Geniospasm

Involuntary movement disorder of the chin

Geniospasm is a rare movement disorder characterized by involuntary, episodic contractions of the mentalis muscle, which is located in the chin. These contractions can cause visible trembling or quivering of the chin and lower lip. Geniospasm is typically benign and does not lead to any serious health complications, but it can be socially embarrassing for those affected.

Presentation

Diagram of the mentalis muscle

The primary symptom of geniospasm is the involuntary movement of the chin, which can occur spontaneously or be triggered by stress, fatigue, or emotional states. The episodes can last from a few seconds to several minutes and may vary in frequency and intensity. Some individuals may experience these episodes multiple times a day, while others may have them less frequently.

Causes

The exact cause of geniospasm is not well understood. It is believed to have a genetic component, as it often runs in families. Some cases have been linked to mutations in the gene that encodes the protein involved in muscle contraction. However, environmental factors and other unknown triggers may also play a role in the manifestation of the disorder.

Diagnosis

Diagnosis of geniospasm is primarily clinical, based on the observation of symptoms and family history. A thorough neurological examination may be conducted to rule out other movement disorders or underlying neurological conditions. In some cases, electromyography (EMG) may be used to assess the electrical activity of the mentalis muscle during episodes.

Treatment

There is no specific cure for geniospasm, but several treatment options can help manage the symptoms. These may include:

• Botulinum toxin injections: These can be used to temporarily paralyze the mentalis muscle, reducing the frequency and severity of the spasms.
• Medications: Certain medications, such as anticonvulsants or muscle relaxants, may be prescribed to help control the muscle contractions.
• Behavioral therapy: Techniques such as biofeedback or cognitive behavioral therapy (CBT) may help individuals manage stress and reduce the occurrence of episodes.

Prognosis

Geniospasm is generally considered a benign condition with no serious health consequences. The impact on quality of life varies among individuals, depending on the frequency and severity of the episodes. With appropriate management, many people with geniospasm can lead normal, active lives.

Related pages

• Movement disorder
• Muscle contraction
• Botulinum toxin
• Neurological examination