Functional Movement Disorder: Symptoms, Types, Causes and Treatment

Functional Movement Disorder (FMD) is a complex and often misunderstood condition that affects a person's ability to move normally. Unlike other neurological diseases, the symptoms of FMD are real and disabling but are not due to structural damage or a classic neurological illness. Instead, these disorders are rooted in abnormal functioning of the nervous system, often involving a mix of both physical and psychological factors. Understanding FMD is essential for patients, families, and clinicians to support accurate diagnosis and effective treatment.

Symptoms of Functional Movement Disorder

Functional Movement Disorder presents with a range of symptoms that can be confusing and distressing. People with FMD may experience abnormal movements, such as tremors or jerks, but also a host of non-motor symptoms like pain and fatigue. Recognizing the full spectrum of symptoms is crucial, as these impact quality of life and guide the approach to care.

Symptom	Description	Impact on Life	Source(s)
Tremor	Involuntary shaking, often variable	Disrupts daily tasks	3 5
Dystonia	Abnormal muscle contractions	Posture, movement issues	5 3
Myoclonus	Sudden, brief jerks of a muscle group	Startling, unpredictable	5 2
Gait Disorder	Abnormal walking, often with good balance	Mobility limitations	2 3
Pain	Chronic or episodic pain	Reduces quality of life	1
Fatigue	Persistent tiredness	Limits activity	1
Cognitive Complaints	Memory, attention issues	Work, relationships	1
Speech Abnormalities	Slurred, stuttered, or lost speech	Communication problems	3 5
Anxiety/Depression	Emotional distress	Mood, coping	1 3

Table 1: Key Symptoms of Functional Movement Disorder

Motor Symptoms Explained

The hallmark of FMD is abnormal movement that does not match patterns seen in classic neurological diseases. Common motor symptoms include:

• Tremors: These may vary in frequency and can often change or disappear with distraction. Unlike tremors in Parkinson’s disease, FMD tremors are usually inconsistent and influenced by focus or attention 2 5.
• Dystonia: Sustained or intermittent muscle contractions lead to abnormal postures. Fixed dystonia (persistent abnormal positioning) is more likely to be functional in origin 2 5.
• Myoclonus: Sudden muscle jerks that can be complex and sometimes triggered by touch or movement. The latency between stimulus and movement is often longer than in organic myoclonus 2 5.
• Gait Disorders: People may have trouble walking but often retain good balance despite dramatic symptoms. This contrasts with neurological gait disorders, where balance is genuinely impaired 2 3.

Non-Motor Symptoms

Non-motor symptoms are common and can be just as disabling as movement problems. These include:

• Pain and Fatigue: Chronic pain and a persistent sense of tiredness are frequent complaints 1.
• Cognitive Difficulties: People often describe “brain fog,” poor concentration, or memory lapses, which can be as distressing as movement symptoms 1.
• Mood Disorders: Anxiety and depression are commonly reported, though not always present. These can worsen the impact of FMD on daily life 1 3.

Impact on Quality of Life

Research shows that non-motor symptoms like anxiety and cognitive complaints often have a greater effect on quality of life than the severity of movement symptoms themselves 1. This underlines the importance of addressing the whole person in treatment, not just focusing on physical symptoms.

Types of Functional Movement Disorder

FMD encompasses a spectrum of movement abnormalities, each with its own features. Understanding the different types helps in making a positive diagnosis and tailoring treatment to the individual.

Type	Key Features	Distinguishing Signs	Source(s)
Tremor	Shaking, often variable or distractible	Frequency changes, entrainment	2 5
Dystonia	Abnormal postures, fixed positions	Fixed dystonia, inconsistent	2 5 3
Myoclonus	Sudden jerks, often complex	Long latency, stimulus-induced	2 5
Parkinsonism	Slowness, stiffness, tremor	Rapid improvement, inconsistency	5
Tics	Sudden twitches, vocalizations	Unusual features, suggestibility	5 8
Gait Disorders	Abnormal walk, preserved balance	Dramatic symptoms, little falling	2 5 3
Speech Abnormalities	Slurred, stuttering, aphonia	Inconsistent, variable	3 5

Table 2: Major Types of Functional Movement Disorders

Tremor

Tremor is the most common type of FMD, especially affecting the arms and legs. Functional tremors tend to:

• Change in frequency and amplitude over time
• Fade or disappear when the patient is distracted
• Be influenced by suggestion or external cues (entrainment) 2 3 5

Dystonia

Functional dystonia is characterized by abnormal posturing, which is often fixed. Unlike organic dystonia, the presentation may be inconsistent and may not follow known neurological patterns. Fixed dystonia, where a limb stays permanently in an abnormal position, is especially suggestive of FMD 2 5.

Myoclonus

Myoclonus in FMD is often more complex than in organic diseases, with jerks that may be stimulus-induced and have longer latencies. Movements may be bizarre or not match typical neurological myoclonus 2 5.

Parkinsonism and Tics

Some patients show slowness, stiffness, or features resembling Parkinson’s disease, but symptoms often have rapid onset, fluctuate, and improve with distraction. Functional tics can mimic Tourette’s but are more variable, suggestible, and may include unusual vocalizations or movements 5 8.

Gait and Speech Disorders

Gait disturbances in FMD are dramatic but typically do not lead to falls or injuries. Patients may complain of severe difficulty walking but can maintain balance when distracted. Speech abnormalities, including slurred or stuttered speech, can be present and often fluctuate 2 3 5.

Causes of Functional Movement Disorder

The causes of FMD are complex and multifactorial, involving a mix of psychological, physical, and neurobiological factors. Contrary to outdated beliefs, FMD is not simply “all in the mind,” but is instead a disorder at the intersection of mind and brain.

Cause Type	Description	Notes/Features	Source(s)
Psychological	Stress, trauma, anxiety, depression	Not present in all cases	3 6 9 10
Physical Event	Injury, infection, pain, surgery, illness	Often precedes onset	10
Neurobiology	Abnormal brain connectivity, sense of agency	Changes in motor and limbic systems	7 9 11
Social Factors	Secondary gain, social stress	May influence onset or persistence	2 6 9

Table 3: Contributing Factors in Functional Movement Disorder

Psychological Factors

Historically, FMD was attributed to emotional trauma or psychiatric illness, but research shows this is only true for some patients. Many do report histories of stress, anxiety, or depression, but these are not present in all cases. Importantly, psychological symptoms may be a consequence rather than a cause of the movement disorder 3 6 9.

Physical Precipitating Events

Physical events such as injuries, infections, or pain frequently occur before the onset of FMD symptoms. In some studies, up to 80% of patients reported a physical trigger shortly before their symptoms began. These events may provide abnormal sensory input, which—when combined with psychological factors—can lead to FMD 10.

Neurobiological Mechanisms

Recent advances highlight changes in brain networks involved in movement, attention, and emotion:

• Abnormal Attention and Agency: People with FMD may have heightened focus on bodily sensations and lack the usual sense of control (agency) over their movements 7 9.
• Brain Imaging Findings: Functional MRI studies show altered activity in areas like the motor cortex, amygdala, insula, and supplementary motor area, as well as abnormal connectivity between these regions 7 9 11.
• Impaired Motor Preparation: Decreased activation in brain regions that plan and initiate movement may contribute to symptoms 9 11.

Social and Environmental Factors

Stressful life events, social pressures, or potential “secondary gain” (such as increased attention or relief from work) can play a role in some cases. However, these are neither necessary nor sufficient to explain FMD in most patients 2 6 9.

Treatment of Functional Movement Disorder

Treating FMD requires a comprehensive, patient-centered approach that addresses both physical and psychological aspects. While FMD can be challenging to manage, a growing body of evidence supports multidisciplinary interventions.

Treatment Type	Approach/Description	Effectiveness/Notes	Source(s)
Patient Education	Clear explanation of diagnosis	Essential first step	16 14
Physical Therapy	Goal-oriented motor retraining	Significant symptom improvement	12 13 14
Psychotherapy	CBT, supportive counseling	Reduces symptoms, improves mood	14 15 16
Multidisciplinary	Combined PT, OT, speech, psychotherapy	Best outcomes, especially inpatient	12 13 14 16
Medication	Antidepressants, anxiolytics (as needed)	For comorbid mood disorders	14 16
Other/Experimental	TMS, hypnosis	Promising, but further study needed	14 16

Table 4: Treatment Options for Functional Movement Disorder

Patient Education

A clear, empathetic explanation of the diagnosis is a crucial first step. Patients benefit from understanding that their symptoms are real, common, and potentially reversible—not imagined or feigned 16 14. This step alone can reduce anxiety and lay the groundwork for improvement.

Physical Therapy and Motor Retraining

• Intensive, goal-oriented physical therapy has shown substantial benefits. Programs focus on “retraining” normal movement patterns and often incorporate distraction techniques to reduce abnormal movements 12 13.
• In studies, up to 70–80% of patients reported significant improvement after a week-long multidisciplinary rehabilitation program. Benefits were often sustained for months or even years 12 13.

Psychotherapy

• Cognitive Behavioral Therapy (CBT) and other psychological interventions can help patients manage symptoms, cope with stress, and address underlying mood disorders 14 15 16.
• While evidence is still evolving, therapy is generally more effective when integrated into a multidisciplinary approach 15.

Multidisciplinary Rehabilitation

• The best outcomes are seen with collaborative, multidisciplinary teams that include physical therapists, occupational therapists, speech therapists, and psychologists or psychiatrists 12 13 14 16.
• Inpatient programs may be especially useful for severe or long-standing cases 14.

Medication and Experimental Treatments

• Medications are not used to treat FMD itself, but may be helpful for associated depression or anxiety 14 16.
• Other therapies like hypnosis and transcranial magnetic stimulation (TMS) are being explored but require more research 14 16.

Conclusion

Functional Movement Disorder is a complex condition at the intersection of neurology and psychology. Understanding its diverse symptoms, underlying mechanisms, and evidence-based treatments is essential for improving patient outcomes.

Key Takeaways:

• FMD involves both motor (tremor, dystonia, gait problems) and non-motor (pain, cognitive complaints) symptoms, all of which can be disabling 1 3 5.
• Multiple types of movement abnormalities exist, with tremor and dystonia being most common 3 5.
• Causes are multifactorial, involving psychological stress, physical events, and neurobiological changes in brain connectivity and function 7 9 10 11.
• Effective treatment is multidisciplinary, combining education, physical therapy, and psychotherapy, often within a team-based approach 12 13 14 16.
• While prognosis can be challenging, substantial improvement is possible, especially when treatment is started early and is tailored to the individual 12 13 14.

Empathy, collaboration, and continued research are key to supporting those living with Functional Movement Disorder.