New Neurorehabilitation Therapies Emerge for Stroke
by James Cavuoto, editor
November 2020 issue
In recent years, the market for neurorehabilitation systems has matured as it has differentiated, with several new neurotech startups and research institutions now targeting a range of disorders related to stroke and brain injury. Among the conditions being targeted with neurotech therapies are dysphagia, aphasia, upper-extremity paralysis, and neurogenic pain.
At the joint virtual meeting of the European Stroke Organization and the World Stroke Organization earlier this month, researchers affiliated with MicroTransponder Inc. presented results from the VNS-REHAB trial of implanted VNS paired with physical rehabilitation. Jesse Dawson from the University of Glasgow reported a statistically significant improvement in Fugl-Meyer scores in the treatment arm, which received six months of paired VNS therapy, compared to the sham stimulation arm.
Also this month, Phagenesis Ltd., a neurotech startup in Manchester, U.K., announced publication of their PHADER study on pharyngeal electrical stimulation in the journal EClinicalMedicine-The Lancet. The company’s Phagenyx system uses PES to treat the cause of dysphagia by restoring the neurological control of swallowing. The study demonstrates that patients with dysphagia due to stroke, TBI, or following mechanical ventilation and tracheotomy can benefit from treatment with Phagenyx.
“This largest ever study of PES shows that PES is a potential game changer for patients with severe swallowing problems who previously were at high risk of complications including pneumonia,” said co-lead investigator of PHADER, Philip Bath from University of Nottingham.
Neurogenic dysphagia affects up to 78 percent of stroke patients, up to 90 percent of TBI patients, and 50 to 83 percent of tracheotomized patients. Reinhard Krickl, Phagenesis CEO, said, “Dysphagia is a frequent complication and may be life-threatening.”
Investigators at Baycrest’s Rotman Research Institute at the University of Toronto are pioneering the use of individualized brain stimulation therapy to treat aphasia in recovering stroke patients. Aphasia is a debilitating language disorder that impacts all forms of verbal communication. It affects around one-third of stroke survivors, but can also be present in those with dementia, especially in the form of primary progressive aphasia.
In a recent study published in Scientific Reports, Jed Meltzer and his team tested language performance and used magnetoencephalography to measure brain waves in 11 stroke survivors with aphasia before and after they underwent brain stimulation therapy. They found that the participants had abnormal electrical activity in brain regions close to but outside the area destroyed by the stroke. This abnormal activity was mainly a shift to slower brain waves, a pattern they have also observed in individuals with dementia. “We mapped that abnormal activity and targeted it using noninvasive brain stimulation,” said Meltzer. “We found that the stimulation made the activity more normal—that is, faster—and improved language performance in the short term.”
Previous research has demonstrated that brain stimulation can improve language performance in aphasia patients. However, this study is one of the first to link this performance improvement to changes in the brain activity surrounding the tissue destroyed by stroke. In other words, this study suggests not only that brain stimulation works in aphasia patients, but also that the reason it works may be because it addresses abnormalities in the brain surrounding the destroyed tissue. Another novel aspect of this work is that the scientists targeted each individual’s abnormal brain activity with the stimulation treatment. In contrast, the standard approach in previous studies has been to use the exact same treatment, targeting the same brain areas, on every patient.
In a recent issue of the journal NeuroRehabilitation, several authors reported significant advances in knowledge regarding the pathology, etiology, assessment, and treatment of several significant neurogenic pain disorders regularly encountered by neurorehabilitation professionals. Types of neurogenic pain include neuropathic pain due to nerve damage or disease, central pain arising from a lesion in the central nervous system, such as thalamic pain following stroke, and deafferentation pain (the interruption or destruction of the afferent connections of nerve cells), among other mechanisms.