Wednesday, 23 November 2011

Bimanual coordinated rhythmic movements

This study is my first proper taste of real experimental science. So the results of which could either be a source of immense frustration, relieve or equally delight. The first part of my study is relatively simple and involved 12 younger adult participants aged 18-27 (M=21) performing bimanual coordinated rhythmic movement training using one of two displays; Lissajous display or a coordination feedback display. With assessments at baseline and post training tests on both of these. In addition to this judgement tasks were performed at baseline and post training. The aim of this research is to directly compare the two feedback methods as they are both established but have not yet been compared.
After compiling and analysing my control group data for the current study a number points became clear. Results were either reassuring relationships or slightly surprising but none the less logical and somewhat exciting developments.
To start with the reassuring results. As this is my first study without peers or a supervisor present throughout all the data collection I was impressed to see my results conformed with almost everything written in this subject. To no great surprise 0 and 180 degrees mean relative phase were the most stable conditions during coordinated rhythmic movement performance. 90 degrees was the least stable with a significantly lower proportion of time on task compared to the two stable states. To make things even better, a relatively well established effect of training in younger adults was recorded. Training at 90 degrees in both feedback methods resulted in improved stability at 90 degrees in the trained condition with no generalisation to other phases.
This however is where the frustration began...
There was no transfer of learning from the trained feedback methods to the untrained method. Initially this was a little disappointing as this was not expected or more correctly not the desired outcome. It was originally hoped that the coordination feedback training group would show transfer to the Lissajous feedback but not vice versa. However on closer inspection the actual results provide strong evidence for perceptual learning and differing task dynamics. This is evident as people learnt to use the trained feedback method correctly. In such that people do not learn the desired movement pattern per se, but learn how to produce the desired feedback display. As a result people learn to perceive their movements in the form of a movement display not as an action. Since this is the case and no transfer occurred it suggests that the two feedback methods are informationally distinct from one another. With the learnt perceptual information encapsulated within the specific feedback displays. Therefore each group learnt fundamentally different task dynamics where subjects learnt to generate 90° mean relative phase using specific visual feedback.
With a bit of dedicated time and thought these results are not altogether surprising and tie up loose ends between the Lissajous and Coordination feedback displays; as direct comparisons are now possible between the two feedback methods.
Despite this, questions still arose from other areas of the results. Firstly in our study 0 degrees and 180 degrees are defined in terms of visual feedback not muscle activation. As a consequence 0 degrees produced a non-homologous muscle group activation whilst 180 degrees produced homologous muscle group activation. Which may account for a slightly higher than normal 180 degree performance. Secondly the judgement data did not change with training, but this may have been due to the design of the study. As judgements were performed at 1Hz which may be too fast to allow successful judgements of phase to occur.
In conclusion after dipping my toe into the water for the first time so to say the results were very positive and have produced favourable and exciting data from which my thesis and first paper can be written. So all in all I would say so far so good.

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