Effect of Noise on Biomark in Individuals with Learning Disability

Abstract

Several studies have reported poor temporal processing and speech-in-noise problems in children with learning disability (LD) (Chandrasekaran, Hornickel, Skoe, Nicol & Kraus, 2009; Hayes, Warrier, Nicol, Zecker & Kraus, 2003). Electrophysiological techniques such as speech ABR have been used (King, Warrier, Hayes & Kraus, 2002; Russo, Nicol, Zecker, Hayes & Kraus, 2005) to determine the auditory processing deficits in children with LD. The present study utilised BioMARK to find out the differences in speech sound processing in children with LD, in quiet and noise. Fifteen children in the age range of 8 to 12 years were selected for the study which included 5 children with LD and 10 typically developing children. All the 15 participants had a normal peripheral hearing sensitivity and they underwent BioMARK response testing with 40 ms /da/ stimulus. The stimulus was presented in quiet as well as in presence of white noise (+30 dB SNR) ipsilaterally. The peaks were marked as wave V, A, C, D, E, F, and O. The waveforms were converted into ASCII codes and processed using Brainstem Toolbox on Matlab vR2009B (Skoe & Kraus, 2010). Amplitudes of the formant of fundamental frequency, first formant and higher frequency were obtained and compared. Results showed a significant difference (p<0.05) in latency of the peaks V, A, D, E, F and O, of BioMARK in children with LD as compared to typically developing children. This was true for both quiet and noise conditions. Also, a significant difference (p<0.05) in the amplitudes of various formants was found in noise condition for children with LD and typically developing children. So, it can be concluded that there is a problem in decoding of information in presence of noise which is more pronounced in children with LD. Hence, other management strategies along with environmental modifications should be employed.