The Study Of Adaptive Deep Brain Stimulation

Adaptive deep brain stimulation has been the focus of research,because of its superior efficacy in the treatment of Parkinson’s disease over drug therapy,nuclear lesioning,and open loop operation of deep brain stimulation.Adaptive deep brain stimulation determines the disease development status by collecting relevant biomarkers as feedback signals,and adjusts the stimulation parameters objectively and adaptively.In order to study the control algorithm of adaptive deep brain stimulation system,a smallvolume,portable adaptive deep brain stimulation system was designed for small animals.The following points was in included by the research content:Firstly,the stimulation target,feedback signal and key techniques of the adaptive deep brain stimulation system were analyzed and compared,and the subthalamic nucleus and its local field potential were determined as target and feedback signals.The design requirements of the adaptive deep brain stimulation system were studied.The adaptive deep brain stimulation system was established for the long-term research of Parkinson’s disease.The system includes two parts: portable acquisition device and host computer.The portable acquisition device includes a main control module,an acquisition module,a stimulation module,and a wireless communication module.The main control module is the core of the device.The signal acquisition module is composed of a signal acquisition front end with low-pass filtering and high-resolution analog-to-digital conversion chip to realize the acquisition of weak signals in a specific frequency band;the stimulation module is composed of a digital-to-analog conversion chip and a positive side of adder is composed of a bidirectional pulse signal,and the amplitude,frequency and pulse width of the stimulus signal are adjustable.The wireless communication module completes the data exchange between the portable acquisition device and the host computer,and the portable device transmits data to the host computer through the wireless communication module and receives the control command of the host computer.The host computer is responsible for processing the received data,extracting pathological features,and using the control strategy,the control device generates appropriate stimulation parameters.Secondly,the signal analysis method is studied and the advantages and disadvantages of Fourier transform,short-time Fourier transform and wavelet transform are analyzed and compared.The characteristics of Parkinson’s disease in local field potential signal are analyzed,and the wavelet transform is studied as a local field method of feature extraction of potential signals.The off-line data simulation is used to extract the anomalous features of the local field potential beta segment by wavelet transform.At the same time,the wavelet basis function selects the Daubechies class db4 wavelet,and finally uses the d5 coefficient as the Parkinsonian feature component to design a threshold-based parameter control method.Finally,the system was tested,which mainly completed the system power consumption,signal acquisition function,stimulus signal generation function and wireless communication function test and verification.After testing,all the indicators met the system design requirements,and verified the analysis ability of the host computer.Meanwhile,the parameter adjustment of the hardware device are adjusted in real time according to the setting threshold.