Table 1.

Confounding factors in the evaluation of cognitive decline after transient ischemic attack (TIA) and potential methods to address the problem in future studies.

Confounder	Potential Methods to Address the Problem
Pre-existing cognitive decline or dementia	Obtain a standardized measure of pre-TIA cognitive decline using an instrument such as the IQCODE [27]
Fatigue	Measure fatigue in participants using a standard scale such as the Chalder Fatigue Scale [68] and adjust cognitive test results for these scores (or match with corresponding controls without TIA) Consider adjusting for the time-of-day for the cognitive assessments, or standardizing the timing of the cognitive assessments
Depression	Measure depression in participants using a standard scale such as the Beck Depression Inventory-II [63], the Montgomery Asberg Depression Rating Scale [64], or the Centre for Epidemiological Studies Depression Scale (CES-D) [69,70] and adjust cognitive test results for these scores (or match with corresponding controls without TIA)
Attrition	Use multiple follow-up methods (telephone or virtual visit, home visits, and primary care records) to ascertain long-term cognitive outcomes without relying on in-person clinic visits alone
Differences in education	Adjust for years of education or highest educational milestone achieved
Patients being Untestable	Keep track of patients who are untestable in the cohort and the reason Offer cognitive testing in multiple languages where feasible Consider less culturally biased cognitive tests for multi-cultural populations (though validation in TIA or stroke may be lacking)