Revolutionizing Health: MEMS Accelerometer Applications in Medical and Healthcare
January 28, 2025
Blog
In the last few years, microelectromechanical systems (MEMS) accelerometers have become important components in many medical and healthcare products. Among others, accelerometers are implemented in non-invasive, minimally invasive, and invasive medical devices.
There are several reasons for this impressive penetration of MEMS accelerometers into medical applications. The early accelerometers were bulky, with high power consumption, analog output, and without any embedded intelligent features. However, there have been breathtaking advances in these accelerometers in the last few years. These advances have not only accelerated the implementation of accelerometers in a large number of medical products but also enabled a variety of innovative use cases in diagnostics, monitoring, and treatment.
Let's look at some of the major applications of MEMS accelerometers in the medical and healthcare industries.
MEMS sensors have enabled transformative and cost-effective solutions for patient monitoring and diagnostics. These sensors are widely used in devices such as blood pressure monitoring systems, pacemakers, and insulin pumps, where their high precision, accuracy, and robustness ensure reliable measurements.
MEMS accelerometers and inertial measurement units (IMUs) are critical in many portable and wearable devices to track physical activity and detect falls. MEMS pressure sensors are essential for respiratory monitoring and fluid management, as they provide accurate pressure measurements. Their small and compact size, low power consumption, and integrated features make MEMS sensors vital in advancing personalized and real-time healthcare technologies. Figure 1 summarizes the major applications of MEMS sensors.
Figure 1. MEMS sensor applications in medical and healthcare devices.
The MEMS accelerometer is one of the most widely used MEMS sensors in medical and healthcare applications. An accelerometer is a device that can sense linear acceleration, vibration, shock, tilt, and orientation detection concerning the force of gravity.
Medical and healthcare applications require devices with a small package size, low power consumption, high volume manufacturability, high performance and reliability, and low cost. MEMS accelerometers meet all these requirements and have become important components in a wide range of medical and healthcare applications. They consume very low power while offering high sensitivity and high resolution [1]. These advances have enabled a wide range of applications in medical and healthcare.
Accelerometers provide critical real-time data for motion detection, activity tracking, and position monitoring applications, which improve patient care, enhance device functionality, and assist physicians in diagnosis, rehabilitation, and chronic disease management. For example, accelerometers are used in several medical devices to monitor motion, movement, position, and other parameters, offering significant improvements in functionality, precision, and patient safety.
Physical Activity Recognition and Tracking
Many wearable fitness devices use an accelerometer to monitor physical activity and provide data on steps, movement intensity, calorie expenditure, and more [2,3]. This is valuable in both consumer fitness and medical applications, as activity levels (steps, distance, intensity) and exercise habits can be tracked in patients recovering from surgery, with chronic conditions, or as part of weight management and lifestyle improvement plans.
In physical therapy, accelerometers measure a patient’s range of motion, speed, and frequency of movements. They provide real-time feedback to therapists and patients, helping them track progress and adherence to recovery programs. This is especially useful in recovering from muscle and bone injuries or surgeries and in improving mobility in conditions like Parkinson’s disease.
In stroke recovery, accelerometer data is used to monitor movement patterns, assessing improvements in motor control, range of motion, and strength. By quantifying the progress in affected limbs, they support tailored rehabilitation plans and provide feedback on therapy effectiveness.
For example, some wearable and rehabilitation devices on the market today use accelerometers to track joint movement during therapy sessions, helping physical therapists adjust exercises accordingly. These sensors provide real-time data on a patient’s movements, which can be analyzed to design personalized rehabilitation programs [4].
Another example is the use of accelerometers in smart wheelchairs to track wheel rotation speed, assisting in mobility assessments and helping prevent sedentary complications such as pressure sores.
Enhancing Safety: Fall and Drop Detection
Fall detection applications use a MEMS accelerometer to monitor a person’s or object’s movement and detect when a fall has occurred. Accelerometers are crucial in wearable devices for detecting falls in elderly or at-risk patients. Devices equipped with fall detection applications can be particularly useful for elderly patients, patients with neurological conditions, or those recovering from surgery, as they can automatically alert caregivers or emergency services in case of a fall.
The working principle is based on sensing sudden changes in body position or acceleration patterns typical of falls, triggering alerts to caregivers or emergency services. This application enhances response time, reducing potential complications from prolonged periods on the floor after a fall.
For example, a smartwatch with embedded fall detection applications uses MEMS accelerometers to detect falls. When a fall is detected, the watch sends an emergency alert with the user’s location.
There are dedicated medical wearable devices on the market that use an accelerometer to monitor the elderly for falls and send alerts to caregivers when a fall is detected [5].
Advanced Sleep Monitoring and Anomaly Detection
Sleep monitoring devices incorporate accelerometers to detect sleep patterns, sleep stages (rapid eye movement, deep sleep, etc.), and movement throughout the night. This data is important for diagnosing sleep disorders like sleep apnea, restless leg syndrome, wakefulness, and insomnia, and guides treatment plans aimed at improving sleep quality.
For example, wearable rings use MEMS accelerometers to monitor movement during sleep to provide insights into sleep quality and disturbances [6].
References [7,8] are examples of devices that use accelerometer data alongside other sensors to monitor sleep patterns and help diagnose sleep disorders, including sleep apnea.
Enhancing Posture and Gait Analysis Techniques
Wearable devices use accelerometers, inclinometers, and gyroscopes to assess posture and balance by detecting body position and movement. Clinics use this information to analyze and correct postural issues, monitor patients with neurological conditions like Parkinson’s disease or multiple sclerosis, and prevent falls in elderly patients.
Gait analysis systems use accelerometers to accurately measure gait speed, stride length, and movement asymmetries. They can detect irregularities in walking and balance that may signal health issues. These data provide important insights into conditions like Parkinson’s, multiple sclerosis, cerebral palsy, and other neuromuscular disorders. Clinicians use accurate gait analysis to diagnose movement disorders and assess the effectiveness of treatments or therapies.
Devices for Parkinson’s disease monitoring use accelerometers to track motor symptoms such as dyskinesia (involuntary movement), bradykinesia (slowness of movement), and tremors (shakes) in patients with Parkinson’s disease [9]. Accelerometers are highly sensitive to the small, repetitive movements typical of shaking in Parkinson’s disease. This capability is applied in monitoring Parkinson’s disease and other movement disorders, where shaking frequency and amplitude are analyzed to adjust medication or therapy, track disease progression, and improve symptom management.
Systems developed for gait and balance analysis use multiple sensors to evaluate balance and coordination, aiding in diagnosing conditions like stroke or balance-related disorders [10].
Advanced prosthetic solutions use accelerometers to detect motion and orientation, allowing users to control the device based on natural body movements. This enhances the functionality of prosthetic limbs and improves the user experience for those with limb loss or mobility impairments.
The Future of Surgery: Robotics in the Operating Room
MEMS accelerometers and gyroscopes play an important role in surgical robotics by providing real-time motion feedback. Surgical systems in robotic-assisted surgeries use MEMS accelerometers to detect tiny movements of the surgeon or the robot. This data provides feedback to surgeons, ensuring precise instrument control during operations and that surgical instruments move in the correct direction with high accuracy.
Some surgical systems today use MEMS accelerometers to provide crucial data for precise instrument control during operations, such as accurate joint replacement surgeries [11, 12].
Innovations in Implantable Devices
Accelerometers aid in personalizing patient care, improving diagnostic accuracy, and facilitating remote and continuous health monitoring across medical applications.
Some implantable devices on the market today, such as those monitoring heart rate or pacing activity, use accelerometers to adjust the device’s operation based on patient movements and activities. Accelerometers are integrated into implantable medical devices (such as orthopedic implants) to monitor the position, rotation, or movement of the device within the body. This helps ensure the device remains in place, detects wear or malposition, and can even track the healing process.
An example of implantable devices is pacemakers that adjust pacing rates based on detected activity, improving responsiveness to patient needs.
Smart knee and hip implants use accelerometers to track patient activity and implant stability after surgery [13]. Spinal fusion devices use accelerometers to track movement and ensure proper alignment during healing [14].
Cardiac Monitoring and ECG
The latest advanced applications use accelerometers to capture subtle chest or body movements associated with breathing and heartbeats. These applications, often integrated with other sensors, help monitor respiratory rate and heart rate, especially in patients with chronic respiratory or cardiovascular conditions.
Accelerometers in wearable devices can provide indirect measurements related to cardiovascular health by tracking movement and correlating it with cardiovascular data. This can be particularly useful in ambulatory blood pressure monitoring, where movement data helps differentiate between active and rest periods for more accurate blood pressure readings.
Wearable ECG (Electrocardiogram) monitors combine accelerometers and ECG sensors to detect irregular heartbeats. By analyzing the body’s motion and changes in activity, these sensors can identify irregularities that might indicate a cardiac event or irregular heartbeat. The collected and analyzed data notify users and doctors of potential issues [15,16,17].
Implantable cardiac devices deploy accelerometers to track motion and monitor heart function in patients with pacemakers [18].
Personal Safety
Wearable devices and smart clothing integrate MEMS to continuously monitor health and safety in vulnerable populations such as infants, children, and elderly individuals. These devices provide real-time alerts for falls, lack of movement, or unusual activity patterns that could signal a health emergency.
For example, smart clothing for infants uses accelerometer data to analyze babies’ sleep patterns, oxygen levels, and movement, alerting parents or caregivers if the baby’s health is compromised [19].
Wearables for elderly individuals and people with physical disabilities implement accelerometers and sometimes pressure sensors to detect falls and notify caregivers, ensuring the safety of those individuals [20].
Motion Sickness Detection
During medical treatments like chemotherapy or traveling for medical purposes, patients can experience motion sickness or nausea. Some of the latest applications use accelerometer data to track the motion of the patient’s body and adjust stimuli to reduce discomfort.
Wearable devices equipped with motion sickness relief features use sensor data to monitor the patient’s motion and apply therapeutic pulses to help alleviate symptoms of motion sickness [21]. Devices developed for nausea management use motion sensors combined with other treatments to manage nausea induced by chemotherapy.
Predictive Medicine
Precision medicine uses accelerometers to collect data about a patient’s daily physical activities, which is critical for tailoring treatment plans. These sensors provide healthcare providers with insights into patients’ behavior, activity levels, and potential health issues in real-time. Devices used in clinical trials deploy accelerometers to monitor patients’ physical activity levels and responses to treatments, ensuring that the therapy aligns with specific treatment goals.
Accelerometers integrated into wearable devices collect data on patients’ movements, which can be used to customize treatment plans for chronic disease management (e.g., diabetes or obesity) [22].
Medical Instruments
MEMS accelerometers are used to calibrate medical equipment and monitor the movement or orientation of medical instruments. This is especially important for diagnostic equipment that requires precise measurements or for ensuring the accuracy of devices like imaging systems.
For example, Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scanners can use accelerometers to ensure accurate alignment and positioning during imaging, preventing errors in diagnostics. Surgical tools can use motion sensors to track the correct positioning of surgical instruments, improving precision during minimally invasive surgeries.
Seizure Monitoring
In epilepsy (seizure disorder) management, accelerometers help detect seizure-related movements. This sensor information is used to notify caregivers or medical personnel, allowing for real-time monitoring, especially in patients with nighttime/sleep seizures or those at high risk of unobserved episodes.
Smart Inhalers
Smart inhalers for asthma management using MEMS accelerometers have been available for quite some time. The accelerometers in smart inhalers detect use frequency, shake intensity, and orientation, helping ensure proper medication intake. They also provide feedback on inhaler usage techniques, helping patients use inhalers effectively and track adherence.
Conclusion
MEMS accelerometers are important components in several medical and healthcare applications. Thanks to the latest improvements in accelerometer technology, these sensors provide precise and accurate motion tracking and real-time data, helping to revolutionize diagnostics, patient care, and treatment strategies. Their use spans from simple fall detection to advanced monitoring of complex medical conditions, as well as enhancing the precision of surgical procedures and ensuring the safety of medical devices. As technology continues to advance, the scope of MEMS accelerometers in healthcare will expand even further, enabling more personalized, effective, and efficient medical care.
References:
- MIS2DH - 3-axis accelerometer for medical/healthcare applications, ±2g/±4g/±8g/±16g user selectable full-scale - STMicroelectronics
- LIS2DU12 - Ultralow-power accelerometer with antialiasing and motion detection - STMicroelectronics
- LIS2DW12 - MEMS digital output motion sensor: high-performance ultralow-power 3-axis "femto" accelerometer - STMicroelectronics
- Motus Nova Stroke Rehab Recovery at Home
- Philips Lifeline Medical Alert Services with AutoAlert - Media library | Philips
- https://www.ouraring.com
- https://www.whoop.com/
- https://www.resmed.com/
- Parkinson's KinetiGraph (PKG) | Dementech Neurosciences
- Biodex Balance System - Physiopedia
- da Vinci Surgery: Treatment & Recovery
- Learn about robotic-arm assisted knee surgery | Stryker
- Zimmer Biomet: Innovations in Orthopedic Care
- Home | NuVasive
- https://www.st.com/en/mems-and-sensors/biosensors.html
- https://blog.st.com/st1vafe3bx/
- https://www.researchgate.net : Wearable Technology for Monitoring Electrocardiograms (ECGs)in Adults: A Scoping Review
- https://www.accessdata.fda.gov/cdrh_docs/pdf15/p150033c.pdf
- https://cdn.competec.ch/documents2/6/4/8/206896846/206896846.pdf
- https://www.researchgate.net/ : Pathway of Trends and Technologies in Fall Detection: A Systematic Review
- https://www.accessdata.fda.gov/cdrh_docs/pdf19/K191547.pdf
- https://dl.theactigraph.com/gt3xp_wgt3xp_device_manual.pdf
- https://www.gehealthcare.com/products/imaging
Jay Esfandyari brings over 20 years of experience in semiconductor technology, integrated circuit fabrication processes, MEMS and sensor design, sensor networking, product marketing, business development, and product strategy. He holds a master's degree and a Ph.D. in Electrical Engineering from the University of Technology of Vienna in Austria and has authored more than 80 publications and conference contributions. Currently, Jay serves as the Product Marketing Manager at STMicroelectronics in Dallas, Texas.