Ultrasound Neurostimulation Parameter Optimization for Depression
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Solution Overview
Problem
Current treatments for major depression, including antidepressants and neurostimulation techniques, are limited by inefficacy and invasiveness, and there is a need for a non-invasive method that can effectively target deep brain areas to modulate emotion and reduce anxiety-related behaviors.
Innovation Solution
A method and device using transcranial ultrasound neurostimulation with a neurostimulation device equipped with an ultrasound probe to emit controllable ultrasound pulses, setting parameters such as ultrasound power and frequency to achieve a specific ratio with motor threshold excitation, targeting the prefrontal cortex to provide antidepressant-like effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If transcranial ultrasound neurostimulation is applied to treat major depression, then non-invasiveness and therapeutic potential are improved, but treatment efficacy and precision in targeting deep brain areas need to be ensured
Solution Approach 1:
The patent applies parameter changes by optimizing ultrasound power settings based on the motor threshold excitation. Specifically, the ultrasound power is set to a ratio between 1.2 and 2.0 times the motor threshold, which ensures sufficient stimulation strength to achieve antidepressant effects while maintaining non-invasive safety. This parameter optimization resolves the contradiction between non-invasiveness and treatment efficacy.
Solution Approach 2:
The patent replaces invasive mechanical or chemical intervention (such as deep brain stimulation electrodes or antidepressant medications) with non-invasive ultrasound waves. By using acoustic energy to modulate neural activity in deep brain regions like the prefrontal cortex, the system achieves therapeutic effects without physical intrusion, thus resolving the contradiction between non-invasiveness and treatment reliability.
2Reliability
If ultrasound power is increased to enhance stimulation effect, then therapeutic efficacy is improved, but risk of tissue damage and safety issues increases
Solution Approach 1:
The patent employs feedback control by using the motor threshold excitation as a reference point to determine the appropriate ultrasound power level. The motor threshold, which represents the minimum power needed to elicit a motor response, serves as a safety boundary. The therapeutic ultrasound power is set at a controlled ratio (1.2-2.0 times) above this threshold, ensuring efficacy while preventing tissue damage. This feedback mechanism resolves the contradiction between therapeutic efficacy and safety.
Solution Approach 2:
The patent applies dynamics by making the ultrasound power setting adaptive rather than fixed. The power level is dynamically adjusted based on the individually measured motor threshold for each subject, allowing optimization of therapeutic effect while maintaining safety margins. This dynamic approach resolves the contradiction between achieving sufficient stimulation for efficacy and maintaining power levels below tissue damage thresholds.
3Measurement precision
If precise parameter setting is implemented to target specific brain regions, then treatment precision is improved, but complexity of parameter adjustment and measurement increases
Solution Approach 1:
The patent applies preliminary action by measuring the motor threshold excitation before initiating the actual therapeutic ultrasound treatment. This preliminary measurement establishes a personalized baseline that simplifies subsequent parameter setting. By determining the motor threshold first, the system creates a reference point that guides the selection of therapeutic power levels, thereby reducing the complexity of real-time parameter adjustment while maintaining high targeting precision.
Solution Approach 2:
The patent simplifies parameter adjustment by establishing a clear relationship between the motor threshold and therapeutic power settings. Rather than requiring complex multi-parameter optimization, the system uses a single key parameter (motor threshold) to determine all subsequent power settings through a fixed ratio (1.2-2.0 times the threshold). This parameter linkage reduces adjustment complexity while preserving measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively alleviates anxiety-related behaviors and provides antidepressant-like effects by activating targeted brain regions and areas distant from the stimulation zone, as demonstrated in a mouse model of major depression, with potential for treating major depression and other neuropathological illnesses.
Implementation Method 1
at least an ultrasound probe adapted to emit ultrasound pulses with a controllable ultrasound power
Implementation Method 2
The production of ultrasound is used in many different fields, typically to penetrate a medium and measure the reflection signature or to supply focused energy
Data Source
AI summary
The present invention relates the field of ultrasound and neurostimulation. The inventors have shown that using ultrasound neurostimulation with specific parameters provides similar or better effects that fluoxetine administration in depression. Such assessment was made in unpredictable chronic mild stress model in mouse. The proposed use also provides with positive effects in other cases, such as modulating emotion or attenuating anxiety-related behaviours (stress notably).