Motorcycle drivers

were requested to wear hearing protection during driving and be present at the lab at least half an hour before the tests would start. We decided to include all these participants into the analysis. Audiological tests Participants were H 89 price subjected to an extended audiological test battery containing tests on audiometric thresholds, loudness perception, diplacusis, tinnitus, speech perception in noise, and otoacoustic emissions. The tests were performed at the ENT-/audiological department of the Academic Medical Centre. Before testing the otoacoustic emissions, the participant had otoscopic inspection in order to check for cerumen. If present, the cerumen was removed by an ENT-doctor. Audiometric thresholds (PTA) Pure-tone air-conduction thresholds at 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz were measured using an Interacoustics AC40 audiometer with TDH39 headphones. The audiometer was calibrated according to ISO 389 (1991). Pure-tone measurements were all performed in a sound–isolated booth. Bone-conduction thresholds were measured at 0.5, 1 this website and 2 kHz when air-conduction thresholds exceeded 20 dB. All audiometric thresholds were KPT-330 order assessed with adequate masking

and were expressed in dB HL, according to standards of diagnostic audiometry. Loudness perception We used an adaptive procedure for categorical loudness scaling ACALOS (Adaptive, Categorical Loudness Scaling) as described by Brand and Hohmann (2002) for three different stimuli: octave-band noises with 0.75 and 3 kHz as the centre frequency, and a wide band noise with a speech-shaped spectrum. Each stimulus was presented for 1,000 ms in a free-field condition. The participant was

seated at 1 m from the speaker producing the noise. For safety purposes, the maximum output was limited to 105 dB (SPL), according to the JBL control1X specifications. Based on the participant’s judgment of Phospholipase D1 the loudness of the test sound for various intensities, an individual loudness curve was fitted. Thus, the dynamic range and the increase of loudness within this dynamic range can be assessed in a single measurement. Diplacusis An adaptive procedure was used to compare the pitch of tonal signals presented alternating to the right and left ear by headphones on three different frequencies: 1, 2 and 4 kHz. First, participants had to match the loudness of the tone in the left ear to the tone in the right ear, presented at 60 dB HL. Then, the musician was asked to match the pitch of the tone in the left ear to that of the right ear. Adjustment on the basis of the participants’ feedback on both loudness and pitch was done by the test leader, changing the presentation level or the frequency of the tone presented to the left ear in steps of 1 dB or 1 Hz, respectively. Tinnitus When participants suffered from tinnitus at the time of testing, a tinnitus matching procedure was conducted. First, the tinnitus was localized (i.e.