A powerful new robotic testing method has shed light on a critical yet often overlooked aspect of stroke recovery: proprioception. This is the body's ability to sense movement and position, and it's a game-changer for those affected by stroke.
The Story of Don Lewis
Don Lewis, a stroke survivor and cancer warrior, has been instrumental in helping researchers at the University of Delaware uncover the challenges of proprioception deficits. At 55, Don suffered a stroke that left him paralyzed on one side. Despite extensive therapy, his left arm remains paralyzed, causing him pain and difficulty in daily tasks.
Uncovering the Hidden Challenge
Associate Professor Jennifer Semrau, an expert in kinesiology and applied physiology, explains that proprioception is like having an internal GPS for your body. She uses a simple test in her classes: close your eyes and touch your nose. If you can't do it, you likely have impaired proprioception.
Semrau and her team, including doctoral candidate Joanna Hoh, have published findings in Neurorehabilitation and Neural Repair, suggesting a way to identify these sensory losses without requiring patients to move their affected arm. This breakthrough could make assessments more accessible and improve stroke recovery outcomes.
Assessing Movement with Robotics
In the lab, Don is placed in a KINARM robotic exoskeleton, which tracks upper limb movement. This allows Semrau to study the neural and behavioral mechanisms contributing to sensory and motor function recovery. Using various tests, including the innovative single-arm measurement, they gauge perception-based movement. The test moves Don's stroke-affected arm robotically, and he responds with his non-affected arm, indicating if he can feel the movement.
The Impact of Stroke on Proprioception
The average person can feel movement as little as a half-centimeter. However, for stroke survivors, it varies. Some may not detect movement of 10 centimeters, which could have serious implications in daily life, such as touching a hot stove or a knife.
The communication between the brain and muscle receptors, responsible for detecting movement, is disrupted after a stroke. This affects the ability to coordinate movement properly.
The Complexity of Sensory Deficits
Interestingly, someone with a proprioceptive deficit may still feel pain and have no touch impairment. Pain and touch are part of the somatosensory system, relayed on different sets of nerves. Every stroke survivor is unique, and their impairments require individualized treatment.
Semrau faces the challenge of teasing apart sensory deficits from motor deficits, as they are deeply intertwined. The tasks in her lab aim to get to the heart of this complex issue.
Advocating for Sensory Assessment
Hoh, an occupational therapist, became interested in upper-limb stroke research after working with patients in rehabilitation. She realized the importance of considering the sensory system in stroke recovery, an area often overlooked by clinicians.
Semrau's research aims to raise awareness and encourage more clinicians to integrate precision testing for proprioception. Their studies have found that only 1% of clinicians assess proprioception in stroke patients, despite the critical role it plays in full recovery of function.
Personalized Medicine for Stroke Recovery
Both Semrau and Hoh emphasize the need for a better understanding of post-stroke impairments to develop a personalized medicine approach to treatment. Just because someone has motoric impairments doesn't mean they won't also have sensory impairments, and vice versa. Understanding the connection between motor and sensory impairments is key to tailoring recovery plans for each individual.
This research highlights the importance of considering the whole person in stroke recovery, ensuring that no aspect of their health and well-being is overlooked.
