous studies were adjusted to take into account the possibility of conservative response tendencies by the subjects. These adjusted findings agree well with the results of the present study and the pressure-discrimination hypothesis. It is concluded that variations in sound pressure are very useful for perceiving changes in listener-source distances, even at close distances.

Perceptual sensitivity to dimensional and similarity relations in free and rule-governed classifications.

Two experiments were conducted to investigate the perceptual primacy of dimensional and similarity relations in the stimulus classifications of younger and older subjects. In Experiment 1, 4- and 10-year-olds were given free classifications in which they could group stimuli according to overall similarity or identities in size, color, or orientation. Both age groups classified stimuli most frequently according to identities on separate dimensions. In Experiment 2, 4-year-olds and adults were given free classifications followed by rule-governed classifications which required them to group stimuli according to specific relations. In the free classifications, a majority of subjects in both age groups classified the stimuli most frequently according to identities on separate dimensions. In the rule-governed classifications, both age groups were more accurate when a single separate relation was required for solution than when overall similarity was required. These results support a differential-sensitivity view of perceptual development, which asserts that individuals at all ages primarily perceive and use separate relations.

Effects of perceptual training on the salience of information in a recall problem.

Kindergarten children were given a salience-assessment task to determine each child's salience hierarchy for the dimensions of form, color, and position. The children were then assigned to either a control condition or one of 3 conditions providing different types of perceptual training with the child's least salient dimension. In a subsequent location recall task, children in all 3 training groups made significantly fewer errors recalling values of their least salient dimension than children in the control group. The results indicated that perceptual exposure alone was sufficient to increase the perceptual salience of the least salient dimension and its subsequent conceptual evaluation.

The role of perceptual salience in the development of analysis and synthesis processes.

The ability of 6- and 11-year-old children to solve problems requiring the analysis or the synthesis of salience-assessed stimulus relations was investigated. The relative salience of the relations of form, color, and position was assessed and a salience hierachy determined for each child. Following salience assessment, children were given a recall problem in which the salience of the relations and the type of evaluation required for solution were varied. In analysis problems, the relative salience of the irrelevant relation was either higher or lower than that of the relevant relation. In synthesis problems, the two relations to be evaluated were either more or less salient. Both younger and older children were able to solve problems requiring the analysis or the synthesis of relations, but the rate of solution varied as a function of the salience of the relations involved. There was no evidence that either analysis or synthesis preceded the other in the course of development.

Effects of perceptual salience on the matrix task performance of four- and six-year-old children.

The effects of salience on 4- and 6-year-old children's ability to classify multiplicatively was investigated. A rank-ordered salience hierachy consisting of 3 dimensions was first assessed for each S. Several weeks later half the Ss of each age group were presented with a series of 9 3 times 3 matrix problems consisting of values from 2 dimensions ranked high in salience. The remaining half received identically structured matrices consisting of values from 1 highly salient dimension and of others from a dimension ranked low in salience. The goal in each problem was to select that compound stimulus from a set of alternatives that appropriately filled an empty cell in the matrix. Prior to the matrix problems, half the Ss in each matrix condition received sensitization training designed to increase the salience of the relevant dimensions in the matrix problems. The results showed that the pre-assessed salience of the relevant dimensions affected matrix solution in that more accurate performance was associated with those problems with both relevant dimensions relatively high in salience than those with one high and one low. Although the older Ss solved more problems, the evidence for coordination in the younger Ss was clear. No effects of sensitization training were found.