Ski helmets could attenuate the sounds of danger.

OBJECTIVE

To determine whether a ski helmet reduces skiers' hearing particularly sounds that can warn skiers of potentially dangerous situations.

DESIGN

Randomized repeated measures (first part), environmental field measurements (second part).

SETTING

Audiology Centre of Rijeka Medical School, ski slopes at Platak resort.

PARTICIPANTS

Thirty healthy subjects not used to wearing a helmet each served as their own control.

INTERVENTION

Ski cap, ski helmet, and no intervention in randomized order.

MAIN OUTCOME MEASUREMENTS

Laboratory open-field audiometric testing: bareheaded, ski cap, and ski helmet (0.125-8 kHz protocol), and environmental A-weighted sound measurements on the slope for potentially dangerous situations like snowboarder breaking or skier passing by. In both parts of the study, the sound pressure levels (dB) and sound spectrum frequencies were analyzed.

RESULTS

First part-No differences were found between bare head and wearing only a ski cap. Significant sound attenuation characteristics of the helmet were determined for frequencies 2, 4, and 8 kHz (P < 0.001). Second part-High sound pressure levels were found for all the danger sounds measured on the slope, especially at frequencies that were most affected by helmet sound attenuation (2-8 kHz) in previously conducted laboratory tests.

CONCLUSIONS

Helmets could influence the level of the hearing threshold in frequencies between 2 and 8 KHz. The spectrum of danger sounds on the slope has high pressure levels at frequencies that were most affected by helmet sound attenuation characteristics (2-8 kHz), so the helmet wearers might misinterpret the sounds of potentially dangerous situations because the sound might be distorted.