RESUMO
This article presents the results of a multiple baseline design, across subjects, to assess the effect of vibratory stimulation on head-erect behavior in subjects who were prone. The subjects were three children with severe multiple handicaps whose mean age was 2 years 4 months and whose conditions included seizures and muscle tone disorders. Frequency of head lifts and cumulative duration of head-erect behavior were recorded during three-minute sessions with the subjects positioned prone on their forearms over a wedge. After baseline observations were recorded, vibration was applied to the paraspinal muscles of the neck and upper back for the first two minutes of each intervention session. In addition, electromyographic activity was recorded for a three-minute session at least once during both the baseline and intervention conditions. Results of the study demonstrated an increase in the cumulative duration of head-erect behavior for the three subjects and an accompanying increase in EMG activity during muscle vibration. The diversity of handicapping conditions (ie, seizures, hypertonia, and hypotonia) appeared to have no effect on the benefits received from muscle vibration for these subjects. Limitations of the study and implications for future research are discussed.
