Objective: The aim of the present study was to evaluate the feasibility to objectively assess clinical effects on rigidity obtained during intraoperative test stimulation based on acceleration measurements. Background: Deep brain stimulation (DBS) has few uncertainties associated with suboptimal target selection. The feasibility of using acceleration measurements to evaluate tremor quantitatively during DBS surgery has been shown earlier (1). However, to be able to quantitatively evalute the clinical effects of intraoperative stimulation on Parkinson’s disease patients, it is important to take rigidity as a symptom into consideration. Methods: 3 patients referred for bilateral subthalamic nucleus DBS-implantation were included in the study. To quantitatively evaluate rigidity, a 3-axis acceleration sensor was fixed to the neurologist’s wrist during the evaluation of the patient (Fig 1). Accelerometer data was post-peratively analyzed, statistical features were extracted similar to those in (1) but with different cut-off frequencies for the filters. The effective stimulation amplitudes (thresholds) were identified (Fig 2). Wilcoxon two sided rank test was used to identify the significance of changes in the statistical features 1) before and at thresholds identified by medical experts and 2) those before and at thresholds found using acceleration data alone. Results: Out of the calculated statistical features, standard deviation, signal energy and peak frequency amplitude were the most sensitive to changes in patient rigidity. The changes in the features when compared to baseline were in the range of 0 - 40%. The thresholds identified based on acceleration data were lower in 40% of the cases compared to the one chosen by the neurologist. Changes at the acceleration thresholds were significantly higher than at the ones identified subjectively. Conclusions: The results of this study suggest that acceleration measurements of the neurologist’s wrist can be used to quantitatively evaluate the changes in patient’s rigidity. This simple method may provide additional support to the neurosurgeon in selecting the optimal target even if identified changes (0-40%) are less significant than for tremor (0-99%).