Toshizo Koizumi

Functional lateralization of speech processing in adults and children who stutter.

Developmental stuttering is a speech disorder in fluency characterized by repetitions, prolongations, and silent blocks, especially in the initial parts of utterances. Although their symptoms are motor related, people who stutter show abnormal patterns of cerebral hemispheric dominance in both anterior and posterior language areas. It is unknown whether the abnormal functional lateralization in the posterior language area starts during childhood or emerges as a consequence of many years of stuttering. In order to address this issue, we measured the lateralization of hemodynamic responses in the auditory cortex during auditory speech processing in adults and children who stutter, including preschoolers, with near-infrared spectroscopy. We used the analysis–resynthesis technique to prepare two types of stimuli: (i) a phonemic contrast embedded in Japanese spoken words (/itta/ vs. /itte/) and (ii) a prosodic contrast (/itta/ vs. /itta?/). In the baseline blocks, only /itta/ tokens were presented. In phonemic contrast blocks, /itta/ and /itte/ tokens were presented pseudo-randomly, and /itta/ and /itta?/ tokens in prosodic contrast blocks. In adults and children who do not stutter, there was a clear left-hemispheric advantage for the phonemic contrast compared to the prosodic contrast. Adults and children who stutter, however, showed no significant difference between the two stimulus conditions. A subject-by-subject analysis revealed that not a single subject who stutters showed a left advantage in the phonemic contrast over the prosodic contrast condition. These results indicate that the functional lateralization for auditory speech processing is in disarray among those who stutter, even at preschool age. These results shed light on the neural pathophysiology of developmental stuttering.

Differential cortical responses in second language learners to different vowel contrasts

Near-infrared spectroscopy was used to measure hemodynamic responses in Korean subjects learning Japanese as a second-language to Japanese phonemic contrasts that are either phonologically distinctive or non-distinctive in their first-language. These results were compared with those of Japanese native listeners reported previously. Unlike the results observed in the Japanese subjects, the Korean subjects did not show category-specific neural responses to a durational contrast that is non-distinctive in their first-language. The /a-e/ contrast elicited the larger response in the left auditory area, consistent with the results of the Japanese. These phoneme-dependent responses imply that the neuronal networks subserving the first and second-languages are either shared or exclusive according to the mutual relationship between the phonemic properties of the first and second-languages.

Comparison between bone-conducted ultrasound and audible sound in speech recognition

Conclusion: This study showed that it is possible to transmit language information using bone-conducted ultrasound (BCU) in normal-hearing subjects. Our results suggest the possibility of a difference in speech recognition between BCU and air-conducted audible sound (ACAS). Objective: Ultrasound was audible when delivered by bone conduction. Some profoundly deaf subjects as well as normal-hearing subjects can discriminate BCU whose amplitude is modulated by different speech sounds. These findings suggest the usefulness of developing a bone-conducted ultrasonic hearing aid (BCUHA). However, the characteristics of BCU are still poorly understood. The aim of the present study was to compare BCU and ACAS in terms of their associated speech perception tendency and to investigate the different perceptual characteristics of BCU and ACAS. Subjects and methods: Speech discrimination tests using both BCU and ACAS were performed with normal-hearing subjects. BCU and ACAS were compared for intelligibility and hearing confusion. Results: With BCU, the maximum percentage correct totaled about 75%. Our comparison of the hearing confusion with ACAS and BCU according to the individual syllabic nuclear group showed a clear difference in the incorrect rates. In addition, the stimulus nuclear groups were often perceived in other nuclear groups in BCU.

Estimation of factors influencing the results of tinnitus retraining therapy

Conclusion: The factors of tinnitus loudness and Tinnitus Handicap Inventory (THI) score in tinnitus patients have the potential to relate to therapeutic results of tinnitus retraining therapy (TRT). Objectives: To confirm what factors in tinnitus influence the results of TRT. Patients and methods: Twelve factors were investigated in 53 patients with tinnitus, examining the relationship between these factors and the results of TRT. A THI score was determined before and 6 months after TRT introduction (pre- and post-TRT). Moreover, the change of THI score from pre- to post-TRT (ΔTHI) was referred to as the therapeutic effect of TRT. Based on the 12 factors, subjects were respectively divided into two groups, comparing Δ THI between groups. Results: Two groups of greater tinnitus loudness and higher THI score showed significant increases in ΔTHI, indicating that two factors of tinnitus loudness and THI score were related to the therapeutic effect of TRT.

A Method of Transoral Finger Dissection for a Giant Epiglottic Lipoma

Background. Subcutaneous lipomas that occur in the trunk and proximal extremities are commonly dissected by low-invasive method. However, a standard surgical method for lipomas of the epiglottis has been absent. Microscopic laryngeal surgery is appropriate to extirpate small epiglottic lipomas. However, microscopic laryngeal surgery may be insufficient for giant epiglottic lipomas because there is restricted visualization of the operating field of the tumor under the microscope. Furthermore, microscopic surgical instruments are very small to manipulate giant lipomas, and it would be excessive to approach these lipomas via external cervical incisions. Case Presentation. A 57-year-old female presented with a giant lipoma on the lingual surface of the epiglottis. Following a tracheotomy, microscopic surgery was inadequate to manipulate the epiglottic lipoma. Instead, we performed macroscopic surgery in which the epiglottic lipoma was pulled into the oral cavity with forceps and then separated from the surrounding tissues using the surgeons finger to dissect the tumor en bloc. Conclusion. The low-invasive method of transoral finger dissection enabled the giant lipoma to be extirpated without leaving any remnants or causing excessive epiglottic damage.

Cervical Lymphadenopathy Showing Pathological Findings of Histiocytic Necrotizing Lymphadenitis (HNL) in a Patient with Systemic Lupus Erythematosus (SLE)

We report 26-year-old female whose cervical lymph node became swollen, accompanied by aggravation of systemic lupus erythematosus (SLE) symptoms. Histologically, the lymph node showed necrosis with a geographic pattern, and increments in the macrophages and histiocytes preying upon the apoptotic lymphocytes. The clinical and pathological findings were consistent with histiocytic necrotizing lymphadenitis (HNL). Recently, however, it has been considered that histological finding of HNL in an SLE patient indicates that the lymphadenitis is related to SLE (lupus lymphadenitis). Thus, the present case was diagnosed as lupus lymphadenitis. Steroid administration to improve the SLE symptoms was also effective for lymphadenitis. The present case indicates that cervical lymphadenitis associated with an autoimmune disease, such as SLE, is occasionally difficult to differentiate from HNL, and suggests that treatment of the primary disease is important to improve disease-associated lymphadenitis.

Effects of prosody on phoneme recognition in cochlear implant patients

KOICHI MORI, AKIHIRO TANAKA, National Rehabilitation Center for Persons with Disabilities, Tokorozawa-city, 359-8555, Japan TOSHIZO KOIZUMI, National Rehabilitation Center for Persons with Disabilities, Tokorozawa-city, 359-8555, Japan, and Department of Otorhinolaryngology, Nara Medical University, Kashihara-city, 634-8522, Japan HIKARU TAUCHI, National Rehabilitation Center for Persons with Disabilities, Tokorozawa-city, 359-8555, Japan