Tongue exercise boosts surviving neurons in a rodent study

In amyotrophic lateral sclerosis (ALS), the disease also known as Lou Gehrig's disease, the nerves that drive muscle movement die, and there is still no cure. Not all the nerves that control the tongue die, though, particularly in the early stages. A team at the University of Missouri asked a simple question: can the survivors be made to work harder? In a rodent model, the answer was yes. Tongue exercise improved the activity of the surviving neurons that control tongue movement, helping them make up for those that were lost.

The mechanism is called neuroplasticity: the nervous system changes how it operates to compensate for damage. As the neurons that remain take on more of the load, the function they support can last longer. "This adaptation is called neuroplasticity, meaning the nervous system changes how it operates to compensate for damage, and this finding offers hope for those with motor neuron diseases," said Nicole Nichols, an associate professor in the College of Veterinary Medicine and co-author of the study.

The result is still preclinical, meaning it comes from animal research and has not been tested in people. Nichols said the findings could inform future therapies that mimic the effects of exercise, for patients who may not be able to train their tongue. One idea she raised is an injectable that would activate surviving motor neurons. Both approaches, she noted, would require human clinical trials. The team also wants to check whether people with motor neuron diseases show the same boost in surviving neurons that the researchers saw in the model.

For people living with ALS, the change would be measured in daily life. Keeping the swallowing reflex and the airway steady reduces the risk of sleep apnea, and it can decide whether a patient needs a feeding tube or keeps eating normally. "That's incredibly meaningful for quality of life," Nichols said. Nothing of this reaches patients yet: the team hopes to move tongue exercise toward human trials within the next several years, through collaborations at Mizzou's NextGen Precision Health program.

The study brought together several disciplines. Teresa Lever, a swallowing researcher and professor at the School of Medicine, and Filiz Bunyak-Ersoy, an expert in artificial intelligence and assistant professor at the College of Engineering, took part alongside Nichols. The first author, Amy N. Keilholz, is listed on the publication. "This team science approach ultimately helps move foundational science from the lab bench to the clinic faster," Nichols said.