Reduction of Stimulus Artifacts in ASSR: An Investigation of a Stimulus Approach

Abstract

Auditory steady state responses at high stimulus levels were contaminated by artifacts when weighted averaging method as well as phase coherence method is used detect responses. The current study aimed to determine the upper limit for artifact free ASSR for stimuli presented through headphone and bone vibrator. The current study also investigated whether artifacts can be avoided by changing the carrier frequency in such a way that they are not integer multiple of sampling frequency. ASSR was recorded in 30 individuals with profound hearing loss who did not show behavioural responses even at the upper limit of ASSR system. The results revealed that the upper limit for artifact free ASSR measurement for head phone is 90 dB HL and for bone vibrator is 50 dB HL. Changing the carrier frequency enhanced the dynamic range for artifact free ASSR measurement obtained through headphone and bone vibrator