Acta Neurol Belg DOI 10.1007/s13760-015-0464-6

LETTER TO THE EDITOR

Psychogenic tremor in Parkinson’s disease Carlo Colosimo1

Received: 27 December 2014 / Accepted: 21 March 2015 Ó Belgian Neurological Society 2015

Keywords Tremor

Parkinson’s disease  Psychogenic disorders 

The correct diagnosis of patients with psychogenic movement disorders is not straightforward, nor is it always easy to differentiate them from patients with organic movement disorders [1]. In addition, psychogenic disorders may arise within the context of established organic diseases [2] and have been described in asymptomatic family members, who carry the mutation, of subjects with an inherited disorder [3]. The phenomenon of overlap between functional and organic neurological disorders (functional overlay) appears to be common in neurological practice, including up to 12 % of all those with neurological diseases [2]. The occurrence of functional overlay within the context of established Parkinson’s disease (PD) has recently been described in a case series by Paree´s and co-workers [4]. Here, we describe a further case of psychogenic tremor in a patient with otherwise typical PD. A 62-year-old shop owner, with no relevant family or personal medical history came to my clinic with a 2-year history of right arm slowness and tremor. Upon examination, he was found to have a mild parkinsonian picture [total score of 18 in the Unified Parkinson’s Disease Rating Scale (UPDRS) part III]. Tremor on the right had side was very mild, present at rest and with the arms stretched (he Electronic supplementary material The online version of this article (doi:10.1007/s13760-015-0464-6) contains supplementary material, which is available to authorized users. & Carlo Colosimo [email protected] 1

Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy

had combined score of two in items 20–21 of the UPDRSIII). Brain magnetic resonance imaging was unremarkable, and a clinical diagnosis of PD was consequently made. He was given extended-release pramipexole (2.1 mg/day), which led to a considerable general improvement by the follow-up visit. During the following 18 months, the patient’s parkinsonian picture remained relatively stable, the only change being an adjustment of therapy (pramipexole, which caused sleepiness, was replaced with 300/75 mg of levodopa/carbidopa), which yielded satisfactory results. One morning I was called by the patient’s wife, who asked me to urgently examine him because of an abrupt worsening of the clinical picture. I saw the patient the same week. He and his wife both stated that the prescribed dose of antiparkinsonian medications had remained unchanged. On examination tremor has markedly worsened (score at items 20 and 21 of the motor UPDRS was now four bilaterally with the patient presenting repeated bouts of coarse, large-amplitude rest and postural tremor). Upon prolonged observation, tremor was found to vary in direction, frequency and amplitude. In addition, when the patient performed motor tasks with the contralateral hand, tremor improved considerably. Sequential finger movements on the right side were impaired but difficult to judge because of the severe tremor, whereas muscular tone, balance and gait were unchanged. Owing to this sudden change in the patient’s clinical picture, I requested a brain CT scan, which was normal. After receiving the imaging results, I reassured the patient explaining that the increase of tremor was not due to a sudden worsening of PD or any other organic cause, but to a unconscious brain ‘‘reaction’’ to stress. The patient admitted he had been through a highly stressful period in the previous months owing to an excessive workload and financial problems due to the current economic recession. I

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prescribed a small dose of benzodiazepines for his anxiety, and suggested that he come to see me again in 3 weeks. When I did see him again, the tremor had returned to its previous state (i.e. very mild and intermittent), and I suggested to slowly taper down benzodiazepines. In order to confirm my clinical diagnosis, I asked for a dopamine transporter single photon emission tomography scan (DaTSCANÒ), which showed a bilateral striatal deficit in tracer uptake, more marked on the left side. Following this isolated episode, the patient remained stable over the next 24 months. At the last visit, the patient’s total score in the UPDRS part III was 24, while the combined score for tremor in items 20–21 was always two. A diagnosis of clinically established functional movement disorder, according to the Fahn and Williams criteria, was eventually made [5]. PD is a disorder that progresses slowly and in which rapid changes in cardinal signs are rarely observed unless sudden changes in the drug dosage or schedule are made. When the neurological picture suddenly worsens, the symptoms are incongruous with the known picture of this disease, and the presence of a life stressor (which, however, is not mandatory) is documented, a diagnosis of functional overlay should be considered. Recognition of functional overlay in PD is important to avoid an unnecessary increase in PD medications. A simple clinical re-evaluation by the same neurologist, who should fully explain the

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implications of this type of diagnosis, is often the best way to reassure the patient. Early recognition of this phenomenon is critical since short disease duration correlates with a better prognosis. Conflict of interest paper.

I have no conflict of interest regarding this

Ethical standard This case report was approved by the Ethics committee of the Sapienza University Medical School.

References 1. Morgante F, Edwards MJ, Espay AJ (2013) Psychogenic movement disorders. Continuum 19(5 Movement Disorders):1383–1396 2. Stone J, Carson A, Duncan R, Roberts R, Coleman R, Warlow C, Murray G, Pelosi A, Cavanagh J, Matthews K, Goldbeck R, Sharpe M (2012) Which neurological diseases are most likely to be associated with ‘‘symptoms unexplained by organic disease’’. J Neurol 259:33–38 3. Bentivoglio AR, Loi M, Valente EM, Ialongo T, Tonali P, Albanese A (2002) Phenotypic variability of DYT1-PTD: does the clinical spectrum include psychogenic dystonia? Mov Disord 17:1058–1063 4. Paree´s I, Saifee TA, Kojovic M, Kassavetis P, Rubio-Agusti I, Sadnicka A, Bhatia KP, Edwards MJ (2013) Functional (psychogenic) symptoms in Parkinson’s disease. Mov Disord 28:1622–1627 5. Fahn S, Williams DT (1988) Psychogenic dystonia. Adv Neurol 50:431–455

Psychogenic tremor in Parkinson's disease.

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