Evaluation for mattress comfort by using MEG

It is important to develop the comfort and pressure release properties of a mattress for elderly people and bed-ridden patients. In particular, the mattress provides a large influence for the feeling of staying in bed. We developed two new types of mattress and evaluated their comfort. Four kind of mattress were chosen, including the developed mattress, and subjects lay on the mattress for 10 min. A magnetoencephalogram (MEG) and pressure distribution of the mattress were measured. After the experiment, the feeling of the bed was asked by questionnaire. It is popular to use an electroencephalogram (EEG) to evaluate the relaxation. Thus MEG data were compared with EEG data. As results for MEG data, it was confirmed that the power spectrum of a wave was more dominant than that of β wave in all trials. However, there was a similar tendency appearance ratio of a wave and β wave in different mattresses. On the other hand, the questionnaire of subject corresponded to the pressure value of pressure distribution. These results suggested that the appearance of a wave could not distinguish enough to compare with mattress materials.