Definition

A tremor is an abnormal movement in body parts that occurs involuntarily; sufferers usually cannot control the shaking felt in their body parts. Tremor occurs for a long duration and typically appears in the hands, although it can affect the arms, head, vocal cords, tongue, and chin. Tremor rarely occurs in the lower extremities. Some tremors appear at rest and are not very noticeable during activity (resting tremor), and some tremors are visible when the sufferer raises their hand against gravity (postural tremor).

Cerebellar or intention tremor is an involuntary muscle contraction that occurs when the sufferer is performing a deliberate movement, originating from a disturbance in the cerebellum. In intention tremor, symptoms can be found in 50% of the arms, 27% of the legs, and 9% of the head. This condition is caused by damage to the same side of the cerebellum as the tremor movement. Cerebellar tremor is prone to occur in people with diseases such as stroke or tumors. Tremor itself is not dangerous but can be embarrassing and disrupt daily activities and life.

Causes

Tremors can occur due to problems in the brain area that regulates body muscle movements. In an intentional tremor, there is a disturbance in cerebellar feedback in the central nervous system with the muscles, resulting in a tremor. Intention tremor is associated with damage to the areas around the cerebellar tracts in the brainstem and thalamus, as well as the cerebellar peduncles. Cerebellar degeneration is also found in patients with alcohol abuse. In alcoholic patients, there is damage to cells in the cerebellum, such as Purkinje cells.

Cerebellar diseases that also present with tremor include:

• Spinocerebellar ataxia
• Fragile X-associated tremor
• Acute cerebellitis
• Tumor or injury to the brain affecting the cerebellum
• Paraneoplastic cerebellar degeneration
• Secondary symptoms of stroke

In addition to the above diseases, tremors can also be caused by certain conditions such as multiple sclerosis, liver or kidney failure, nerve function-related diseases such as Parkinson's disease, hyperthyroidism, and hypoglycemia.

Some medications used long-term can also cause tremors. These medications include amphetamines, corticosteroids, psychiatric medications, and anticonvulsants (phenytoin and carbamazepine). Excessive caffeine consumption and mercury poisoning can also cause tremors. Vascular diseases such as cerebellar infarction, autoimmune diseases, and metabolic symptoms such as hepatocerebral degeneration can also cause tremors. All these are underlying factors that can cause tremors.

Risk factor

Risk factors influencing tremor include age and hereditary or genetic mutations. Excessive alcohol and caffeine consumption can also increase the risk of tremors. Drive safely and wear head protection to avoid head trauma that can affect the cerebellum. The use of anticonvulsants can also increase the risk of tremors.

In tremor caused by acute cerebellitis, although the exact cause is unknown, the disease usually occurs due to viral infections, such as rotavirus, Epstein-Barr virus, varicella-zoster virus, herpes simplex virus, and HIV. Bacterial infections, although rare, have also been reported as causes of cerebellitis.

Symptoms

Not all tremors caused by cerebellar diseases appear as intentional tremors. Moreover, not all tremors resulting from cerebellar diseases manifest with the same symptom characteristics. As described above, various types of tremor include postural tremor and resting tremor.

Patients with tremors usually report difficulties in daily activities, such as drinking from a cup or picking up utensils. Tremor also causes movement problems for sufferers.

Other symptoms related to cerebellar issues include:

• Nystagmus (difficulty controlling rapid eye movements) and problems with eye coordination
• Dysmetria (inability to estimate the speed or distance of an object)
• Dysdiadochokinesia (inability to perform rapid alternating movements)
• Hypotonia (reduced muscle tone)
• Ataxia (difficulty controlling body movements, characterized by an abnormal gait)

Diagnosis

The diagnosis of cerebellar tremor can be established through a detailed interview (anamnesis) about the symptoms experienced and the patient's medical history, physical examination, and supporting tests. Common physical examinations for detecting cerebellar disturbances include:

• Finger-to-nose and heel-to-shin tests, where patients are asked to perform these quickly
• Fine finger movement tests to observe coordination and speed, such as buttoning/unbuttoning a shirt, and picking up objects like a cup or pencil. Tremor will increase when attempting to reach an object
• Tremor amplitude decreases when eyes are closed
• Dysdiadochokinesia detection by having patients alternately turn both palms in opposite directions
• Ataxia detection through walking tests such as tandem walking and the Romberg test

Depending on the etiology of the tremor, patients may have increased physiological reflexes and pathological reflexes (reflexes not present in healthy individuals).

In the physical examination, the presence of involuntary muscle movements or tremors will be observed. Besides the physical examination, supporting tests such as imaging, especially MRI (Magnetic Resonance Imaging), are used to evaluate the brain and cerebellum.

Management

Treatment of tremor depends on the underlying disease. Some treatment options include:

• Medications

Beta-blockers like propranolol, atenolol, and metoprolol. Anticonvulsants if beta-blockers are ineffective, such as primidone and gabapentin, sedative benzodiazepines, Parkinson's medications (levodopa and carbidopa), and botulinum toxin injections.

• Focused Ultrasound Therapy

Surgery using ultrasound waves guided by MRI imaging to reduce lesions in brain areas causing tremors.

• Surgery

Performed if the condition does not improve with medication or if the tremor is severe. In addition to medications, ultrasound, and surgery, physical therapy such as gait training, tendon vibration, and body positioning techniques can restore body function.

Complications

If the underlying cause of tremors is not addressed, tremors can interfere with daily activities and increase stress and depression in patients. Fortunately, life-threatening complications from cerebellar tremors have not been found. However, untreated underlying diseases may lead to other complications.

Prevention

To prevent tremors from worsening, avoid stress and anxiety, which can exacerbate tremors. Engage in light exercise to strengthen muscles, reduce caffeine consumption, and increase water intake. Ensure sufficient sleep and rest, as fatigue can trigger tremors.

When to see a doctor?

It is recommended to see a doctor immediately if experiencing sudden tremor or if the tremor worsens and occurs frequently.

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