ROME, ITALY — Diagnosing a psychogenic movement disorder is among the biggest challenges confronting the movement disorder neurologist. The pattern, intensity, and even pain can match those of organic disorders, and the patient may wander from specialist to specialist for years before receiving the correct diagnosis. Exacerbating the difficulty is that, despite real suffering, the patient almost invariably resists the diagnosis and proper treatment.
The difficulties of establishing a psychogenic diagnosis, and important tips and caveats in doing so, were highlighted in a video seminar here at this year's Congress of Parkinson's Disease and Movement Disorders in June by two leading experts in psychogenic movement disorders, Anthony E. Lang, MD, and John Morris, MD. Dr. Lang is Director of the Movement Disorders Clinic at Toronto Western Hospital in Ontario, Canada, and Dr. Morris is Professor of Neurology at Westmead Hospital in Sydney, Australia.
A VERY COMMON ETIOLOGY
Movement disorders of psychogenic origin make up about 3 percent of all disorders seen at movement disorder clinics, according to several studies. Tremor and myoclonus are the most common, followed by dystonia, which together account for over half of all psychogenic cases. Other disorders are less common.
Psychological distress underlies most psychogenic disorders, which are often somatoform disorders. Another possibility is malingering, and ongoing litigation is a red flag for the diagnosis of a psychogenic disorder.
They can be classified as “documented,” “clinically established,” “probable,” or “possible,” based on the degree of certainty of diagnosis, which in turn is based on clinical observation. A “possible” psychogenic disorder will show consistent movements that are compatible with a recognized movement disorder, but in the presence of obvious psychological distress.
A “probable” psychogenic disorder will show inconsistent or incongruent signs, or, if they are consistent, will be accompanied by other false neurological signs, or multiple somatisizations. Dr. Lang noted there is disagreement on this last point; for him, consistent signs even in the presence of false signs and multiple somatisizations relegates the disorder to the “possible” category.
In a “clinically established” psychogenic disorder the movements are inconsistent over time or incongruent with the “true” clinical condition, and there should also be other manifestations, including multiple somatisizations, “false neurological signs,” or obvious psychiatric disturbance. Finally, documentation requires reversal of the symptoms, which may occur with suggestion, physical therapy, psychotherapy, or placebo treatment. It may also occur when patients believe they are not being observed.
EXPERTISE IN MOVEMENT DISORDERS
“The diagnosis of a psychogenic movement disorder cannot be made by a psychiatrist,” Dr. Lang stressed. “The diagnosis should only be made by a neurologist, preferably one with considerable experience in movement disorders,” he said. The diagnosis is also not one of exclusion, he added; there are characteristic features that argue for a non-organic diagnosis.
Numerous clues in the history can suggest a psychogenic origin: abrupt onset; onset triggered by only minor trauma, especially if litigation is in the picture; rapid progression to the peak of severity, followed by a static course; spontaneous remission; multiple prior investigations or hospitalizations (which may not be voluntarily disclosed); clear secondary gain; and, occasionally, employment in an allied health profession.
The clinical picture also provides vital clues, with incongruities and inconsistencies dominating the decision-making process. “Often the movements are mixed and bizarre,” said Dr. Lang, not congruent with clearly described organic disorders. They may be paroxysmal, and may be precipitated by suggestion or startle. Inconsistencies over time or context are also telling. The movement may occur only in specific situations, “although we have to be careful about these,” Dr. Lang said, in light of the well-known task-specific dystonias.
Distraction may be useful to determine if the movement can be lessened, “but again, caution is advised, because we know tics, for example, will go away when you distract the patient,” as will akathisia. Attention may intensify the psychogenic disorder, and its frequency may also be entrained – asking the patient to tap rapidly with an unaffected limb may cause the affected limb to begin moving at the same frequency.
Other clinical clues include extreme slowness of movement, atypical pain or tenderness, non-anatomic sensory disturbances, false give-away weakness, and the ability to resist external movements in muscles that volitionally are immobile, as well as inappropriate behavior and affect. “Frequent sighing is common in these patients,” said Dr. Lang. While it occurs due to organic causes as well, self-inflicted injury can be seen in psychogenic movement disorders. The consequences can be severe: Dr. Lang related the case of one patient with psychogenic dystonia whose self-inflicted injuries led to gangrene and limb amputation.
Incongruous speech difficulties can also be telling, said Dr. Morris. He presented videos of one patient whose speech changed from normal when her head tilted to the right, to accented and dysarthric when tilted to the left. Despite a deep limp, she could walk backwards normally, and even dance. Her movement symptoms resolved when she lifted her left arm. And yet, Dr. Morris asked, might this be an example of a “geste antagoniste”? Many dystonia patients use these simple sensory tricks to relieve abnormal movements, he said. An important clue for this patient was her history: “Pages and pages of different symptoms over 40 years,” said Dr. Morris. “It's easier if they do that.”
MISDIAGNOSING ORGANIC DISORDERS
On the other hand, organic dystonias are likely to be misdiagnosed as psychogenic. They too can worsen with stress and abate with relaxation and distraction, and may remit spontaneously. Further, psychic distress is common in organic dystonias, for several reasons. Patients may have psychological effects from the long-term distortion of posture and body image, said Dr. Lang, and may become depressed. A diagnosis of psychogenesis in a patient with organic dystonia can cause further psychological damage.
“Indeed, there are many good physicians who make mistakes,” he said. He also stressed that diagnosis cannot usually be made from a videotape alone: “You need the history, you need to see the patient at the bedside.”
To underscore this point, the two experts discussed difficult cases, in which even their own diagnostic skills were challenged. A woman with convincingly severe generalized dystonia, but with the incongruence of adult onset, who had a placebo response to thalamotomy; a man with an unusually violent, ballistic tremor of sudden onset, whose neuroimaging revealed Wilson disease; a woman with marital difficulties whose orthostatic tremor was distractible, but electromyography indicated an underlying organic source (“you can't mimic a sixteen-Hertz tremor,” said Dr. Morris); and a woman whose leg tremor worsened with stress and remitted after a visit to a faith healer. Brain imaging showed moyamoya disease, which was probably not the direct cause of the tremor, but may have “lessened her coping reserves,” allowing the stresses of her life to bring on the psychogenic tremor. Dr. Morris noted that poor coping skills are a typical feature of many patients with psychogenic movement disorders.
DELIVERING THE DIAGNOSIS
Once the physician has reached the conclusion that the disorder is psychogenic, the diagnosis must be delivered to the patient, an act that generates its own challenges. Dr. Lang tells the patient he believes the disorder is due to psychological factors, and then emphasizes “the part of the brain that deals with emotions and behavior is large and complex, one we don't understand well, but it has connections to the parts of the brain that control movements.”
This explanation gives the patient an opportunity to begin to accept that psychological factors might be the cause of the movement disorder in a non-threatening way. “The way you present it is critical,” he said. “When I finish, I always point out to the patient I've not told them two things. I say to the patient, ‘Please notice I've never said you're crazy, and I've never said you're doing this on purpose.’ They do appreciate that you understand the physical disability they have from this kind of problem.” That is the point at which Dr. Lang involves a neuropsychiatrist.
Treatment is nonetheless difficult, and the prognosis for many of these patients is “terrible.” Outcomes may be “improved considerably” in many cases when a neuropsychiatrist joins the treatment team. “There is clearly a role for a team approach,” he said. Multiple interviews may be needed for the evidence of psychiatric disturbance to come out. “There's a great deal of denial in these patients,” he concluded.