An apparatus, system and process for measuring, tracking, and analyzing unintentional muscle movements associated with upper body freezing of a user while using a handheld tool are described. The method may include receiving signals from a motion sensor of a handheld tool, the signals indicating motions of the handheld tool when used by a user during an activity. The method may also include analyzing the motions of the handheld tool. The method may also include detecting motions of the handheld tool having one or more predetermined characteristics. Furthermore, the method can include determining that the user experienced an upper extremity freezing while using the handheld tool during the activity based on the detected one or more predetermined characteristics.
