van der Salm SM, van Rootselaar AF, Cath DC, de Haan RJ,
Koelman JH, Tijssen MA. Clinical decision-making in functional and hyperkinetic
movement disorders. Neurology. 2016 Dec 2. pii: 10.1212/WNL.0000000000003479.
[Epub ahead of print]
Abstract
OBJECTIVE:
Functional or psychogenic movement disorders (FMD) present a
diagnostic challenge. To diagnose FMD, clinicians must have experience with
signs typical of FMD and distinguishing features from other hyperkinetic
disorders. The aim of this study was to clarify the decision-making process of
expert clinicians while diagnosing FMD, myoclonus, and tics.
METHODS:
Thirty-nine movement disorders experts rated 60 patients
using a standardized web-based survey resembling clinical practice. It provided
5 steps of incremental information: (1) visual first impression of the patient,
(2) medical history, (3) neurologic examination on video, (4) the
Bereitschaftspotential (BP), and (5) psychiatric evaluation. After full
evaluation of each case, experts were asked which diagnostic step was decisive.
In addition, interim switches in diagnosis after each informational step were
calculated.
RESULTS:
After full evaluation, the experts annotated the first
impression of the patients as decisive in 18.5% of cases. Medical history was
considered decisive in 33.3% of cases. Neurologic examination was considered
decisive in 39.7%, the BP in 8%, and the psychiatric interview in 0.5% of
cases. Most diagnostic switches occurred after addition of the medical history
(34.5%). Addition of the neurologic examination led to 13.8% of diagnostic
switches. The BP results led to diagnostic switches in 7.2% of cases.
Psychiatric evaluation resulted in the lowest number of diagnostic switches
(2.7% of cases).
CONCLUSIONS:
Experts predominantly rely on clinical assessment to
diagnose FMD. Importantly, ancillary tests do not determine the final diagnosis
of this expert panel. In general, the experts infrequently changed their
differential diagnosis.
_________________________________________________________________________
“In general, the experts infrequently changed their
differential diagnosis,” said Marina AJ Tijssen, MD, PhD, a neurologist at the
University of Groningen and her colleagues. “Importantly, ancillary tests did
not determine the final diagnosis of this expert panel.
”Patients with functional movement disorders report a range
of involuntary movements — usually tremor, jerking movements, abnormal gait,
and imbalance problems. Many neurologists believe that the symptoms are
commonly feigned.
“Establishing a diagnosis in clinical practice can be
difficult, but it has been shown in many studies that late diagnosis due to
diagnostic delay in functional movement disorders (FMD) and other functional
neurological symptoms results in a worse prognosis for full recovery,” Dr.
Tijssen told Neurology Today. “Therefore, every clinician can learn from the
diagnostic process of this expert panel, and this may help to establish the diagnosis
of FMD sooner.”
“As can be gathered from our findings, even in very
experienced hands, the diagnosis is challenging, and opinions can vary,” Dr.
Tijssen said…
The study authors noted that one limitation of the study is
the lack of information on the neurologist's motives for their responses. “It
could be that the non-switching was a result of a lack of added value of the
next step information as judged by the experts, or the consequence of the fact
that current diagnosis was strengthened by the added information. Future
studies should therefore investigate this aspect in the decision-making process
as well.”
“Because the inter-rater agreement was moderate and opinions
of the expert panel differed, we think that the honest answer is that there can
be no ‘right’ diagnosis in some of the challenging cases of our cohort,” said
Dr. Tijssen…
“The diagnosis of FMD cannot be made by any imaging or
neurophysiologic tests, although they may provide supportive information,” he
said. “The diagnosis relies on careful history and examination by an
experienced movement disorders specialist, who often suspects the diagnosis
immediately at the initial encounter.”
He added: “One issue that might contribute to the results in
both studies is the fact that it was not based on an in-person examination but
a web-based survey. The inability to personally interview and examine the
patients may have influenced the results of both studies.”
“The take-home message for general neurologists is to
initially refer patients with suspected FMD to a reputable movement disorder
center rather than to a psychiatrist. Although psychiatrists can be helpful in
unraveling some of the psychodynamic factors and helping the patient understand
the role of stress in causation or exacerbation of the FMD, they should not be
called up to make the diagnosis. This is the responsibility of a movement
disorder specialist.”
Dr. Jankovic pointed out that although the Diagnostic and
Statistical Manual-5 (DSM-5) no longer requires identifiable psychological
etiology as a prerequisite for the diagnosis of FMD, nearly all patients with
FMD have some underlying psychological issues, even though this may or may not
be easy to uncover, particularly during the initial visit, and sometime
additional visits are needed to better understand possible underlying
mechanisms.
“I often see patients who initially deny any stressors as
precipitants of their FMD, but later I find important conflicts or other stress
factors that were likely relevant as triggers of the FMD,” Dr. Jankovic said…
Thomas Swift, MD, FAAN, professor emeritus of neurology at
Medical College of Georgia in Augusta, said that “neurologists make a lot of
instantaneous judgments.” He said that he is often right on his first
impressions, although he admits that he once diagnosed functional movement
disorder when the patient actually had Creutzfeldt-Jakob disease.
Dr. Swift said that it is not difficult to recognize
symptoms of an organic movement disorder. He cited the case of a patient who
was referred to him with complaints of numbness, and who had been in a
wheelchair for a decade. He got her to stand up, then walk and finally run, but
she got right back in her wheelchair at the end of the exam. “Telling her the
weakness was not real did no good,” he said.
http://journals.lww.com/neurotodayonline/Fulltext/2016/12220/How_to_Diagnose_Functional_Movement_Disorders_.7.aspx
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