Two improvements to the twisted pair of wires of the sensor, which was composed of two wires of 0.4mm diameter was made. The authors first replaced the sensor wires with thinner and flexible enameled wires. The twisted pair of wires was cut at about 1 cm from the sensor, and the enameled wires were then soldered to the original wire. The joint was coated with a silicone tube for insulation. One 6DOF reference sensor was attached to the nasion, assuming that its relative position on the head was invariant during the experiment, and seven 5DOF sensors were adhered to positions on the midsagittal plane. To adhere the 5DOF sensors to the tongue and the incisors medical superglue was used. The speakers uttered the beginning of a Japanese folk story ?Momotaro' with the original and improved sensors, and the measurements were conducted every 10 min immediately after sensor attachment. The connectors added to the sensor wires enabled the experimenters to easily connect the sensors to the sensor control unit (SCU). As a result, the improved sensors can shorten the setup time and lengthen the data collection time.