Effects of WiFi Exposure on Sleep

Introduction: Since several years Wireless Local Networks (WLAN, WiFi) are widely spread and operated in households. Many people feel that the presence of radiofrequency technologies impairs their health. Sleep problems are among the most often complained complaints. The present study aims to contribute to answer the question, whether biological effects of a WiFi exposure can be assessed by objective measures. The results of this study will expand the database on possible acute effects of WiFi exposure and thus qualitatively contribute to the discussion whether sleep is affected by exposure from radiofrequency electromagnetic fields.

Methods: A double-blind, sham-controlled experiment in the sleep laboratory with exposure conditions delivered in a balanced randomized cross-over design. Subjective sleep quality of volunteers is assessed by questionnaires. Macro- and microstructure of sleep are measured by polysomnography. Furthermore, a possible impact on sleep related memory consolidation is tested. To do so declarative, procedural and emotional memory tasks are used. Exposure is delivered by a specially developed system, which simulates field strengths and signals occurring in a subject sleeping in the close proximity of a WiFi-access point. This exposure system is necessary to allow for a double-blind implementation and monitoring as well as for the realization of defined exposure parameters.

Inclusion criteria

• Only right-handed
• non-smokers
• Pittsburgh Sleep Quality Index (PSQI) score < 5
• no extreme morning/evening preference [Morningness-Eveningness Questionnaire (MEQ) score ≥ 31 or ≤ 69
• no indication of depression or somatic symptoms as assessed by a medical examination and validated questionnaires [Patient Health Questionnaires (PHQ-9 and PHQ-15) scores ≤ 5 and ≤ 10, respectively

Exclusion criteria

• history of a psychiatric disorder,
• history of a neurological and/or sleep disorder
• excessive daytime sleepiness [Epworth Sleepiness Scale (ESS) score > 9;
• non-regular sleep-wake schedule as assessed by a sleep diary
• a regular intake of medication that affects the central nervous system, excessive caffeine and/or alcohol consumption, regular and occasional drug use,
• metal implants
• periodic leg movement arousal index > 10/h in the Adaptation night
• apnoea-hypopnoea-index > 5/h in the Adaptation night.