Article,
Hearing , communication and cognition in low-frequency noise from armoured vehicles
Noise & Health, (2007)
Abstract
An experiment was performed to study auditory perception and cognitive
function in the presence of low-frequency dominant armoured vehicle
noise (LAV III). Thirty-six normal hearing subjects were assigned
to one of three noise backgrounds: Quiet, pink noise and vehicle
noise. The pink and vehicle noise were presented at 80 dBA. Each
subject performed an auditory detection test, modified rhyme test
(MRT) and cognitive test battery for three different ear conditions:
Unoccluded and fitted with an active noise reduction (ANR) headset
in passive and ANR modes. Auditory detection was measured at six
1/3 octave band frequencies from 0.25 to 8 kHz. The cognitive test
battery consisted of two subjective questionnaires and five performance
tasks. The earmuff, both in the conventional and ANR modes, did not
significantly affect detection thresholds at any frequency in the
pink and vehicle noise backgrounds. For the MRT, there were no significant
differences between the speech levels required for 60% correct responses
for three ear conditions in the pink and vehicle noise backgrounds.
A small but significant (4 dB) increase in speech level was required
in pink noise as compared to vehicle noise. For the serial reaction
time task, the mean response time in the vehicle noise background
(751 ms) was significantly higher than in pink noise and quiet (709
and 651 ms, respectively). The mean response time in the pink noise
background was also significantly higher than in quiet. Thus, the
presence of noise, especially low-frequency noise, had a negative
effect on reaction time.
