Frequency-specific efficacy of intratympanic steroid on idiopathic sudden sensorineural hearing loss.

Background: Hearing recovery would be different in each sound frequency in patients with idiopathic sudden sensorineural hearing loss (ISSNHL).Aims/objectives: To analyze frequency-specific efficacy of intratympanic steroid on ISSNHL.Materials and methods: Of a total of 381 patients with ISSNHL (hearing threshold ≥40 dB; ≤30 days until treatment), 174 patients (174 ears) received systemic steroid plus hyperbaric oxygen therapy (HBO group), and 207 patients (208 ears) received systemic plus intratympanic steroid (IT group). Hearing thresholds at 125-8000 Hz were measured at every octave before and after treatment.Results: % of patients with hearing gains ≥10 dB in the IT group was significantly higher for 500 Hz and the average of 5 mid-frequencies, tended to be higher for 1000 Hz, but was significantly lower for 8000 Hz, compared to the HBO group. Multiple regression analysis showed that hearing recovery was negatively correlated with patients' age for 125/2000/4000/8000 Hz and with days from onset to treatment for all frequencies, and also revealed better hearing recovery at 500/1000 Hz in the IT group than in the HBO group.Conclusions: Intratympanic steroid is more effective than hyperbaric oxygen to yield better hearing outcomes at mid-frequencies and would be advantageous to restore sound/speech perception.Significance: Superiority of intratympanic steroid over hyperbaric oxygen for treating ISSNHL was verified.

Effects of a subconvulsive dose of kainic acid on the gene expressions of the arginine vasopressin, oxytocin and neuronal nitric oxide synthase in the rat hypothalamus.

Arginine vasopressin (AVP) synthesis in the hypothalamo-neurohypophysial system (HNS) is up-regulated by kainic acid (KA)-induced seizure in rats. However, it remains unknown whether a subconvulsive dose of KA affects the HNS. Here we examined the effects of subcutaneous (s.c.) administration of a low dose of KA (4 mg/kg) on the gene expressions of the AVP, oxytocin (OXT) and neuronal nitric oxide synthase (nNOS) in the supraoptic (SON) and paraventricular nuclei (PVN) of the rat hypothalamus, using in situ hybridization histochemistry. The expression of the AVP gene in the SON and PVN was judged to be up-regulated in KA-treated rats in comparison with saline-treated rats as controls. Next, the expression of the OXT gene was significantly increased in the SON at 6-24h and in the PVN at 6 and 12h after s.c. administration of KA. Finally, the expression of the nNOS gene was significantly increased in the SON and PVN at 3 and 6h after s.c. administration of KA. These results suggest that up-regulation of the gene expressions of the AVP, OXT and nNOS in the rat hypothalamus may be differentially affected by peripheral administration of a subconvulsive dose of KA.