Validation of the QUEST for German-speaking countries.
OBJECTIVE
To explore the clinimetric attributes of the German version of the quality of life in essential tremor (ET) questionnaire (QUEST) as a tremor-specific measure of quality of life.


METHODS
This was an observational, cross-sectional study. The QUEST German version was obtained by translation-back translation procedure. ET cases were diagnosed according to the tremor investigation group criteria. Assessments included Archimedes spirals rating, EQ-5D, Beck Depression Inventory (BDI-II) and QUEST German version. Missing data were imputed for those cases in which the loss of data for one domain of the QUEST was <30%.


RESULTS
Ninety three patients out of 138 (67.4%) with definite or probable ET had complete QUEST data after 43 item imputations and they constituted the sample for this study. The QUEST summary index (QSI) displayed no floor or ceiling effects. QUEST internal consistency (Cronbach's alpha) ranged between 0.50 and 0.89. Item-total domain correlations ranged from 0.26 to 0.82 and the item homogeneity indexes were satisfactory (range: 0.28-0.60). The QSI correlated weakly with the EQ-5D (rS=0.20) and moderately with the BDI-II (rS = 0.31) and the QUEST self-evaluation of tremor severity (rS = 0.44).


CONCLUSIONS
The QUEST German version has, despite recognized data quality problems, satisfactory acceptability and internal consistency as a whole. The correlation analysis showed that tremor in the head, voice and right hand was moderately associated with quality of life.
a Department of Neurology , University Hospital Schleswig-Holstein , Campus Kiel , Kiel , Germany.
Franziska
F
Hopfner
a Department of Neurology , University Hospital Schleswig-Holstein , Campus Kiel , Kiel , Germany.
Adelheid
A
Nebel
b Department of Neurology , University of Kansas Medical Center , Kansas City , MO , USA.
Kelly E
KE
Lyons
c Department of Clinical Neuropsychology and Center for Neuromodulation , Barrow Neurological Institute , Phoenix , AZ , USA.
Alexander I
AI
Tröster
a Department of Neurology , University Hospital Schleswig-Holstein , Campus Kiel , Kiel , Germany.
Gregor
G
Kuhlenbäumer
a Department of Neurology , University Hospital Schleswig-Holstein , Campus Kiel , Kiel , Germany.
Günther
G
Deuschl
d Area of Applied Epidemiology, National Center for Epidemiology, and CIBERNED , Carlos III Institute of Health , Madrid , Spain.
Pablo
P
Martinez-Martin
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D020329:Essential Tremor / Q000523:psychology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D012044:Regression Analysis; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014175:Translating; D055815:Young Adult
Archimedes spiral; ET; QUEST; QUEST German version; essential tremor; quality of life; tremor