Validation of the triple timed up-and-go test in Lambert-Eaton myasthenia

Muscle Nerve. 2019 Sep;60(3):292-298. doi: 10.1002/mus.26625. Epub 2019 Jul 18.

Abstract

Introduction: There are no validated, practical, and quantitative measures of disease severity in Lambert-Eaton myasthenia (LEM).

Methods: Data from the Effectiveness of 3,4-Diaminopyridine in Lambert-Eaton Myasthenic Syndrome (DAPPER) trial were analyzed to assess triple timed up-and-go (3TUG) reproducibility and relationships between 3TUG times and other measures of LEM severity.

Results: The coverage probability technique showed ≥0.90 probability for an acceptable 3TUG difference of ≤0.2, indicating that it is reproducible in LEM patients. The correlation between 3TUG times and lower extremity function scores was significant in subjects who continued and in those who were withdrawn from 3,4-diaminopyridine free base. Worsening patient-reported Weakness Self-Assessment Scale and Investigator Assessment of Treatment Effect scores corresponded with prolongation of 3TUG times.

Discussion: The 3TUG is reproducible, demonstrates construct validity for assessment of lower extremity function in LEM patients, and correlates with changes in patient and physician assessments. These findings, along with prior reliability studies, indicate 3TUG is a valid measure of disease severity in LEM.

Keywords: Lambert-Eaton myasthenia; Lambert-Eaton myasthenic syndrome; Lambert-Eaton syndrome; outcome measures; timed up-and-go test; validation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Humans
  • Lambert-Eaton Myasthenic Syndrome / physiopathology*
  • Lower Extremity / physiopathology*
  • Mass Screening / methods
  • Muscle Weakness / drug therapy
  • Muscle Weakness / physiopathology*
  • Potassium Channel Blockers / therapeutic use
  • Reproducibility of Results
  • Severity of Illness Index

Substances

  • Potassium Channel Blockers