Intraindividual Variability of the Cortisol Awakening Response, Sleep Dynamics, Stress, and Emotion in Two Persons With Poststroke Aphasia

Purpose: The current exploratory pilot study examines intraindividual cortisol awakening response (CAR) variability and its relation to modifiable variables in two persons with aphasia over the course of 4 weeks. By investigating the intraindividual variability of two individuals over 4 weeks with consideration of modifiable variables (e.g., self-reported stress, emotion, sleep quality, and sleep quantity), we aim to (a) describe the long-term intraindividual variability of the CAR, (b) better understand the association of the CAR to modifiable variables, and (c) inform future methods related to the CAR in persons with poststroke aphasia. Additionally, we explore the feasibility of independent at-home saliva sampling within and across multiple days in two persons with aphasia. Method: Two persons with aphasia, one identifying as male and the other identifying as female, with similar aphasia severities and age, participated in their home environment. Both participants collected saliva samples upon awakening and 30 and 60 min postawakening across 12 days over the course of a 4-week period. Self-reports of stress and emotion were taken the night prior to and on the day of cortisol sampling. Self-reports of sleep quality and quantity were collected on the day of cortisol sampling. Results: The CAR was consistent across days and weeks, showing little intraindividual variability. Associations between modifiable variables and the CAR did not reach statistical significance. However, there were weak-to-moderate correlations observed between some of the variables and the CAR. Conclusions: This small exploratory pilot study demonstrated that the modifiable variables of self-reported sleep quality, sleep quantity, perceived stress, and emotion were consistent over time and varied in their association with the CAR in two persons with aphasia. These findings could inform future, larger scale research designs exploring the CAR in persons with aphasia. Supplemental Material: https://doi.org/10.23641/asha.31152235