Early Parkinson’s Symptoms: 3 Subtle Signs That Can Appear Years Before Tremors

Parkinson’s disease may begin decades before movement symptoms. Learn the early warning signs — sleep disorders, loss of smell, and chronic constipation — and when to seek care.

For decades, people have regarded a tremor as the most typical sign of Parkinson’s disease, but a growing body of research now underscores the idea that there are other symptoms that appear much earlier, and many of those don’t even involve movement.

“Parkinson’s is defined as a neurological disorder with tremors and we’ve known this since [James} Parkinson wrote about it [in 1817],” says Corneliu Luca, M.D., Ph.D., a movement disorders neurologist with the University of Miami Health System. “But we now know that some non-motor symptoms can show up in the prodromal stage 10-15 years earlier.”

While not everyone with these symptoms will go on to develop Parkinson’s, those who do have a higher chance. Knowing this gives movement disorder clinicians “a way to identify early on and intervene with treatment for the particular symptoms,” adds Dr. Luca.

 What’s more, these clinical symptoms — acting out dreams, loss of smell and chronic constipation — can be used along with a blood test measuring abnormal alpha‑synuclein to identify people in the earliest, prodromal stages of the disease. (Alpha‑synuclein is the protein that misfolds and accumulates in Parkinson’s.)

Parkinson’s disease (PD) is the second most common progressive neurodegenerative disorder after Alzheimer’s.

It is marked by tremors, bradykinesia (slowness of movement), limb rigidity, and gait/balance problems. Scientists have yet to determine the cause or find a cure, but they do know that the disease affects the neurons that produce dopamine. Dopamine is essential in controlling movement and coordination in the brain.

As many as 70% of those neurons in the brain have died by the time the tell-tale symptoms of tremors and rigidity have been noted — which makes the detection of early Parkinson’s symptoms critical for early intervention.  “If we can detect early, we can possibly save these neurons,” Dr. Luca adds. The symptoms themselves can also be treated, which can improve an individual’s well-being and help them maintain independence longer

PD affects more than 1 million people in the U.S. and about 10 million globally, according to the the Parkinson’s Foundation.

Almost 90,000 people are newly diagnosed each year. The condition occurs roughly one‑and‑a‑half times more often in men than in women. and prevalence is higher ins regions like Florida, California and the Rust Belt. Cases are expected to rise as the U.S. population ages, with 1.2 million Americans living with the disease by 2030.

Age is considered the highest risk, with the average onset of the disease showing up in a person’s mid-60s’. However, about 10% of cases are diagnosed before age 50.

Parkinson’s has long confounded those who treat and study it. Only about 10 to 15% of cases are genetic, and most who develop the disorder don’t have a strong family history. Some environmental factors, however, may be to blame. These include exposure to pesticides and herbicides, industrial toxins, and, in rural areas, consumption of well water.

 It’s a slow disease that can take years to develop and, as Dr. Luca explains, “The disease is a lot more complex than we thought it was. It’s not just a movement disorder marked by dopamine loss but a disease that begins before motor systems show up and it involves multiple brain regions and systems.”

The early symptoms of PD include:

REM (rapid eye movement) sleep behavior disorder.  

A chronic disorder, the condition is marked by the loss of the almost total paralysis of the body that occurs during REM sleep. This results in people acting out their dreams physically. For example, they may punch or kick or shout or have one-sided conversations. People who have this disorder have  a 30% chance risk of developing PD or another related condition within three years. It is considered to be one the most predictive signs and can occur up to 10 years before the onset of tremors and other body movement.

Several studies have confirmed this. One large study showed that up to 80% of people with the idiopathic form of this sleep disorder eventually developed PD or another neurodegenerative disease. Predicting when and which disease, however, is difficult.

While treatment for REM sleep disorder does not stop the potential progression of Parkinson’s, dealing with it is important. “Sleep is the way your brain cleans waste and recovers balance,” says Dr. Luca.  “You need it for better brain function. Poor sleep quality is not only a risk for neurodegenerative disease but also for cardiovascular, metabolic and mental health.”

Constipation.

Everyone suffers from this malady at some point, but it’s chronic constipation that has been found to be an early sign of PD, affecting about two-thirds of people with Parkinson’s. In fact, a meta-analysis of individuals with chronic constipation were twice as likely to develop PD.

Several studies have shown that those misfolded alpha‑synuclein in the brain that cause tremors and rigidity also appear in the intestines lining, but the faulty neurons appear earlier in the gut.

Loss of smell.

Like constipation, many people have experienced losing their sense of smell (known as anosmia) after a cold or a sinus infection, but for those with PD, that loss lasts a lot longer. Of all the early PD symptoms, this is probably the one that occurs earliest – as many as 20 years before motor symptoms manifest — and it’s present in 90% of patients.

Interestingly, idiopathic anosmia (anosmia with no known cause) is also associated with sleep issues, gastrointestinal problems, and depressive symptoms, prodromal PD signs.

Displaying any one of these symptoms alone is not predictive of a person developing PD. However, the combination of all three is “highly predictive,” Dr. Luca says. One longitudinal study found that men who are chronically constipated, act out dreams, and lose their sense of smell have an “exponentially increased” risk of developing Parkinson’s.

If you’re experiencing any of these symptoms, Dr. Luca recommends consulting your doctor, who can refer you to a neurologist or further testing as needed. That said, there are ways that may prevent, or at least slow the progression, of PD. These include eating fewer processed food and more organic food that is not exposed to pesticides, improving and maintaining your sleep quality, and exercising regularly.

“We can’t control genetic factors,” he says, “but we can control our environment and our behavior.”

Written by Ana Veciana-Suarez. Reviewed by Corneliu Luca, M.D., Ph.D.

Tags: chronic constipation Parkinson’s, Dr. Corneliu Luca, loss of smell Parkinson’s, neurodegenerative disease early signs, prodromal Parkinson’s disease