Most people picture Parkinson's disease as a tremor. But that shaking hand is often not the first thing to change. Subtler signs frequently show up earlier, and some can appear a decade or two before motor symptoms send a person to a neurologist.
That timing is well documented in the medical literature. A review of premotor Parkinson's symptoms published in the National Library of Medicine's PubMed Central reports that clinical studies have found the onset of REM sleep behavior disorder or constipation 10 to 20 years before diagnosis.
The Parkinson's Foundation, a leading US patient organization for the disease, lists warning signs that clinicians and researchers consider most useful for spotting Parkinson's early. Here are eight, starting with the ones most people never associate with the condition.
1. A fading sense of smell
Loss of smell, called hyposmia, is one of the earliest recognized markers. People may struggle to identify strong foods such as bananas, dill pickles or licorice long before any movement problems begin.
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2. Acting out dreams in sleep
This is REM sleep behavior disorder, in which a sleeper physically enacts vivid dreams by yelling, punching or kicking. The Michael J. Fox Foundation says the condition can be one of the first symptoms of Parkinson's, appearing years before motor changes.
3. Chronic constipation
Straining to move bowels every day, without an obvious dietary or medication reason, is another non-motor sign flagged by the Parkinson's Foundation as a possible early clue.
4. Small, cramped handwriting
Neurologists call this micrographia. Letters shrink and words crowd together on the page. Because the change is gradual, patients often do not notice it until someone else points to an old signature.
5. A masked face
A serious, blank or angry-looking expression may appear even when the person is in a neutral mood. Family members often notice this before the person does.
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6. A soft or breathy voice
The voice may become quieter, hoarser or more breathy over time. Friends and relatives may start asking the person to repeat themselves.
7. Slowness and changes in walking
Movements slow down, arms swing less during walking, and one leg may drag slightly. The changes often show up on one side of the body first.
Neurologist Dr. Michael Hayes told Mass General Brigham in March 2025 that non-motor signs can precede the classic Parkinson's symptoms like tremor and balance issues. "These non-motor signs can occur decades before motor symptoms," he said.
8. A resting tremor
The classic tremor typically appears in a hand or finger while the limb is at rest. It usually begins on one side of the body before spreading.
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When to talk to a doctor
None of these signs on its own confirms Parkinson's disease. A poor sense of smell can follow a bad cold, and constipation has many everyday causes. The pattern matters more than any single symptom. According to the Parkinson's Foundation, someone who notices more than one of these signs should consider making an appointment to speak with a doctor.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.