Parkinson's Disease vs Essential Tremor — How Are They Different?

Shaking hands is one of the most common reasons people visit a neurologist. Two very different conditions — Parkinson's disease and essential tremor — can both cause hand shaking, but they look different, have different causes, and need different treatment. Getting the diagnosis right matters enormously.

What Is Essential Tremor?

Essential tremor (ET) is the most common movement disorder in the world — affecting an estimated 7 million people in India. Despite being far more common than Parkinson's disease, it is often misdiagnosed or dismissed as "just anxiety" or "just old age."

Essential tremor causes shaking during action — when you are using the hand (writing, holding a cup, pouring water). The hand is relatively still at rest. It commonly affects both hands, and often the head and voice as well. It frequently runs in families.

What Is Parkinson's Disease?

Parkinson's disease is caused by the death of dopamine-producing cells in the brain. It causes a characteristic tremor that is present at rest — the hand shakes when it is lying in the lap, doing nothing — and reduces or disappears when the hand is in use. The tremor is typically worse on one side. Alongside the tremor, Parkinson's causes slowness of movement (bradykinesia), stiffness (rigidity), and changes in walking and balance.

Key Differences at a Glance

• When it shakes: ET shakes during action (using the hand). Parkinson's shakes at rest (hand idle in lap)
• Which side: ET usually both sides. Parkinson's almost always starts on one side
• Other symptoms: ET has no other major features. Parkinson's has slowness, rigidity, small handwriting, reduced arm swing when walking, soft speech
• Family history: ET often runs in families. Parkinson's is usually not inherited
• Effect of alcohol: ET usually improves briefly with a small amount of alcohol. Parkinson's tremor does not
• Age of onset: ET can start at any age including young adults. Parkinson's usually starts after 55–60

"The easiest way to distinguish them at the bedside: ask the person to hold a cup of water. In essential tremor, the cup shakes while held. In Parkinson's, the hand was shaking while empty, but steadies when gripping the cup."

Why Does the Distinction Matter?

The treatment is completely different. Essential tremor responds to propranolol or primidone. Parkinson's disease is treated with levodopa (a dopamine replacement). Giving the wrong treatment not only fails to help — it can make things worse. An accurate neurological diagnosis from an experienced clinician is essential before any medication is started.

What If I Am Not Sure?

If you or a family member has a hand tremor, see a neurologist for a clinical assessment. In most cases, the distinction between essential tremor and Parkinson's can be made from clinical examination alone — without any special tests. In uncertain cases, a DaTscan (a nuclear medicine brain scan) can reliably distinguish Parkinson's from essential tremor.

At Sri Anand Child and Neuro Center, Chanda Nagar, Dr. Anand Karnam (DrNB Neurology) diagnoses and treats both essential tremor and Parkinson's disease. Call +91 90633 66983 to book an appointment.