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Tests Used to Diagnose Tremor

Internists and neurologists use a series of approaches to diagnose a patient with tremor. Tremors might be an isolated condition like essential tremor or ET. But tremor may also be a symptom of an underlying condition rather than a standalone issue.

One diagnostic tool that doctors may use to test and diagnose a tremor is a drawing task known as a spiral test or an Archimedes spiral test.

If you have an undiagnosed tremor, it’s important to note that this article is for informational purposes only and doesn’t replace the professional opinion, advice, and treatment from your doctor.

Keep reading to learn more about the writing tests used to diagnose essential tremor (ET) and how it’s used to differentiate ET from other health conditions like Parkinson’s and dystonia.


Tremor Writing Tests

There are three pen and paper tasks that can be used as evidence for neurological issues and tremor diagnoses: Archimedes spirals, handwriting, and line drawing.

The handwriting test involves telling a patient to write out a simple phrase or sentence with his or her dominant hand. Although sometimes one repetition is enough, repeated writing of the phrase can reveal aberrations that need repeated tasks to fully present.

For the line drawing test, patients are asked to draw horizontal and vertical lines that are at least 10 centimeters long with each hand, to allow time for any tremor or movement to manifest.

To conduct the Archimedes spiral test, a doctor will either draw a spiral on paper first and have the patient try to emulate it, or the doctor will simply trace a spiral in the air so the patient draws their own spiral independently. First, the patient draws the spiral with their dominant hand, followed by a spiral drawn with their non-dominant hand. The Archimedes spiral test is often one of the most illuminating tasks because it helps to pinpoint more information about a patient’s specific tremor characteristics. We’ll dive into the specifics of the Archimedes spiral test and why it’s such an important diagnostic tool below.

Sometimes, the patient will be asked to lift up their hand while performing these tests, since resting the palm on the writing surface can have a stabilizing effect.

A visible tremor might be seen in all three writing tasks, or just one–which is why it’s critical for a patient to perform all three tasks.

The Archimedes Test

The Archimedes spiral is important because it captures the frequency, direction, and amplitude of a tremor. During this test, patients are required to draw an unbroken spiral, once with their left hand and once with their right hand.

The resulting spiral can provide evidence for the type and severity of a tremor. This drawing task, alongside other clinical data and tests, can help inform diagnoses and treatments for tremor. It can also be repeated over time, to show the patient’s progress and whether or not he or she is responding to treatment.

Because it’s a continuous movement, it’s much easier for doctors to observe any tremors that might be present. Although handwriting tests can also be helpful, the breaks in between writing separate words can “hide” subtle tremors. The spiral test helps to manifest any tremors, from more obvious to very subtle.

The Archimedes test also allows the neurologist or physician to better determine the severity of the tremor. It’s important to note that these visual exams are just one tool used for diagnosis of tremor.

Besides the spiral test, a doctor may ask a patient if any other symptoms are present like weakness, balance issues, slowness, and stiffness. Blood tests and other neurological testing are also sometimes required.

Tremor Differences and Spiral Test Results

Essential Tremor

The spirals drawn by someone with essential tremor usually presents as spirals with higher frequency, smaller amplitude, and more symmetry compared to other types of tremor like dystonia. Patients with ET may notice shakiness when they’re holding their hands up or during activities like eating or drinking. ET presents as rhythmic involuntary shaking in the hands, arm, head, voice, or legs.

Stress, medications, and fatigue can worsen tremors. ET isn’t linked to an underlying health condition, which is why doctors rule out other health problems like Parkinson’s and multiple sclerosis first if a patient has an unexplained tremor.

Essential tremor can be mild but may worsen over time. The written diagnostic tasks can help a doctor and patient better understand the response to treatment and management of symptoms.

Dystonic Tremor

Patients with dystonia tremor draw spirals that typically have a lower frequency, more variable amplitude, more asymmetry, and harder pen pressure compared to spirals drawn by patients with essential tremor.

Dystonia causes involuntary muscle contractions, forcing sufferers into slow, repetitive movements or postures.  Sometimes, dystonia only affects one muscle, but it can also impact groups of muscles and entire limbs.

Those with dystonia may have a tremor in the neck, hands, or limbs. They may also have difficulty speaking.

Parkinson’s Disease

Patients with Parkinson’s typically write and draw at a slow pace. As a result, handwriting and spirals tend to be smaller and tightly bunched. The slower speed and smaller size of the writing movements signal a motor symptom associated with Parkinson’s. Spiral tests are typically a better diagnostic tool than using handwriting, which can simply be small and bunched as a lifelong habit.

Patients with Parkinson’s disease who have tremor will usually show asymmetric patterns in writing tests.

Parkinson’s disease is a progressive nervous system disorder with no cure but many treatment options. Resting tremors, stiffness, and balance issues are common symptoms.

Other Tremor Diagnostic Tools

In addition to using the Archimedes spiral test, doctors might also use other diagnostic and performance evaluations. For example, your physician might ask you to drink from a glass, walk, eat from a spoon, or hold your arms outstretched.

Here are the types of exams you can expect beyond writing tests:

Neurological Examinations

During a neurological exam, a doctor will evaluate how well your nervous system functions. Physicians might examine the following:

  • Muscle strength and tone
  • Ability to feel different sensations
  • Posture and coordination
  • Gait
  • Reflexes

Lab Tests

Urine and blood samples may need to be tested for underlying issues related to the tremor, including:

  • Thyroid issues
  • Drug side effects
  • Chemical concentrations
  • Metabolic problems

Dopamine Transporter Scan

If your doctor can’t determine if your tremor is due to Parkinson’s or essential tremor, you might need a dopamine transporter scan. This scan can show whether or not a patient has a healthy dopamine system.



Wearables are another diagnostic tool that can be used by doctors to monitor treatment effectiveness and tremor progression.

Cala Trio™ and Therapy Options for Essential Tremor

Cala Trio™  is a revolutionary customized therapy for essential tremor. This wearable therapy for patients with essential tremor is the first non-invasive, targeted therapy that reduces tremor and provides relief for many patients. Cala Trio wrist-worn device is calibrated specifically to match a patient’s unique tremor.

The wearable works by sending electrical signals to the brain to disrupt the parts of the brain responsible for movement. The peripheral nerve is stimulated by the Cala Trio wristband to target the central tremor network.

62% of patients experienced an improvement in physician ratings of the tremor from at-home usage. The most significant improvement occurred with activities like writing, drinking, and eating. Sixty-four percent of patients reported that they experienced relief for an average of 94 minutes after Cala Trio therapy.

Before Cala Trio, patients only had a few options at their disposal. One option was to rely on pharmacothrapies like propranolol and primidone, which may reduce tremor but can also have unpleasant side effects. Surgical interventions, such as deep brain stimulation (DBS), is another option, which comes with serious risks and is invasive.

Essential Tremor: Getting the Right Diagnosis

Essential tremor, while not life-threatening on its own, can cause serious disruptions in your life and prevent you from performing certain tasks effectively—or sometimes at all. In order to get the essential tremor diagnosis, your physician will likely conduct a series of tests and ask you questions about what tasks you find difficult.

Pen and paper tasks are often employed to differentiate between the types of tremors and their associated health conditions. However, if you’re diagnosed with essential tremor, there are treatment options available to help.

Ultimately, you and your doctor will be the ones to decide on a treatment plan that works for your lifestyle and the severity of your essential tremor. For patients who want a non-invasive therapy to manage symptoms, Cala Trio is an FDA-cleared medical device that can provide meaningful relief in the form of targeted electrical signals to the brain. Available only by prescription, the Cala Trio wrist-worn device is designed to help patients with ET enjoy one day at a time.

Ready to get started? Talk to your doctor today to find out if Cala Trio is right for you.

Cala Trio therapy is the only medical device cleared by the FDA to treat essential tremor without the risk of surgery or pharmaceutical side effects. Find out if Cala Trio therapy is right for you.

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