Objective: In the current study, we compared the kinematics of planar reaching movements between patients with Spinocerebellar Ataxia Type 12 (SCA12) and healthy control using a novel tracking device.

Background: Reaching to a target is frequently abnormal in patients with movement disorders. A trained clinical eye can often localise the affected region by observing the movement pattern of reaching; we investigated whether this could be quantified and automated in SCA12 patients. SCA12 is a rare and slowly progressive heredodegenerative condition where a cerebello-striato-cortical circuit is affected.

Method: In our custom-made reaching task, participants sat in front of the device in a quiet, comfortable, and semi-illuminated room. The device has five transparent illuminating buttons placed at the four corners and center of a plus shape. The peripheral buttons illuminate randomly separated by illumination of the central button. Each button illuminates for 16 times with an interval between two consecutive illumination of 2 sec. The participants were instructed to press the button rapidly once illuminated. A digital camera installed in the device recorded the movement from above. The captured video was then processed in the DeepLabCut (DLC) platform to generate a text file of the estimated pixel locations of the annotated point on the dorsal surface of the index finger. This output was then processed through a customized Matlab (MathWorks) script.

Results: While comparing the reaching kinematics of four SCA12 patients and four healthy subjects, we found that the maximum distance from the straight line connecting peripheral targets from the centre was significantly higher in the disease group compared to control. Interestingly, reaching the target forward and furthest from the subject were least affected in SCA12 patients. Trajectory variability was significantly greater in SCA12 patients. The speed and precision of landing on the target was also affected in these patients.

Conclusion: As expected, the variability of reaching trajectory and the velocity were compromised in SCA12 patients, suggestive of cerebellar and striatal involvement. But the observation that reaching was least impaired in the forward direction (furthest) is interesting and may have clinical importance is the subject of further investigation.

« Back to 2023 International Congress

MDS Abstracts - https://www.mdsabstracts.org/abstract/reaching-kinematics-in-patients-with-spinocerebellar-ataxia-type-12-using-a-markerless-motion-tracking-system/