Overview

Functional neurologic disorders — a newer and broader term that includes what some people call conversion disorder — feature nervous system (neurological) symptoms that can't be explained by a neurological disease or other medical condition. However, the symptoms are real and cause significant distress or problems functioning.

Signs and symptoms vary, depending on the type of functional neurologic disorder, and may include specific patterns. Typically these disorders affect your movement or your senses, such as the ability to walk, swallow, see or hear. Symptoms can vary in severity and may come and go or be persistent. However, you can't intentionally produce or control your symptoms.

The cause of functional neurologic disorders is unknown. The condition may be triggered by a neurological disorder or by a reaction to stress or psychological or physical trauma, but that's not always the case. Functional neurologic disorders are related to how the brain functions, rather than damage to the brain's structure (such as from a stroke, multiple sclerosis, infection or injury).

Early diagnosis and treatment, especially education about the condition, can help with recovery.

Source: http://www.mayoclinic.com

Symptoms

Symptoms of functional neurologic disorders may vary, depending on the type of functional neurologic disorder, and they're significant enough to cause impairment and warrant medical evaluation. Symptoms can affect body movement and function and the senses.

Signs and symptoms that affect body movement and function may include:

• Weakness or paralysis
• Abnormal movement, such as tremors or difficulty walking
• Loss of balance
• Difficulty swallowing or feeling "a lump in the throat"
• Seizures or episodes of shaking and apparent loss of consciousness (nonepileptic seizures)
• Episodes of unresponsiveness

Signs and symptoms that affect the senses may include:

• Numbness or loss of the touch sensation
• Speech problems, such as inability to speak or slurred speech
• Vision problems, such as double vision or blindness
• Hearing problems or deafness

When to see a doctor

Seek medical attention for signs and symptoms listed above. If the underlying cause is a neurological disease or another medical condition, quick diagnosis and treatment may be important. If the diagnosis is a functional neurologic disorder, treatment may improve the symptoms and help prevent future problems.

Source: http://www.mayoclinic.com

Causes

The exact cause of functional neurologic disorders is unknown. Theories regarding what happens in the brain to result in symptoms are complex and involve multiple mechanisms that may differ, depending on the type of functional neurologic disorder.

Basically, parts of the brain that control the functioning of your muscles and senses may be involved, even though no disease or abnormality exists.

Symptoms of functional neurologic disorders may appear suddenly after a stressful event, or with emotional or physical trauma. Other triggers may include changes or disruptions in how the brain functions at the structural, cellular or metabolic level. But the trigger for symptoms can't always be identified.

Source: http://www.mayoclinic.com

Diagnosis

There are no standard tests for functional neurologic disorders. Diagnosis usually involves assessment of existing symptoms and ruling out any neurological or other medical condition that could cause the symptoms.

Functional neurologic disorders are diagnosed based on what is present, such as specific patterns of signs and symptoms, and not just by what is absent, such as a lack of structural changes on an MRI or abnormalities on an EEG.

Testing and diagnosis usually involves a neurologist, but may include a psychiatrist or other mental health professional. Your doctor may use any of these terms: functional neurologic disorders (FNDs), functional neurological symptom disorder or conversion disorder.

One advantage to using the term "functional neurologic disorders" is that it can be used to specify the type of functional neurological symptoms you have. For example, if your symptoms include problems walking, your doctor may refer to functional gait disorder or functional weakness.

Evaluation may include:

• Physical exam. Your doctor examines you and asks in-depth questions about your health and your signs and symptoms. Certain tests may eliminate medical disorders or neurological disease as the cause of your symptoms. Which tests you'll have depends on your signs and symptoms.
• Psychiatric exam. If appropriate, your neurologist may refer you to a mental health professional. He or she asks questions about your thoughts, feelings and behavior and discusses your symptoms. With your permission, information from family members or others may be helpful.
• Diagnostic criteria in the DSM-5. Your doctor may compare your symptoms to the criteria for diagnosis in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), published by the American Psychiatric Association.

DSM-5 lists these criteria for conversion disorder (functional neurological symptom disorder):

• One or more symptoms that affect body movement or your senses
• Symptoms can't be explained by a neurological or other medical condition or another mental health disorder
• Symptoms cause significant distress or problems in social, work or other areas, or they're significant enough that medical evaluation is recommended

Source: http://www.mayoclinic.com

Complications

Some symptoms of functional neurologic disorders, particularly if not treated, can result in substantial disability and poor quality of life, similar to that caused by medical conditions or disease.

Risk factors

Factors that may increase your risk of functional neurologic disorders include:

• Having a neurological disease or disorder, such as epilepsy, migraines or a movement disorder
• Recent significant stress or emotional or physical trauma
• Having a mental health condition, such as a mood or anxiety disorder, dissociative disorder or certain personality disorders
• Having a family member with a functional neurologic disorder
• Possibly, having a history of physical or sexual abuse or neglect in childhood

Women may be more likely than men to develop functional neurologic disorders.

Source: http://www.mayoclinic.com