Parkinson’s can begin years before a tremor: 3 early signs neurologists want people to know

A trembling hand is what most people picture when they hear the word Parkinson’s. But neurologists say the disease can begin showing signs long before someone notices a tremor. In fact, some people with Parkinson’s never develop one.

Years before the familiar movement problems appear, there may be changes that seem completely unrelated to the brain. Some of these symptoms are common and could have other explanations. However, researchers have found that they can sometimes be part of the earliest stages of Parkinson’s disease, particularly when several occur together.

Parkinson’s can develop long before movement problems begin

Doctors call this early period the prodromal stage. It is a time when changes associated with Parkinson’s may already be happening in the nervous system, even though the usual movement symptoms haven't appeared.

According to neurologist Dr. Michael Hayes of Mass General Brigham, non-movement symptoms can appear decades before the more recognizable signs, such as tremors and balance problems.

Research published through the US National Institutes of Health describes cases in which constipation and certain sleep disturbances appeared 10 to 20 years before a Parkinson’s diagnosis.

That doesn't mean these symptoms will eventually lead to Parkinson’s. Most people experiencing them have another explanation.

1. Constipation that has been going on for years

Constipation is one of the less obvious symptoms researchers have linked to Parkinson’s disease.

The condition affects more than movement. It can also involve the nerves that help control digestion, which may cause the intestines to work more slowly.

According to the Parkinson’s Foundation, difficulty passing stools can be an early sign, particularly when there is no obvious explanation.

But constipation is extremely common, especially as people get older. Not drinking enough water, eating too little fiber, and taking certain medications can all contribute.

Constipation alone is therefore not a reliable indication of Parkinson’s. Doctors are more interested in whether it occurs alongside other unusual changes.

2. Coffee and familiar foods don't smell as strong anymore

Another possible early sign involves the sense of smell.

Someone may notice that their morning coffee has lost some of its aroma, or that foods such as bananas and licorice no longer smell as strongly as they once did.

This reduced ability to smell, known medically as hyposmia, can develop gradually. Because the change is often subtle, people may not recognize it until much later.

The Parkinson’s Foundation explains that some patients experience a declining sense of smell years before their diagnosis.

However, colds, sinus problems, allergies and viral infections are much more familiar explanations. A weaker sense of smell does not automatically point to a neurological condition.

3. Shouting, kicking or acting out dreams

One of the more unusual early signs may be noticed first by a husband, wife, or partner.

During normal REM sleep, when most vivid dreaming occurs, the body temporarily prevents most muscle movements. But in people with REM sleep behavior disorder, or RBD, this protection doesn't work properly.

Someone might shout, punch, kick or make sudden movements while dreaming. They may have no memory of doing so the following morning.

The Parkinson’s Foundation explains that RBD can appear years before Parkinson’s is diagnosed.

Still, an occasional jerk while falling asleep is normal and is not the same condition. Other problems, including sleep apnea and certain medications, may also be associated with dream-enacting behavior.

Repeated episodes deserve medical attention, particularly if someone could accidentally hurt themselves or their partner.

Why doctors look at several symptoms together

Constipation, smell changes and disrupted sleep can each have an ordinary explanation. What makes them more interesting to neurologists is the possibility of a pattern.

Other changes associated with early Parkinson’s include depression, anxiety, increasingly small handwriting, a softer voice and reduced arm movement while walking.

However, even several of these symptoms do not establish a diagnosis. Doctors also consider medical history, medication use, and physical examination findings.

When should you speak with your doctor?

If you have noticed several persistent changes, particularly if they are getting worse, it is worth discussing them with your primary care doctor.

Before your appointment, write down when the symptoms began, whether they have changed, and which medications you take. If you share a bed, ask your partner whether they have noticed unusual movements or shouting during sleep.

You don't need to wait for several symptoms if one is persistent or troublesome. Repeatedly acting out dreams, for example, is worth getting checked even without other signs.

The important thing is not to assume that constipation, poor sleep or a fading sense of smell means Parkinson’s is developing. For most people, these complaints have other causes.

But knowing that Parkinson’s can involve more than trembling hands may help you recognize when a conversation with your doctor makes sense.