The overall objective of the application is to provide the neural basis for human VEMP testing (vestibular evoked myogenic potentials) by rigorously examining vestibular afferent responses to clinical VEMP stimuli. Since the discovery of cervical neck muscle myogenic potentials in 1992, there has been a rapid growth of VEMP publications and clinical use. Investigators worldwide have used the VEMPs to characterize vestibular deficiencies related to aging and a variety of peripheral and central vestibulopathies, including Tullio/superior canal dehiscence syndrome, vestibular neuritis, Meniere's disease and tumors. The application is motivated by two basic facts. First, there is a need of rigorous animal basic science research on the neural basis for VEMP testing. Second, our studies clearly demonstrated that the canal as well as otolith afferents responded to VEMP stimuli. Since neck muscles receive inputs from both the canals and the otoliths, our results cast doubt on the current interpretation of VEMP testing, and call into question which vestibular organs are responsible for VEMP responses under various experimental and clinical conditions-knowledge important for clinical design of discriminating VEMP tests and interpretation of clinical results. In the application, we will examine single unit vestibular afferent responses from identified organs to air-conducted (Aim 1) and bone-conducted sound stimuli (Aim 2) that are used clinically. We will determine if certain sound stimuli preferentially activate specific vestibular end organs. Our preliminary results support this idea and have shown that sound stimuli with certain intensity and frequency preferentially activate the otoliths vs. the canals. The results from the proposed experiments would lead to optimal VEMP testing protocols and interpretive guidelines. The basis of the organ selectivity is hypothesized to be biomechanical- i.e., related to how acoustic energy is transmitted through the labyrinth. We will examine the hypothesis by constructing a 3D biomechanical model of sound activation of the vestibular end organs.
Sound-evoked vestibular myogenic potentials (VEMPs) are becoming a common clinical test of vestibular function, yet we really do not know how the vestibular organs are activated by sound. The knowledge obtained from the study will contribute to understanding sound activation of vestibular end organs and provide insights into developing and interpreting human VEMP tests.
|Luis, L; Lehnen, N; MuÃ±oz, E et al. (2016) Anticompensatory quick eye movements after head impulses: A peripheral vestibular sign in spontaneous nystagmus. J Vestib Res 25:267-71|
|Stewart, Courtney; Yu, Yue; Huang, Jun et al. (2016) Effects of high intensity noise on the vestibular system in rats. Hear Res 335:118-27|
|Mohammad, Ramzi M; Muqbil, Irfana; Lowe, Leroy et al. (2015) Broad targeting of resistance to apoptosis in cancer. Semin Cancer Biol 35 Suppl:S78-103|
|Kumar, Nagi B; Pow-Sang, Julio; Egan, Kathleen M et al. (2015) Randomized, Placebo-Controlled Trial of Green Tea Catechins for Prostate Cancer Prevention. Cancer Prev Res (Phila) 8:879-87|
|Zhu, Hong; Tang, Xuehui; Wei, Wei et al. (2014) Input-output functions of vestibular afferent responses to air-conducted clicks in rats. J Assoc Res Otolaryngol 15:73-86|
|Maklad, Adel; Reed, Caitlyn; Johnson, Nicolas S et al. (2014) Anatomy of the lamprey ear: morphological evidence for occurrence of horizontal semicircular ducts in the labyrinth of Petromyzon marinus. J Anat 224:432-46|
|Luis, Leonel; Zhu, Hong; Costa, JoÃ£o et al. (2014) Reply to the Commentary on Luis et al. ""Spontaneous plugging of the horizontal semicircular canal with reversible canal dysfunction and recovery of vestibular evoked myogenic potentials"". Otol Neurotol 35:379-83|
|Mahmoud, Amany; Reed, Caitlyn; Maklad, Adel (2013) Central projections of lagenar primary neurons in the chick. J Comp Neurol 521:3524-40|
|Kumar, Nagi; Chornokur, Ganna (2012) Molecular Targeted Therapies Using Botanicals for Prostate Cancer Chemoprevention. Transl Med (Sunnyvale) Suppl 2:005|