Abstract
Making the diagnosis of functional movement disorders can be challenging. Identifying positive physical signs and diagnostic maneuvers is critical to this process. Distractibility, entrainability, and variability are examples of classic physical findings in these patients. In this case series, we identify and characterize another phenomenon observed in some of these patients. In this phenomenon, movement suppression of one body part is followed by immediate reemergence of movement in another. We propose that this phenomenon be referred to as the “whack‐a‐mole” sign. This name is derived from the arcade game whack‐a‐mole, in which a mole, when hit into its original hole, re‐emerges elsewhere. We present a case series of 4 patients with functional movement disorders who exhibit this sign.
Keywords: functional movement disorder, physical signs
Case 1
A 45‐year‐old woman presented with a 5‐year history of involuntary movements involving all four extremities, often associated with stuttering of speech (see Video 1, Segment A). Symptoms waxed and waned, and she reported a 2.5‐year period of complete symptom resolution. Her movements were found to be variable and distractible, often worsening with auditory or visual stimuli. For example, as shown in the video, if the examiner held down the right upper extremity when it was moving, there was emergence of involuntary movements involving the head, shoulder, and upper and lower extremities on the left.
Case 2
A 58‐year‐old woman presented with a 2‐year history of involuntary movements involving bilateral lower extremities, abdomen, trunk, and head. Repetitive hip abduction and adduction were observed on examination (see Video 1, Segment B). When the examiner held down the left lower extremity, large‐amplitude, variable‐frequency movements of the trunk were observed.
Case 3
A 44‐year‐old woman presented with a 1.5‐year history of involuntary movements (see Video 2, Segment A). Distractible, slightly suppressible choreiform‐like movements involving the arms, legs, and trunk, as well as intermittent jaw‐opening dystonia and variable head tremor, were observed. As shown in the video, when the head tremor was suppressed by the examiner, synchronous jerky movements of the bilateral upper extremities subsequently developed.
Case 4
A 29‐year‐old woman presented with a 1.5‐year history of involuntary, jerky movements involving the right upper and lower extremities (see Video 2, Segment B). The movements were noted to be both distractible and entrainable on examination. Emergence of movements in the trunk was noted when the examiner held down the affected body part.
Discussion
The “whack‐a‐mole” sign reported in this case series is characterized by the immediate appearance of an involuntary movement in one body part after movement suppression in a separate body part (Fig. 1). The spread of these abnormal movements to different anatomical locations can be described to patients as evidence in support of a “software” problem involving broader networks, as opposed to a “hardware” problem affecting a particular anatomical location.
Figure 1.
Whack‐a‐mole arcade game being played by one of the authors.
Three of the four cases presented are examples of functional paroxysmal movement disorders. The presence of odd precipitating factors has previously been used as a diagnostic clue for these disorders.1 The whack‐a‐mole sign may serve similarly as a diagnostic clue, but is modifying and not precipitating.
Providing functional movement disorder patients with evidence of positive physical signs is considered critical for both arriving at and conveying the diagnosis of functional movement disorder.2 The importance of incorporating multiple physical diagnostic maneuvers has been emphasized in previous studies, given the limited sensitivity and specificity of any particular measure.3 An international committee of movement disorders specialists recently emphasized the need to expand these positive signs,4 which can be shared with the patient when conveying the diagnosis of functional movement disorder. We propose that the whack‐a‐mole sign is a valuable addition to this inventory of positive physical signs and diagnostic maneuvers.
Author Roles
(1) Research Project: A. Conception, B. Organization, C. Execution; (2) Manuscript: A. Writing of the First Draft, B. Review and Critique.
J.E.P.: 1A, 1B, 1C, 2A, 2B
C.W.M.: 1B, 1C, 2B
M.H.: 1A, 1B, 2B
Disclosures
Funding Sources and Conflicts of Interest: The authors report no sources of funding and no conflicts of interest.
Financial Disclosures for previous 12 months: Dr. Park has received a research grant from the Dystonia Medical Research Foundation. Dr. Hallett serves as Chair of the Medical Advisory Board for and receives honoraria and funding for travel from the Neurotoxin Institute. He may accrue revenue on US Patent #6 780 413 B2 (Issued: 24 August 2004): Immunotoxin (MAB‐Ricin) for the treatment of focal movement disorders, and US Patent #7 407 478 (Issued: 5 August 2008): Coil for Magnetic Stimulation and methods for using the same (H‐coil); in relation to the latter, he has received license fee payments from the National Institutes of Health (NIH; from Brainsway) for licensing of this patent. He is on the editorial board of 20 journals and received royalties and/or honoraria from publishing from Cambridge University Press, Oxford University Press, John Wiley & Sons, Wolters Kluwer, Springer, and Elsevier. He has received honoraria for lecturing from Columbia University. Dr. Hallett's research at the NIH is largely supported by the NIH Intramural Program. Supplemental research funds have been granted by the Kinetics Foundation for studies of instrumental methods to monitor Parkinson's disease, BCN Peptides, S.A. for treatment studies of blepharospasm, Medtronics, Inc., for studies of DBS, Parkinson Alliance for studies of eye movements in Parkinson's disease, Merz for treatment studies of focal hand dystonia, and Allergan for studies of methods to inject botulinum toxins.
Supporting information
Videos accompanying this article are available in the supporting information here.
Video 1. Patient 1: A 45‐year‐old woman with involuntary movements and associated stuttering of speech. Patient 2: A 58‐year‐old woman with involuntary movements involving various body parts. When the examiner held down an affected body part, patients developed involuntary movements in other parts of the body.
Video 2. Patient 3: A 44‐year‐old woman with a variety of involuntary movements, including chorea, dystonia, and tremor. Jerky movements of the bilateral upper extremities developed with suppression of the movements. Patient 4: A 29‐year‐old woman with involuntary, jerky movements of the right upper and lower extremities. Emergence of movements in the trunk was noted with suppression of the affected body part.
Acknowledgment
Video of case 2 was provided through the courtesy of Oh Panyakaew, MD.
Relevant disclosures and conflicts of interest are listed at the end of this article.
References
- 1. Ganos C, Aguirregomozcorta M, Batla A, Stamelou M, Schwingenschuh P, Munchau A, Edwards MJ, Bhatia KP. Psychogenic paroxysmal movement disorders–clinical features and diagnostic clues. Parkinsonism Relat Disord 2014;20:41–46. [DOI] [PubMed] [Google Scholar]
- 2. Stone J, Edwards M. Trick or treat? Showing patients with functional (psychogenic) motor symptoms their physical signs. Neurology 2012;79:282–284. [DOI] [PubMed] [Google Scholar]
- 3. Schwingenschuh P, Katschnig P, Seiler S, et al. Moving toward “laboratory‐supported” criteria for psychogenic tremor. Mov Disord 2011;26:2509–2515. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4. Espay AJ, Goldenhar LM, Voon V, Schrag A, Burton N, Lang AE. Opinions and clinical practices related to diagnosing and managing patients with psychogenic movement disorders: an international survey of movement disorder society members. Mov Disord 2009;24:1366–1374. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Videos accompanying this article are available in the supporting information here.
Video 1. Patient 1: A 45‐year‐old woman with involuntary movements and associated stuttering of speech. Patient 2: A 58‐year‐old woman with involuntary movements involving various body parts. When the examiner held down an affected body part, patients developed involuntary movements in other parts of the body.
Video 2. Patient 3: A 44‐year‐old woman with a variety of involuntary movements, including chorea, dystonia, and tremor. Jerky movements of the bilateral upper extremities developed with suppression of the movements. Patient 4: A 29‐year‐old woman with involuntary, jerky movements of the right upper and lower extremities. Emergence of movements in the trunk was noted with suppression of the affected body part.