Handwriting shifts to sleep issues: Experts decode early Parkinson's signs

Doctors explain the subtle non-motor symptoms that can appear years before tremors, offering early clues into the brain changes linked to Parkinson's

Parkinson’s disease is commonly associated with tremors and slowed movement. However, long before stiffness or shaking appear, subtle changes in handwriting, a reduced sense of smell or disturbed sleep may signal that something is unfolding in the brain. Experts say these early non-motor symptoms can surface years in advance, although they are often overlooked because they seem unrelated to a neurological condition.

 

This early window is known as the prodromal phase, and it reflects slow and progressive changes in the brain that remain largely invisible in routine clinical practice.

 

What happens in the brain in Parkinson’s

 

Parkinson’s disease is linked to the build-up of an abnormal protein called alpha-synuclein, explains Dr Mohit Bhatt, director of neurosciences at Kokilaben Dhirubhai Ambani Hospital, Mumbai.

 

 

“These early symptoms occur because alpha-synuclein first accumulates in brain regions that control sleep and smell, and in gut neurons, before spreading to areas responsible for classic Parkinson’s symptoms such as tremor, slowness, rigidity and postural changes,” he said.

 

In simple terms, the disease process may begin in areas controlling sleep, smell and digestion, and only later affect parts of the brain responsible for movement.

 

Earlier onset in Indians

 

Parkinson’s prevalence in India has increased by 21 per cent over the past two decades, according to a 2025 study published in the journal Movement Disorders.

 

“The disease occurs here at least 10 years earlier than the world, with around 7.5 lakh estimated patients,” says Dr Elavarasi A, associate professor of neurology at the All India Institute of Medical Sciences (AIIMS), Delhi.

 

She adds that non-motor symptoms can appear 15 to 20 years before motor symptoms begin. However, she emphasises caution. “Motor symptoms remain essential for diagnosis. As long as there is no clear slowness of movement, we do not diagnose Parkinson’s disease.”

 

Dr Bhatt notes that although experimental biomarkers such as alpha-synuclein seed assays using saliva or skin biopsy are being studied, there is currently no routine test to diagnose Parkinson’s in its early non-motor phase. Identifying these symptoms is mainly useful for monitoring patients and managing individual complaints.

 

Moreover, early identification does not yet change long-term outcomes because no therapy can stop or slow progression at this stage.

 

What are some early non-motor signs?

 

“Parkinson’s disease is not a single-symptom disorder. It affects motor and non-motor functions, which is why early signs are often overlooked,” says Dr Shrikant Sharma, director of neurosciences at Kailash Hospital & Neuro Institute.

 

1. Loss of smell (Anosmia)

 

Often one of the earliest symptoms, loss of smell can appear decades before tremors. It occurs because the olfactory regions of the brain are affected early.

“When a patient in their 50s or 60s mentions a gradual loss of smell without a history of sinus issues, it raises an important flag for us. It’s a non-motor symptom that can precede the classic tremor by a decade or more,” says Dr Sharma.

 

2. Sleep disturbances

 

Rapid Eye Movement (REM) Sleep Behaviour Disorder (RBD) occurs when people physically act out their dreams during the Rapid Eye Movement stage of sleep and may shout, kick or punch. It is considered one of the strongest early markers of Parkinson’s disease and medication can help manage symptoms.

 

Dr Asha Kishore, Neurologist and Director of the Parkinson and Movement Disorders Centre at Aster Medcity, Kochi, says, “Only a proportion of people with RBD or reduced sense of smell go on to develop Parkinson’s, often after many years.”

 

3. Constipation and gut problems

 

Constipation is closely linked to Parkinson’s severity and may precede motor symptoms by years. Researchers believe alpha-synuclein may spread from the gut to the brain, although constipation itself does not cause the disease. Dietary changes and medication can help manage symptoms.

 

4. Change in handwriting (Micrographia)

 

Handwriting may become noticeably smaller, cramped and crowded, and letters may trail off at the end of words or sentences. This happens because the brain struggles to coordinate fine motor movements.

 

Dr Sharma says, “Compare a cheque signature from five years ago to one today. If the recent one is consistently tiny and squeezed, it’s not just ‘getting older’ but a potential neurological sign worth discussing with a specialist.”

 

5. Soft or low voice (Hypophonia)

 

A person’s voice may gradually become softer or flatter, and others may frequently ask them to repeat themselves. Parkinson’s affects the automatic control of muscles involved in speech.

 

“This change is so gradual that the individual often doesn’t notice it,” says Dr Sharma. “Family members are key here. If they say, ‘You’re not speaking clearly anymore,’ it should be taken seriously.”

 

6. Reduced facial expressions (Hypomimia)

 

Some people develop fewer spontaneous facial expressions, which can make them appear serious or withdrawn. Blinking may reduce and smiling may become less frequent.

 

“It’s often mistaken for depression or disinterest,” Dr Sharma explains. “But in the context of other signs, it’s part of the motor circuitry slowing down. The emotion is there but its physical expression is dampened.”

 

7. Stooped posture and balance changes

 

A gradual stooped posture or slight forward lean can develop over time and some people may take short, shuffling steps. This results from rigidity in trunk muscles and reduced postural reflexes. “This stooped posture isn’t poor habit but a neurological symptom,” says Dr Sharma. Early physiotherapy and targeted exercises can help maintain mobility and reduce the risk of falls.

 

8. Depression, anxiety and fatigue

 

Mood disorders and persistent tiredness are frequently reported in the early phase. Counselling and medication can ease these symptoms and addressing them early improves quality of life.

 

Experts caution that not everyone with constipation, sleep disturbances or loss of smell will develop Parkinson’s disease. Careful evaluation by a specialist remains essential, and informed awareness should empower patients rather than alarm them.     

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This report is for informational purposes only and is not a substitute for professional medical advice.