This proof-of-principle study describes the methodology and explores and demonstrates the applicability of a system, existing of miniature inertial sensors on the hand and a separate force sensor, to objectively quantify hand motor symptoms in patients with Parkinson’s disease (PD) in a clinical setting (off- and on-medication condition). Four PD patients were measured in off- and on- dopaminergic medication condition. Finger tapping, rapid hand opening/closing, hand pro/supination, tremor during rest, mental task and kinetic task, and wrist rigidity movements were measured with the system (called the PowerGlove). To demonstrate applicability, various outcome parameters of measured hand motor symptoms of the patients in off- vs. on-medication condition are presented. The methodology described and results presented show applicability of the PowerGlove in a clinical research setting, to objectively quantify hand bradykinesia, tremor and rigidity in PD patients, using a single system. The PowerGlove measured a difference in off- vs. on-medication condition in all tasks in the presented patients with most of its outcome parameters. Further study into the validity and reliability of the outcome parameters is required in a larger cohort of patients, to arrive at an optimal set of parameters that can assist in clinical evaluation and decision-making.

From the model simulations we conclude that the HD lead in steering-mode with optimized stimulation parameter selection can stimulate more STN cells. Next, the clinical impact of the increased number of activated STN cells should be tested and balanced across the increased complexity of identifying the optimized stimulation parameter settings for the HD lead.

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Objective: In this study we introduce the use of the current source density (CSD) method as a way to visualize the spatial organization of evoked responses in the rat subthalamic nucleus (STN) at fixed time stamps resulting from motor cortex stimulation. This method offers opportunities to visualize neuronal input and study the relation between the synaptic input and the neural output of neural populations.Approach: Motor cortex evoked local field potentials and unit activity were measured in the subthalamic region, with a 3D measurement grid consisting of 320 measurement points and high spatial resolution. This allowed us to visualize the evoked synaptic input by estimating the current source density (CSD) from the measured local field potentials, using the inverse CSD method. At the same time, the neuronal output of the cells within the grid is assessed by calculating post stimulus time histograms.Main results: The CSD method resulted in clear and distinguishable sources and sinks of the neuronal input activity in the STN after motor cortex stimulation. We showed that the center of the synaptic input of the STN from the motor cortex is located dorsal to the input from globus pallidus.Significance: For the first time we have performed CSD analysis on motor cortex stimulation evoked LFP responses in the rat STN as a proof of principle. Our results suggest that the CSD method can be used to gain new insights into the spatial extent of synaptic pathways in brain structures.

The aim of the study is to test whether the PowerGlove (PG), an instrumented glove which consists of inertial (accelerometers and gyroscopes) and magnetic sensors, is a valid and reliable instrument to measure different degrees of hand motor impairments in patients with Parkinson's disease (PD). Background: Assessment of hand movements is an important part of the motor function section of the Unified PD Rating Scale (UPDRS). Unfortunately, the assessment often varies per physician and is highly dependent on experience. This subjective nature sometimes makes it hard to interpret the UPDRS correctly. Recently, the University of Twente developed the PG which enables accurate and ambulant measurement of hand and finger movements (Fig. 1A)[1]. Application of the PG during the clinical scoring will enable more accurate observation of hand function and quantification of the PD motor symptoms. Methods: We plan to include 35 PD patients. We will assess the hand movements of the patients in medication on/off state with the PG during 7 UPDRS items, i.e. tremor at rest, action and postural tremor, finger tapping, rapid opening/closing of the hand, pro/supination of the hand, and wrist rigidity. Sensor units of the PG are attached to the dorsal side of the left hand and on the finger segments of the thumb, index and middle finger. One additional PG sensor is attached to the forearm to measure the wrist angle. A force sensor is used to measure the force which is applied to passively flex the wrist of the patient. Prior to measurement, an anatomical calibration procedure is performed to determine the sensor-to-segment coordinate systems. Results: Visual inspection of preliminary results showed there were notable differences in the recorded data within a patient in medication on/off state (Fig 1B-D).