title: Rhythmic finger tapping reveals cerebellar dysfunction in essential tremor.
abstract: BACKGROUND
  Cerebellar circuits are hypothesized to play a central role in the pathogenesis of essential tremor. Rhythmic finger tapping is known to strongly engage the cerebellar motor circuitry. We characterize cerebellar and, more specifically, dentate nucleus function, and neural correlates of cerebellar output in essential tremor during rhythmic finger tapping employing functional MRI.
  
  
  METHODS
  Thirty-one propranolol-sensitive essential tremor patients with upper limb tremor and 29 healthy controls were measured. T2*-weighted EPI sequences were acquired. The task consisted of alternating rest and finger tapping blocks. A whole-brain and region-of-interest analysis was performed, the latter focusing on the cerebellar cortex, dentate nucleus and inferior olive nucleus. Activations were also related to tremor severity.
  
  
  RESULTS
  In patients, dentate activation correlated positively with tremor severity as measured by the tremor rating scale part A. Patients had reduced activation in widespread cerebellar cortical regions, and additionally in the inferior olive nucleus, and parietal and frontal cortex, compared to controls.
  
  
  CONCLUSIONS
  The increase in dentate activation with tremor severity supports involvement of the dentate nucleus in essential tremor. Cortical and cerebellar changes during a motor timing task in essential tremor might point to widespread changes in cerebellar output in essential tremor.
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: A W G
authors.initials: AW
authors.lastname: Buijink
authors.affiliation: Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: M
authors.initials: M
authors.lastname: Broersma
authors.affiliation: Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: A M M
authors.initials: AM
authors.lastname: van der Stouwe
authors.affiliation: Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Psychiatry, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: G A
authors.initials: GA
authors.lastname: van Wingen
authors.affiliation: Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Radiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: P F C
authors.initials: PF
authors.lastname: Groot
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: J D
authors.initials: JD
authors.lastname: Speelman
authors.affiliation: Department of Neurology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Neuroimaging Center, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: N M
authors.initials: NM
authors.lastname: Maurits
authors.affiliation: Department of Neurology and Clinical Neurophysiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Brain Imaging Center, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. Electronic address: a.f.vanrootselaar@amc.uva.nl.
authors.forename: A F
authors.initials: AF
authors.lastname: van Rootselaar
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping; D002526:Cerebellar Diseases / Q000503:physiopathology*; D002529:Cerebellar Nuclei / Q000503:physiopathology*; D020329:Essential Tremor / Q000503:physiopathology*; D005260:Female; D005385:Fingers; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009847:Olivary Nucleus / Q000503:physiopathology*; D012720:Severity of Illness Index; D055815:Young Adult
keywords: Cerebellum; Essential tremor; Finger tapping; Inferior olive nucleus; Motor task; fMRI