Date Presented 3/30/2017
This study employed a precise methodology to measure the visual abilities of children with cerebral palsy and cerebral visual impairment. Unique patterns of response to unimodal and bimodal sensory stimuli were identified. The results provide a foundation for evidence-based interventions for multiply challenged children.
Primary Author and Speaker: Naomi Ferziger
PURPOSE: Visual assessment of the multiply challenged pediatric population is a difficult yet vitally important process. Precise knowledge of visual responses and the environments in which they occur is of critical significance to occupational therapists in order to create settings suited to the needs of the child and to facilitate exploration, learning, and communication. The purpose of this study was to assess the effectiveness of implementing a computerized video coding system to measure the visual responses of children with cerebral palsy (CP) and cerebral visual impairment (CVI), particularly their visual function when engaged in visional, nonvisual, and/or bimodal activities. As such, the study adheres to the Activities and Participation domain of the International Classification of Functioning, Disability and Health (Rosenbaum & Stewart, 2004; World Health Organization, 2001).
DESIGN: This study used a quantitative experimental design. Forty participants with CP, severe spastic quadriplegia, and severe to profound intellectual disabilities, 20 with CVI and 20 with no visual impairment (No VI), were recruited from the Aleh Rehabilitation Educational Center in Bnei Brak, Israel, after having undergone a clinical visual examination by an on-site ophthalmologist (22 female, 18 male; age range = 3–20 yr, M = 8 yr, 3mo, SD = 4 yr, 3 mo; Gross Motor Classification Scale Level V; Manual Ability Classification System Level V). Participants were unable to communicate consistently via verbal or assisted communication.
METHOD: In a quiet, darkened room in the educational facility, participants were presented with a series of unimodal light and nonlight stimuli—auditory and tactile—as well as bimodal sensory stimuli. Gaze responses were recorded using two synchronized cameras and subsequently analyzed by a computerized microanalytic coding system, the Observer (Noldus Information Technology, Wageningen, the Netherlands).
RESULTS: Children diagnosed with CVI were found to use gaze as part of their response repertoire, exhibiting a significantly longer duration of gaze (p < .05) toward light stimuli than toward nonlight unimodal stimuli. Yet compared to the No VI group, their visual responses showed an increased latency (p < .01) and were found to be of significantly shorter duration (p < .05) as well. In addition, stimulus enhancement occurred for the CVI group during the bimodal intervals as depicted by a significantly increased duration of gaze beyond that which took place during the unimodal nonlight intervals (p < .01). Interestingly, both groups demonstrated increased duration of gaze response during in-hand haptic stimulation in both the unimodal and bimodal conditions beyond more passive tactile stroke or tactile pressure stimuli (p < .001), highlighting the importance of such stimuli to increased visual attention.
CONCLUSION: The computerized video coding system enabled precise measurement of the gaze responses of children with severe CP to unimodal and bimodal sensory stimuli, and unique patterns of visual responses were identified, particularly among participants with CVI.
IMPACT STATEMENT: The results of this study provide the foundation for developing evidence-based interventions for children with CP and CVI. The methodology is already being applied by the presenter to assess performance during daily activities and other areas of function as well as with other multiply challenged populations.
References
Denver, B. D., Froude, E., Rosenbaum, P., Wilkes-Gillan, S., & Imms, C. (2016). Measurement of visual ability in children with cerebral palsy: A systematic review. Developmental Medicine and Child Neurology, 58, 1016–1029. https://doi.org/10.1111/dmcn.13139
Ferziger, N. B., Nemet, P., Brezner, A., Feldman, R., Galili, G., & Zivotofsky, A. Z. (2011). Visual assessment in children with cerebral palsy: Implementation of a functional questionnaire. Developmental Medicine and Child Neurology, 53, 422–428. https://doi.org/10.1111/j.1469-8749.2010.03905.x
Rosenbaum, P., & Stewart, D. (2004). The World Health Organization International Classification of Functioning, Disability, and Health: A model to guide clinical thinking, practice and research in the field of cerebral palsy. Seminars in Pediatric Neurology, 11, 5–10. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/15132248
World Health Organization. (2001). International classification of functioning, disability and health. Geneva: Author.
