Audiology Clinical Practice Patterns in Acoustic Reflex Testing.

PURPOSE: Periodic reports of audiology clinical practice patterns, including acoustic reflex threshold (ART) protocols, provide insights into trends and assist in clinical decision making. Therefore, the purpose of this study was to examine audiologists' ART protocols, factors influencing audiologists' decision to test, and considerations for mentoring Doctor of Audiology (AuD) students in ART testing. METHOD: This study used a paper survey distributed by mail to a random sample of audiologists. Participants were 102 audiologists, representing diversity across age, clinical experience, and work setting. The survey asked participants to provide (a) demographics, (b) ART protocols, (c) rationale for ART testing, and (d) perspectives on mentoring of ART testing. RESULTS: When ART testing is conducted, 100% of respondents conduct ipsilateral ART testing, compared to 75% for contralateral testing. Most use 500-, 1000-, and 2000-Hz stimulus frequencies, and 56% report 4000 Hz. Patient-related factors are the primary reason participants cite for conducting, or not conducting, ART tests. Most supervisor-participants encourage AuD students to conduct ART tests, based on patient-centered and student learning-centered reasons, and use a variety of strategies to guide students when ART findings are unusual. CONCLUSIONS: Fewer than half (43%) of participants conduct ART testing for all new patients, suggesting it is ancillary to the standard test battery for most participants. When ART testing is conducted, ipsilateral testing only or a combination of ipsilateral and contralateral testing is used. Ongoing trends in ART testing include continued popularity of 500-2000 Hz and ipsilateral-only or ipsilateral plus contralateral testing. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.21513987.

Central serotonergic neurons activate and recruit thermogenic brown and beige fat and regulate glucose and lipid homeostasis.

Thermogenic brown and beige adipocytes convert chemical energy to heat by metabolizing glucose and lipids. Serotonin (5-HT) neurons in the CNS are essential for thermoregulation and accordingly may control metabolic activity of thermogenic fat. To test this, we generated mice in which the human diphtheria toxin receptor (DTR) was selectively expressed in central 5-HT neurons. Treatment with diphtheria toxin (DT) eliminated 5-HT neurons and caused loss of thermoregulation, brown adipose tissue (BAT) steatosis, and a >50% decrease in uncoupling protein 1 (Ucp1) expression in BAT and inguinal white adipose tissue (WAT). In parallel, blood glucose increased 3.5-fold, free fatty acids 13.4-fold, and triglycerides 6.5-fold. Similar BAT and beige fat defects occurred in Lmx1b(f/f)ePet1(Cre) mice in which 5-HT neurons fail to develop in utero. We conclude 5-HT neurons play a major role in regulating glucose and lipid homeostasis, in part through recruitment and metabolic activation of brown and beige adipocytes.