Poor sleep measured across many dimensions has been linked to adverse physical and mental health outcomes including cardiovascular disease, diabetes, cancer, increased mortality, depression, and anxiety. Current research typically relies upon brief, subjective, inadequately validated methods to assess limited dimensions of sleep, resulting in inaccurate measurements and possibly faulty conclusions. Specifically, research validating objective (e.g., actigraphy) and subjective (e.g., sleep diaries, retrospective surveys) measurement methods against the gold standard of polysomnography (PSG, an overnight sleep study) is primarily limited by a) a lack of reliability based on too short (e.g., 24 or 48 hours) of an assessment period to capture night-to-night variability, b) a lack of ecological validity (e.g., full PSG in a laboratory setting), and c) a lack of generalizability due to limited or special populations (e.g., individuals with insomnia). Barriers such as prohibitive cost, extensive setup time, and personnel training requirements diminish the ability of researchers to conduct measurement comparison studies using gold standard measures like traditional PSG. These barriers can be circumvented with the use of low-cost, minimally invasive single-channel EEG devices (e.g., Zmachine), but to date few studies have employed these devices. The current study evaluated the accuracy of retrospective surveys, sleep diaries, and actigraphy compared to a single-channel EEG device for assessment of sleep timing, duration, and efficiency in participants' homes over one week using a broad community sample (N = 80). Actigraphy generally demonstrated the best agreement with Zmachine across sleep variables, followed by diary and then survey. Circadian midpoint was the most consistent across measures, followed by sleep duration and then sleep efficiency. Implications and future directions are discussed.
