## 2 Methods
### Dose Calculations  
We aimed to calculate personal cumulative RF-EMF doses in the brain and the whole-body combining exposure from different sources emitting RF-EMF. The processes of learning and memory are located in the hippocampus, while processes for behaviour and cognitive functions in the prefrontal cortex. The hippocampus and the prefrontal cortex consist mainly of gray matter. Therefore, specific absorption rates (SARs) for _brain gray matter_ were used for the brain exposure. Additionally, the same calculations were performed for _brain white matter_ and compared with the brain exposure obtained for brain gray matter since the white matter is important for these processes as well. The personal dose in terms of the time-averaged specific absorption rate (SAR) can be calculated as follows:  
\[\text{dose}=\sum_{\text{i}}\text{dose}_{\text{i}}=\sum_{\text{i}}\text{SAR}_{ \text{i}}*\text{time}_{\text{i}} \tag{1}\] \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Frequency Band**} & \multicolumn{2}{c}{**Frequency Range (MHz)**} & \multicolumn{2}{c}{**Quantitation Limit (V/m)**} & \multicolumn{2}{c}{**Reporting Limit (V/m)**} \\ \cline{2-5}  & **Expom 1 and Expom 3** & **Expom 1** & **Expom 3** & **Expom 1 and Expom 3** \\ \hline TV & 470–790 & 0.010 & 0.005 & 0.0025 \\ Uplink 900 * & 880–915 & 0.015 & 0.005 & 0.0025 \\ Downlink 900 * & 925–960 & 0.015 & 0.005 & 0.0025 \\ Uplink 1800 * & 1710–1785 & 0.015 & 0.005 & 0.0025 \\ Downlink 1800 * & 1805–1880 & 0.005 & 0.005 & 0.0025 \\ DECT & 1880–1900 & 0.005 & 0.005 & 0.0025 \\ Uplink 1900 * & 1920–1980 & 0.003 & 0.003 & 0.0015 \\ Downlink 2100 * & 2110–2170 & 0.010 & 0.003 & 0.0015 \\ WLAN & 2400–2485 & 0.005 & 0.005 & 0.0025 \\ \hline \hline \end{tabular}  
* The uplink and downlink bands include all technologies using the particular frequency range. Downlink means the transmission from mobile phone base stations to mobile phone handsets and uplink the transmission from mobile phone handsets to mobile phone base stations.  
\end{table} 
Table 1: Frequency range, quantitation limits and reporting limits for the frequency bands of the measurement devices Expom 1 and Expom 3 used for the personal measurements. calls with headset. For the whole-body exposure we used the same SAR for calls with and without headset referring to a similar distance to the body when having the mobile phone close to the ear or in front of the body while using a headset. For DECT phone calls [PERSON] _et al._ derived an average output power from the general transmission power of a DECT phone [18], resulting in a brain SAR of 0.373 mW/kg and a whole-body SAR of 0.051 mW/kg. The SEAWIND report showed a decrease in the SAR by a factor of 10 for calls with an eco mode DECT phone compared to a DECT phone without eco mode [20], therefore we used a brain SAR of 0.0373 mW/kg and a whole-body SAR of 0.0051 mW/kg for calls with a DECT phone provided with eco mode. For the output power of mobile phones during data transmission we took the following available knowledge into account: [PERSON] _et al._ measured on average an increased output power for data connections compared to voice connections in the UMTS network in the range of a factor of 3.25 to 6.8, depending on rural or urban environment and the bit rates used for the data transmission [24]. In the framework of the LEXNET project an output power increased by about a factor of 4 for data traffic service compared to voice service in the 3G network of Orange in France was found [23]. [PERSON] _et al._ found a mean output power increased by about 6 dB on average for data traffic mode compared to voice mode [21]. Therefore, we used a by a factor of 4 increased output power of the mobile phone for data traffic compared to calls on the UMTS network.