## 4 Discussion  
In this study, we investigated the predictive ability of the newly developed _Fahrenheit_ in accordance with the BRS criteria and the derived cutoff values. The AUC analyses showed high predictability for the nine tasks recorded with _Fahrenheit_ (all AUC values \(\geq\) 0.7), which is comparable to the therapists' assessments. These results indicate that all tasks recorded by _Fahrenheit_ can be used to evaluate hand impairment after CeVD, similar to the BRS assessment. Instruments using Microsoft Kinect version 2 as infrared cameras, which assess the synergistic patterns and muscle contractions of the upper limbs of CeVD patients, have been reported in previous studies [17; 18]. One study, which developed the automated FMA tests, showed that both \"finger mass flexion\" and \"finger mass extension\" were measured by infrared cameras, but the other hand function items, such as \"cylindrical grasp\" or \"spherical grasp\" were measured by pressor sensors [18]. The agreement rate of each \"finger mass flexion\" and \"finger mass extension\" between the automated and original FMA tests were 66.7% and 88.9%, respectively [18]. In the present study, the agreement rate of each \"finger mass flexion\" (93.3%) and \"finger mass extension\" (93.3%) between the _Falrenheit_ and BRS were higher than those between the automated and original FMA tests. Other studies did not measure all hand function items using infrared cameras [17; 19]. The virtual reality and hand tracking system, using the LMC, have been able to evaluate and classify tremors in patients with [PERSON]'s disease in two recent studies [20; 21]. No instrument has used infrared cameras to assess the synergistic patterns and muscle contractions in the hand function of patients with CeVD, other than _Falrenheit_, described in the present study. A systematic review of movement quality in robot-assisted upper limb rehabilitation reported the various parameters of kinematic assessments with statistically significant outcomes, but there was a controversial correlation between the various parameters of kinematic and clinical assessments for hand impairment in patients with CeVD [22]. Since _Falrenheit_ was developed based on the clinical assessment of hand motor function after CeVD, it may have clinical application as a clinical instrument to assess hand impairment in CeVD patients. The clinical utility of _Fahrenheit_ is demonstrated by the significance of the differences in numeric values derived by _Falrenheit_ versus the therapists, according to the BRS assessment. The BRS assessment is not conducive to identifying subtle differences in hand motor function within each stage, although the BRS assessment is widely used in clinical rehabilitation. _Fahrenheit_ enables more finely graded measurement by recording movements in the range of 0 to 1 with a temporal resolution of 60 Hz, from movement initiation to maximum attainment, and can potentially obtain clinically useful information for a therapist about hand motor recovery in patients post-CeVD. As a result, it may serve as a measurement instrument that will lead to the development of new methods of intervention for rehabilitation. The _Falrenheit_ prediction accuracy as inferred from the AUC was low (0.77) for the index-middle finger flexion, similar to the agreement rate among the three therapists' assessments. This movement is used to assess whether, starting from a position in which all fingers are extended, the radial index and middle fingers can move separately from the