The following is part of a series on brain-machine integration and biomechanical solutions to restore function to tissues damaged by disease, trauma, or time. This and the subsequent piece focus on wearable sensors and their immediate and future applications.
Advances in wearable sensor technology may improve health outcomes for those at risk of mobility limitation later in life. Loss of mobility is a common byproduct of aging, manifesting in unsteady gait, loss of balance, muscle weakness, and knee pain. In the United States, at least one in four adults suffers from chronic knee pain, with diagnosed knee arthritis rates doubling since 1940.
With regular monitoring of knee motion in day-to-day life, experts could improve knee health outcomes through early diagnosis of complications. However, monitoring typically requires lab-based observation, for which many Americans lack the time.
Recent improvements in wearable systems may circumvent lab-based observation entirely. Wearable systems are textiles equipped with stretchable circuitry that collect data. In essence, it’s a flexible, wearable computing device. In many instances, wearable sensors are used for fitness applications, such as monitoring heart rate, caloric output, sleep patterns, and so on. In many ways, it’s akin to an advanced smartwatch but without a user interface.
Gupta et al. applied this technology for knee health monitoring. While most existing wearable sensors are externally attached to a user’s clothes, this would not be ideal for knee monitoring, as unrestricted motion is the primary motivation. Therefore, Gupta et al. needed a self-contained wearable sensor knee brace with circuitry woven into the fabric itself. Their result was a highly stretchable textile combining electrically conductive and dielectric yarn of high elasticity.
FIGURE 1: Knitted knee brace wearable sensor, including the sensor itself, interconnecting circuitry, resistor, and power supply.
GUPTA ET AL.
The sensor collects data on knee motion, including during walking, jogging, running, and steps. The knee brace also closely monitors the knee joint, analyzing the angle and ensuring healthy lower and upper leg interaction. Data is delivered to a Bluetooth-connected smart device in real-time, then to healthcare professionals for examination.
FIGURE 2: Schematic representation of the wearable sensor knee brace with a smartphone receiver connected via Bluetooth.
GUPTA ET AL.
While there are no treatments for arthritis of the knee and similar ailments, early detection and treatment can significantly improve health outcomes over time. Similar to how those with poor hearing from loud environments have irreparably damaged hearing systems, it is difficult to treat without a total replacement once the knee joint and surrounding areas are damaged. Physical therapy and regular use of a stabilizing brace will reduce knee damage over time, and the earlier, the better for those at risk.
In addition to monitoring for joint degradation, wearable sensor technologies like that of Gupta et al. could also be used during rehabilitation, monitoring progress for joint movement, range of motion, and muscle activity. Further, applications for sports medicine could see athletes improve technique, efficiency, and injury prevention in sports with high pressure in the knees, such as basketball.
We are likely to see wearable systems extended to other problematic regions of the body with age, for instance, the ankles, wrists, back, or neck. So long as the sensors do not impede regular day-to-day activity, they could vastly improve our capacity to monitor mobility later in life, improving health conditions for many in their later years.
As wearable technology advances, some characteristics to improve may be the battery life, which ought to be maximized to reduce responsibility for the wearer, and cost; as a technology, this novel will likely be too expensive for the average American. Otherwise, we are excited to see how this relatively young field of therapeutic technology advances.
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