Functional near-infrared spectroscopy-based prefrontal cortex oxygenation during working memory tasks in sickle cell disease.

ABSTRACT

Significance: Sickle cell disease (SCD), characterized by painful vaso-occlusive crises, is associated with cognitive decline. However, objective quantification of cognitive decline in SCD remains a challenge, and the associated hemodynamics are unknown. Aim: To address this, we utilized functional near-infrared spectroscopy (fNIRS) to measure prefrontal cortex (PFC) oxygenation responses to N-back working memory tasks in SCD patients and compared them with healthy controls. Approach: We quantified the PFC oxygenation rate as an index of cognitive activity in each group and compared them. In half of the participants, a Stroop test was administered before they started N-back to elevate their baseline stress level. Results: In SCD compared to healthy controls, we found that (1) under a high baseline stress level, there were significantly greater oxygenation responses during the 2-back task, further elevated with histories of stroke; (2) there was a marginally slower N-back response time, and it was even slower with a history of stroke; and (3) the task accuracy was not different. Conclusions: Additional requirements for processing time, PFC resources, and PFC oxygenation in SCD patients offer an important basis for understanding their cognitive decline and highlight the potential of fNIRS for evaluating cognitive functions.