title: Patients with scans without evidence of dopaminergic deficit: a long-term follow-up study.
abstract: BACKGROUND
  We previously reported on a cohort of dystonic tremor and patients with scans without evidence of dopaminergic deficit (SWEDDs). We aim to report the long-term clinical and imaging follow-up of these patients.
  
  
  METHODS
  Patients with at least 5-year follow-up were included. These patients had an asymmetric arm tremor, a previous diagnosis of Parkinson's disease (PD), and a subsequent normal DaTscan. The imaging and clinical follow-up was done on the clinical basis.
  
  
  RESULTS
  Sixteen patients were included. The mean gap between the first and subsequent scans was 5.4 years. Two patients (12.5%) had reduced nigrostriatal uptake on follow-up DaTscan, whereas 14 continued to have normal dopaminergic imaging.
  
  
  CONCLUSIONS
  This is the longest follow up of patients with asymmetric rest tremor and normal DaT scans (SWEDDs) reported to date. We show here that only a minority of them show reduced striatonigral uptake over long term follow up.
authors.affiliation: Sobell Department of Motor Neuroscience and Movement disorders, UCL Institute of Neurology, London, United Kingdom.
authors.forename: Amit
authors.initials: A
authors.lastname: Batla
authors.forename: Roberto
authors.initials: R
authors.lastname: Erro
authors.forename: Maria
authors.initials: M
authors.lastname: Stamelou
authors.forename: Susanne A
authors.initials: SA
authors.lastname: Schneider
authors.forename: Petra
authors.initials: P
authors.lastname: Schwingenschuh
authors.forename: Christos
authors.initials: C
authors.lastname: Ganos
authors.forename: Kailash P
authors.initials: KP
authors.lastname: Bhatia
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004298:Dopamine / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D020821:Dystonic Disorders / Q000175:diagnosis; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000503:physiopathology*; D013995:Time; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods; D014202:Tremor / Q000175:diagnosis
chemical_list: D050483:Dopamine Plasma Membrane Transport Proteins; D004298:Dopamine
keywords: DaTscan; Parkinson's disease; SWEDD; dopamine; dystonia; dystonic tremor