[(123)I]-FP-CIT SPECT and olfaction test in patients with combined postural and rest tremor

J Neural Transm (Vienna). 2008;115(3):469-72. doi: 10.1007/s00702-007-0851-0. Epub 2008 Feb 4.


Mixed-type tremors pose a clinical diagnostic challenge. The aim of the study was to better characterize patients with combined postural and rest tremor. Patients were categorized into four groups: essential tremor (ET) (n = 7), combined rest + postural tremor (n = 17), PD (n = 17), and control subjects (n = 9). All underwent the University of Pennsylvania Smell Identification Test (UPSIT). The mixed-tremor group was also evaluated with SPECT imaging using the dopamine transporter (DaT) ligand (123)I-labeled FP-CIT. There was no significant difference in olfaction scores between the mixed tremor and essential tremor groups (23.2 +/- 6.6 vs 21.7 +/- 4.9) or between these groups and controls (27.2 +/- 5.0). The patients with PD had significantly lower scores than all the other groups (13.7 +/- 5.4, p < 0.001). Of the 12 patients with mixed tremor evaluated by SPECT, 9 had normal findings. This study suggests that rest tremor is part of the spectrum of ET, even in patients with long-standing disease. However, in a minority of patients, there might be transformation of ET-PD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diagnosis, Differential
  • Diagnostic Tests, Routine
  • Essential Tremor / diagnosis*
  • Humans
  • Middle Aged
  • Parkinson Disease / diagnosis*
  • Parkinson Disease / physiopathology
  • Radiopharmaceuticals
  • Smell / physiology*
  • Tomography, Emission-Computed, Single-Photon*
  • Tremor / diagnosis*
  • Tropanes


  • Radiopharmaceuticals
  • Tropanes
  • 2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane