Depression, Obstructive Sleep Apnea and Cognitive Impairment (DOC) Screen Completion Time Reflects Executive Function, Speed of Processing and Fluency.

Background: The depression, obstructive sleep apnea and cognitive impairment (DOC) screen assesses three post-stroke comorbidities, but additional information may be gained from the time to complete the screen. Cognitive screening completion time is rarely used as an outcome measure.

Objective: To assess DOC screen completion time as a predictor of cognitive impairment in stroke/transient ischemic attack clinics.

Methods: Consecutive English-speaking stroke prevention clinic patients consented to undergo screening and neuropsychological testing (n = 437). DOC screen scores and times were compared to scores on the NINDS-CSC battery using multiple linear regression (controlling for age, sex, education and stroke severity) and receiver operating characteristic (ROC) curve analysis.

Results: Completion time for the DOC screen was 3.8 ± 1.3 minutes. After accounting for covariates, the completion time was a significant predictor of the speed of processing (p = 0.002, 95% CI: -0.016 to -0.004), verbal fluency (p < 0.001, CI: -0.012 to -0.006) and executive function (p = 0.004, CI: -0.006 to -0.001), but not memory. Completion time above 5.5 minutes was associated with a high likelihood of impairment on executive and speed of processing tasks (likelihood ratios 3.9-5.2).

Conclusions: DOC screen completion time is easy to collect in routine care. People needing over 5.5 minutes to be screened likely have deficits in executive functioning and speed of processing - areas commonly impaired, but challenging to screen for, after stroke. DOC screen time provides a simple, feasible approach to assess these under-identified cognitive impairments.