Reliability, Validity, and Diagnostic Accuracy of the Persian Six-Item Cognitive Impairment Test (6-CIT) in Older Adult Outpatients

Abstract

Introduction

Early detection of neurocognitive disorders is crucial for timely intervention in older adults. The Six-Item Cognitive Impairment Test (6-CIT) is a brief screening tool designed for rapid cognitive assessment, but a validated Persian version has not been available to date. This study aimed to translate, culturally adapt, and psychometrically evaluate the Persian version of the 6-CIT among Iranian older adults.

Methods

In this prospective cross-sectional psychometric validation and diagnostic accuracy study, 180 participants aged ≥ 60 years were recruited from outpatient geriatric clinics and categorized into three equal groups: normal cognition, Mild Cognitive Impairment (MCI), and dementia. Diagnoses were established by a geriatric psychiatrist using DSM-5 criteria, and severity was staged using the Clinical Dementia Rating (CDR) criteria. Reliability was assessed through internal consistency (Cronbach's α) and test–retest stability (intraclass correlation coefficient, ICC 3,1). Validity was examined via convergent validity with the Mini-Mental State Examination (MMSE) and exploratory principal component analysis (PCA). Diagnostic accuracy, sensitivity, and specificity were evaluated using receiver operating characteristic (ROC) analysis and Youden's J index.

Results

The Persian 6-CIT demonstrated good internal consistency (Cronbach's α = 0.836) and strong test–retest reliability (ICC = 0.849). A strong negative correlation with the MMSE supported convergent validity (ρ = –0.919, p < 0.001). PCA supported a unidimensional structure explaining 71.72% of the total variance. ROC analysis for dementia yielded an AUC of 0.984 (95% CI: 0.961–1.000); a cutoff score of ≥ 11 provided 96.7% sensitivity and 85.8% specificity, while a cutoff of ≥ 14 maximized overall mathematical accuracy (93.3% sensitivity, 94.2% specificity). Furthermore, diagnostic accuracy for MCI was also high (AUC = 0.976, 95% CI: 0.947–0.997), with an optimal cutoff of ≥ 2 yielding 96.7% sensitivity and 96.7% specificity.

Conclusions

The Persian 6-CIT is a brief, reliable, and valid instrument for screening both MCI and dementia among Iranian older adults in specialized outpatient settings.