Plantar Grasp sign as a screening tool for Orthostatic Tremor (OT)

Rebecca Thompson, Danish Bhatti, Kalyan Malgireddy, Venkata Sunil Bendi, John M. Bertoni, Vekash Raja, Diego Torres-Russotto

Research output: Contribution to journalArticlepeer-review


Introduction: Orthostatic tremor (OT) is a rare neurological disorder characterized by a sensation of instability while standing. Very few clinical signs have been described for OT to date. Finding other symptoms and signs could prove valuable for this hard-to-recognized disease. Methods: This protocol is part of the University of Nebraska Medical Center Orthostatic Tremor longitudinal study. It was noted that OT patients flex their toes and sometimes the foot arch while standing (Plantar Grasp). They reported doing this to “grab” the floor and improve stability. This paper analyses the diagnostic test characteristics of the patient-self-reported Plantar Grasp, a new sign in OT. Results: There were 34 OT patients (88% females), and 20 controls (65% females). Eighty-eight percent of patients with OT reported the plantar grasp sign and none of the controls. The Plantar Grasp Sign was found to be very sensitive (88%), and extremely specific (100%) in our cohort. Non-weighted Negative Likelihood Ratio (NLR) was 0.12. And the 3% prevalence-weighted NLR was so low that the negative post-test probability was close to zero. Conclusion: Due to its high sensitivity, specificity, and ideal likelihood ratio, we propose that the Plantar Grasp sign could be considered to screen patients with possible OT. Further studies are needed to determine the specificity of this sign in OT versus other balance disorders.

Original languageEnglish (US)
Article number100196
JournalClinical Parkinsonism and Related Disorders
StatePublished - Jan 2023


  • Orthostatic tremor
  • Plantar Grasp sign
  • Screening tool
  • Sensitivity and specificity

ASJC Scopus subject areas

  • Clinical Neurology
  • Cellular and Molecular Neuroscience


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