Postural Tremor

Postural Tremor: Symptoms, Causes, Types, Diagnosis, and Treatments

Tremors are involuntary, rhythmic muscle movements that involve shaking in one or more parts of the body. Among the various types of tremors, postural tremor is one that occurs when a person maintains a position against gravity, such as holding the arms outstretched. This article will explore postural-tremor in detail, including its symptoms, causes, classification, diagnostic methods, and treatment options.

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What is Postural Tremor?

A postural tremor is a type of tremor that appears when the muscles are actively maintaining a position against gravity. Unlike resting tremors (which happen when muscles are relaxed), postural-tremors become evident when the affected body part is held still in a specific posture. For example, holding your hands out in front of you or keeping your head upright can trigger this tremor.

Postural tremors can affect different body parts such as the hands, arms, head, or legs and vary in severity. They can be physiological (normal and harmless) or pathological, indicating an underlying health problem.

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Symptoms of Postural Tremor

The hallmark symptom of postural tremor is rhythmic shaking or oscillation of a body part when held in a position against gravity. Common symptoms include:

• Shaking or oscillations in the hands, arms, head, or legs while maintaining a posture.
• Tremors that may worsen with fatigue, anxiety, or stress.
• Fine to coarse trembling, often described as a “shaking” feeling.
• Tremors sometimes interfere with daily activities like writing, holding objects, or eating.
• Tremor frequency can vary, typically between 4 to 12 Hz (cycles per second).
• In some cases, tremor amplitude increases with sustained posture.

Additional signs depending on the underlying cause may include:

• Muscle weakness or stiffness.
• Coordination difficulties or imbalance.
• Other neurological symptoms such as speech difficulties, gait problems, or cognitive changes.

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Causes of Postural Tremor

Postural tremors arise due to abnormal oscillations in the nervous system controlling muscle movement. The causes can be broadly divided into physiological, pathological, and drug-induced categories.

1. Physiological Tremor

Everyone has a mild physiological tremor, which is barely noticeable and occurs due to normal muscle activity and minor neural oscillations. This type is generally harmless and can be enhanced by:

• Anxiety or stress.
• Fatigue.
• Excess caffeine or stimulant intake.
• Certain medications.
• Low blood sugar or hypoglycemia.
• Hyperthyroidism (overactive thyroid).

2. Essential Tremor

Essential tremor (ET) is the most common pathological cause of postural-tremor. It is a progressive neurological disorder characterized by involuntary shaking, primarily affecting the hands and arms but sometimes the head and voice. ET usually runs in families (genetic predisposition) and worsens with age.

3. Parkinson’s Disease

Though Parkinson’s disease is commonly associated with resting tremor, some patients also experience postural tremors. This neurodegenerative disorder affects movement control due to dopamine deficiency in the brain.

4. Cerebellar Disorders

Damage to the cerebellum or its pathways can cause postural-tremors. The cerebellum coordinates voluntary movements, and lesions from stroke, multiple sclerosis, tumors, or trauma may cause intention and postural-tremors.

5. Dystonia

Dystonia is a movement disorder involving sustained muscle contractions that cause twisting and repetitive movements or abnormal postures. Some forms of dystonia can manifest with tremors when holding postures.

6. Drug-Induced Tremor

Certain medications can provoke or worsen postural tremors as a side effect, including:

• Beta-agonists (used for asthma).
• Antidepressants.
• Antipsychotics.
• Lithium.
• Stimulants.
• Valproic acid.

7. Metabolic and Toxic Causes

Metabolic abnormalities such as hyperthyroidism or liver failure, and exposure to toxins like alcohol, heavy metals, or certain poisons, can lead to tremors.

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Types of Postural Tremor

Postural tremors are classified based on their origin and characteristics. The main types include:

1. Physiological Tremor

• Characteristics: Fine, rapid, low-amplitude tremor.
• Frequency: Typically 8-12 Hz.
• Cause: Normal in all individuals, enhanced by stress, fatigue, or stimulants.

2. Essential Tremor

• Characteristics: Symmetrical, rhythmic shaking usually in hands and arms.
• Frequency: 4-8 Hz.
• Cause: Genetic mutation affecting neural circuits.

3. Cerebellar Tremor (Intention Tremor with Postural Component)

• Characteristics: Coarse, low-frequency tremor worsening as the target is approached.
• Frequency: 2-4 Hz.
• Cause: Cerebellar damage.

4. Dystonic Tremor

• Characteristics: Irregular, jerky tremor, often position-dependent.
• Cause: Associated with dystonia.

5. Drug-Induced Tremor

• Characteristics: Variable depending on drug, often symmetrical.
• Cause: Side effect of medications.

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Diagnosing Postural Tremor

Diagnosing postural tremor involves a thorough clinical assessment supported by diagnostic tests to identify the underlying cause.

1. Medical History

• Onset and progression of tremor.
• Family history of tremor or neurological diseases.
• Medication and substance use.
• Associated symptoms (weakness, stiffness, balance issues).

2. Physical and Neurological Examination

• Observation of tremor at rest, during posture holding, and with action.
• Assessment of tremor frequency and amplitude.
• Testing coordination, strength, reflexes, and gait.
• Checking for signs of other neurological disorders.

3. Laboratory Tests

• Blood tests to check thyroid function, glucose levels, liver function, and electrolytes.
• Toxicology screens if drug-induced tremor suspected.

4. Imaging

• MRI or CT scan to rule out cerebellar or brain lesions.
• Dopamine transporter (DAT) scans in suspected Parkinson’s disease.

5. Electrophysiological Tests

• Electromyography (EMG) and accelerometry can measure tremor frequency and characteristics objectively.

6. Tremor Rating Scales

• Tools like the Fahn-Tolosa-Marin Tremor Rating Scale quantify tremor severity and impact on daily life.

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Treatments for Postural Tremor

Treatment strategies depend on the tremor’s cause, severity, and impact on quality of life.

1. Lifestyle and Home Remedies

• Avoid caffeine and stimulants.
• Manage stress and anxiety through relaxation techniques.
• Adequate sleep and regular exercise.
• Occupational therapy for adaptive strategies.

2. Medications

For Essential Tremor and Pathological Postural-Tremors:

• Beta-blockers: Propranolol is commonly used and effective in reducing tremor amplitude.
• Primidone: An anticonvulsant that reduces tremors.
• Gabapentin or Topiramate: Alternative antiepileptic drugs sometimes effective.
• Benzodiazepines: For anxiety-related tremors or as adjunct therapy.
• Botulinum toxin: Injected in specific muscles for head or voice tremors.

For Parkinson’s Disease Tremor:

• Levodopa/carbidopa: Replenishes dopamine.
• Dopamine agonists: Pramipexole or ropinirole.
• Anticholinergics: Sometimes used for tremor control.

3. Physical and Occupational Therapy

• Strengthening and coordination exercises.
• Use of weighted utensils or wrist weights to reduce tremor.
• Training to improve daily function.

4. Surgical Treatments

Reserved for severe, disabling tremors that do not respond to medications.

• Deep Brain Stimulation (DBS): Electrodes implanted in brain areas (usually thalamus) to modulate tremor activity.
• Thalamotomy: Surgical lesioning of thalamic regions.

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Prognosis and Living with Postural Tremor

Postural tremor, particularly essential tremor, is typically a chronic condition. While not life-threatening, tremors can significantly affect quality of life by impairing daily activities and causing social embarrassment.

With appropriate treatment and support, many individuals manage tremors effectively. Advances in neurology continue to improve understanding and therapy options.

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When to See a Doctor

If you experience new or worsening tremors, especially if accompanied by other neurological symptoms such as:

• Weakness or numbness.
• Difficulty walking or maintaining balance.
• Speech or swallowing difficulties.
• Sudden onset of tremor.

Seek prompt medical evaluation.

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Conclusion

Postural tremor is a common neurological phenomenon ranging from harmless physiological tremor to debilitating disorders like essential tremor or cerebellar disease. Early diagnosis and tailored treatment can significantly improve symptoms and quality of life. Awareness of causes, symptoms, and management options empowers patients to seek help and adapt to their condition effectively.

Frequently Asked Questions (FAQs) About Postural Tremor

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