Background This study aims to assess if tgHD Minipigs (124 Q) develop symptoms characteristic of human HD in comparison with wt Minipigs. To investigate this, we developed and test motor, cognitive and behavioural tests.

Aims We here report novel motor function tests, the “Tongue-Test” and the “Hurdle-Test”, and assess their feasibility, tolerability, cross sectional and longitudinal results.

Methods The wt (n = 18) and tg (n = 14) Minipigs have to perform the same motor function tests. The Tongue-Test is divided into a training phase and a test phase. During the training phase the pig is presented with a board containing 10 holes measuring the same in diameter and depth. A treat is placed in each hole and has to be picked up with the tongue. A training session lasts until the pig has successfully recovered all 10 treats. It is repeated three times unless a trial lasts more than 5 min, in which case the assessment is stopped. During the test phase the pig is presented with a board that looks the same as the one used in the training session. However, the holes in this test board increase in their depth and the number of successfully recovered treats is counted. The test is repeated three times.

The Hurdle-Test assesses general motor function of the Minipigs while climbing over hurdles and contains a test 1phase only, since no specific training is needed. Six runs are performed. The test is videotaped for further analysis.

Results Preliminary non-parametric statistics suggested that at baseline tg Minipigs perform both the Tongue and Hurdle-Test faster than wt Minipigs. No differences were seen at follow-up visit 1 (6 months) and 2 (12 months – assessments ongoing). Further analysis (ANOVA) is pending and will be presented at the EHDN meeting.

Conclusion TgHD Minipis are capable to perform both the Tongue and Hurdle-Test successfully and repeatedly. Phenotypical characteristics of the tgHD versus wt comparison will be reported and discussed after completion of ANOVA analysis.