Functional (Psychogenic) Movement Disorders

Functional movement disorders (FMD), previously referred to as “psychogenic” movement disorders, are characterized by abnormal movements, postures or spasms, such as shaking (irregular tremor) or jerks (tic-like or myoclonic-like movements) involving any part of the face, neck, trunk or limbs. In addition, some patients may have bizarre gait or difficulties with their balance that are often triggered by psychological of physical stress. Speech and voice disorders are also relatively common in patients with FMD, in which patients may experience stuttering, speech arrest, lower speech volume (hypophonia), or even a foreign accent. Several other terms have been used to describe functional movement disorders and there has been considerable debate regarding the appropriate naming of the disorder. Other terms, including psychogenic, nonorganic, conversion disorder, psychosomatic, medically unexplained, dissociative motor disorder, and hysteria have been used in the past. One potential pitfall of the term “functional” is that it can be misinterpreted by the patient to perceive themselves as dysfunctional rather than functional. Nevertheless, this has become the favored term to refer to this condition in recent years.

A variety of blood, imaging and other tests are usually normal and do not reveal any physical (organic) cause that could explain these motor abnormalities. It is, however, critical to understand that the diagnosis of FMD is not just based on negative tests or exclusion of other disorders, but on set of well-defined, positive, clinical criteria (see below).

Most functional movements are considered involuntary – performed without conscious awareness or effort. They can mimic organic movement disorders, such as tremor, dystonia, myoclonus, parkinsonism, tics and paroxysmal dyskinesias. Although a FMD may resemble or accompany an organic disorder, a skilled and experienced neurologist should be able to differentiate the two types of movement disorders.

Types of Functional Movement Disorders

• Functional Tremor
• Functional Dystonia
• Functional Myoclonus
• Functional Parkinsonism
• Functional Tics
• Functional Paroxysmal Dyskinesia
• Functional Gait Disorders

Diagnosis

When the movements in question are inconsistent over time (over time the movements are observed to be different over subsequent evaluations) or is not characteristic with a classic movement disorder, then the clinician becomes concerned that the movements may be functional.

The diagnosis is based on a combination of a number of clinical observations and recognition of typical characteristics (phenomenology) that include, but are not necessarily limited to the following:

• Onset of the movements is abrupt/sudden.
• Movements are triggered by emotional or physical trauma, or by some conflict (marital, sexual, work-related).
• Movements are episodic or appear intermittent.
• There are spontaneous remissions of the movements.
• Movements disappear with distraction.
• Movements are suggestible, meaning they may disappear by making a suggestion. For example, suggesting that the application of a tuning fork to the body part affected may help relieve the movements.
• Underlying psychiatric disturbances (depression, anxiety) are present.
• There are multiple somatizations and undiagnosed conditions.
• There is a lack of emotional concern about the disorder (“la belle indifference”).
• There has been exposure to neurologic disorders during one’s occupation (e.g. nurse, physician) or while caring for someone with similar problems.

Other characteristics include:

• Slurred speech, soft voice, gibberish, foreign accent
• Delayed and excessive startle (bizarre movements in response to sudden, unexpected noise or threatening movement)
• Presence of additional types of abnormal movements that are not known to be part of the primary or principal movement disorder pattern that the patient manifests
• Active resistance against passive movement
• Fixed abnormal posture (contracture)

There is no blood test or any other diagnostic test for FMD. Making the diagnosis of FMD is a two-step process. First is to make a positive diagnosis that the movements are functional rather than from an organic illness. Second is to identify either a psychological or physical stress, often with underlying psychiatric disorder, such as depression or anxiety, and try to understand the psychodynamics that could explain the onset and persistence of abnormal movements, spasms or postures. It is very important to make the correct diagnosis when it is a FMD because only then can appropriate treatment be started. Additionally, if the patient has a FMD that is misdiagnosed, then the patient may be given inappropriate treatment, such as medication that may have harmful side effects. This would also postpone appropriate psychiatric treatment. Delay in appropriate diagnosis and treatment may lead to chronic disability.

Cause

Patients should understand that they have a movement disorder, such as tremor or dystonia, but that in their case, the disorder is not due to any damage to the brain, spinal cord or nerves, but it is a manifestation of how their bodies respond to stress. Just as stress can cause elevation in blood pressure, palpitations, gastric ulcers, and tremors, stress can similarly manifest as disorders of movement. Understandably, the diagnosis of functional (stress-induced) movement disorder can be a delicate matter both for physicians as well as patients. Patients manifesting movements or other motor abnormalities that can be quite dramatic and disabling, often do not readily recognize or acknowledge that these are stress-induced (functional) and may disagree with the diagnosis. Most seasoned physicians believe that it is in the patient’s best interest to be honest and to candidly disclose the diagnosis and discuss the psychological nature of the movement disorder. Not all patients are accepting of the diagnosis. In many cases, it takes more time or even several visits before the patient begins to understand the relationship between stress, underlying psychological and psychiatric conditions, and the movement disorder.

Treatment

Many studies, including at Baylor’s Parkinson Disease Center and Movement Disorders Clinic (PDCMDC) have shown that patients who accept the diagnosis of FMD at onset have a much better prognosis, including full recovery, than those who do not accept the diagnosis.  The latter group often seeks many other opinions, tests and treatments and evolve into a chronic condition that has a very poor prognosis for improvement or recovery. Successful treatment of FMD will likely involve a multidisciplinary approach with several practitioners, including a movement disorder neurologist, psychologist, psychiatrist and physical, speech and occupational therapists in implementing a short-term and long-term therapeutic program.

Physical, speech and occupational therapy may be useful not only in improving physical and psychological functioning, such as activities of daily living, but also to alter the abnormally learned pattern of movement - "motor reprograming." Antidepressants and muscle relaxants may be also beneficial. Rarely, transcutaneous electrical stimulation applied to the area of spasm or involuntary movement may be helpful, analogous to the application of a tuning fork during clinic evaluation. Most importantly, however, the patient should try to understand which stress factors may be playing a role and seek the expertise of a psychologist experienced and skilled in stress management. The role of a psychiatrist is not to make the diagnosis but to provide insights into underlying psychological or psychiatric issues and to aid in the treatment of psychiatric issues such as depression or anxiety.

PMD may be difficult to treat, especially if the patient is diagnosed late or is not accepting of the diagnosis. Indeed, patients with the best prognosis are those who initially accept the diagnosis and work with the movement disorder neurologist, psychologist, psychiatrist and physical, speech and occupational therapists in implementing a short-term and long-term therapeutic program. The diagnosis should be disclosed to patients in a manner that is empathetic and nonjudgmental.

Several critical points are worth emphasizing relating to the diagnosis of FMD.

• The movement abnormalities are not deliberate but subconsciously generated.
• The presence of the movement disorder does not mean a psychiatric disease.
• The movements are real and can interfere with normal functioning.
• There is no evidence of brain, spinal cord or any other neurological damage as the cause of the abnormal movements.
• This is a treatable and likely curable disorder.

In addition to disclosing the diagnosis and exploring various potential psychodynamic factors that could have brought on this condition, it is also important to discuss the role of underlying depression and anxiety, even though many patients deny or are not aware of these psychiatric diagnoses.

The severity of functional movement abnormalities and prognosis varies among individuals. Long-term outcomes appear to be best in patients with a shorter duration of symptoms, those with clearly identifiable trigger or a precipitating or exacerbating factor that can be modified, and most importantly, in those patients who accept the diagnosis and work with their physicians and other healthcare professionals to help them return to the mainstream of life.

References

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Functional Neurological Disorders Society (FNDS)
https://www.fndsociety.org/

https://www.neurosymptoms.org