OBJECTIVE: To determine whether central auditory function in preterm infants correlates with peripheral auditory threshold and whether threshold elevation affects central auditory function. METHODS: Brainstem auditory evoked response (BAER) was recorded at term age using maximum length sequence (MLS) with 91-910/s clicks in 133 preterm infants (gestation 28-36 weeks). The relationship between MLS BAER variables and BAER threshold was analyzed. RESULTS: The latencies and amplitudes of all MLS BAER waves correlated significantly with BAER threshold. However, no correlation was found between MLS BAER interpeak intervals and BAER threshold at any rates. In preterm infants with a threshold >20dB nHL (n=30), MLS BAER wave latencies were all significantly longer than in those with a threshold < or = 20dB nHL (n=103) (P<0.01-0.001). MLS BAER wave amplitudes were significantly smaller than in those 20dB nHL (P<0.05-0.001). However, no interpeak intervals differed significantly between the two groups of infants. V/I amplitude ratio was similar in the two groups. These findings were true of all click rates. Click rate-dependent changes in MLS BAER of the preterm infants with an elevated BAER threshold are generally similar to those with a normal threshold. CONCLUSIONS: Brainstem auditory function does not closely correlate with peripheral auditory threshold at term in preterm infants. Elevation in peripheral threshold due to middle ear disorders does not significantly affect functional status of the auditory brainstem. SIGNIFICANCE: Short term peripheral conductive auditory abnormality does not significantly affect the immature central auditory function.
OBJECTIVE: To determine whether central auditory function in preterm infants correlates with peripheral auditory threshold and whether threshold elevation affects central auditory function. METHODS: Brainstem auditory evoked response (BAER) was recorded at term age using maximum length sequence (MLS) with 91-910/s clicks in 133 preterm infants (gestation 28-36 weeks). The relationship between MLS BAER variables and BAER threshold was analyzed. RESULTS: The latencies and amplitudes of all MLS BAER waves correlated significantly with BAER threshold. However, no correlation was found between MLS BAER interpeak intervals and BAER threshold at any rates. In preterm infants with a threshold >20dB nHL (n=30), MLS BAER wave latencies were all significantly longer than in those with a threshold < or = 20dB nHL (n=103) (P<0.01-0.001). MLS BAER wave amplitudes were significantly smaller than in those 20dB nHL (P<0.05-0.001). However, no interpeak intervals differed significantly between the two groups of infants. V/I amplitude ratio was similar in the two groups. These findings were true of all click rates. Click rate-dependent changes in MLS BAER of the preterm infants with an elevated BAER threshold are generally similar to those with a normal threshold. CONCLUSIONS: Brainstem auditory function does not closely correlate with peripheral auditory threshold at term in preterm infants. Elevation in peripheral threshold due to middle ear disorders does not significantly affect functional status of the auditory brainstem. SIGNIFICANCE: Short term peripheral conductive auditory abnormality does not significantly affect the immature central auditory function.