HEARING PROTECTION FOR MOTORCYCLISTS

An investigation to ascertain the most suitable earplug and its effica cy for use by motorcyclists was undertaken. To qualify for testing the earplugs had to be both easily available and cost less than 10 Pounds . Consequently, three types of earplugs ('Silisoft', EARfit and AQUAfi t [both Cabot Safety Ltd]) were tested for sound attenuation scores us ing an 'insertion loss' technique both with and without a motorcycle h elmet and scored for comfort by the test subjects. The optimal plug wa s then assessed as to its effect on the temporary threshold shift occu rring in motorcyclists after prolonged high speed riding. There were n o significant differences between the sound attenuation scores of the three plugs tested, with all three earplugs providing approximately 15 dB of sound attenuation at the low frequencies (250, 500, 1000 Hz) wh en worn under a helmet. The soft yellow foam earplug was felt to be th e optimal plug for motorcyclists as it was significantly more comforta ble (Wilcoxon paired: P < 0.01), readily available (chi2 = 15.2, P < 0 .001) and the cheapest. After one hour of high speed riding (80 mph), riders suffered a mean maximal temporary threshold shift of 11 dB at 1 000 Hz which was abolished by wearing these earplugs. Earplugs appear to provide useful protection against the excessive noise levels experi enced by motorcyclists. The soft yellow foam plug (EARfit, Cabot Safet y Ltd) would appear to be the most suitable, on the grounds of its low cost, comfort and ease of availability.