Abstract
40 4.5-6.5 year olds, 39 6.6-8.5 year olds, 38 8.6-10.7 year olds and 39 adults were tested on two tasks with visual analogue EMG biofeedback with the frontalis muscles on four consecutive days. The fine control task demanded three five-second contractions at three levels alternating with four second rest periods. Two two-minute relaxation periods, one with and one without biofeedback, but with an attentional focus, alternated with the fine control task. Clear developmental differences were found in performance on the fine control task, whatever the analysis employed, unlike the relaxation task where children made greater gains than adults and the developmental pattern identified depended on the method of analysis used. A high level of inter subject variation was found in all ages on both tasks. EMG biofeedback was shown to be effective for adult subjects (and possibly all ages) on the fine control task and for children aged 6.6-10.7 years on the relaxation task. Settling-down and low motivation without biofeedback could explain significant results in the 4.5-6.5 year olds and adults respectively. Improved performance over sessions in the fine control task; lack of relationship between performances on the two tasks and good retention and reminiscence in the relaxation task indicated that EMG biofeedback with the frontalis muscles might operate in a way analogous to that in which motor skills are acquired. Lower levels of resting tone in the frontalis muscles of adult males than adult females, with and without biofeedback, could have resulted from the adoption of somatic strategies by males and cognitive strategies by females while relaxing. No other sex differences were reported. Spatial ability, measured by performance on two tasks involving left/right reversals, was unrelated to performance on the biofeedback tasks. Therefore, tests which could be used as predictors of biofeedback performance were unlikely to be identified.