This study determined whether there is an increased risk of tinnitus in patients with temporomandibular joint (TMJ). We used information from health insurance claims obtained from Taiwan National Health Insurance (TNHI). Patients aged 20 years and older who were newly diagnosed with TMJ disorder served as the study cohort. The demographic factors and comorbidities that may be associated with tinnitus were also identified, including age, sex, and comorbidities of hearing loss, noise effects on the inner ear, and degenerative and vascular ear disorders. A higher proportion of TMJ disorder patients suffered from hearing loss (5.30 vs. 2.11 %), and degenerative and vascular ear disorders (0.20 vs. 0.08 %) compared with the control patients. The crude hazard ratio (HR) of tinnitus in the TMJ disorder cohort was 2.73-fold higher than that in the control patients, with an adjusted HR of 2.62 (95 % CI = 2.29-3.00). The comorbidity-specific TMJ disorder cohort to the control patients' adjusted HR of tinnitus was higher for patients without comorbidity (adjusted HR = 2.75, 95 % CI = 2.39-3.17). We also observed a 3.22-fold significantly higher relative risk of developing tinnitus within the 3-year follow-up period (95 % CI = 2.67-3.89). Patients with TMJ disorder might be at increased risk of tinnitus.

This study investigated the development of subcortical pitch processing, as reflected by the scalp-recorded frequency-following response, during early infancy. Thirteen Chinese infants who were born and raised in Mandarin-speaking households were recruited to partake in this study. Through a prospective-longitudinal study design, infants were tested twice: at 1-3 days after birth and at three months of age. A set of four contrastive Mandarin pitch contours were used to elicit frequency-following responses. Frequency Error and Pitch Strength were derived to represent the accuracy and magnitude of the elicited responses. Paired-samples t tests were conducted and demonstrated a significant decrease in Frequency Error and a significant increase in Pitch Strength at three months of age compared to 1-3 days after birth. Results indicated the developmental trajectory of subcortical pitch processing during the first three months of life.

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Voice pitch carries important information for speech understanding. This study examines the neural representation of voice pitch at the subcortical level, as reflected by the scalp-recorded frequency-following responses from ten American and ten Chinese newborns. By utilizing a set of four distinctive Mandarin pitch contours that mimic the English vowel /yi/, the results indicate that the rising and dipping pitch contours produce significantly better tracking accuracy and larger response amplitudes than the falling pitch contour. This finding suggests a hierarchy of potential stimuli when testing neonates who are born in a tonal or non-tonal linguistic environment.