Multicenter Validation of the English Version of the Depistage Cognitif de Quebec: A Cognitive Screening Tool for Atypical Dementias

Abstract

Background: Early detection of atypical dementia remains difficult partly because of the absence of specific cognitive screening tools. This creates undue delays in diagnosis and management. The Depistage Cognitif de Quebec (DCQ; dcqtest.org) was developed in French and later validated in participants with atypical syndromes. We report the validation of the English version. Methods: This multicentre prospective validation study was conducted in 10 centers across Canada and the United States on 260 English-speaking participants aged over 50. We translated and modified the original French DCQ to add targeted stimuli to the Visusopatial Index and social cognition vignettes to the Behavioral Index. A backward translation was performed and equivalence between languages was assessed by administering both tests to 30 bilingual participants. Results: Mean DCQ total score (out of 100) was 95.0 (SD = 3.6). Spearman's correlation coefficient showed a strong and significant correlation (r = 0.49, p