<p> Centre of pressure (CP) excursion frequency characteristics of normal and
visually impaired children were examined. Thirty-six normal (N) children and 12
visually impaired (VI) children stood on a force platform under 4 conditions (eyes
open or closed, normal or foam surface). CP excursions were analyzed by fast
Fourier transformation. Total power was calculated between 0-4 Hz, and percent of
total power was calculated in the low (0-1 Hz) and high (1-4 Hz) bands. Linear
regression was performed on logarithmically transformed data and the slope was
used to compare the relative power at low and high frequencies. Analysis of
covariance removed the variance due to height in the N children. The Mann-Whitney
test compared theN and VI children. Total power decreased with age. Young
children (4-7 years) had more high frequency power. Young children may respond
intermittently to feedback with ballistic type movements while older children may
continuously monitor and respond to sensory feedback. Vision helped control CP
adjustments, but power did not increase between 0-1 Hz with eyes closed. VI had
higher total power on the normal surface. With eyes closed the differences were
more obvious in the older children (10-12 years) which suggests vision is important
in development to fine-tune the sensory systems. The foam reduced pressor
receptor feedback, reducing the advantage of more finely tuned somatosense in N
children. VI children had more low frequency power than N children (A-P). Young VI
children did not have a large amount of high frequency power, as the N children did,
suggesting that VI children may adapt at a younger age to continuously monitor and respond to feedback without relying on intermittent ballistic type responses. </p> / Thesis / Master of Science (MSc)
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22502 |
| Date | 07 1900 |
| Creators | Portfors, Christine |
| Contributors | Riach, Cindy, Human Biodynamics |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
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