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Biomedical subjects

M H Birnbaum

Publications and source records attributed to M H Birnbaum.

At least 19 recordsLinked to original sources
PubMed1995

Automaticity in fusional vergence therapy.

BACKGROUND: Fusional vergence therapy is typically performed under conditions that permit the patient to direct considerable attention and effort to the visual task. Unless visual function is sufficiently automatic as to require minimal attention and effort, attention directed toward visual function may detract from that available for cognitive processing. This report describes a method to develop greater automaticity of fusional vengence through the use of concurrent demands. METHODS: A retrospective pilot study of patient records was performed to assess the use of a concurrent motor demand (bouncing on a rebounder) to develop automaticity of fusional vergence. RESULTS: In most cases, patients who achieved adequate fusional vergence without the concurrent motor demand demonstrated a decrease in fusional vergence ranges when the motor demand was added, and then improved with practice so that vergence ranges while bouncing on the rebounder approached those achieved while seated. This pattern was obtained in 75 percent of the base-out and 57.1 percent of the base-in protocols. Some patients who showed a decrement in performance with introduction of the concurrent demand failed to improve with practice; this pattern was observed in 28.6 percent of the base-in protocols, but in none of the base-out protocols. Some patients showed no decrease in performance when the concurrent distracting task was introduced (observed in 25 percent of the base-out protocols and 14.3 percent of the base-in protocols). CONCLUSIONS: In most cases, maximum automaticity is not achieved when fusional vergence is trained under conditions that permit the patient to devote full attention to the vergence task. Introducing concurrent distractors may be desirable to automate performance and enable the patient to maintain fusional vergence even while attention is directed to the concurrent task. Heightened automaticity may reduce the effort and attention that must be directed toward binocular function, and hence maximize attentional capacity available for information-processing, comprehension, and performance on the task at hand.

Adolescent↗
PubMed1994

Behavioral optometry: a historical perspective.

BACKGROUND: The term behavioral optometry is often used to refer to all aspects of practice associated with case analysis and vision therapy. Practitioners with differing backgrounds and perspectives may use the term differently, resulting in poor communication. METHODS: The evolution of behavioral optometry is reviewed from a historical perspective, to identify the various lines along which the field has developed and to clarify the differing perspectives that result. RESULTS: Behavioral optometry had its origins in strabismus orthoptics and in case analysis systems developed to resolve asthenopic complaints in nonstrabismic individuals. From these roots, behavioral optometry has evolved along two complementary lines. Traditional, physiologically-based models emphasize accommodation-convergence relationships and the mechanisms of vergence dysfunction. Behavioral approaches emphasize the influence of environment and experience upon visual function, the relationship of vision to other aspects of organismic behavior, and the role of vision as a modality for gathering and processing information. CONCLUSIONS: The past 50 years has brought substantial growth in the scope of behavioral optometric care, with consideration of the role of vision in relation to school achievement, VDT use, sports, spatial and motor organization, and information-processing. Models of care emphasize prevention, remediation, rehabilitation, and enhancement. Behavioral optometry is an integral component of optometric education and practice.

Behavioral Medicine↗
PubMed1990

Judgments of proportions.

This study investigated the processes that underlie estimates of relative frequency. Ss performed 4 tasks using the same stimuli (squares containing black and white dots); they judged "percentages" of white dots, "percentages" of black dots, "ratios" of black dots to white dots, and "differences" between the number of black and white dots. Results were consistent with the theory that Ss used the instructed operations with the same scale values in all tasks. Despite the use of the correct operation, Ss consistently overestimated small proportions and underestimated large proportions. Variations in the distributions of actual proportions affected the extent to which Ss overestimated small proportions and underestimated large proportions in the direction predicted by range-frequency theory. Results suggest that proportion judgments, and by analogy probability judgments, should not be taken at face value.

Adult↗
PubMed1989

Two operations for "ratios" and "differences" of distances on the mental map.

Ss judged "ratios of distances" and "differences of distances" between pairs of U.S. cities. Results fit the theory that Ss used two comparison processes as instructed. A ratio scale of distances between cities was constructed from the 2 rank orders. From this scale, an interval scale of the city locations on an east-west continuum was derived. This scale agrees with the subtractive model fit to "ratios" and "differences" of easterliness and westerliness, and it also agrees with multidimensional scaling of judged distances between cities. These findings are consistent with the theory that Ss use subtraction when instructed to judge either "ratios" or "differences," but that they can use both ratio and difference operations when the stimuli (in this case, distances) constitute a ratio scale on the subjective continuum.

Adult↗
PubMed1985

An esophoric shift associated with sustained fixation.

Some subjects show a progressive increase in their near phoria, in the direction of more esophoria, when the test is repeated. Eighteen of 100 subjects showed 5 delta or more esophoric shift. This result suggests that similar phoria changes may occur during prolonged intensive nearwork. The results reported are not the same as prism adaptation because the esophoric shift was found with dissociated targets. Autonomic arousal with sympathetic activation associated with heightened attention and concentration is proposed as the mechanism.

Accommodation, Ocular↗
PubMed1985

Nearpoint visual stress: clinical implications.

A physiological model of nearpoint stress, based on autonomic arousal, was presented in a companion paper. This paper deals with clinical implications of the nearpoint stress model, including clinical manifestations, adaptive responses to nearpoint stress, and management of nearpoint stress-induced vision disorders.

Accommodation, Ocular↗
PubMed1984

Weight of evidence supports one operation for "ratios" and "differences" of heaviness.

This paper investigates an apparent contradiction between recent studies of "ratios" and "differences" of heaviness. Birnbaum and Veit (1974) found a single rank order for judgments in the two tasks, whereas Rule, Curtis, and Mullin (1981), who used a different stimulus set, procedure, and experimental design, reported two orders. To investigate the cause of this discrepancy, the present study manipulated the experimental design using the same stimuli and procedure as Rule et al. (1981). In one experiment (within-subject designs), each subject judged all combinations of the standard and comparison stimulus; in the other experiment (between-subjects designs) each subject received only one standard, and different groups of subjects were given different standards. "Ratios" and "differences" of heaviness were monotonically related for the majority of subjects who judged all combinations of standards and comparisons. Variations in the modulus and response examples did not affect the rank order of "ratios" within subjects. These results suggest that the contradiction in results is due to the difference in experimental design rather than differences in stimuli or procedure. In the between-subjects designs, the rank order of the "ratio" judgments depended on the standards and examples. Both previous and present results are consistent with the theory that subjects use one operation, subtraction, for both tasks and that the judgment function varies with between-subjects manipulations of the standard, examples, and modulus.

Humans↗
PubMed1984

Noncomitant strabismus: evaluation and management.

A model is presented for the functional evaluation and management of noncomitant strabismus. The model considers the identification of noncomitancy and the differences in approach to evaluation and management depending upon whether the involvement is recent or long-standing.

Diplopia↗
PubMed1984

Nearpoint visual stress: a physiological model.

The nearpoint visual stress theory holds that a tendency for convergence to localize closer than accommodation is intrinsic to the nearpoint visual demands imposed by our culture. A physiological model is presented, suggesting that this effector system mismatch arises from the activation of autonomic reflexes related to stress, vigilant attention and information-processing. Autonomic arousal exerts a cycloplegic-like effect. Excess accommodative effort, which must be exerted to achieve required accommodation, produces a tendency towards overconvergence. The demand for integration of accommodation and convergence, essential for efficient nearpoint function, is thus incompatible with our own physiology, since autonomic arousal is inherent in task demands for attention and mental effort associated with reading. Additionally, autonomic arousal is generated by the high levels of stress pervasive in our society. Various refractive, binocular and accommodative deviations may arise adaptively in order to resolve this mismatch and facilitate efficient nearpoint visual function. These nearpoint stress-induced visual disorders parallel stress-induced systemic illness in that both result from the activation of physiological processes which are inappropriate for the demands and stresses of our society.

Accommodation, Ocular↗
PubMed1984

The power of visual training.

Recent evidence suggests that the capacity to alter human function, including visual function, is substantially greater than previously thought possible. Implications of this research for the modifiability of visual function through vision therapy are discussed.

Accommodation, Ocular↗
PubMed1982

Loci of contextual effects in judgment.

Three experiments investigated the loci of contextual effects in judgment. Experiment 1 demonstrated the effect of stimulus spacing on category ratings and magnitude estimations of the darkness of dot patterns. Variations in the stimulus spacing were shown to affect both category ratings and magnitude estimations in a similar fashion. Experiment 2 was designed to determine whether contextual effects due to stimulus spacing influence the scale values or the judgment function. Subjects judged "differences" and "ratios" of the subjective darkness of dot patterns. Differences in mean judgments of single stimuli from Experiment 1 did not predict the rank order of judged "differences" and "ratios" from Experiment 2. The estimated scale values of the stimuli appeared to be independent of stimulus spacing. These findings suggest that contextual effects due to the stimulus spacing occur in the judgment function for within-modality judgments. Experiment 3 examined contextual effects in cross-modality judgments. Stimulus spacing and stimulus range were manipulated for "difference" and "total" judgments. Unlike the within-modality results, the stimulus range and spacing influenced the scale values. A contextual theory of within- and cross-modality judgment is presented.

Discrimination Learning↗