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Biomedical subjects

J E Letourneau

Publications and source records attributed to J E Letourneau.

At least 19 recordsLinked to original sources
PubMed1992

Visual acuity and stereoacuity among mentally retarded children.

To evaluate the reliability and the validity of Landolt Rings and of the Frisby Test as measures of visual acuity and stereoacuity, respectively, the visual acuity of 30 mentally retarded children was measured with Landolt Rings shown as games, the Sjögren Test, the Dot Visual Acuity Test and stereoacuity with the Frisby Test. Subjects were tested 3 times over a period of 3 weeks to measure the reliability of the tests. No significant difference was observed among these tests. The validity of the Landolt Rings was measured by a correlation of .55 for the highest logMAR values of the Sjögren Test with the highest logMAR values of the Landolt Rings. Visual acuity was systematically lower on the Dot Visual Acuity Test. The Frisby Test was not reliable among a group of 16 normal children who improved systematically over 3 weeks.

Adolescent↗
PubMed1991

Nongaussian distribution curve of heterophorias among children.

The purpose of this study was to measure the distribution curve of horizontal and vertical phorias among children. Kolmogorov-Smirnov goodness of fit tests showed that these distribution curves were not Gaussian among (N = 2048) 6- to 13-year-old children. The distribution curve of horizontal phoria at far and of vertical phorias at far and at near were leptokurtic; the distribution curve of horizontal phoria at near was platykurtic. No variation of the distribution curve of heterophorias with age was observed. Comparisons of any individual findings with the general distribution curve should take the nonGaussian distribution curve of heterophorias into account.

Adolescent↗
PubMed1990

Choice reaction time as a measure of recovery from general anesthesia.

The purpose of the study was to evaluate the reliability and validity of choice reaction time as a measure of recovery from general anesthesia. An experimental group of 43 patients underwent surgery under general anesthesia; they were measured before anesthesia and also 90, 150 and 210 min. after the end of anesthesia. A control group of 38 underwent the same procedure. Choice reaction time was not a valid measure of recovery from general anesthesia since the test was not reliable.

Adult↗
PubMed1989

Heterophoria as a measure of subjects' alertness during recovery from general anesthesia.

The purpose of the study was to measure the influence of subjects' alertness on heterophoria. An experimental group of 43 patients was measured with the Maddox Wing test for heterophoria. Exophoria was greater 1 1/2, 2 1/2, and 3 1/2 hr. after the end of general anesthesia than at baseline level. Data for a control group of 25 did not vary on the Maddox Wing over four hours. The baseline level was not different between the two groups, so heterophoria as measured with the Maddox Wing can be used to evaluate subjects' alertness during recovery from general anesthesia.

Adult↗
PubMed1988

Reliability and validity of the dot visual acuity test.

The reliability of the dot visual acuity test (DVAT) was demonstrated using the test-retest method. The test, however, was not found to be valid when comparing it with the Sjögren test. Since the DVAT has previously been shown to be valid when compared to the Tumble E test, these results bring into question the validity of the Sjögren test when compared to the Tumble E test.

Child↗
PubMed1986

Influence of auditory or visual warning on visual reaction time with variations of subjects' alertness.

The purpose of the study was to determine the effect of visual and auditory warning on visual reaction time with variations of subjects' alertness. An experimental group of 30 subjects was tested with an auditory or visual warning signal; foreperiods lasted 3, 2, and 4 sec. Reaction time was shorter as alertness improved and with an auditory warning signal. Comparable measures in a control group showed that visual reaction time was shorter when an auditory warning signal was used.

Adult↗
PubMed1984

Reliability and validity of psychomotor tests as measures of recovery from isoflurane or enflurane anesthesia in a day-care surgery unit.

The reliability and validity of three psychomotor tests of recovery from anesthesia were evaluated. Rotary pursuit and pegboard tests were not reliable, but the Bender Gestalt Track Tracer was a reliable and valid measure of recovery from anesthesia. The interaction between the reliability and the validity of these tests is discussed along with their relationships to "street fitness" in a day-care surgery unit.

Adult↗
PubMed1981

Effect of auditory stimulation of subjects' chromatic visual fields.

The chromatic visual field of 14 subjects was measured while they heard a sound of 1000 Hz at 95 db during 3 min. Stimuli were produced by a monochromator. Visual threshold was lower under the influence of sound for red (lambda = 550 nm) and green (lambda = 610 nm) stimuli at 40 degrees, 45 degrees, and 50 degrees of temporal eccentricity.

Acoustic Stimulation↗
PubMed1976

Application of biofeedback and behavior modification techniques in visual training.

A review of the biofeedback literature was made and proposals for use in optometry advanced. To this end electromyograph units can be connected to an apparatus which gives a reward when a patient performs proper eye movements. By this means, patients who undergo visual training become conscious of their eye movements. As a reinforcement, they are rewarded by music or the motion of toys when they give the right answer. Application of the system in cases of strabismus, limitation of gaze, convergence insufficiency or excess, ptosis, and other cases are discussed. Methodological and financial advantages of incorporation of biofeedback reinforcement into visual training are enumerated.

Behavior Therapy↗
PubMed1976

Biofeedback reinforcement in the training of limitation of gaze: a case report.

A 22-year-old patient having a history of congenital strabismus with surgery at age 6 and again at age 14 suffered from a limitation of dextroversion following 2 surgical procedures with diplopia initially experienced beyond 18 degrees. Ten sessions of treatment by traditional visual training methods and biofeedback reinforcement were compared in extending the deficient range of dextroversion. Biofeedback was found to be significantly better than conventional approaches in this treatment.

Adult↗
PubMed1976

Effects of training in design on magnitude of the Müller-Lyer illusion.

The Müller-Lyer illusion was measured for 10 design and 10 optometry students. The illusion was smaller for design students and they improved significantly with practice. The results are discussed in relation to size-constancy, according to which part of the figure corresponding to a distant object is overestimated and to the aptitude of design students to draw according to their retinal image.

Adult↗