Background/Aim: Deep brain stimulation (DBS) is an established neurosurgical treatment that can be used to alleviate symptoms in essential tremor (ET) and other movement disorders. The aim was to develop a method and software tool for the prediction of effective DBS electrode contacts based on probabilistic stimulation maps (PSMs) in patients with ET treated with caudal zona incerta (cZi) DBS. Methods: A total of 33 patients (37 leads) treated with DBS were evaluated with the Essential Tremor Rating Scale (ETRS) 12 months after surgery. In addition, hand tremor and hand function (ETRS items 5/6 and 11–14) were evaluated for every contact during stimulation with best possible outcome without inducing side effects. Prediction of effective DBS electrode contacts was carried out in a retrospective leave-one-out manner based on PSMs, simulated stimulation fields, and a scoring function. Electrode contacts were ranked according to their likelihood of being included in the clinical setting. Ranked electrode contacts were compared to actual clinical settings. Results: Predictions made by the software tool showed that electrode contacts with rank 1 matched the clinically used contacts in 60% of the cases. Contacts with a rank of 1–2 and 1–3 matched the clinical contacts in 83 and 94% of the cases, respectively. Mean improvement of hand tremor and hand function was 79 ± 21% and 77 ± 22% for the clinically used and the predicted electrode contacts, respectively. Conclusions: Effective electrode contacts can be predicted based on PSMs in patients treated with cZi DBS for ET. Predictions may in the future be used to reduce the number of clinical assessments that are carried out before a satisfying stimulation setting is defined.
An electrochemical hydrophone based on the principles of molecular electronic transfer (MET) has been described. The paper presents theoretical and experimental results for the sensitivity and the level of selfnoise determination for the MET hydrophone (METH) in the frequency range of 0.02-200 Hz, which determines the fields of acceptance of the devices being developed. An experimental model has been developed by using a force-balancing feedback. Different methods and techniques for its calibration have been developed. The experimental device with 0.75 mV Pa −1 sensitivity flat in the frequency band 0.02-200 Hz has been presented. It has been demonstrated that in the ultra-low-frequency range METH noise could be much lower than the standard Wenz noise model. Easy to produce, cheap and suitable for mass production, the MET hydrophone could be in demand in marine and land acoustic research.Published by Copernicus Publications on behalf of the AMA Association for Sensor Technology.
MET sensors for measuring motion parameters are used in many scientific and technical fields. Meanwhile, the geometries of the transforming cell applied practically are far from optimal, and the influence of many geometric parameters on the sensitivity has not been studied. These parameters include the intercathode distance in a four-electrode conversion cell. In this paper, a mathematical model that allows calculating the behavior of the conversion coefficient depending on the frequency for a cell with flat electrodes at different intercathode distances is constructed. The stationary current is shown to decrease monotonically with the decreasing intercathode distance at the constancy of other system parameters. At the same time, the signal current decreases in the low-frequency region and increases in the high-frequency range. Taking into account the results obtained, practically speaking, it is advisable to reduce the intercathode distance to the technologically possible minimum, which makes the frequency response more uniform and reduces the current consumed by the sensitive element.
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