Evning Exposure to Computer Screen Disrupts Sleep, Attention and Biological Rhythms

Methods:

Participants Participants were between the ages of 20 and 45 years, with BMI 18-25, regular sleep habits in Pittsburgh Sleep Quality Index (PSQI) questionnaire index<5 (Buysse et al., 1989, Shochat et al., 2007), and a normative sleep-wake cycle type (Horne-Ostberg morningness-eveningness questionnaire (Horne & Ostberg, 1976, Lavie & Segal, 1990) measured Sleep quality and continuity were measured for one week using actigraphy with compatible decoding software (Respironics Model II, Philips, Inc). Only participants with 6-8 hours of sleep, normative sleep patterns, and no sleep/wake schedule problems proceeded to the experimental phase of the study stage. Participants were healthy with no history of medical, neurological, sleep disorders (confirmed by polysomnography) or psychiatric conditions and no medication intake (excluding contraceptives for female participants). Participants with ocular damage, such as to their field of vision, color blindness, or impaired functioning of the pupil in reaction to light were excluded, however use of eyeglasses or contact lenses to correct vision was allowed. Participants signed informed consent prior to participation in the study. The study was approved by the Helsinki Committee of Assuta Medical Center and Maccabi Health Services.

Measurements

Three physiological measures were collected in the study:

Polysomnography: The sleep testing room was a standard test room at the Sleep Medicine Research Center at Assuta Medical Center. Standard in-lab polysomnography was conducted using the Somnoscreen-polysomnography (PSG) type sleeping test instrument (Somnomedics, Germany). Sleep channels included: electroencephalography (EEG), electro-oculography (EOG), leg and chin electromyography (EMG), nasal breathing, chest breathing, diaphragm breath, snoring, electro-cardio-graphy (EKG), heart rate, blood oxygen saturation, and body position. Sleep data processing was performed by skilled and trained sleep technicians in accordance with of the Rechtschaffen and Kales criteria (1968). Sleep continuity parameters: latency to stage 1 (SL1) and stage 2 (SL2), percent wake after sleep onset (%WASO), index of awakenings, total sleep time (TST), time in bed (TIB), and sleep efficiency (SE). Sleep architecture parameters: percent stage 1 (%S1), stage 2 (%S2), REM (%REM), and SWS (%SWS), index of sleep stage changes and REM onset latency (ROL).