Profesionales médicos

June 16, 2023

Advances in stroke recovery have lagged the vast improvements achieved in acute stroke treatment. Mayo Clinic uses the latest approved technology — vagus nerve stimulation — to enhance post-stroke recovery of motor skills.

Stimulation is delivered while patients perform rehabilitation exercises with physical or occupational therapists.

"Neurostimulation increases neuroplasticity in various networks of the brain. We are priming the brain so that standard-of-care therapies can take patients closer to their pre-stroke abilities," says Zafer Keser, M.D., a neurologist at Mayo Clinic in Rochester, Minnesota.

Mayo Clinic is committed to rehabilitation as an important part of stroke care. Each of Mayo Clinic's campuses in Arizona, Florida and Minnesota is a Comprehensive Stroke Center. That designation recognizes a center's ability to manage all aspects of complex stroke care, including diagnosis, treatment and post-stroke recovery.

Mayo Clinic's stroke team includes neurologists, neurosurgeons, neuroradiologists, emergency medicine physicians, physical medicine and rehabilitation physicians, and physical and occupational therapists.

"Patients with stroke require a multidisciplinary team," Dr. Parker says. "Our specialists communicate well with one another to coordinate and provide optimal care for these patients."

Improving upper extremity function

The chances of surviving ischemic stroke have increased greatly over the past 15 years, due to clot-busting medications and endovascular clot retrieval.

"But on the recovery side, there's been a lack of innovation to make meaningful changes in our patients' outcomes," Dr. Parker says. "Ischemic stroke is devastating because it tends to affect people in the prime of their later years in life. It has a profoundly negative impact on quality of life — on people's ability to work and to perform basic activities of daily living."

The Food and Drug Administration approved vagus nerve stimulation to treat moderate to severe upper extremity motor deficits — one of the most common deficits experienced after ischemic stroke — in 2021. In a clinical study evaluating the therapy's effectiveness, nearly half of patients who had the therapy had significant increases in motor scores and upper extremity strength.

"That clinical trial was the first to show that neuromodulation improves recovery after ischemic stroke," says Rushna P. Ali, M.D., a neurosurgeon at Mayo Clinic's campus in Minnesota who was a co-leader in the clinical study. "Mayo Clinic has enterprisewide efforts to offer this therapy to stroke survivors with arm weakness."

The vagus nerve stimulation device typically is surgically implanted between nine months and 10 years after ischemic stroke. The stimulation is applied for 10 to 20 minutes during rehabilitation sessions — so-called paired pulse therapy.

"The device delivers very low neuromodulatory pulses that the brain senses. Sometimes, patients don't sense the pulses at all," Dr. Parker says.

Simultaneous physical or occupational therapy is essential. "It's the combined effects of the device and rehab therapy that make the difference," Dr. Keser says.

He notes that the possible side effects of vagus nerve stimulation are generally minor and include hoarseness and tingling in the neck. Vagus nerve stimulation therapy isn't recommended for individuals with severe spasticity or tensing of the arm, lack of sensation in the arm, or lack of hand movement.

Further study is needed to determine if vagus nerve stimulation can facilitate recovery from other stroke-related deficits, such as difficulties with lower extremity strength, swallowing, speech and cognition.

"There is anecdotal evidence of patients reporting improvement in leg strength or speech. But we don't yet have results from clinical studies," Dr. Parker says. "The expectations of patients undergoing this therapy should focus only on help with upper extremity strength and motor coordination."

Potential innovations

Research is also underway on alternative options for boosting stroke recovery.

Mayo Clinic is investigating the use of transcranial magnetic stimulation and transcranial direct current stimulation to enhance stroke rehabilitation. Both noninvasive approaches have the potential to enhance motor and language recovery.

"Typically, the side effects of these types of neurostimulation are also minimal," Dr. Keser says.

Other possible approaches include spinal cord stimulation and pharmaceutical and stem cell therapies that might spur nerve regeneration. "We hope to see tremendous advances in stem cell therapy in the next decade that will really move the needle and help our patients recover," Dr. Parker says.

The ultimate goal is to develop several therapies for boosting stroke recovery, to meet individual patients' needs.

"We would like as physicians to be able to sit across from patients and recommend which therapy is going to be best for them in a personalized fashion," Dr. Parker says. "We want patients to have the fastest recovery possible after ischemic stroke, so they can go back to doing whatever they love in life."

For more information

Refer a patient to Mayo Clinic.