Brain Stimulation Synchronization with Voluntary Limb Movement

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Solution Overview

Problem

Conventional non-invasive brain stimulation systems for rehabilitation are non-focused and non-specific, failing to effectively stimulate specific impaired muscles or limbs, as they are performed without direct patient involvement and do not account for the brain's state, leading to passive stimulation and inadequate rehabilitation outcomes.

Innovation Solution

A system that includes an activity monitor to detect voluntary patient movements, a robotic exoskeleton unit to assist limb movement, and a brain stimulation unit that provides activity-dependent stimulation, synchronizing brain stimulation with neural activity to enhance specific muscle rehabilitation through a sensorimotor loop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional non-invasive brain stimulation is performed without patient involvement, then the stimulation can be applied passively, but the stimulation becomes non-focused and non-specific, failing to effectively rehabilitate specific impaired muscles or limbs

Engineering Contradiction:
Improvepassive stimulation applicationVSAvoidstimulation specificity to impaired muscle representation
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system employs real-time feedback mechanisms where EMG sensors detect muscle activity and activity monitors track limb movements. This feedback is processed by control circuitry that continuously adjusts stimulation parameters to maintain precise targeting of the impaired muscle representation in the brain, resolving the contradiction between passive application ease and stimulation specificity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adapts stimulation parameters based on real-time detection of patient effort and limb activity. The stimulation frequency, intensity, and timing are continuously modified according to detected physiological signals, transforming static passive stimulation into dynamic active stimulation that maintains precision while remaining operationally simple.

Inventive Principle:
Principle #15Dynamics

2Ease of manufacture

If pre-defined stimulation frequencies are applied irrespective of brain state, then the stimulation protocol is simple to implement, but the stimulation cannot account for the brain's state leading to inadequate rehabilitation outcomes

Engineering Contradiction:
Improvestimulation protocol implementationVSAvoidrehabilitation effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The system automatically modifies stimulation parameters including frequency, amplitude, and pulse width based on real-time detection of brain state indicators such as EEG signals and EMG activity. This dynamic parameter adjustment maintains simple protocol implementation while significantly improving rehabilitation effectiveness by adapting to the patient's physiological state.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system performs self-adjustment of stimulation parameters based on internally detected physiological signals without requiring external intervention. The control circuitry autonomously processes EMG, EEG, and motion sensor data to optimize stimulation delivery, combining implementation simplicity with reliable adaptive response to brain state.

Inventive Principle:
Principle #25Self-service

3Device complexity

If conventional stimulation is performed without detecting voluntary patient effort, then the system operation is simplified, but it cannot synchronize stimulation with neural activity to promote use-dependent plasticity

Engineering Contradiction:
Improvedetection system complexityVSAvoidsynchronization precision with neural activity
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The system replaces complex mechanical detection methods with electronic sensing technologies including EMG sensors for muscle activity, EEG sensors for brain activity, and accelerometers for motion detection. This substitution maintains relatively simple device structure while achieving high-precision synchronization of stimulation with neural activity through electronic signal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system introduces intermediate sensing layers that detect physiological signals (EMG, EEG, motion) as mediators between patient effort and stimulation delivery. These intermediaries translate biological signals into control commands, enabling precise synchronization without requiring direct complex interaction between the patient and stimulation device.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Area of stationary object

If non-focused magnetic stimulation is applied to primary motor cortex, then the coverage area is broad, but the stimulation fails to target specific impaired muscle representations leading to non-specific therapeutic effects

Engineering Contradiction:
Improvestimulation coverage areaVSAvoidtargeting accuracy of impaired muscle representation
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The system applies local quality by delivering focused stimulation to specific cortical regions corresponding to impaired muscle representations while maintaining broader monitoring coverage. The stimulation coil or electrode array targets precise anatomical locations identified through neuroimaging or functional mapping, ensuring both adequate coverage and high targeting accuracy for effective rehabilitation.

Inventive Principle:
Principle #3Local quality

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

This approach enables active, patient-involved brain stimulation, improving therapeutic effects by promoting use-dependent plasticity and facilitating faster recovery in neuromuscular disorders by synchronizing brain stimulation with voluntary movements and physiological signals.

Implementation Method 1

A magnetic field is created around the head that generates magnetic pulses to stimulate the brain by inducing low-intensity current inside the brain through the scalp

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3996635B1System for rehabilitation of a limb of a patient
Publication Date: 2024.08.07 INDIAN INSTITUTE OF TECHNOLOGY
  • EP3996635B1 patent drawingFigure 1
  • EP3996635B1 patent drawingFigure 2
  • EP3996635B1 patent drawingFigure 3

AI summary

The invention relates to a system (100), for rehabilitation of a limb of a patient, that comprises a controller (110) communicatively coupled to an activity monitor (102) and operatively coupled to a robotic exoskeleton unit (104) and a brain stimulation unit (106). The activity monitor (102) detects an activity of the limb of the patient by a voluntary attempt of the patient in a first time frame and communicates the voluntary attempt to the controller over a second time frame. The robotic exoskeleton unit completes the movement of the limb, and the brain stimulation unit externally stimulates a local motor region of a brain of the patient based on the effort signal reaching a pre-specified threshold to complete a sensorimotor loop.