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