Sotaro Sekimoto

The early component of the visual evoked magnetic field.

Several EEG studies have reported an early component of the visual evoked potential. However, it is controversial whether this component is cortical or subcortical. Our study has aimed to clarify this problem using MEG and EEG in nine normal volunteers. A total of 4000 stimuli were presented to the monocular visual hemifield through a light-proof stimulating goggle and the visual evoked magnetic field and visual evoked potential was measured above the occipital lobe. The early component was observed in three of the nine subjects. The latency ranged from 40 to 45 ms in MEG and from 39 to 47 ms in EEG. The result of dipole localization analysis showed that its origin was cortical, and specifically, the striate cortex.

Commercially available high-speed system for recording and monitoring vocal fold vibrations

We have developed a special purpose adaptor making it possible to use a commercially available high-speed camera to observe vocal fold vibrations during phonation. The camera can capture dynamic digital images at speeds of 600 or 1200 frames per second. The adaptor is equipped with a universal-type attachment and can be used with most endoscopes sold by various manufacturers. Satisfactory images can be obtained with a rigid laryngoscope even with the standard light source. The total weight of the adaptor and camera (including battery) is only 1010 g. The new system comprising the high-speed camera and the new adaptor can be purchased for about

An fMRI study of whispering: The role of human evolution in psychological dysphonia ☆

3000 (US), while the least expensive stroboscope costs about 10 times that price, and a high-performance high-speed imaging system may cost 100 times as much. Therefore the system is both cost-effective and useful in the outpatient clinic or casualty setting, on house calls, and for the purpose of student or patient education.

Perception of Time-Varying Resonance Frequencies in Speech and Non-Speech Stimuli

Humans are the only species known to use whispering for communication, and humans are also the only species known to suffer from functional (psychological) aphonia, a condition in which only whispered and not vocalized speech can be produced. Thus, whispering is uniquely a human function and psychological aphonia is uniquely a human dysfunction; both can be considered to result from human evolution. We hypothesize that the human brain has developed one or more identifiable switching mechanisms that overlay whispering onto the mechanisms of normal speech production. Thus, for whispering the speech production system operates as for normal speech production, but the switch to whispering activates the laryngeal abductor muscle (and possibly the inferior pharyngeal constrictor) so that the larynx does not completely adduct and turbulence noise is produced at the larynx. We hypothesize that psychological aphonia results from involuntary or subconscious activation of this switching mechanism. Preliminary research leads us to hypothesize that there are two switching mechanisms. This research used functional magnetic-resonance imaging to contrast brain activity for both normal speech and whispering (versus silence) for normally phonic subjects in an imagined social situation. One pattern of results involved a decrease of overall activity for whispering, with possible activation of the corpus callosum, and possible crossover of the main locus of activation from the dominant to the nondominant side. The other involved increased overall activity for whispering versus normal voice, accompanied by an increase of activity in the frontal cortex. More participants exhibited the former pattern than the latter one. These results may be related to the fact that there are actually two types of psychological aphonia, one that occurs after bouts of severe coughing associated with lower-respiratory disorders and the other due to purely psychological factors. We hypothesize that these are associated with the two different switching mechanisms, an upper one associated with the conscious brain and a lower one associated with more basic functions such as protecting the vocal folds. Understanding brain mechanisms for voluntary whispering and relating them to the occurrence of dysphonia has obvious implications for improving clinical assessment and treatment of aphonia, and would also contribute to improved understanding of human function in general.

Novel diagnostic device for oral and pharyngeal examinations of children: folding-scope for the oral and pharyngeal cavities.

Time-varying formant frequencies constitute essential cues for the perception of phoneme sequences in connected speech. This paper investigates the conditions under which such formant transitions elicit perception of two contiguous phonemic segments in a syllablelike unit. Based on the analysis of formant transitions in natural speech, synthetic speech stimuli were generated with various values of magnitude, rate, and duration of formant transitions. Discrimination tests of dynamic and static stimuli indicated the existence of perceptual extrapolation of targets that underlie formant transitions. Results of discrimination tests on non-speech stimuli with similar formant transitions suggested that the extrapolation was to a large extent auditory, and thus was not specific to perception of speech stimuli. On the other hand, identification tests of dynamic and static speech stimuli clearly indicated the short-term context effect in perception of connected segments, which was quantified as the amount of temporary shift in the threshold for phonemic judgment due to perception of the immediately preceding segment. Vowels, semivowels and stop consonants were compared with respect to the magnitude of the context effect which they exert on the perception of the following segment.

Vocal Hygiene Education Program Reduces Surgical Interventions for Benign Vocal Fold Lesions: A Randomized Controlled Trial: Effect of Reinforced Vocal Hygiene Education

Although children may dislike and/or resist oral and pharyngeal examination with a tongue depressor, they enjoy lollipops on sticks, eating with spoons, forks, and chopsticks, and brushing their teeth. Many reports have noted this apparent contradiction, since paediatric patients are often treated after toothbrushes or chopsticks penetrate the pharyngeal wall. We therefore developed a novel device to observe the inside of the mouth without using a flashlight, tongue depressor or head mirror. We previously developed the AWS for tracheal intubation through the mouth for anaesthesia and emergency situations, along with a new device to observe the inside of the oral cavity simultaneously. We have developed a new attachment to the AWS for observations inside the oral cavity and pharynx. Our newly developed oral and pharyngeal examination system is a useful tool for diagnostic examinations and may also enable treatment without causing discomfort or distress to patients and their families.

Independent exercise for glottal incompetence to improve vocal problems and prevent aspiration pneumonia in the elderly: a randomized controlled trial:

Vocal fold polyps and nodules are common benign laryngeal lesions. Currently, the Japanese health insurance system covers surgical interventions. However, the establishment of more cost‐effective conservative methods is required, because healthcare costs are viewed as a major concern, and the government and taxpayers are demanding more economical, effective treatments. In this situation, more suitable vocal hygiene education may be important for the success of cost‐effective conservative treatment. In this study, we developed a novel reinforced vocal hygiene education program and compared the results of this program with those of previous methods of teaching vocal hygiene.

Near-infrared-spectroscopic study on processing of sounds in the brain; a comparison between native and non-native speakers of Japanese

Objectives: To evaluate the effect of a self-controlled vocal exercise in elderly people with glottal closure insufficiency. Design: Parallel-arm, individual randomized controlled trial. Methods: Patients who visited one of 10 medical centers under the National Hospital Organization group in Japan for the first time, aged 60 years or older, complaining of aspiration or hoarseness, and endoscopically confirmed to have glottal closure insufficiency owing to vocal cord atrophy, were enrolled in this study. They were randomly assigned to an intervention or a control group. The patients of the intervention group were given guidance and a DVD about a self-controlled vocal exercise. The maximum phonation time which is a measure of glottal closure was evaluated, and the number of patients who developed pneumonia during the six months was compared between the two groups. Results: Of the 543 patients enrolled in this trial, 259 were allocated into the intervention group and 284 into the control; 60 of the intervention group and 75 of the control were not able to continue the trial. A total of 199 patients (age 73.9 ±7.25 years) in the intervention group and 209 (73.3 ±6.68 years) in the control completed the six-month trial. Intervention of the self-controlled vocal exercise extended the maximum phonation time significantly (p < 0.001). There were two hospitalizations for pneumonia in the intervention group and 18 in the control group, representing a significant difference (p < 0.001). Conclusion: The self-controlled vocal exercise allowed patients to achieve vocal cord adduction and improve glottal closure insufficiency, which reduced the rate of hospitalization for pneumonia significantly. Clinical Trial.gov Identifier-UMIN000015567

Sound Localization and Lateralization of Patients with Auditory Neuropathy

Abstract Conclusions The result suggested that mother tongue Japanese and non- mother tongue Japanese differ in their pattern of brain dominance when listening to sounds from the natural world—in particular, insect sounds. These results reveal significant support for previous findings from Tsunoda (in 1970). Objectives This study concentrates on listeners who show clear evidence of a ‘speech’ brain vs a ‘music’ brain and determines which side is most active in the processing of insect sounds, using with near-infrared spectroscopy. Methods The present study uses 2-channel Near Infrared Spectroscopy (NIRS) to provide a more direct measure of left- and right-brain activity while participants listen to each of three types of sounds: Japanese speech, Western violin music, or insect sounds. Data were obtained from 33 participants who showed laterality on opposite sides for Japanese speech and Western music. Results Results showed that a majority (80%) of the MJ participants exhibited dominance for insect sounds on the side that was dominant for language, while a majority (62%) of the non-MJ participants exhibited dominance for insect sounds on the side that was dominant for music.

Good News for Patients and Medical Staff: A New System to Assist With Intravenous Procedures

To investigate the spatial abilities of patients with auditory neuropathy (auditory nerve disease, AN), we applied a sound localization task with a speaker array as well as a binaural sound lateralization task. In the sound localization task, subjects were asked to choose the direction of actual sound source of short (duration, 3 ms) or long (duration, 100 ms) noise bursts centered at 500 Hz played from 1 of 12 surrounding (220°) speakers. The AN patients identifi ed the direction of the longduration sound fairly well. However, they could localize few sources of the shortduration sound. The results were compared with non-AN patients and normal persons to discuss the auditory neural processing of cues for transient or prolonged source estimation, that is, interaural intensity and time differences (IID, ITD) and spectral difference by head-related transfer function (HRTF).