The use of 3 dimensional motion analysis to determine whether quantitative criteria can be found for the Prechtl’s Qualitative Assessment Method of General Movement (GMsA) classifications of writhing and fidgeting in the normative infant population

Prechtl’s Method on the Qualitative Assessment of General Movement (GMsA) of infants (Alexander et al., 1993, Darsaklis et al., 2011, Einspieler, 2004, Haywood and Getchell, 2009, Piek, 2006) is one method of early prediction of neurodevelopmental outcomes in infants. This movement assessment uses video recordings and the naked eye of the assessor and has established 2 distinct movement classifications (Writhing and Fidgeting) which occur in healthy infants aged from term to 1 month and 3 months, respectively.


GMsA relies on qualitative classification, resulting in potential intra-, inter- assessor reliability and naked eye errors. A review from Darsaklis et al. (2011) found that there was conflicting evidence that GMsA could accurately predict neurodevelopmental outcomes particularly in cases where the neurological dysfunction was mild. Three Dimensional Motion Analysis (3DMA) may be a useful tool in measuring small movements that maybe missed in predicting neurodevelopmental outcomes using GMsA’s naked eye approach.
Compared to GMsA’s, 3DMA gives insight in all three planes (sagittal, coronal & transverse) of infant movement without “naked eye” error. Complemented by force plate data, enhanced understanding of the infant postural behaviour can be determined.


This novel preliminary study developed an infant 3DMA technical protocol to collect infant movement using the latest 3D motion analysis technology. The collected data was used to quantify GMsA movement classifications using mathematical pattern recognition techniques, in a small cohort of healthy full term infants. Fuzzy entropy was found to be the most useful mathematical pattern recognition technique to separate movement patterns in the writing and fidgeting datasets especially in the force datasets. It was found that there was a marked decrease in force fuzzy entropy between the writhing and fidgeting data. It is believed this decrease in entropy is due to the infants’ postural stability and control development.


This normative-reference data, along with the developed infant technical protocol and fuzzy entropy, could be used, in future studies, to differentiate between potential normal and abnormal child development and the need for targeted early interventions.

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