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Introduction
Sensory tricks, defined as 'episodic and specific manoeuvres that temporarily improve dystonia in a manner that is not easily physiologically perceived as necessary to counteract the involuntary movement', are well-recognised features of organic dystonia. 1 The term 'alleviating manoeuvres' (AlM) has been proposed as a more appropriate term because 'sensory trick' suggests that only sensory input is required, and the word 'trick' wrongly implies that is 'fake'. 2 'Reverse sensory trick' is the term used when a manoeuvre worsens dystonia, the latter can also be called 'aggravating manoeuvres' (AgM). AlMs are usually internally generated and rarely effective when applied by another person. However, patients with functional (psychogenic) movement disorders (FMDs) may show improvement or aggravation with stimuli applied by another person, that is, examiner manoeuvre (EM). In this study, we aimed to assess the frequency and characterise the clinical features of EMs in a large cohort of patients with FMDs.
Patients and methods
We reviewed medical records and video recordings of all cases of FMDs evaluated at Baylor College of Medicine Movement Disorders Clinic during a 2-year period. We assessed the stimuli type that improved or worsened the movements and which FMDs they influenced; in some cases patients reported such tricks, in other cases, they were discovered during the clinical examination. Additionally, in a proportion of these patients, we assessed the effect of a vibrating tuning fork placed on the body part involved in the 'involuntary' movement or some other body area if there was no ongoing movement, as in paroxysmal FMDs. Before applying the tuning fork, the patients were told that 'sometimes vibration may improve or worsen these type of movements' avoiding potentially deceiving statements such as 'my tuning fork has magic powers...', etc. All patients or their legal guardian signed written informed consent for videotaping approved by our Institutional Review Board for Human Research.
Results
We studied...