A clinical trial of Nicergoline to prevent temporary threshold shift

Abstract

Background: In Thailand, military personnel attending the annual firing practice are at risk for noise-induced hearing loss (NIHL). Nowadays, hearing protection devices have been approved to prevent NIHL. Furthermore, N-acetyl-cysteine, Vitamin B12 or Magnesium were proved to be effective against temporary threshold shift (TTS). However, limited research regarding the effectiveness of nicergoline on preventing TTS has been reported. Methods: A randomized controlled trial was conducted. Two hundred twenty-four participants were evaluated for general physical status, hearing threshold levels and blood chemistry. After the inform consent form was explained and signed, the participants were divided into 2 groups. Nicergoline 30 mg twice daily intake was prescribed to the study group (n=119) for 3 weeks. The placebo was prescribed to the control group (n=105) for 3 weeks, as well. At the end of the second week, they had to attend the firing practice. All participants had to wear the silicone ear plugs. In addition, the audiometry was measured within 48 hours after the end of the firing practice. Moreover, aural symptoms (tinnitus and aural fullness) and the side effects of the medication were recorded. Results: TTS was detected in both groups 14 ears – 10 ears from the control group and 4 ears from the study group (p=0.075). The post-firing practice audiometry showed that the average hearing threshold levels of the study group significantly improved than that of the control group across all frequencies (p<0.05). Moreover, the audiometry from the control group worsened at 250 and 6K Hz (p<0.05). The duration of tinnitus and aural fullness in the study group occurred over a shorter period than that in the control group. Conclusion: The TTS was found in both groups without statistical significant differences. The effectiveness of nicergoline from the study demonstrated tinnitus reduction after the firing practice. Furthermore, the hearing threshold significantly improved in the study group.