Multiple auditory steadystate responses to bone-conduction stimuli in adults with normal hearing

(ASSRs) probably will be incorporated into the di-agnostic test battery for estimating hearing thresh-olds in young infants in the near future. Limiting this, however, is the fact that there are no published bone-conduction ASSR threshold data for infants with normal or impaired hearing. The objective of this study was to investigate bone-conduction ASSR thresholds in infants from a Neonatal Intensive Care Unit (NICU) and in young infants with normal hearing and to compare these with adult ASSR thresholds. Design: ASSR thresholds to multiple bone-conduc-tion stimuli (carrier frequencies: 500 to 4000 Hz; 77 to 101-Hz modulation rates; amplitude/frequency modulated; single-polarity stimulus) were obtained in two infant groups [N 29 preterm (32 to 43 wk PCA), tested in NICU; N 14 postterm (0 to 8 mo), tested in sound booth]. All infants had passed a hearing screening test. ASSR thresholds, ampli-tudes, and phase delays for preterm and postterm infants were compared with previously collected adult data. Results:Mean (1 SD) ASSR thresholds were 16 (11), 16 (10), 37 (10), and 33 (13) dB HL for the preterm infants and 14 (13), 2 (7), 26 (6), and 22 (8) dB HL fo