Systemic lupus erythematosus in three ethnic groups. X. Measuring cognitive impairment with the cognitive symptoms inventory.
OBJECTIVE
To determine the factor structure of the Cognitive Symptoms Inventory (CSI) in patients with systemic lupus erythematosus (SLE) participating in a multiethnic longitudinal study of outcome, the Lupus in Minority populations, Nature versus nurture (LUMINA) study.


METHODS
LUMINA patients of Hispanic (n = 48), African American (n = 64), and Caucasian (n = 44) ethnicity who had a study visit (enrollment or followup) between January 1 and September 30, 2000 were included. Patients completed the CSI, a 21-item self-report measure of cognitive function. Sociodemographic, clinical, immunologic, psychosocial, and behavioral variables were ascertained per protocol and as previously described. Data were analyzed with SPSS. The factor structure of the CSI was determined using the principal axis method with oblique rotation as decided by Gorsuch. All factors having an Eigenvalue greater than 1 were considered. A 4-factor solution was derived that accounted for 42.6% of the common variance. The correlations between patient factor scale scores and variables from the demographic, clinical, psychosocial, and behavioral domains were then examined.


RESULTS
The four factors and their respective variance are, Attention/Concentration (28.8%), Pattern Recognition/Activity Management (5.7%), Intermediate Memory (4.7%), and Initiation of Executive Functions (3.4%); each factor correlated with the total CSI score. Overall, patients' factor scale scores were positively and significantly correlated with other measures of cognitive dysfunction such as the Systemic Lupus Activity Measure (neuromotor domain) or the Systemic Lupus International Collaborating Clinics Damage Index (neurocognitive impairment), as well as with measures of fatigue, maladaptive coping skills, poor mental functioning, poor social support, and helplessness. They were, however, not correlated with sociodemographic or clinical variables.


CONCLUSIONS
In addition to demonstrating that the CSI can be used to measure cognitive impairment in patients with SLE in the research setting, we have determined a 4-factor solution for the CSI that appears to have adequate metric properties. At present, the CSI may best be used as a screen for difficulties in daily activities involving intermediate memory, concentration, attention, and executive function. Nevertheless, further work with the CSI items and factor scales is necessary to establish internal and test-retest reliability of the factor scales; and provide additional evidence of the convergent and predictive validity of these scales in larger samples of patients from each ethnic subgroup.
Schools of Medicine and Public Health, University of Alabama at Birmingham, USA. graciela.alarcon@ccc.uab.edu
Graciela S
GS
Alarcón
Leanne
L
Cianfrini
Laurence A
LA
Bradley
Martha L
ML
Sanchez
Kemi
K
Brooks
Alan W
AW
Friedman
Bruce A
BA
Baethge
Barri J
BJ
Fessler
Holly M
HM
Bastian
Jeffrey M
JM
Roseman
Gerald
G
McGwin
John D
JD
Reveille
D000328:Adult; D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D001288:Attention; D003072:Cognition Disorders / Q000175:diagnosis* / Q000208:ethnology*; D003657:Decision Making; D005260:Female; D006630:Hispanic or Latino / Q000706:statistics & numerical data; D006801:Humans; D008137:Longitudinal Studies; D008180:Lupus Erythematosus, Systemic / Q000208:ethnology* / Q000523:psychology*; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D010364:Pattern Recognition, Visual; D011584:Psychology; D015203:Reproducibility of Results; D044465:White People / Q000706:statistics & numerical data