Identifying Markers of Autonomic Nervous System Functioning During Sleep in Adults with Fibromyalgia Using the E4 Wristband

Poor sleep quality, disturbed sleep, and unrefreshed sleep are some of the cardinal characteristics of fibromyalgia (FM). In addition to having a direct impact on functioning and quality of life, evidence suggests that poor sleep is linked to other symptoms, including pain, fatigue, and depressed mood, and poor functioning in FM. Therefore, interventions that are successful at improving sleep in FM may have downstream effects in terms of improved daytime symptom burden and functional ability. Typically, sleep researchers rely on two main types of sleep measurement: 1) self-report measures of sleep, or 2) polysomnography (PSG). Self-report measures of sleep are limited by tenuous reliability and validity in terms of correspondence to objective sleep measures. PSG is considered the “gold standard” of objective sleep measures, but is limited by the fact that it is expensive and cumbersome for researchers to utilize and may lack ecological validity. Researchers would greatly benefit from an inexpensive, feasible, accessible, and objective means of measuring sleep that can be employed in the research participant’s own sleep environment, rather than in the sleep lab. 

One promising avenue for efficient measurement of sleep is to assess autonomic activity during sleep, which can serve as a proxy for sleep quality and sleep architecture. Furthermore autonomic activity during sleep may have a major impact on the restfulness of sleep, independent of other measures of sleep quality or structure of sleep. Autonomic balance is maintained during normal sleep by shifting between sympathetic and parasympathetic dominance across sleep stages. While some PSG measures, such as cyclic alternating pattern are indicative of autonomic activity during sleep, there are much more direct measures of autonomic functioning that can be employed, such as galvanic skin response (GSR) and heart rate variability (HRV). 

The E4 Wristband is a wrist-worn device designed for unobtrusive, continuous, real-time acquisition of GSR, HRV, accelerometry, and peripheral skin temperature data in daily life. The E4 Wristband was designed for research and provides state-of-the-art measurement of these variables with high fidelity, as demonstrated in numerous peer-reviewed papers. Before launching a large study of sleep using this promising device, our team of researchers seeks to conduct a pilot study to examine the feasibility and acceptability of this device and to generate pilot data in our target populations. 

The overarching aim of this study is to examine the feasibility and acceptability of the E4 wristband in individuals with and without FM (i.e., healthy controls).This study will provide the study team with pragmatic experience using the E4 to collect physiological data in research. Furthermore, it will provide crucial preliminary data that will help us to secure future grant funding to study autonomic nervous system functioning in clinical populations using the E4 Wristband. As such, the study specific aims are as follows:

Specific Aim #1: To examine the feasibility and acceptability of the E4 Wristband in those with FM and matched healthy controls.  

Specific Aim #2: To compare E4 Wristband-generated physiological data during sleep between patient (FM) and matched controls.