THE INFLUENCE OF ADDITIVE NOISE AND REVERBERATION ON LISTENING DIFFICULTY: REACTION TIME STUDY
Blaszak MA (1), Majewska N (2), Rydzewski B (3).
(1) Adam Mickiewicz University, Poznan, Poland; (2) Karol Marcinkowski Medical University, Poznan, Poland; (3) ENT Department, Franciszek Raszeja Municipal Hospital, Poznan, Poland.
Background: in common situations, word recognition scores do not discriminate well among various acoustic conditions. Listening difficulty, measured by the reaction time, is proposed as a new subjective measure for the evaluation of speech transmission in enclosures.
Aims: the main purpose of the present study was to investigate the process of speech perception in difficult noisy and reverberated conditions and examine the validity of "listening difficulty" measured by the delay in listeners’ responses.
Method: traffic and multitalker babble noises have been added to the phonetically balanced 100-element CVC lists and generated in three enclosures (RT = 2, 1.3 and 0.9 s) and in the anechoic chamber. The experiment has been performed under various conditions of signal to noise-ratio (SNR = -5, +5, +15 dB and no noise). The analysis were made on the basis of: (a) nonsense words’ recognition scores, and (b) reaction time for correctly repeated signals.
Results: the obtained results were consistent with the expectation that the longest duration of signal recognition in mental process is needed in enclosures with the highest reverberation and level of noise. Even if no differences were noticed in speech comprehension for various acoustic conditions, significant differences were found in listening difficulty. Therefore, reaction time can evaluate speech transmission performance more accurately and sensitively than intelligibility scores and seems to be an alternative to classic measures of speech perception in enclosures.
Conclusions: it seems important to use unconventional tests and to obtain, in addition to correctness of response, other measures of speech perception that are correlated with the ease of communication.
E-mail: blasaku@gmail.com
