Abstract
Gait analysis of transgenic mice and rats modeling human diseases often suffers from the condition that those models exhibit genotype-driven differences in body size, weight, and length. Thus, we hypothesized that scaling by the silhouette length improves the reliability of gait analysis allowing normalization for individual body size differences. Here, we computed video-derived silhouette length and area parameters from a standard markerless gait analysis system using image-processing techniques. By using length- and area-derived data along with body weight and age, we systematically scaled individual gait parameters. We compared these different scaling approaches and report here that normalization for silhouette length improves the validity and reliability of gait analysis in general. The application of this silhouette length scaling to transgenic Huntington disease mice and Parkinson´s disease rats identifies the remaining differences reflecting more reliable, body length-independent motor functional differences. Overall, this emphasizes the need for silhouette-length-based intra-assay scaling as an improved standard approach in rodent gait analysis.
Footnotes
The authors declare no competing financial interests.
I.K.T. received financial support from DAAD for research studies (Research Grant 57129429). S.M., A.-C.P., J.H., F.C. and S.v.H., were supported by the EU Joint Programme-Neurodegenerative Disease Research (JPND) project CrossSeeds (Grant 01ED1501C). J.W. and J.K. were supported by the Interdisciplinary Center of Clinical Research (IZKF; Grants E21 and E11) of the University Hospital Erlangen, Germany, and the Bavarian State Ministry of Education and Culture, Science and Arts in the framework of the Bavarian Research Network for Induced Pluripotent Stem Cells (ForIPS) and the European Institute of Innovation and Technology Health (EIT Health; MoveIT). J.K. was supported by the Deutsche Forschungsgemeinschaft (DFG; Grant KL1395/8-1). N.C. and O.R. were supported by NEURASYNC: an Academic Industrial Initial Training Network (ITN) through the people program FP7 of the European Union and FCT (Grant PTDC/SAU-NEU/105215/2008). B.E. was supported by the DFG within the framework of the Heisenberg Professorship program (Grant ES 434/8-1). S.M., F.C., and S.v.H. acknowledge the support by the JPND project CrossSeeds (Grant 01ED1501C). This research was supported by the DFG and Friedrich-Alexander-Universität Erlangen-Nürnberg within the funding program Open Access Publishing.
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