Prawin Kumar, Himanshu Kumar Sanju, Vaishnavi Bohra, Astha Khanna
(Department of Audiology, All India Institute of Speech and Hearing, Mysore, India)
JHS 2015; 5(2): OA9-15
The neural representation of different speech stimuli (phonemes) can be measured at the cortex using electrophysiological techniques, a procedure called speech-evoked cortical potentials. Each phoneme produces cortical potentials with different temporal and spectral properties. Latency and amplitude measures reflect changes in the way different phonemes are neurally represented, so these measures are expected to change with maturation of the system, that is with age. The aim of the present study was to investigate whether there were differences in latency and amplitude between children and adults in response to the three phonemes /m/, /g/, and /t/.
MATERIAL AND METHODS: Exactly 10 normal-hearing children of age 5–7 years and 10 normal-hearing adults of age 17–24 years were recruited. Speech-evoked cortical potential were recorded using the HEARLab (v.1.0) auditory evoked potential system. Non-parametric statistics were used to compare both groups.
RESULTS: Mann-Whitney U-tests shows statistically significant differences between children and adults for both the latency and amplitude of wave P1 and N1 at the 0.05 level. At the same time, there were no significant differences between /m/, /g/, and /t/ for children and adults at the same level when a Kruskal-Wallis test was applied.
CONCLUSIONS: The present study shows there are differences between children and adults in terms of the latency and amplitude of their cortical potential responses, but the particular phoneme used does not appear to make a difference.
Keywords: Adult Children, Auditory Cortex, Speech