Shinobu Adachi

Early event-related brain potentials that reflect interest for content information in the media.

This study investigated the relationship between event-related brain potentials (ERPs) to abridged content information in the media and the subsequent decisions to view the full content. Student volunteers participated in a task that simulated information selection on the basis of the content information. Screenshots of television clips and headlines of news articles on the Web were used as content information for the image condition and the headline condition, respectively. Following presentation of a stimulus containing content information, participants decided whether or not they would view the full content by pressing a select or a reject button. When the select button was pressed, participants were presented with a television clip or a news article. When the reject button was pressed, participants continued on to the next trial, without viewing further. In comparison with rejected stimuli, selected stimuli elicited a larger negative component, with a peak latency of ∼250 ms. The increase in the negative component was independent of the type of visual stimulus. These results suggest that interest toward content information is reflected in early-stage event-related brain potential responses.

A Proposed Speech Discrimination Assessment Methodology Based on Event-Related Potentials to Visual Stimuli

Objective and quantitative assessment methods are needed for the fitting of hearing aid parameters. This paper proposes a novel speech discrimination assessment method using electroencephalograms EEGs. The method utilizes event-related potentials ERPs to visual stimuli instead of the conventionally used auditory stimuli. A spoken letter is played through a speaker as an initial auditory stimulus. The same letter can then be visually displayed on a screen as a match condition, or a different letter is displayed mismatch condition. The participant determines whether the two stimuli represent the same letter or not. The P3 component or late positive potential LPP component are elicited when a participant detects either a match or mismatch between the auditory and visual stimuli, respectively. The hearing ability of each participant can be estimated objectively via analysis of these ERP components.

Controlling interfered area in interferential current stimulation by electrode-area patterning

Interferential current therapy is a noninvasive therapy using simultaneously two or more medium-frequency currents passing through tissue. By controlling the interfered area of the current flows, selective stimulation is possible in target muscles, including deep muscles. However, controlling the interfered area or the intensity of the current precisely is still lacking. Using simulations based on a biological model of the thigh as well as electrical muscle stimulation (EMS) experiments, we investigated the influence of electrode area ratio in changing the interfered area of the currents. Simulation and experiments were conducted under the same conditions, whereby current signals were applied through electrodes placed on the quadriceps and hamstring with an electrode area ratio of either 1:1 or 3:1. A comparison of the simulation results showed that the interferential current density decreased near the larger area electrode but increased near the smaller area electrode. In addition, the EMS experiment also showed that the quadriceps were stimulated using electrodes in a 1:1 area ratio, and the hamstrings were stimulated using electrodes in a 3:1 area ratio. These results demonstrated the possibility of controlling the area application of interferential current through electrode area patterning.

Assessment of Speech Discrimination Based on the Event-Related Potentials to the Visual Stimuli

Monitoring user states is one of the main applications in the e-Health field. This paper focuses on the assessment of speech discrimination for fitting the parameters of hearing aids using the electroencephalogram (EEG). The characteristic of our method is to utilize the event-related potentials (ERPs) to visual stimuli instead of the conventional auditory stimuli. A letter is played through a speaker as an initial auditory stimulus; then, the same letter is displayed on a screen as a following visual stimulus as a match condition (p = .50), and sometimes a different letter is displayed as a mismatch condition (p = .50). The participant then determines whether the two stimuli represent the same letter or not. The conventional evaluation focused on the evoked potentials just after the initial auditory stimuli. A larger component of late positive potential (LPP) is elicited when a participant detects the mismatch between the auditory and visual stimuli. These results suggest the possibility of assessing speech discrimination using EEG potentials.