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RESEARCH TOPICS Tongue-Controlled Electro-Musical Instrument Human-Computer Interface System using Oral Functions A MIDI (musical instrument digital interface) Controller using a Mat Switch Operable by a User in a Wheelchair Measurements of pressure distribution by the tongue of infants on an artificial nipple (2008 ESEM Award)

Tongue-Controlled Electro-Musical Instrument This study aims to develop a new electronic instrument that even severely handicapped people with quadriplegia can play in order to improve their quality of life (QOL). Ordinary orchestral and percussion instruments require fine movements of the limbs and cannot be used by those with quadriplegia. In this study, we made a prototype of an electronic musical instrument that can be played by tongue movement. This instrument is composed of an operation board inside the mouth and a sound generator. The signals emitted from the operation board are transmitted to the sound generator equipped inside a personal computer. Music is generated through speakers. A plastic plate on which switches are arrayed is fixed to the palate so that musical scales can be regulated by pushing the switch with the tongue. The plastic plate was formed into a three dimensional cross shape to ensure stability of attachment. Furthermore, the sound generator was equipped with a musical sound matrix to generate a wide range of musical notes with only a limited number of switches on the operation board inside the mouth. We played music with this instrument, confirming its usability. T. Niikawa: "Tongue-Controlled Electro-Musical Instrument", The 18th International Congress on Acoustics, Vol.III, pp.1905-1908, (2004.4)
Human-Computer Interface System using Oral Functions We developed two kinds of interfaces having two independent inputs based on mandibular movement for position control, and a ‘press-type’ switch input operated by tongue movements. The main components of the interfaces are an acryl board, a slide-type potentiometer and a ‘press-type’ switch. In type I, a mouth piece is used and fixed to the upper jaw. In type II, the interface is fixed between the upper and lower lips.Using these interfaces, we developed a PC based Japanese language input system. The user follows operating instructions shown on the PC display to use this interface. The display consists of a two dimensional matrix showing the elements of the 50 syllables of the Japanese language and elements of a variety of signs. Operation involves the user looking at character patterns displayed on the PC screen and selecting elements by making a ‘biting’ movement. The final selection of a character element is made by pushing a switch with the tip of the tongue.Four subjects carried out the input experiments over a period of fourteen days. In the result, the time required to input a single syllable was found to be between 3 and 4 seconds. T. Niikawa and R. Kawachi, "Human-Computer Interface System using Oral Functions", International Federation for Medical and Biological Engineering Proceedings, Vol. 11, 1954 (2005.11)
A MIDI (musical instrument digital interface) Controller using a Mat Switch Operable by a User in a Wheelchair In this study, we devised a MIDI controller that a user with severe physical dysfunction was able to operate by depressing a mat switch with an electric wheelchair, and proposed a new method for musical education and therapy employing the system. This system comprises a mat switch resistant to 100N of a movement load in a 500 mm x 700 mm area, an A/D converter, a PC, and a MIDI device. Signal output from the mat switch is converted to MIDI signals by the PC and transmitted to the MIDI device. By pushing down 10 mat switches arranged in a matrix pattern, a user can manipulate all elements necessary to control MIDI signals, such as volume and musical sounds. As a result, it was confirmed that a user in an electric wheelchair was able to control musical notes, volume, tunes, and scales. Furthermore, since it was possible to use it for a hand bell and a musical game mimicking the card game “Concentration”, it may be applicable for musical education. T. Niikawa, R. Kawachi, K. Minato, T. Yoshihara and N. Terayama: "A MIDI (musical instrument digital interface) controller using a mat switch operable by a user in a wheelchair.", J. Acoust. Soc. Am., Vol.120, No.5, Pt.2, 3074 (2006.11) T. Niikawa, K. Yamagishi, E. Onishi, R. Kawachi, K. Minato, T. Yoshihara and N. Terayama:"Music therapy with a large-scale midi controller using a mat switch", The 19th International Congress on Acoustics, MUS-07-020. (2007.9) http://www.acoustics.org/press/152nd/lay_lang.html
Measurements of pressure distribution by the tongue of infants on an artificial nipple Infants can feed themselves immediately after birth by using the primitive human sucking reflex. Infants place their tongues on and around the nipple to apply pressure and extract milk with peristaltic-like movements of the tongue. Measurements of tongue movement are very important to elucidate the maturation of sucking behavior to obtain nourishment. It is necessary to directly measure pressure on the nipple at various sites to describe tongue movement. In this study, an artificial nipple with several small pressure sensors was developed, and the pressure distribution exerted by the tongue on the artificial nipple was measured. The small pressure sensors, 10 mm in length, 3 mm in width, and 4 mm in height, have a cantilever structure and include a strain gauge. Pressure was measured by the strain on the stainless steel cantilever caused by contact of the tongue with a pressure transducer block. The artificial nipple for pressure measurement was in the form of a resin plate with two sensors located longitudinally and covered by an artificial silicon nipple, which allowed measurement of pressures at the tip and root of the nipple. Pressure signals were amplified, converted (A/D) at the sampling rate of 100 Hz and quantization resolution of 12 bits, and were input to a personal computer via a USB connection. This system measured pressure distribution on the artificial nipple by the tongue of an infant of 34 weeks gestation. Results showed that the largest pressures at the tip and root of the nipple were 358 kPa and 266 kPa, respectively, and pulsation at 1.7 Hz was confirmed at the two sites. T. Niikawa, R. Kawachi, K. Minato and Y. Takada: "Measurements of pressure distribution by the tongue of infants on an artificial nipple", International Federation for Medical and Biological Engineering Proceedings, Vol. 22, pp. 1149-1152 (2008.11)