Related Experiment Video
Updated: Feb 9, 2026

MRI-guided Focused Ultrasound Thalamotomy for Patients with Medically-refractory Essential Tremor
Published on: December 13, 2017
Independent validation of the Quality of Life in Essential Tremor Questionnaire (QUEST)
Márton Kovács1, Attila Makkos1, József Janszky1,2
1Department of Neurology, University of Pécs, Pécs.
Background And Purpose:
Quality of Life in Essential Tremor Questionnaire (QUEST) was specially developed for essential tremor population to measure the health-related quality of life. Besides the development of the Hungarian version, we performed an independent testing of the scale adding further information on its clinimetric properties.
Methods:
In this study 133 ET patients treated at University of Pécs, Hungary, were enrolled. Besides QUEST, we assessed Patient's Global Impression-Severity (PGI-S) and Fahn-Tolosa-Marin Tremor Rating Scales. After the independent validation in accordance to the Classic Theory of Tests, we evaluated cut-off values for detecting clinically meaningful ET-related disabilities based on receiver operating characteristics analysis.
Results:
Cronbach's a was 0.897. QUEST demonstrated high convergent validity with PGI and divergent validity with disease-duration, positive family history, need for deep brain stimulation surgery, and the presence of depression and anxiety. Presence of moderate ET-related disabilities was identified by scores > 11.25 points on QUEST-SI (sensitivity: 77.4%, specificity: 83.3%); whereas scores > 20.35 points indicated severe ET-related disabilities (sensitivity: 83.3%, specificity: 59.1%).
Conclusion:
We demonstrated that the fundamental clinimetric properties of the QUEST are satisfactory.
Related Concept Videos
Half-life of a Reaction
Characteristics of Life
Introduction to Test of Independence
The test statistic for a test of independence is similar to that of a goodness-of-fit test:
Hypothesis Test for Test of Independence
H0: The two variables (factors)...
Reliability and Validity
The Angiosperm Life Cycle

