Cedars-Sinai Blog

Understanding Parkinson's Disease

A granddaughter working as a nurse and taking care of her disabled grandmother.

Michele Tagliati, MD came to Cedars-Sinai with two goals: first, to create a specialized movement disorders clinic to fill a critical need for patients, and second, to advance the field and provide patients with more options through cutting-edge research.

Michele Tagliati, MD

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"Parkinson's disease is one of the fastest growing neurological conditions, likely due to our aging population," said Tagliati, who holds the Caron and Steven D. Broidy Chair in Movement Disorders.  

To increase access to care, Cedars-Sinai has established the Movement Disorders Program. Led by Tagliati and his team, including Echo Tan, MD, Elliot Hogg, MD, and Camille Malatt, MD, the program was the first of its kind in the long history of the hospital and quickly became one of the best in the U.S.  

The program provides expertise and treatment for a variety of conditions, with Parkinson's disease being chief among them. 

"We have built the program around Parkinson's disease because it is unique in its need for a multidisciplinary team to treat a constellation of symptoms," Tagliati said. 

"Patients with suspected Parkinson's disease should see a movement disorder specialist as early as possible."

Making sense of the symptoms

Tremor, stiffness and slowness are symptoms that likely come to mind when thinking of Parkinson's disease. However, over the last decade, nonmotor symptoms have drawn increasing attention. 

"There are around 30 nonmotor symptoms of a wide variety that usually present staggered over time," Tagliati said. "Combined, potential symptoms manifesting with Parkinson's disease surpass the expertise of a single doctor, no matter how specialized they are." 

Nonmotor symptoms can include cognitive decline, memory loss, hallucinations, psychosis, mood problems, anxiety, depression, apathy and more. Issues such as insomnia, sleep apnea and restless leg syndrome can also mean that sleep is not restorative for the brain, resulting in excessive fatigue, headaches and pain during the day.  

"If a patient comes to see you and simply says they aren't doing well without providing specificity, the temptation could be to increase dopaminergic medication if they are already diagnosed with Parkinson's disease, or a physician could proceed to treat certain symptoms on their own without realizing the bigger issue," Tagliati said. "Either course of action would fail to address the problem as a whole." 

Successful treatment that addresses both motor and nonmotor symptoms requires a systematic approach that dives deeper to investigate potential connections between symptoms that are likely not readily apparent to patients. 

A systematic approach by a multidisciplinary team

The Parkinson's Disease Center, part of the Cedars-Sinai Movement Disorders Program, is staffed by neurologists and neurosurgeons with additional specialized training and is designed to provide a one-stop shop for patients. Over the course of three to four hours, patients may be evaluated by physicians; behavioral, physical, and speech and swallow therapists; nutritionists; and other specialists who collaborate to examine each patient's symptoms and create a personalized care plan.   

Patients see all of these experts on the same day, in the same place, in an outpatient setting. Central to the evaluation is a checklist designed to help the team gather the most comprehensive information possible about each patient's history and symptoms. 

"Patients may not link lesser associated symptoms like constipation, urinary frequency or cognitive decline to each other or to Parkinson's disease," Tagliati said. "We inquire about everything. Our approach helps us zone in on the root of what's bothering them so we can have the biggest positive impact." 

Tagliati says Parkinson's disease becomes very evident over time, but patients could have months or years of unsatisfactory or unnecessary treatment if symptoms are misdiagnosed early. 

"The most common sources of diagnosis are motor symptoms—specifically tremor," Tagliati said. "But if a patient presents with tremor as the only symptom, a physician could provide treatment solely for that without looking deeper. Some patients have tremor for years before other symptoms present." 

Similarly, if a patient complains only of muscle stiffness, they may see an orthopaedic physician instead of a neurologist and receive a totally different diagnosis. 

"Patients with suspected Parkinson's disease should see a movement disorder specialist as early as possible," Tagliati said. "Every patient experiences Parkinson's disease in a unique way. We are dedicated to understanding the disease and the different ways it might present itself." 

Connecting more dots through research

In pursuit of his second goal, Tagliati and his team continue to seek ways to identify new therapies to improve outcomes and quality of life for patients with Parkinson's disease. 

As early as the 1960s, researchers observed that patients with diabetes seemed to suffer from Parkinson's disease at higher rates than their age or other risk factors alone would suggest, and they experienced comparatively faster and more severe disease progression.  

One common link between the diseases is insulin resistance. A 2018 Cedars-Sinai study published in the Journal of Parkinson's Disease found insulin resistance to be prevalent in nondiabetic patients with Parkinson's disease and correlated with increasing body weight.  

Based on that and similar studies, Tagliati began to wonder if improved insulin resistance could lead to an improved condition in those with Parkinson's disease. As principal investigator, he assembled a multidisciplinary team spanning neuropsychologists, pharmacists and statisticians to design and implement a randomized clinical study to examine the effectiveness of addressing insulin resistance for patients with Parkinson's disease using a medication currently approved to treat type 2 diabetes.  

"Using this connection between diabetes and Parkinson's disease is a new concept—a new line of research—that is a little outside the box," Tagliati said, noting that Cedars-Sinai is one of a handful of centers worldwide investigating this application for insulin-resistance therapies. 

The study was completed during and despite the COVID-19 pandemic under Cedars-Sinai's safety protocols. Preliminary data analysis is promising, and the researchers expect to communicate and publish their peer-reviewed findings in 2022.  

"I'm hopeful this study will open the door to new opportunities and take us to the next level of research," Tagliati said. "We want to help shape the future and give our patients access to new therapies and treatments that wouldn't be available otherwise."