Description of the bug
A bug was found in the Arm Posture Perturbation (Dexterit-E Version 3.9) task that allowed a trial without a perturbation to occur under rare conditions. This situation will occur if the subject leaves the target (after the background load has been applied) and does not return for 10 seconds. This behaviour causes the trial to time out. At this point, the next trial will run without background loads. All following trials will run correctly. This erroneous trial would be analyzed incorrectly as if it had background loads.
The task has been corrected in Dexterit-E 3.10 (to be released Feb-23) so that this situation will not occur. Additionally, the analysis in Dexterit-E 3.10 has been updated to recognize these trials that do not contain loads and properly exclude them from analysis. We strongly recommend reanalyzing all Arm Posture Perturbation data that you have collected once you’ve upgraded to Dexterit-E 3.10.
Impact of the bug
A review of nearly 900 impaired assessments from 195 individuals who were assessed with this task found that about 10% of assessments contained timeouts and therefore would be affected by this issue. Of those affected assessments 70% had 4 or fewer timeouts. At that level we expect the Task Score would increase by 0.5 or less with the updated analysis. The maximum number of timeouts possible is approximately 10. At that number of timeouts we would expect an increase in task score of approximately 2 with the updated analysis.
If you are concerned about the integrity of your analysis, please contact Kinarm support. We can help identify specifically impacted data files.