Proposal for simple temporal modu-lation transfer function (TMTF)measurement method for use in clinical settingsRion has undertaken R&D on hearing aids for decades. e development team examines issues associated with the hearing of various people on a daily basis and pursues research on hearing aids to address di erent kinds of hearing impair-ment. In Japan, currently, those aged 65 or older account for over 27% of the population, making the country the rst in the world to have a super-aging society, thus the number of hearing-impaired people due to aging is expected to grow. Ways to address hearing impairments and the use of hearing aids by the elderly are important issues for realizing a society of good health and longevity. Hearing impairments have also been reported as a risk factor in dementia, underscoring the importance of prevention, early diagnosis, and early treatment of the impairment.When people notice something wrong with their hearing, they rst Background of New Hearing Test TechnologyModelling TMTFIt has been reported that the modulation detection threshold remains nearly constant in the low modulation frequency range but increases with increasing modulation frequency past a certain modulation frequency. This has prompted suggestions that the temporal modulation transfer function (TMTF) can be approximated by the waveform of low pass filters.Thus, it is believed that the TMTF can be expressed by the two parameters for low pass filters, peak sensitivity (Lps) and cutoff frequency (fcutoff), for modulation at low modulation frequencies.visit an ENT doctor, who performs various tests to determine the degree of hearing impairment. e term hearing impairment is commonly considered to mean the condition of not being able to hear well—in other words, a condition in which quiet sounds are inaudible (a state of increased minimum auditory thresh-old). People typically raise their voices when talking to the hearing-impaired person. Or the person will use a hearing aid that ampli es the sound. But in addition to the increase in the minimum auditory threshold, hearing impairment is known to involve positive recruitment, deterioration in frequency selectivity, and reduction in temporal resolution. It’s been suggested that the combined e ect of the above factors means that a person with a hearing impairment encounters di culty in hearing spoken words compared to those with normal hearing, especially in noisy environments. To compensate for the hearing impairment, we have to separately address the deterioration in each of these functions.Against this background, Takashi [Frequency selectivity]This refers to the auditory ability to analyze sound within a frequency range. One approach to compensate for impaired frequency selectivity involves enhancing the spectral contrast of sounds.[Recruitment]Recruitment refers to a phenomenon whereby a person with a hearing impairment will perceive that sounds grow louder with increasing sound pressure than someone with normal hearing. In other words, changes in loudness are exaggerated. One compensation technology is to enhance the amplification of sounds with low input sound pressure while suppressing the amplification of sounds with high input sound pressure.Grasping the Degree of Reduction in Temporal ResolutionExploring the Possibilities ofTemporal Modulation Transfer Function(TMTF)MeasurementHere we interview Takashi Morimoto from the Technical Development Center, who proposed a simple method for measuring the temporal modulation transfer function (TMTF) that can be performed quickly in clinical settings in otorhinolaryngology departments.Interview and article by Kana YokotaIN THE BACKYARDOn the Front Lines of Technology Takashi MorimotoJoined Rion in 2009. Group 2, Component Technology Development Department, Tech-ni cal Development Center. He is involved with R&D on test methods incorporated in-to medical testing devices and hearing aids used at otorhinolaryngology departments. Since his time as a student, his ambition has been to “do something to help people in need with hearing disabilities.” He contin-ues to devote his time to research to ful ll this ambition.12

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