Comparison of visual assessment tests in multiply handicapped children

Abstract

SUMMARYThe aims of this study were to compare acuity estimates achieved with visual evoked potential (VEP) and acuity card techniques and to examine the success rates of each test in a group of multiply handicapped children. Subjects were 52 children (3-183 months) with multiple handicaps associated with prematurity (n = 17), congenital anomalies (n = 16), hypoxic insult (n = 10) and other disorders (n = 9). Success rates for completing the tests were: YEP 88% and acuity cards 85% (Keeler or Cardiff). The acuity card tests were less likely to be successfully completed in the severely disabled (p<0.05) and in those children with nystagmus (p<0.05). When both acuity cards were successful, results agreed to within ±1.75 octaves. Acuity card thresholds were significantly correlated with YEP thresholds (p<0.02), but thresholds achieved with VEPs were better in children with poor vision.

Cerebral Visual Impairment in Children

“…This procedure has therefore largely been replaced by other methods ), but may be helpful in assessing functional vision in children with severe CVI. It should be noted that PL methods yield lower spatial resolution values compared with orienting responses and VEP recordings (Katsumi et al 1995(Katsumi et al , 1997Mackie et al 1995 ;Watson et al 2009 ). In this way, attention and accuracy and duration of fi xation are enhanced, and false-negative responses can be reduced (Müller et al 2009 ).…”

“…Complete cerebral blindness lasted a few weeks, then perception of movement returned, followed by progressive recovery of visual acuity, visual fi eld and oculomotor functions. Unfortunately, the use of electrophysiological correlates of vision may yield equivocal results because children with cerebral blindness may sometimes show preserved pattern-generated VEP (Frank and Torres 1979 ), but for many children with CVI, there is a good correlation between VEP and preferential looking methodologies (Mackie et al 1995 ) showing that results warrant interpretation in the context of the whole clinical picture. overlapping fi gures) and complex visual-spatial tasks (e.g.…”

The Apparently Blind Infant

“…365,386 Sweep and step VEP have been shown to be a useful and repeatable way to quantitate vision in children with cortical visual loss. 200,201,375,376 Highly specialized orientationreversal visual event related potentials have been found to correlate with severity of perinatal brain damage as assessed by MR imaging in preterm infants. 22 However, it is not known to what extent CVI, PVL, and selective injury to higher cortical centers differentially affect the VEP.…”

“…While conventional visual evoked potential (VEP) testing has not proved to be a reliable method of quantitative visual evaluation in patients with cerebral palsy, mental retardation, or severe neurological disease, 19,61,176,182,395,396,557 modified techniques using sweep and step VEP may provide more accurate information. 200,375,376 In children with poor vision and nystagmus due to anterior visual pathway disorders, Jan et al 298 proposed the performance of the "unequal nystagmus test" to determine which eye, if either, has better vision. The test is performed by noting the degree of nystagmus while the child views an attractive toy at a distance with both eyes open and then with alternate eyes covered.…”

Visual Acuity Assessment of Children with Special Needs

“…Providing such care can be a signifi cant emotional, social, and economic burden for the family. 5,[9][10][11][12] Even in school-age children, a recent study classifi ed a large percentage (19%) of children with multiple disabilities as having unknown vision impairment severity due to diffi culty establishing a precise visual acuity (VA). 8 However, the presence of multiple disabilities can make it diffi cult to assess vision in infants and preschool children using standard clinical examination techniques.…”