Fig. 6: Desired vs. realistic block diagram of chronoadaptive feedback DBS control system. | npj Parkinson's Disease

Fig. 6: Desired vs. realistic block diagram of chronoadaptive feedback DBS control system.

From: Diurnal modulation of subthalamic beta oscillatory power in Parkinson’s disease patients during deep brain stimulation

Fig. 6

a Desired control system. In the desired DBS control system, therapeutic goals (i.e., % suppression of beta power) are specified by clinicians for specific times of the day. A feedback controller modulates the DBS parameters to maintain the controlled variable, the biomarker, at the specified target level. Time-based adjustments of control goals synchronized to patient-specific chronotypes can then be incorporated to accommodate known disturbances such as the medication-schedule and diurnal variation of the monitored biomarker. In this manner, time-localized adjustments to stimulation parameters are provided in response to physiological variations. b Actual control system. In the actual control system at present diurnal variations in artifact sources may couple into the sensor in the feedback pathway. This can confound observations of physiological fluctuations in the monitored biomarker signal due to the amplitude of artifacts being greater than the signal of interest.

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