title: Direct Intracochlear Acoustic Stimulation Using a PZT Microactuator.
abstract: Combined electric and acoustic stimulation has proven to be an effective strategy to improve hearing in some cochlear implant users. We describe an acoustic microactuator to directly deliver stimuli to the perilymph in the scala tympani. The 800 µm by 800 µm actuator has a silicon diaphragm driven by a piezoelectric thin film (e.g., lead-zirconium-titanium oxide or PZT). This device could also be used as a component of a bimodal acoustic-electric electrode array. In the current study, we established a guinea pig model to test the actuator for its ability to deliver auditory signals to the cochlea in vivo. The actuator was placed through the round window of the cochlea. Auditory brainstem response (ABR) thresholds, peak latencies, and amplitude growth were calculated for an ear canal speaker versus the intracochlear actuator for tone burst stimuli at 4, 8, 16, and 24 kHz. An ABR was obtained after removal of the probe to assess loss of hearing related to the procedure. In some animals, the temporal bone was harvested for histologic analysis of cochlear damage. We show that the device is capable of stimulating ABRs in vivo with latencies and growth functions comparable to stimulation in the ear canal. Further experiments will be necessary to evaluate the efficiency and safety of this modality in long-term auditory stimulation and its ability to be integrated with conventional cochlear implant arrays.
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA, USA Department of Precision Instruments, Tsinghua University, Beijing, China.
authors.forename: Chuan
authors.initials: C
authors.lastname: Luo
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Omelchenko
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Manson
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, USA.
authors.forename: Carol
authors.initials: C
authors.lastname: Robbins
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, USA.
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Oesterle
authors.affiliation: Department of Materials Science, University of Washington, Seattle, WA, USA.
authors.forename: Guo Zhong
authors.initials: GZ
authors.lastname: Cao
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA, USA ishen@u.washington hume@uw.edu.
authors.forename: I Y
authors.initials: IY
authors.lastname: Shen
authors.affiliation: Virginia Merrill Bloedel Hearing Research Center, Department of Otolaryngology-Head and Neck Surgery, University of Washington, Seattle, WA, USA VA Puget Sound, Seattle, WA, USA.
authors.forename: Clifford R
authors.initials: CR
authors.lastname: Hume
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation* / Q000379:methods*; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology; D019929:Cochlear Implantation / Q000379:methods; D003054:Cochlear Implants; D004195:Disease Models, Animal; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006168:Guinea Pigs; D059745:Piezosurgery / Q000379:methods; D011474:Prosthesis Design; D011897:Random Allocation; D012680:Sensitivity and Specificity
keywords: Cochlear implant; PZT; cochlea; electroacoustic; hearing aid; hybrid; perilymph; piezoelectric