Psychometric evaluation of the Rasch-based depression screening in patients with neurologic disorders.
OBJECTIVE
To provide a first evaluation of the Rasch-Based Depression Screening (DESC) in consecutive patients with neurologic disorders.


METHODS
Cross-sectional study.


METHODS
Hospital specializing in neurologic disorders.


METHODS
Eligible patients (N=323; mean age +/- SD, 53.4+/-17.2y; 49.3% women) age 18 years and older.


METHODS
Not applicable.


METHODS
DESC with 2 parallel versions.


RESULTS
Both versions of the DESC showed good item separation (DESC-I=4.96; DESC-II=4.94) and person separation (DESC-I=2.01; DESC-II=2.14) as well as item separation reliability (DESC-I=.96; DESC-II=.96) and person separation reliability (DESC-I=.80; DESC-II=.82). All items fit the Rasch model (infit and outfit mean squares < or =1.3). There were no signs of violation of unidimensionality. One item of DESC-I showed differential item functioning because of age and 1 item because of sex. Parallel test reliability of the 2 DESC forms was r equal to .92.


CONCLUSIONS
The DESC shows good psychometric characteristics that suggest high psychometric quality of the instrument in patients with neurologic disorders. Differential item functioning on single items needs further examination but should not substantially interfere with the valid interpretation of DESC sum scores.
Forkmann
Thomas
T
Institute of Medical Psychology and Medical Sociology, University Hospital of Rheinisch-Westfälische Technische Hochschule, Aachen, Germany. tforkmann@ukaachen.de
Norra
Christine
C
Wirtz
Markus
M
Gauggel
Siegfried
S
Boecker
Maren
M
D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D003866:Depressive Disorder / Q000150:complications* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000150:complications*; D026741:Physical Therapy Modalities; D011594:Psychometrics; D012680:Sensitivity and Specificity