Conclusions: EGb761 treatment has a significant benefit with an early and preventive effect, reversing the deleterious effect of aging in the integrity of the rat cochlea, even in the late stage of the rat lifespan. Objectives: We previously reported a significant relationship between aging and apoptosis in the rat cochlea. This study was designed to investigate the effects of Ginkgo biloba leaf extract (EGb761) on age-associated cochlear caspase activation. Methods: Sprague-Dawley rats (n = 80) divided into two groups according to their age (4 months old, younger, YR, and 12 months old, aged-mature, AM) were treated with 100 mg/kg/day body weight of EGb761 extract dissolved in tap water for two periods: 4 and 12 months. Then cochleae were harvested to measure caspase activities, ATP levels, total superoxide dismutase (SOD) activity, and caspase-3 gene expression. Auditory steady-state responses (ASSR) threshold shifts were also measured before sacrifice of the rats. Results: EGb761 treatment prevents significantly aging-related caspase-induced activities within the cochleae in YR and AM rats. In the short EGb761 treatment, YR rats showed lower levels of caspase-3/7 than AM rats. In contrast, longer treatment did not show significant differences between YR and AM rats. Reduced caspase-3/7 activity in presence of EGb761 correlates with significant improvements of ASSR threshold shifts.
Objective: To evaluate vestibular restoration and the evolution of the compensatory saccades in acute severe inflammatory vestibular nerve paralysis, including vestibular neuritis and Ramsay Hunt syndrome with vertigo. Study Design: Prospective. Setting: Tertiary referral center. Patients: Vestibular neuritis (n = 18) and Ramsay Hunt syndrome patients with vertigo (n = 13) were enrolled. Intervention: After treatment with oral corticosteroids, patients were followed up for 6 months. Main Outcome Measures: Functional recovery of the facial nerve was scored according to the House–Brackman grading system. Caloric and video head impulse tests were performed in every patient at the time of enrolment. Subsequently, successive video head impulse test (vHIT) exploration was performed at the 1, 3, and 6-month follow-up. Results: Eighteen patients with vestibular neuritis and 13 with Ramsay Hunt syndrome and associated vertigo were included. Vestibular function was significantly worse in patients with Ramsay Hunt syndrome than in those with vestibular neuritis. Similar compensatory saccades velocity and latency values were observed in both groups, in both the caloric and initial vHIT tests. Successive vHIT results showed a significantly higher vestibulo-ocular reflex gain recovery in vestibular neuritis patients than in Ramsay Hunt syndrome patients. A significantly faster reduction in the latency, velocity, and organization of the compensatory saccades was observed in neuritis than in Ramsay Hunt syndrome patients. Conclusions: In addition to the recovery of the vestibulo-ocular reflex, the reduction of latency, velocity and the organization of compensatory saccades play a role in vestibular compensation.
Background: In the suppression head impulse paradigm (SHIMP) vHIT protocol, the participant is instructed to follow with his gaze a mobile target generated by a laser placed on the participant’s head. Recent studies have reported that the refixation saccade latencies are in relation with the time evolution of the vestibular dysfunction in both (standard and SHIMP) procedures. We hypothesized that some central mechanisms like head impulse prediction could be one of the causes for the differences in the saccadic eye responses. Methods: A prospective cohort non-randomized study was designed. For the SHIMP protocol, recorded with the ICS Impulse ver. 4.0® (Otometrics A/S, Taastrup, Denmark) vHIT device, three different algorithms were performed: “predictable,” “less predictable,” and “unpredictable” depending on the target’s predictability. A mathematical method was developed to analyze the SHIMP responses. The method was implemented as an additional tool to the MATLAB open source script for the extended analysis of the vHIT responses named HITCal. Results: In cohort 1, 52 participants were included in “predictable” SHIMP protocol. In cohort 2, 60 patients were included for the “less predictable” and 35 patients for the “unpredictable” SHIMP protocol. The participants made more early saccades when instructed to perform the “predictable” paradigm compared with the “less predictable” paradigm (p < 0.001). The less predictable protocol did not reveal any significant difference when compared with the unpredictable protocol (p = 0.189). For the latency of the first saccade, there was statistical difference between the “unpredictable” and “predictable” protocols (p < 0.001) and between the “less predictable” and “predictable” protocols (p < 0.001). Finally, we did not find any relationship between the horizontal vestibulo-ocular reflex (hVOR) gain and the latency of the saccades. Conclusion: We developed a specific method to analyze and detect early SHIMP saccades. Our findings offer evidence regarding the influence of predictability on the latency of the SHIMP saccadic responses, suggesting that early saccades are probably caused by a conditioned response of the participant. The lack of relationship between the hVOR gain and the latency of the saccades suggests that the predictive behavior that caused the early eye saccades are independent of the vestibular function.