Within this study, the Lifestyle product Qi-Shield manufactured by Waveguard GmbH shall be investigated regarding its subjective psychological and neurophysiological effects. Thereby, the constructs well-being, stress feeling in the everyday life and subjectively perceived sleep quality as well as (neuro)-physiological correlates are of particular interest. The physical effects of the product will not be scope of this study. According to the World Health Organization (WHO), the number and variety of sources of electromagnetic fields (EMF) has increased over the last decades. These sources include video display units (VDUs) associated with computers, cell phones and their base stations, which does not exclude possible health risks from EMF emissions. In this context, several studies report a variety of health problems associated with exposure to EMFs. The sensitivity to EMF is called electromagnetic hypersensitivity. EHS is characterized by a variety of non-specific effects that people attribute to exposure to EMFs. Among the most frequently reported effects are dermatological symptoms and neurasthenic and vegetative symptoms. Some laboratory studies explored the relationship between EMF (short-term exposure) and EHS and observed highly inter-subjectively varying effects. However, EHS has no clear diagnostic criteria and there is no scientific basis to link EHS effects to EMF exposure, at least not to short-term EMF exposure. However, the limited quantity and quality of research on possible effects of EMF does not allow excluding long-term effects.

The Qi-Shield device aims to reduce effects of EMF exposure and enable to maintain subjective well-being, low stress perception and good sleep quality.

Previous literature reported neuronal correlates characterized with (acute) stress exposure and effects on well-being (especially emotional regulation) at the physiological (autonomic nervous system) and neurophysiological level (central nervous system). These measurements can also be observed during the resting state. On a physiological level, heart rate variability (HRV) -recorded by the electrocardiography (ECG) - can be derived as a constant measure of the influence of stress. The most frequently reported parameter under acute stress was low parasympathetic activity, characterized by a decrease in the high frequency band (0.15-0.4 Hz, HF) and an increase in the low frequency band (0.04-0.15 Hz, LF). Furthermore, the measurement of sweat production of the skin - recorded by the derivation of the electrodermal skin activity (EDA) - is suitable to characterize specific influences on the autonomic nervous system. For this purpose, the EDA signal can be segmented into phasic reactions (individual rapid reactions - usually responses to a given stimulus) and tonic components (longer lasting basic skin resistance value). From these two components, the number of individual phasic responses, the summed amplitude of the phasic responses, and the change in the tonic state of the electrical conductivity are the most suitable feature to investigate effects of stress on the physiological level. On a neurophysiological level, acute stress leads to effects in the resting state networks of the brain. A recently published study showed that acute stress weakens the connectivity of the front-parietal module and strengthens the connectivity of the module in the default mode network. Thus, it can be assumed that stress influences the information flow in networks that are important for salience processing (especially attention control) and self-referential mental processing or even emotional processing. Possible quantitative markers from EEG resting state measurements are the derivation of the frequency spectrum (derived by calculating the Fourier transform) as well as connectivity measures (calculating coherence measures from the EEG frequency spectrum). In particular, the ratio of frontal theta (4-7 Hz) to beta (13-30 Hz) activity can be derived from the resting EEG as an indicator of possible influences on cognitive control abilities (attention-control). Possible influences on one's own well-being, such as the ability to control one's emotions (impulse control), can be observed in changes in frontal alpha (8-14 Hz) activity both in frequency spectrum and coherence and in the determination of so-called frontal alpha asymmetry. Since there could be possible effects of Qi-shield may result in a reduction of EMF, power and coherence measures in individual alpha and beta band resting activity already observed in connection with EMF exposure may serve as a basis for this study. Regarding subjective influences on effects of the here studied device, various studies reported correlations between personality characteristics (i.e, critical thinking), fluid intelligence and the tendency towards and openness for paranormal beliefs. Matrix intelligence tests such as the Vienna Matrix Test 2 (WMT-2) detect inferential thinking and correlate strongly positively with manifestations in critical thinking. Both constructs show a negative correlation between manifestations of paranormal beliefs and statements about paranormal experiences. An influence of personality factors such as openness to new experiences can also be assumed. To control possible moderating or mediating factors, these constructs will be investigate, too.

The study design is a double-blind Pre-Post Between-Subject Design. This means that the subjects are invited twice (pre-session and post-session). Between the two sessions, there is one week of exposure time during which the subjects of the invention groups take the device home.

At the beginning of the experiment in the pre-session, all subjects (N=90) are checked for the presence of inclusion and exclusion criteria and if necessary excluded from the study. The subjects are assigned to the trial groups in a semi-randomized latin-square counterbalanced manner. The assignment is double-blind, i.e. neither the volunteer nor the investigator is informed which group receives a placebo or real intervention. The real devices resemble the sham devices in appearance, composition and weight, so that a traceability based on these factors is not possible. The products are marked with the letters A and B. The assignment which letter belongs to which intervention group is explained in a sealed envelope and will be opened after completion of the study and analysis. Prior to the start of the study, participants are informed about their rights and potential risk of participation with an authorized deception in case of the assumed effects of the intervention and asked to sign the declaration of consent in line with the declaration of Helsinki. The information for the intervention groups differs from the information for the no-intervention group, as the latter serves as a control group and therefore does not receive any information about the intervention.

Afterwards the test person is asked to answer a control item for the examined product (only for group A - correct product and B - sham product) and then fill in questionnaires about sleep quality and current fatigue (in detail below). Subsequently, the sensors for EEG, ECG and EDA are prepared and fixed to the head and body accordance with the corresponding guidelines. After this preparation, the resting state measurements of electrophysiological signals (EEG, ECG and EDA) are recorded during relaxation. In order to identify possible effects in the alpha band, resting measurements are taken with eyes closed (so-called eyes closed EC) as well as with eyes open (so-called eyes open, EO) according to a standardized procedure. This consists of an alternating task (20 minutes in total) in which the subjects are asked to alternately "relax with eyes open" and "relax with eyes closed" for 60 seconds each. In the phase with open eyes, the test persons are asked to fixate a crosshair on a screen. The change between the phases is signalled by an acoustic tone.

Afterwards, the measurement equipment is removed from the head and body and the test person is asked to answer several questionnaires and scales (in detail below).

At the end of the session, test persons from groups A and B receive the information on handling the device and the device with the respective label (A or B). During the seven days exposure period, subjects are asked daily to answer questions about their current condition and special events via an online survey. The subjects in groups A and B are also asked to answer two questions related to the handling of the product. During the exposure period, subjects are supervised via WhatsApp or E-mail from employees of the University of Stuttgart and Fraunhofer IAO. A short standardized text will be used as a reminder to fill in the questionnaires if participants have not been completed by a certain time (6 pm). The second session is similar to the first session in terms of the way the study is conducted. At the beginning of the session, the subjects are again given detailed written information about the study and asked to sign the declaration of consent for the second session. Afterwards the participants are asked to fill in the daily questions about well-being, everyday stress and special events as well as the questionnaires about sleep quality and current fatigue. Afterwards, we will conduct the neurophysiological measurement during the resting state as in the pre-session. Afterwards, the measurement sensors are removed from the head and body and the participant is asked to answer the questionnaires and scales. At the end of the post-session the test persons will be informed in detailed and the deception will be dissolved. The experimenter will answers further questions.