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Biomedical subjects

H A Solan

Publications and source records attributed to H A Solan.

At least 19 recordsLinked to original sources
PubMed1990

Binocular advantage and visual processing in dyslexic and control children as measured by visual evoked potentials.

The role of visual processing in dyslexia continues to stir controversy. Previous research using early components of visual evoked potentials (VEP's) has revealed differences in visual processing between dyslexics and controls. VEP's have successfully indexed binocular advantage. Intrasensory functioning could conceivably be deficient in dyslexics. This study recorded VEP's in response to contrast-reversing checkerboards binocularly and monocularly from dyslexic and control children. The overall monocular and binocular amplitudes of the major positive peaks (P100) were greater for controls than dyslexics; however, contrary to the original hypothesis, the magnitude of binocular advantage was higher for dyslexics than for the control children. Stimulus factors had an effect, but did not interact with reading ability.

Analysis of Variance↗
PubMed1990

Age and binocular advantage: A VEP assessment.

Monocular and binocular visual evoked potentials (VEP's) were recorded in response to contrast-reversing checkerboard patterns of 2 check sizes (14 and 28 min arc) and 2 contrast-reversal rates (1.88 and 7.50 rps) in children (10 and 11-year-olds) and young adults (20 to 30-year-olds). The magnitude of binocular advantage, expressed as the ratio of the binocular to the average monocular response, was assessed by amplitude measurements of the major positive peak. The overall VEP amplitudes were larger for children than for adults across all conditions. The VEP amplitudes for binocularly viewed patterns were also consistently larger than the VEP amplitudes for the monocularly viewed patterns for both age groups. However, when the binocular advantage was expressed as a ratio of binocular to monocular average (MAV), the amplitude difference between the age groups was no longer apparent; although the children's average VEP responses were of a larger amplitude, the binocular advantage remained the same regardless of age.

Adult↗
PubMed1990

Irlen lenses: a critical appraisal.

The purpose of this paper is to assess the credibility of the Irlen lenses, Irlen's hypotheses, and the scotopic sensitivity syndrome. The analysis includes a review of 13 pro and con research papers. Of special interest is the dichotomy which developed between researchers who were Irlen participants and the professional and scientific community who required less disputable evidence. Even the former, however, failed to find scientific support for Irlen's concept of dysfunction in the discharge rate of the retinal receptor cells. Furthermore, in the absence of any evidence that it is a separate and distinct entity, it appears that the scotopic sensitivity syndrome is, in fact, a symptom complex which results primarily from various refractive, binocular, and accommodative disorders. Some of the papers which support Irlen's hypotheses provide reason to believe that there is a strong placebo effect.

Dyslexia↗
PubMed1990

A study of perceptual and verbal skills of disabled readers in grades 4, 5 and 6.

This investigation addresses the role of the optometrist in diagnosing and treating children in grades 4, 5, and 6 who have been identified as reading disabled. Fifty-one subjects with average intelligence, but whose reading comprehension skills were below the 31st percentile (mean, 20th percentile), were evaluated using verbal and perceptual tests. When the performance of this experimental group was compared with the mean scores from standardized test norms for each of the various tasks, the disabled readers scored significantly lower in seven of the eight perceptual and five of the six verbal tasks. These results lend support to the hypothesis that both perceptual and verbal deficits are related to reading comprehension. Using step-wise multiple correlation analysis, three perceptual factors; eye-movements, Auditory-Visual Integration Test (AVIT), and grooved peg-board, contributed 38 percent of the variance whereas the addition of two verbal factors (digit span and token test) provided just 2 percent. That is, 38 percent of the variations in reading comprehension could be accounted for by variations in perceptual skills in the disabled readers. The results were interpreted in terms of spatial-simultaneous and verbal-successive processing skills.

Child↗
PubMed1989

Nonlinearities in binocular visual evoked potentials in children.

Evidence is controversial in respect to the optimal conditions in which visual evoked potentials provide an objective measure of binocular visual function, related and unrelated to stereopsis, and there is little emphasis on the type of stimulus that produces facilitation in binocular recording. We investigated the effects of stimulus type (flicker or pattern), contrast, and temporal modulation on facilitation, which was defined as a binocular response greater than sum of monocular responses. Monocular and binocular responses to sinusoidally modulated flicker and grating patterns were recorded in children and Fourier analyzed. The relationship of the fundamental Fourier component for flicker and the second harmonic component for pattern were each examined as function of temporal modulation at two levels of contrast for monocular and binocular visual evoked potentials. Binocular facilitation was found across all conditions for flicker. Data suggest that processing of pattern and flicker has different sites of origin within the visual system. Facilitation in binocular visual evoked potentials also indicates that they are not a result of simple summation of monocular responses, since there appears a nonlinear component to such interaction.

Analysis of Variance↗
PubMed1989

Visual perception and learning: issues and answers.

The role of the optometrist in treating children who are identified as learning disabled is not always understood by members of an interdisciplinary team. It is the purpose of this paper to develop a brief philosophical foundation for optometric intervention and to review some of the literature which supports the validity of optometric therapy. Correlational studies are cited to establish a basic relationship between perceptual dysfunctions and learning readiness in normal children. After establishing that perceptual training does indeed improve perceptual skills, we cite a number of investigations where intervention enabled children who had been classified as learning disabled to respond more effectively to school learning. The role of the optometrist as a member of an interdisciplinary team is addressed.

Humans↗
PubMed1988

On Helveston.

Explore the source record for details and available documents.

Child↗
PubMed1987

Perceptual norms in grades 4 and 5: a preliminary report.

Norms from a sample population (38) of normal-achieving children in grades 4 and 5 are reported using three different perceptual tasks: tachistoscope, 5 digits at .1 and .01 seconds; grooved pegboard, dominant hand; and auditory-visual integration test (AVIT). Percentiles provide within-group norms. Central tendencies are developed using means, standard deviations, and ranges. The perceptual tasks are correlated with reading vocabulary and comprehension and written and mental arithmetic. The results suggest the developmental nature of the tasks from kindergarten through grade 5. When combined with previously published data, the norms presented should enable the optometrist to conduct the tests described using standardized procedures and to interpret the results, albeit with some caution, based on data derived from the performance of normal-achieving students.

Achievement↗
PubMed1987

The effects of visual-spatial and verbal skills on written and mental arithmetic.

The relative influences of visual-spatial and verbal factors on the performance of written and mental arithmetic by normally achieving fourth and fifth grade children are compared. The independent perceptual and verbal measures were correlated with the Arithmetic Subtest of the Wide Range Achievement Test (WRAT) and the Arithmetic Subtest of the WISC-R using both bivariate and multivariate analysis. In the performance of the written arithmetic, spatial factors yield a statistically significant higher positive correlation than verbal skills. On the other hand, verbal skills appear to render a higher positive, but not statistically significant, correlation with mental arithmetic than spatial skills. Optometrists should be aware of the potential for treatment of visual and perceptual dysfunctions present in children who are experiencing problems in written and mental arithmetic.

Child↗
PubMed1986

The correlations of perceptual-motor maturation to readiness and reading in kindergarten and the primary grades.

This study lends further support to the additive nature of perceptual-motor skills and their correlation with reading. Using multivariate analysis, the investigation quantifies the extent to which success in readiness and reading in kindergarten and grades one and two is related to perceptual-motor organization. In addition to establishing concurrent validity, the results support the hypothesis that perceptual skills in kindergarten predict reading proficiency at the end of grade one. Perceptual skills play a significant role in learning to read in the primary grades. Beyond grade two, however, when cognitive and language skills appear to have a greater influence in normal children, perceptual organization remains a necessary but not a significant condition for learning.

Auditory Perception↗
PubMed1985

Eye movement problems in achieving readers: an update.

There is extant a population of subjects who have average or better than average interpretive reading skills as measured by standardized tests but who read slowly and inefficiently. Ten cases are presented where both Iowa Silent Reading Tests (ISRT) (Level III) and eye movement recordings were completed. Three of the subjects received training to improve reading efficiency. Reducing the cognitive level of the reading selections did not result in improved reading efficiency for subjects who have good interpretive skills. Substantial improvement in reading efficiency was measured in each of the three subjects selected for training.

Adolescent↗
PubMed1985

Selected perceptual norms and their relationship to reading in kindergarten and the primary grades.

This study provides standardized procedures and norms for four perceptual-motor tests and their correlations with readiness/reading in grades K-2. Theoretical constructs and cognitive implications underlying these tasks are discussed. One hundred forty-four normal children in grades K-2 were tested with the Tachistoscope, Divided Form Board, Grooved Pegboard, and Auditory-Visual Integration Test (AVIT), using standardized procedures. Norms including means, standard deviations, ranges of scores, and percentiles were established for each test at each grade level. Except for the AVIT, the correlations between the perceptual tasks and readiness or reading were not only strong in kindergarten, but remained significant in grades 1 and 2. The data suggests that as reading becomes more dependent upon language skills, cognition gradually becomes more dominant. Beyond grade 2, it appears that perception remains a necessary but not a sufficient condition for learning.

Auditory Perception↗
PubMed1979

Learning disabilities: the role of the developmental optometrist.

The role of the optometrist in treating children experiencing learning disabilities embraces numerous areas beyond the customary optometric services. Etiological, diagnostic and therapeutic factors are discussed stressing visual functional disorders, perceptual-motor and developmental lags and cognitive style. Their effects on the learning disabled child are analyzed; and the rationale of optometric procedures frequently used in treating LD children is reviewed. The optometrist may also be helpful in counseling patients who have learning readiness problems, reading disorders, psychological difficulties and nutritional deficits.

Child↗