Functional movement disorder

Functional movement disorders also known as Functional Neurological Symptom Disorder are neurological disorders thought to be psychogenic in origin.

Functional Neurological Symptom Disorder (FNsD) is a neurological disorder for which very little is currently known. It is an umbrella term for a variety of symptoms which look similar to those caused by neurological conditions such as Multiple Sclerosis (MS) or Parkinson's disease, including weakness, fatigue and seizures. It is currently believed that Functional Neurological Symptom Disorder arises from a problem with the patient's Central Nervous System, which is not sending and receiving signals correctly. The brain of a patient with Functional Neurological Symptom Disorder is structurally normal, but functions incorrectly.

Currently, traditional tests and investigations such as blood tests, MRI and CT scans will show no abnormalities in patients with FNsD; however, it has been discovered that there is a difference in blood flow to certain key areas of the brain when scanned using Functional Magnetic Resonance Imaging (fMRI). Although currently there is no way to 'see' whether a patient has FNsD, their symptoms are real, and often cause disability and distress to the individual. It is widely accepted that those with FNsD are equally disabled as those with Multiple Sclerosis or Parkinsons, and often are more distressed.

The first mention of Functional Neurological Symptom Disorder in literature dates from Ancient Egypt, and little progress has been made in understanding the condition since. FNsD has also previously been referred to as Hysteria and Conversion Disorder (CD). The term Conversion Disorder is still used by some clinicians, however refers specifically to those who have a psychological stressor causing their symptoms, such as a traumatic event or mental illness. It is "a psychoanalytic concept that describes the occurrence of motor or sensory neurological symptoms other than pain and fatigue that cause distress, are not explained by disease, not malingered but are thought to relate to psychological factors"

Diagnostic labeling is causing a great amount of confusion amongst patients and doctors alike. One doctor may use the term Functional Neurological Disorder or Functional Movement Disorder, but then another may use Conversion Disorder.

History of FNsD
The first evidence of FNsD dates back to 1900 BC, where the symptoms were blamed on the uterus moving within the female body. The treatment varied "depending on the position of the uterus, which must be forced to return to its natural position. If the uterus had moved upwards, this could be done by placing malodorous and acrid substances near the woman’s mouth and nostrils, while scented ones were placed near her vagina; on the contrary, if the uterus had lowered, the document recommends placing the acrid substances near her vagina and the perfumed ones near her mouth and nostrils."

In Greek mythology, hysteria, the original name for FNsD, was thought to be caused by a lack of orgasms, uterine melancholy and not procreating. Plato, Aristotle and Hippocrates believed that a lack of sex upset the uterus. The Greeks believed that it could be prevented and cured with wine and orgies. Hippocrates argued that a lack of regular sexual intercourse led to the uterus producing toxic fumes and caused it to move in the body, and that this meant that all women should be married and enjoy a satisfactory sexual life.

Throughout the middle ages melissa, a natural remedy, was used to treat hysteria. Women with the condition were seen as the cause of the condition, which was then referred to as amor heroycus, or the madness of love, unfulfilled sexual desire. Trotula de Ruggerio, the first female doctor in Europe, believed that abstinence caused illness, and advised women to take remedies such as mint or musk oil.

From the 13th Century, women with hysteria were exorcised, as it was believed that they were possessed by the devil. They believed that if doctors could not find the cause of a disease or illness, it must be caused by the devil.

In the beginning of the 16th Century, women were sexually stimulated by midwives in order to relieve their symptoms. Girolamo Cardano and Giovanni Battista Della Porta believed that polluted water and fumes caused the symptoms of hysteria. Towards the end of the century however, the role of the uterus was no longer central to the disorder, with Thomas Willis discovering that the brain and central nervous system were the cause of the symptoms. Thomas Sydenham argued that the symptoms of hysteria may have an organic cause. He also proved that the uterus is not the cause of symptoms.

In 1692, in Salem (MA), there was an outbreak of hysteria. This led to the Salem witch trials, where the 'witches' had symptoms such as sudden movements, staring eyes and uncontrollable jumping.

From the 18th century, there is a move from the idea of hysteria being caused by the uterus to it being caused by the brain. This led to an understanding that it could affect both sexes. Jean Martin Charcot argued that hysteria was caused by "a hereditary degeneration of the nervous system, namely a neurological disorder"

In the 19th Century, hysteria moved from being considered a neurological disorder to being considered a psychological disorder, when Pierre Janet argued that "dissociation appears autonomously for neurotic reasons, and in such a way as to adversely disturb the individual’s everyday life"

Freud referred to hysteria as conversion disorder. He believed that those with the condition could not live in a mature relationship, and that those with the condition were unwell in order to achieve a 'secondary gain' in that they are able to manipulate their situation to fit their needs or desires. He also found that both men and women could suffer with the disorder.

The DSM-5 changed the name of the condition from Conversion Disorder to Functional Neurological Symptom Disorder. Today, there is growing evidence that psychological stress does not cause FNsD. A recent study by the charity FNDHope found that psychological triggers affected only 30% of patients. Some doctors still follow Freud's theory about Conversion Disorder, however others are moving on to look at the role of the Central Nervous System in FNsD symptoms.

Alternative Names for FNsD
Although the DSM-5 uses the term Functional Neurological Symptom Disorder, many other names for the same condition are widely used by doctors. These include
 * Functional Neurological Disorder (FND)
 * Conversion Disorder (in cases where there is a psychological stressor causing symptoms)
 * Functional Movement Disorder (FMD)
 * Medically Unexplained Neurological Symptoms
 * Functional Symptoms
 * Psychogenic Movement Disorder
 * Non-Epileptic Attack Disorder
 * Psychogenic Non-Epileptic Seizures

Signs and Symptoms
There are a great number of symptoms experienced by those with Functional Neurological Disorder. It is important to note that all the symptoms which are experienced by those with FNsD are real, and often debilitating. These include, but are not limited to
 * Weakness
 * Paralysis
 * Dizziness
 * Nausea
 * Changes in vision
 * Non-epileptic seizures
 * Blackouts
 * Tremors
 * Fatigue
 * Chronic pain
 * Sensory abnormalities
 * Bladder or bowel changes

Diagnostic Criteria from DSM-5
Functional Neurological Symptom Disorder was added to the DSM-5 to replace the term Conversion Disorder. There are two subcategories of Functional Neurological Symptom Disorder, those with a psychological stressor and those without. Functional Neurological Disorder is the widely accepted term for those without, while Conversion Disorder refers to those with a psychological stressor. However, some doctors are advising the discontinuation of the term 'Conversion Disorder' entirely.

The diagnostic criteria for Functional Neurological Disorder is:

A. The patient has ≥1 symptoms of altered voluntary motor or sensory function.

B. Clinical findings provide evidence of incompatibility between the symptom and recognised neurological or medical conditions.

C. The symptom or deficit is not better explained by another medical or mental disorder.

D. The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning or warrants medical evaluation.

Specify type of symptom or deficit as: Specify if: Specify if:
 * With weakness or paralysis
 * With abnormal movement (e.g., tremor, dystonic movement, myoclonus, gait disorder)
 * With swallowing symptoms
 * With speech symptoms (e.g., dysphonia, slurred speech)
 * With attacks or seizures
 * With anaesthesia or memory loss
 * With special sensory symptom (e.g., visual, olfactory,or hearing disturbance)
 * With mixed symptoms.
 * Acute episode: symptoms present for less than 6 months
 * Persistent: symptoms present for 6 months or more.
 * Psychological Stressor (See: Conversion disorder)
 * No Psychological Stressor

Prevalence
Functional Neurological Disorder is a common problem, with estimates suggesting that up to a third of neurology outpatients having functional symptoms. In Scotland, around 5000 new cases of FND are diagnosed annually. Furthermore, non-epileptic seizures account for 1 in 7 referrals to neurologists after an initial seizure, and functional weakness has a similar prevalence to Multiple Sclerosis.

Common Myths about Functional Neurological Symptom Disorder
Patients are imagining their symptoms

Patients are feigning their symptoms

Functional Neurological Disorder is caused by psychological dysfunction or a problem with emotional processing

Cognitive Behavioural Therapy (CBT) will cure Functional Neurological Symptom Disorder

Functional Neurological Symptom Disorder only affects females

Functional Neurological Symptom Disorder only affects young adults

Functional Neurological Symptom Disorder is rare

Research
Currently, little research is being carried out into Functional Neurological Disorder, with most research focusing on symptoms caused by Conversion Disorder. This research focuses on Freudian ideas and the theory that patients attitudes towards their illness directly correlate with the continuation of symptoms.

Researchers studying Functional Neurological Symptom Disorder without psychological stressors are looking at various possible causes including
 * Neurotoxicity
 * Central Sensitization Syndrome

Debate
There is much debate surrounding the FND diagnosis. Some doctors continue to believe that all FND patients have unresolved traumatic events (often of a sexual nature) which are being expressed in a physical way. However, some doctors do not believe this to be the case. Wessely and White state that all somatic illnesses, including Fibromyalgia, Irritable Bowel Syndrome and Chronic Fatigue Syndrome "still fall under the title of ‘unexplained’ since no consensual scientific explanation has been advanced for any of them that meets with universal acceptance. Unexplained means what it says on the tin, and is not a code for psychiatric, still less for ‘all in the mind’." They go on to argue that "A somatoform disorder can only be so classified in the absence of an adequate physical explanation (World Health Organization, 1992). Furthermore, a somatoform pain disorder can only ‘... occur in association with emotional conflict or psychosocial problems that are sufficient to allow the conclusion that they are the main causal influences’ (World Health Organization, 1992). How can the clinician be sure that the psychosocial problem actually caused the illness?"

Alternative Diagnoses
Functional Neurological Symptom Disorder can mimic many other conditions. Although doctors state that misdiagnosis rates are very low, with some research suggesting that only 2% of patients were misdiagnoses after 12.5 years. Some alternative diagnoses for FNsD can be
 * Hemiplegic migraine
 * Multiple sclerosis
 * Motor Neurone Disease
 * Parkinsons syndrome
 * Autoimmune Disorders
 * Ehlers–Danlos syndrome
 * Stroke

Other Functional Conditions

 * Irritable Bowel Syndrome (IBS)
 * Fibromyalgia
 * Chronic pelvic pain|Chronic Pelvic Pain (CPP)]
 * Interstitial cystitis|Interstitial Cystitis (IC)
 * Temporomandibular joint dysfunction|Temporomandibular Joint Dysfunction (TMJ)
 * Chronic Fatigue Syndrome

Notable studies

 * 2012, Functional (psychogenic) movement disorders