By: Mallory Bachmann
Parkinson’s disease is widely recognized for its motor symptoms, including tremors, bradykinesia and rigidity. But for many people, symptoms may actually begin in the gut. Gastrointestinal issues such as constipation, abdominal discomfort and reduced gastric motility are increasingly believed to appear years before a formal diagnosis.
For Manuel Amaris, M.D., an associate professor at the University of Florida’s College of Medicine and motility program director for UF Health Shands Hospital, the fact that GI symptoms are so common in Parkinson’s yet often overlooked and understudied has become a key focus of his work.
His research focuses on links between gut biomarkers and severity of Parkinson’s symptoms as well as how coordinated care can contribute to overall quality of life in Parkinson’s patients with GI issues. In a recent study published in the Journal of Parkinson’s Disease, Amaris looked at the benefits of PRISM — a single‑visit, interdisciplinary pyramid model with the goal of identifying GI causes and providing targeted treatments. The study concluded that the model significantly improved GI symptoms and quality of life for patients with more severe Parkinson’s-related gastrointestinal dysfunction.
“In traditional models, providers don’t meet regularly and often follow different protocols. In our integrated care approach, every provider works within the same framework, meets consistently, and uses shared paradigms and protocols,” Amaris said. “This means a patient can see the neurologist, nutritionist, physical therapist, speech pathologist and other specialists all in the same visit whenever possible.”
In the integrated‑care model, the pyramid structure begins with diet at its base. Diet is an essential first step as it improves symptoms across the entire gut — from swallowing to stomach emptying to constipation — before medications or procedures are needed. The model calls for a personalized nutrition plan, fiber‑and‑hydration recommendations, gut‑friendly meals, texture‑modified diets for swallowing disorders when necessary and guidance on Mediterranean‑style principles to support overall gut function.
From there, the care team uses targeted testing, such as swallow studies and motility tests, to treatments that include medications and other therapies. Pharmacological tools are positioned higher on the pyramid due to their dopaminergic and cholinergic effects that may contradict Parkinson’s medications.
This is why an integrated team that can offer alternative solutions is essential, Amaris said.
“It is patient‑centric and essentially precision medicine because it is grounded in the testing we perform,” he said.
Amaris is launching a new research project to explore how neuromodulation may help improve gastrointestinal symptoms. Supported by the Norman Fixel Institute for Neurological Diseases Catalyst Award, which provides researchers with time and funding to advance high-impact neuroscience studies, the study will incorporate point-of-care testing and a Parkinson’s-related GI questionnaire.
By using neuromodulation, or electrical stimulation, the team can offer a noninvasive, nonpharmacologic treatment that reduces medication interactions and lowers risk and recovery time. By also administering a gastrointestinal symptom questionnaire and a tool that evaluates pelvic floor dysfunction and hypersensitivity during the initial visit, Amaris hopes to accelerate the diagnostic process.
“So instead of running studies three, six or 12 months later in the traditional ‘up-the-pyramid’ approach, we want to test patients during their initial visit,” Amaris said. “That way, we don’t lose time trying to determine the root cause of their symptoms.”
This research aims to bridge the gap in recognizing and treating GI symptoms in Parkinson’s patients before motor symptoms even appear. By building an integrated model and developing faster, safer diagnostic tools, Amaris hopes to ensure patients receive long-needed care.
“It is definitely a big deal for these patients. The challenge is that nobody really owns these symptoms, because they rarely end up in a GI clinic,” Amaris said. “Neurologists typically start with first-line therapies, but without a coordinated team, many patients still go without the level of management they need.”