4 frequently asked questions about functional movement disorder

Functional movement disorder (FMD) is a type of movement disorder that causes abnormal and involuntary body movements such as jerks, tics, and tremors in the limbs or head. Although FMD causes similar symptoms as most movement disorders, the cause of FMD is not the same as of other movement disorders, which is damage to the brain or neurons. In fact, FMD is caused due to a problem in the way the nervous system functions.

Diagnosing FMD is a challenge most doctors face today. As the tests or scans do not always show any anomaly in the brain, most people who suffer from FMD may feel that the symptoms experienced are imaginary. However, the symptoms are not imaginary and are in fact real.

There are few other terms used to address FMD; these include psychogenic movement disorder, nonorganic disorder, and conversion disorder. Read on to know more about the types, symptoms, diagnoses, and treatments of this disorder.

What are the different types of FMD?

• Functional tremor – This is one of the most common types of FMD that accounts for nearly 50 percent of FMD cases. Functional tremor is caused when there are oscillatory movements produced by the rhythmic contractions of muscles. These tremors can occur in any part of the body when it is at rest or in action and can also spread to other parts.
• Functional dystonia – This is another common type of FMD that causes involuntary, repetitive, or sustained muscle spasms or contractions. The involuntary movements caused by this disorder are patterned, twisting, and often tremulous.
• Functional myoclonus – This disorder causes sudden and brief involuntary jerks in a muscle or group of muscles. Patients who suffer from functional myoclonus often have an excessive startle response to sudden loud noises or another type of sensory stimuli.
• Functional parkinsonism – This disorder is one of the least common types of FMD that causes symptoms like early disability, slow movements, bilateral shaking, stuttering speech, and bizarre gait. Although functional parkinsonism differs from Parkinson’s disease, it can coexist in patients with the latter.

What are the symptoms of FMD?

• Patients with FMD may experience weakness or paralysis of a limb.
• They can also experience numbness or a tingling sensation, muscle spasms, fatigue, pain in the arms or legs, and pain in the head or neck.
• Other symptoms include poor concentration, disturbances in sleep, slurred speech, blurred vision, and derealization, which is a feeling of things around not being real.
• Additionally, FMD also causes symptoms like gait problems, where people face problems while walking and imbalance, which may cause them to fall often.
• Patients with FMD may also experience attacks that may look like epilepsy but are not.
• Because of these symptoms, people suffering from FMD often feel frustrated, angry, depressed, and worried.

How is FMD diagnosed?

• Contrary to popular belief, FMD is not just a diagnosis of exclusion. In fact, diagnosing FMD includes obtaining a thorough neurological, personal, and family history of the patient.
• Doctors often face challenges in diagnosing FMD as the symptoms are similar to other movement disorders. This makes it important to thoroughly understand the nature of FMD.
• A correct diagnosis of FMD, therefore, requires proficiency in neuroanatomy and neurophysiology.
• Though there is no standard diagnosis of FMD, electrodiagnostic studies provide supporting evidence for diagnosing certain types of FMD like functional tremor and functional myoclonus.
• Doctors may run a single-photon emission computed tomography (SPECT) scan with dopamine transporter imaging for excluding organic causes of parkinsonism and thereby diagnosing functional parkinsonism.

What are the treatments for FMD?

• Doctors often use a multidisciplinary treatment approach for the management of patients with FMD.
• These treatments emphasize physical therapy and are aimed at restoring movement and function.
• Along with physical therapy, other treatments that may be helpful in treating FMD include occupational therapy, psychotherapy, cognitive behavioral therapy, antidepressant medications, exercise, hypnosis, and transcranial magnetic stimulation.
• The prognosis of FMD is generally poor; however, these treatments help patients experience an improvement in the symptoms caused by FMD.