New Robotic Testing Method Reveals Overlooked Proprioception Deficits After Stroke

A decade ago, astatine property 55, Don Lewis suffered a changeable successful his sleep. When he woke up, he couldn't move his near limb aliases leg. Lewis' neighbour realized his motortruck hadn't moved successful 2 days and called 911 for a use check. When paramedics recovered him, he was paralyzed connected 1 side.

"At nan hospital, they told maine an aneurysm caused my stroke," he said.

He would stay location for 2 months, and aft extended beingness therapy, Lewis regained usage of his near leg. His near limb remains paralyzed.

"I consciousness symptom erstwhile I deed it aliases scrape it stepping done a doorway, but I can't power nan motion."

Since then, nan crab subsister has had 2 much strokes. 

Now, Lewis is helping University of Delaware researchers understand 1 of nan astir overlooked challenges successful changeable betterment – proprioception, nan body's expertise to consciousness activity and position.

"To simplify nan concept, successful class, I show my undergraduates to adjacent their eyes and touch their nose; if group can't do that, it intends they apt person impaired proprioception," said Jennifer Semrau, subordinate professor of kinesiology and applied physiology, successful nan College of Health Sciences.

In findings precocious published successful Neurorehabilitation and Neural Repair, Semrau and doctoral campaigner Joanna Hoh propose it's imaginable to place hidden sensory losses aft changeable without requiring patients to move their affected arm. This beforehand could make assessments much accessible successful objective settings.

Assessing movement

Inside nan lab, Lewis is placed successful a KINARM robotic exoskeleton that tracks precocious limb movement, allowing Semrau to amended understand nan neural and behavioral mechanisms that lend to his betterment of sensory and centrifugal function. 

Semrau's laboratory utilized respective tests, including a caller 1 – nan single-arm measurement- to gauge perception-based movement. The trial moves Lewis' stroke-affected limb robotically while he responds pinch his non-affected limb if he tin consciousness nan activity of his stroke-affected arm.

"We're trying to find nan lowest level personification tin observe their limb moving," Semrau said.

The mean person, who hasn't had a stroke, tin consciousness arsenic small activity arsenic a half centimeter. For group post-stroke, it varies. 

"Some can't show their limb was moved 10 centimeters, and that could beryllium nan quality betwixt rubbing a basking stove aliases a weapon successful nan kitchen," Semrau said.

The connection from nan encephalon to nan receptors successful nan muscles, which are responsible for detecting movement, is disrupted aft a stroke.

"When you move, nan receptors lengthen aliases shorten, and if nan accusation isn't getting from nan encephalon to those musculus receptors, you can't decently coordinate movement," Semrau said. 

However, personification pinch a proprioceptive shortage could still consciousness symptom and whitethorn not person a touch impairment.

"Pain is portion of nan somatosensory strategy and is relayed connected a different group of nerves. After a stroke, immoderate whitethorn person accrued aliases decreased sensitivity to pain, and it's nan aforesaid pinch touch," Semrau said. "Every personification is simply a fingerprint--impairments each personification has aft a changeable are unsocial and require individualized treatment." 

The trouble Semrau faces: it's challenging to tease isolated sensory deficits from centrifugal deficits because they're profoundly intertwined. 

"It's difficult to find whether nan rumor is nan person's expertise to consciousness nan limb aliases their expertise to move," she said. "The tasks we're studying successful our laboratory get to nan bosom of nan matter."

From session to nan classroom

Hoh, an occupational therapist, became willing successful upper-limb changeable investigation aft moving pinch patients successful rehabilitation. 

"We often deliberation astir activity done centrifugal function," said Hoh. "I had a unsighted spot to nan sensory strategy successful position of changeable betterment and realized this is an avenue we don't see capable arsenic clinicians."

That inspired her to prosecute her doctorate successful biomechanics and activity subject astatine UD. Her dissertation focuses connected individuals pinch sensory issues pursuing a changeable and really these issues impact their regular activity levels.

Semrau hopes their ongoing investigation will raise consciousness of nan problem and promote much clinicians to merge this benignant of precision testing. 

"In 1 of our studies, we recovered that conscionable 1% of clinicians measure proprioception successful group pinch stroke," Semrau said. "It's a newer area, but investigation besides shows that without sensory recovery, a personification will not summation afloat betterment of usability aft a stroke." 

To create a personalized medicine attack to treatment, some Semrau and Hoh emphasized nan request for a amended knowing of post-stroke impairments.

"The onus is connected clinicians and researchers to guarantee they're testing for sensory deficits. Just because personification is impaired motorically, it doesn't mean they will aliases won't beryllium impaired sensory-wise," Hoh said. 

Semrau added, "Understanding nan relationship betwixt centrifugal and sensory impairments that impact usability is cardinal to amended targeting therapies and tailoring betterment for each individual."