Search Results
Results 601 - 650 of 1096
< 8 9 10 11 12 13 14 15 16 17 18 >
Tsuneishi S - - 1995
To establish normal values for flash visual evoked potentials (VEPs) in the preterm period, we analyzed 356 records from 63 neurologically normal infants (26-35 weeks gestation) followed longitudinally. Using both sleep and drowsy state recording within the same session and a mean of 5.7 weekly recording sessions per infant, we ...
Pierson L L - - 1995
The Auditory Brainstem Response (ABR) was recorded from fetal sheep in utero between gestational ages of 111 days and 136 days (Normal gestation is 145 days). The ABR was detected at 111 days gestation (dGA) and morphology of the waveform improved rapidly from 116 to 123 dGA. At 123 dGA, ...
Breton M E - - 1995
PURPOSE: To describe and analyze developmental change from birth through maturity of human electroretinogram (ERG) response, especially in terms of rod phototransduction as represented in the ERG a-wave. METHODS: Electroretinograms were recorded from 16 human infants from 5 to 270 days of age, two children 1.9 and 3.4 years of ...
Bargones J Y JY Department of Speech and Hearing Sciences, University of Washington, Seattle 98195, - - 1995
Psychometric functions are described for individual 6- to 9-month-old infants and for individual adults for auditory detection of repeated, long- and short-duration tone bursts in quiet and for single, long-duration tone bursts in quiet and in noise. In general, infant psychometric functions have reduced upper asymptotes, shallower slopes, and poorer ...
Hansen R M - - 1995
We tested the hypothesis that the dark-adapted sensitivity of the near central retina is lower than that of peripheral retina in 10-week-old infants. A spatial two alternative forced-choice psychophysical method was used to estimate the threshold for 2-deg spots presented 10 deg and 30 deg from the center of a ...
Bieber M L - - 1995
Spectral efficiency functions based on heterochromatic flicker photometry (HFP) were measured for three adults and 42 infants using a rapid visually-evoked potential (VEP) method. A 5 degrees-diameter, broadband standard (0.6 cd/m2) was presented in square-wave counterphase (15 Hz) with one of 13 monochromatic lights (420-660 nm; 20 nm steps). The ...
Abdala C - - 1995
The results of previous research reports have led some investigators to hypothesize that frequency contribution to the infant click-evoked auditory brain-stem response (ABR) is low-frequency dominated and derived primarily from the apical cochlea. This is in contrast to latency and morphology of the adult click-evoked ABR which reflects contributions from ...
Luna B - - 1995
Grating acuity and visual fields were assessed in 66 children who had had perinatal asphyxia (ASPH). Also tested were 41 healthy preterm children (H-PT). Subjects were tested at birth to one month, and four, nine, 12, 17, 24, 30 and 36 months corrected age. The mean acuity scores of the ...
Preisler G M - - 1995
Results from two longitudinal studies of blind infant--sighted mother and of deaf infant-hearing mother/deaf mother interaction, are summarized in this paper. The aim is to shed light on the role of visual and auditory stimulation in the development of communication. Video-recorded interactions taken during infancy were transcribed in a systematic, ...
Hansen R M - - 1995
Dark-adapted adults' electroretinographic b-wave thresholds are approximately 2 log units below a-wave thresholds and approximately 3 log units above the perceptual threshold, and their perceptual and the visually evoked cortical potential (VEP) thresholds are similar. Dark-adapted infants' scotopic a- and b-wave thresholds for full-field stimuli are both about 0.5 log ...
Uauy-Dagach R - - 1995
There is now clear evidence that dietary supplementation of omega-3 fatty acid is essential for normal eye and brain development. Corn oil-based diets induce omega-3 deficiency in preterm infants, affecting retinal responses to light, cortical visual evoked potentials, and behavioral measures of visual acuity. Preterm infants require docosahexanoic acid (DHA) ...
Roy M S - - 1995
The purpose of this study was to evaluate the visual development of preterm infants from 1 to 6 mo of age, using the pattern visual evoked potentials (VEP) in response to three check sizes: 60, 30, and 15 min of arc. Pattern VEP were recorded in 24 full-term and 24 ...
Mukai Y - - 1995
To find how larval fish sense mechanical stimuli via their free neuromasts, we examined morphological changes in free neuromasts in the larval willow shiner, Gnathopogon elongatus caerulescens. Free neuromasts were found on the body surface of newly hatched larvae and their number increased on both the head and trunk with ...
Hartmann E E - - 1995
Studies of sensory and perceptual abilities in infants require creative, innovative techniques. Although the young infant's response repertoire may appear limited to the naive individual, a number of highly refined procedures have been developed and implemented with these non-verbal humans over the last twenty years. The most successful protocols for ...
Schaal B - - 1995
Two-day-old newborns were videotaped during a double-choice test contrasting the odours of their amniotic fluid (AF) and of a control stimulus. To control for early motor asymmetries, the lateral position of both stimuli was balanced both between and within subjects. On average, neonates oriented their nose for a significantly longer ...
Slater A - - 1995
In recent years it has been demonstrated that cognitive development from infancy to later childhood displays some degree of (correlational) continuity. Studies that have demonstrated this continuity are reviewed, focusing on measures of visual information processing, means-ends problem-solving and other cognitive indices of infant performance. Models of continuity are described ...
Sinskey R M - - 1994
A cataract extraction and primary capsulotomy with intraocular lens (IOL) implantation was performed on a 17-day-old infant with a monocular mature congenital cataract. The IOL power, calculated at the time of surgery, was undercorrected to compensate for the growth of the eyeball. Two additional surgical procedures were required to resolve ...
Yu X H - - 1994
Adaptive implementation of an optimal time-varying filter (TVF) for evoked potential (EP) estimation is addressed in this paper. A data-adaptive scheme is used, which converges asymptotically to the optimal TVF solution. Two basic adaptive TVF's (ATVF's) are first introduced, namely least mean square (LMS) ATVF and recursive least-squares (RLS) ATVF. ...
Neuringer M - - 1994
Low levels of dietary n-3 fatty acids during development lead to changes in the electroretinogram and visual acuity in rats, monkeys, and human infants. Additional aspects of vision can be measured in infants and may provide further useful information about the nature of the changes induced by n-3 fatty acid ...
Bronson G W - - 1994
Visual scanning patterns of 6-13-week-old infants are derived from some 50 half-minute assessments in which the infants viewed static geometric figures. Measures include fixation dwell-times, saccade lengths, and the choices and sequences of saccadic targets. From the patterns of change across 3 age periods, it appears that as infants grow ...
Hamer R D - - 1994
Using the sweep visual evoked potential (VEP), we have measured oscillatory displacement thresholds (OMTs) in 49 infants ranging in age from 7 to 54 weeks of age. The stimuli were high-contrast (80%), sine-wave gratings (1 c/deg) undergoing oscillatory displacements at 6 Hz. In addition to the motion thresholds, contrast thresholds ...
Fern K D - - 1994
BACKGROUND: Resistance to occlusion and fix and follow are often used to make inferences about the acuity of young children. In this study, the acuity of 6- to 12-month-old infants was degraded monocularly to elicit resistance to occlusion or loss of fixation. METHODS: Occlusion foils and optical blur were used ...
Safran A B - - 1994
We treated five patients with vestibular neuritis who had strabismus. Three of them spontaneously noted vertical diplopia. During the following weeks and months, strabismus progressively resolved, indicating the recently acquired nature of the oculomotor condition. In three of these individuals, a change in visual vertical and cyclo-torsion of the globes ...
Brown A M - - 1994
It has been shown previously that relatively low stimulus levels (L1 = 55, L2 = 40 dB SPL) elicit recordable levels of ADP from healthy adult ears (Gaskill and Brown, 1990). We have used the same stimulus levels in healthy term infants within 6 days of birth. The results from ...
Worley G - - 1994
Thirty-seven infants with myelomeningocele received brainstem auditory evoked potentials (BAEPs) at a median age of eight days. No infant had brainstem dysfunction at the time of testing. Median follow-up was at 30 months. Of 12 infants who subsequently developed brainstem dysfunction at a median age of three months, 11 had ...
Alais D - - 1994
When motion aftereffects (MAEs) are measured by adapting to a drifting plaid (simultaneous adaptation) or by adapting to the plaid's component gratings in alternation (alternating adaptation), it has been shown that the velocity and duration of the MAE are smaller in the latter case [Wenderoth, P., Bray, R. & Johnstone, ...
Rudduck G A - - 1994
We have previously reported on the development of black/white pattern reversal VEPs in premature babies of more than 30 weeks post-menstrual age (PMA). Unlike the flash VEP, the pattern reversal VEP shows a similar morphology to that of the full term infant and the major positive component (P1) decreased in ...
Hermans A J - - 1994
Visual functions (grating acuity, visual field size, optokinetic nystagmus and eye alignment) were tested as part of a longitudinal study in 96 low-birth-weight infants (birth weight 1500-2500 g) at one year of corrected age. Except for optokinetic nystagmus, deficit rates of all visual functions were low, and the obtained values ...
Cocker K D - - 1994
PURPOSE: To determine the age of onset of the pupil grating response (PGR). To compare estimates of resolution acuity obtained by pupillometric and behavioral methods in early infancy. METHODS: Dynamic infrared pupillometry was undertaken on 19 newborn infants while they fixated a uniform background upon which a 0.1 c/deg sine ...
Hansen R M - - 1994
The large critical areas for complete spatial summation in infants may be due to immaturities of receptive field organization in both dark and light adapted scotopic conditions. Scotopic lateral excitatory/inhibitory interactions have been previously studied in adults using Westheimer's [(1965) Journal of Physiology, London, 181, 881-894] paradigm. We modified this ...
Hansen R M - - 1994
PURPOSE: To compare psychophysical and reflexive optokinetic nystagmus (OKN) estimates of dark-adapted scotopic thresholds mediated by the posterior retina in 10-week-old infants and adults. METHODS: A staircase procedure was used to determine the stimulus intensity needed to produce an OKN response to a moving 19 degrees x 19 degrees grating. ...
Thorn F - - 1994
PURPOSE: To measure and compare the development of ocular alignment, sensory binocularity, and convergence in infants during the first 5 months of life. METHODS: Healthy infants were tested between 2 and 21 weeks of age. Ocular alignment was measured by the Hirschberg test; convergence was determined by visual examination as ...
Riddell P M - - 1994
PURPOSE: The Hirschberg ratio has been defined as the ratio of the change in angular position of the line of sight to the change in location of the first Purkinje image relative to the pupil center. This study was designed to determine empirically whether the adult value of the Hirschberg ...
De Vries L S - - 1994
The data reported in the literature and our own findings have shown, that evoked potentials (EPs) can be performed at the bedside and provide additional information about the integrity of the central nervous system. Auditory brainstem responses (ABRs) are especially useful for early identification of audiological problems and whenever possible, ...
Mintz-Hittner H A - - 1994
PURPOSE: Flash and pattern visual-evoked potentials (VEPs) were recorded in 89 former preterm infants (< or = 1500 g birth weight), in whom retinopathy of prematurity (ROP) developed that spontaneously regressed without macular detachment (stages 2-4a). METHODS: Linear and stepwise regression analyses were performed to determine the correlations between transient ...
Eken P - - 1994
A prospective follow-up study was conducted of a cohort of 65 at-risk neonates to assess the predictive value of neonatal cranial ultrasound abnormalities for cerebral visual impairment in infancy. Visual function was assessed using the acuity card procedure and behavioural visual responses were tested. Normal visual function was found in ...
Morrone M C - - 1993
We have monitored the development of contrast sensitivity to equiluminant red-green chromatic patterns by monitoring visual evoked potentials (VEPs) in 13 infants. The results confirm our previous report [Morrone, Burr and Fiorentini, Proceedings of the Royal Society B, 242 (1990a)] that, before 7-8 weeks of age, there was no response ...
Allen D - - 1993
Chromatic sensitivity is very low in humans during the first few months of life. We examined whether low chromatic sensitivity reflects a deficiency among chromatic mechanisms or whether it is simply a manifestation of poor visual sensitivity in general. The sweep VEP was used to measure contrast sensitivity to gratings ...
Frank Y - - 1993
Fourteen infants and children with AIDS had serial BAER studies, with stimuli delivered at a frequency of 10 and 50 per second. The latencies of waves I, III, V and interpeak latencies I-III, III-V and I-V were measured, and their changes over time were calculated. A significant correlation was found ...
Berg K M - - 1993
Behavioral thresholds of 6-month-old infants and adults were determined for 1/3-octave filtered clicks and 300-msec noise bursts with center frequencies ranging from .5 to 8 kHz. For noise bursts, differences between infant and adult thresholds were largest at low frequencies and smallest at 8 kHz. For clicks, infants' thresholds were ...
Teller D Y - - 1993
Tested monocularly, young infants classically show directional eye movement asymmetries, with optokinetic nystagmus (OKN) being more readily elicited by stimuli moving in the temporal-to-nasal (T-N) than in the nasal-to-temporal (N-T) direction. Since a counterphase grating is physically identical to two superimposed sinusoidal components moving in opposite directions, we wondered whether ...
Hansen R L - - 1993
Prenatal exposure to cocaine and amphetamines has been associated with many adverse effects in infants, including neurological abnormalities. Recent evidence shows that the visual system may be useful in infancy to evaluate neurological functioning. Visual evoked potentials (VEPs) and visual recognition memory testing were carried out on eight infants with ...
Holmes J M - - 1993
The feasibility of a practical preferential looking technique, similar to Teller acuity cards, was investigated for the assessment of vernier acuity in preverbal infants. Forty-two infants ages 1 to 13 months were tested with cards having vernier offsets of 2 to 64 minutes of arc and spatial frequencies of 0.25 ...
Hartnett M E - - 1993
Despite surgical reattachment of the retina in infants with severe retinopathy of prematurity (ROP), visual acuity may decline. We performed gonioscopy and applanation tonometry on 26 eyes of 17 infants with severe ROP who were randomly selected and followed prospectively for 2 years. Of these 26 eyes, one eye of ...
Friendly D S - - 1993
Behavioral improvement in the quality of infant vision parallels neuroanatomic and neurophysiologic brain development. Progressive refinement of acuity can be tracked by means of tests that employ fixation and following, optokinetic nystagmus, preferential viewing, and pattern-evoked visual responses. These methods of evaluating vision in the preverbal child differ from each ...
Freeseman L J - - 1993
Cognitive performance and development is negatively correlated with fixation duration patterns during infancy, and evidence suggests that long-looking infants may process visual information more slowly than short-looking infants. 3 experiments described here tested the possibility that these differences may be due to differential sensitivity to global and local visual information. ...
Morrow J D - - 1993
The purpose of this article is to provide the pediatric nurse practitioner with an introduction to the literature on the use of visual-attention measures to screen for cognitive deficits in the infant. These measures rely on an infant's preference for novelty, that is, the tendency to look at a new ...
Carlson S E - - 1993
Docosahexaenoic acid (DHA; 22:6n-3) is important for normal visual development. We hypothesized that preterm infants fed formulas with marine oil as a source of DHA would have better visual acuity than infants fed formulas without marine oil, as measured by the Teller Acuity Card procedure. Marine oil (P < 0.001) ...
Flinn J M - - 1993
Auditory evoked potentials (AEPs) to click and name stimuli were recorded for 23 malnourished infants on admission to and 17 on discharge from hospital, together with those from age-matched controls. The number of peaks on the AEPs and the amplitude were examined. The malnourished infants' AEPs to click stimuli differed ...
Catherwood D - - 1993
The robustness of infant haptic memory was assessed in terms of its capacity to withstand either a brief delay or potential retroactive "interference" from other haptic input. 48 infants (mean age 8 months) were familiarized haptically to a small cube or sphere with smooth or rough surface texture and subsequently ...
< 8 9 10 11 12 13 14 15 16 17 18 >