Nail-Mounted Strain Gauge Sensor for Grip Strength Monitoring
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Solution Overview
Problem
Patients with degenerative neurological diseases like Parkinson's face challenges in monitoring their condition due to burdensome existing methods that require manual dexterity and skin-based wearable sensors, which can be painful and lead to infections in older patients with thin, brittle skin.
Innovation Solution
A system using nail-mounted strain gauges that measure deformation to quantify grip strength and characterize movement idioms, transmitting data wirelessly to a receiver for interpretation, allowing for non-invasive monitoring without skin contact and reducing the burden on patients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If skin-based wearable sensors are used for monitoring, then continuous monitoring capability is achieved, but skin contact causes pain and infections in older patients with thin, brittle skin
Solution Approach 1:
The patent uses the fingernail as an intermediary structure to mount sensors, eliminating direct skin contact. The strain gauge is attached to the nail plate, which transmits mechanical deformation from the underlying soft tissue during grip activities, allowing indirect measurement of grip strength and movement patterns without touching the vulnerable skin.
Solution Approach 2:
The patent replaces direct mechanical contact with skin (electrodes or pressure sensors on skin) with a mechanical coupling through the nail structure. The strain gauge measures mechanical deformation of the nail plate, which correlates with grip force and movement, substituting the need for direct skin-based mechanical sensing.
2Measurement precision
If manual dexterity tasks are required for monitoring, then disease state can be evaluated, but patients with cognitive deficits and depression find the burden overwhelming
Solution Approach 1:
The system enables passive self-service monitoring where the patient's natural grip activities during daily life automatically generate measurement data. The sensor on the fingernail continuously captures strain information during normal movements without requiring the patient to consciously perform specific tasks or interact with monitoring equipment.
Solution Approach 2:
The monitoring system operates continuously during the patient's natural daily activities, capturing grip strength and movement patterns throughout the day. This continuous passive data collection eliminates the need for discrete testing sessions, providing ongoing evaluation of disease state without adding operational burden.
3Productivity
If wearable patches are applied and removed daily for monitoring, then continuous data can be collected, but skin tears and infections occur in patients with thin, brittle skin
Solution Approach 1:
The fingernail serves as a durable intermediary mounting surface that eliminates repeated skin contact. The sensor attached to the nail can remain in place for extended periods (weeks or months) as the nail grows, eliminating the need for daily application and removal of patches from the skin, thereby preventing skin damage while maintaining continuous data collection.
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
Enables continuous, non-invasive monitoring of grip strength and movement patterns, reducing the burden on patients and avoiding skin issues, while providing accurate data for disease state tracking and therapy evaluation.
Implementation Method 1
a sensor having a bridge circuit including one or more strain gauges mounted on a nail plate, the bridge circuit outputting a voltage signal
Data Source
AI summary
A sensor includes a bridge circuit including one or more strain gauges mounted on a nail plate, the bridge circuit outputting a voltage signal, an amplifier circuit amplifying the voltage signal output by the bridge circuit to generate an amplified signal, an analog-to-digital (A/D) converter converting the amplified signal into a digital signal, a controller receiving the digital signal and facilitating communication with a receiver, and an antenna configured to transmit the digital signal.