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Objective: After nerve injury, an exaggerated neuroinflammatory process may hinder neuron regeneration and recovery. Immunomodulation using glucocorticoids may therefore improve facial nerve injury outcomes. This study aims to examine the effect of both local and systemic dexamethasone administration on facial nerve functional recovery after axotomy in a rat model., Study Design: Randomized, placebo-controlled, blinded animal study. Setting Animal laboratory., Subjects and Methods: Seventy-four Wistar rats underwent facial nerve axotomy with immediate neurorrhaphy. Rats were randomly assigned a postoperative group: control (no therapy); systemic dexamethasone 0.5, 1, 5, or 10 mg/kg for 3 administrations; or topically applied dexamethasone at 2 or 4 mg/mL. Blinded, standardized facial assessments and nerve conduction studies (NCS) were performed. Gross facial motion assessments were corroborated with vibrissae frequency video analysis., Results: At 8 weeks, rats receiving systemic dexamethasone at 5 mg/kg attained greater eye blink closure (P = .004) and vibrissae motion (P = .012) compared with controls. Systemic dexamethasone at 0.5, 1, and 10 mg/kg and intraoperative topical application of dexamethasone at 2 or 4 mg/mL did not produce a significant improvement in facial motion compared with controls. Nerve conduction studies show a trend of increased return of compound muscle action potential amplitude levels compared with baseline among rats that received systemic dexamethasone 5 mg/kg but do not achieve statistical significance., Conclusion: In a rat facial nerve axotomy model, high-dose systemic dexamethasone therapy may improve functional recovery when administered in the immediate period following neurorrhaphy.

Objective: To test the feasibility of using the deaf white cat model of early-onset deafness. We studied the neuronal effects of prosthetic intervention with a clinical, "off-the-shelf" multichannel cochlear implant., Methods: We placed cochlear implants in 5 deaf white kittens at age 12 and 24 weeks. The devices were activated and stimulated in the laboratory using a clinical speech processor programmed with a high-resolution continuous interleaved sampling (CIS) strategy for 8 to 24 weeks. Stimulus parameters were guided by electrically evoked brainstem responses and intracochlear-evoked potentials. Kittens were assessed with respect to their tolerance and general behavior in response to speech, music, and environmental sounds., Results: Surgical complications were minimal, and kittens tolerated the experimental procedures well. Subjects were able to detect and respond to a specific sound played from a computer speaker. Electrophysiologic responses were reliably attainable and showed consistency with observed behavioral responses to sound. This experimental paradigm, using clinical devices, can be used in a practical research setting in cats., Conclusions: Deafness and other variations in neural activity result in many distinct changes to the central auditory pathways. Animal models will facilitate assessment of the reversibility of deafness-associated changes at the level of the neuron and its connections. Our observations of the feasibility of using clinical devices in animal models will enable us to simulate clinical conditions in addressing questions about the effects of "replacement" activity on the structure and function within the central auditory pathways in deafness.