title: Tremor pattern differentiates drug-induced resting tremor from Parkinson disease.
abstract: OBJECTIVE
  DAT-SPECT, is a well-established procedure for distinguishing drug-induced parkinsonism from Parkinson's disease (PD). We investigated the usefulness of blink reflex recovery cycle (BRrc) and of electromyographic parameters of resting tremor for the differentiation of patients with drug-induced parkinsonism with resting tremor (rDIP) from those with resting tremor due to PD.
  
  
  METHODS
  This was a cross-sectional study. In 16 patients with rDIP and 18 patients with PD we analysed electrophysiological parameters (amplitude, duration, burst and pattern) of resting tremor. BRrc at interstimulus intervals (ISI) of 100, 150, 200, 300, 400, 500 and 750 msec was also analysed in patients with rDIP, patients with PD and healthy controls. All patients and controls underwent DAT-SPECT.
  
  
  RESULTS
  Rest tremor amplitude was higher in PD patients than in rDIP patients (p < 0.001), while frequency and burst duration were higher in rDIP than in PD (p < 0.001, p < 0.003, respectively). Resting tremor showed a synchronous pattern in all patients with rDIP, whereas it had an alternating pattern in all PD patients (p < 0.001). DAT-SPECT was normal in rDIP patients while it was markedly abnormal in patients with PD.
  
  
  CONCLUSIONS
  In the absence of DAT-SPECT, the pattern of resting tremor can be considered a useful investigation for differentiating rDIP from PD.
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Nisticò
authors.affiliation: Institute of Neurology, Department of Medical Sciences, University Magna Graecia, Catanzaro, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Fratto
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Vescio
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical Sciences, University Magna Graecia, Catanzaro, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Arabia
authors.affiliation: Department of Medical and Surgical Sciences and Advanced Technologies "G.F. Ingrassia" University of Catania, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Sciacca
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical Sciences, University Magna Graecia, Catanzaro, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Morelli
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical Sciences, University Magna Graecia, Catanzaro, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Labate
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Salsone
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Novellino
authors.affiliation: Department of Medical and Surgical Sciences and Advanced Technologies "G.F. Ingrassia" University of Catania, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Nicoletti
authors.affiliation: Department of Clinical and Experimental Medicine, University of Catania, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Petralia
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical Sciences, University Magna Graecia, Catanzaro, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Gambardella
authors.affiliation: Department of Medical and Surgical Sciences and Advanced Technologies "G.F. Ingrassia" University of Catania, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Zappia
authors.affiliation: Neuroimaging Research Unit, Institute of Bioimaging and Molecular Physiology, National Research Council, Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical Sciences, University Magna Graecia, Catanzaro, Italy. Electronic address: quattrone@unicz.it.
authors.forename: A
authors.initials: A
authors.lastname: Quattrone
mesh_terms: D000368:Aged; D001767:Blinking; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis*; D015899:Tomography, Emission-Computed, Single-Photon; D014202:Tremor / Q000175:diagnosis* / Q000209:etiology*
keywords: Drug-induced parkinsonism; Electromyography; Resting tremor