Air and Bone Conduction Click and Tone-Burst Auditory Brainstem Thresholds Using Kalman Adaptive Processing in Nonsedated Normal-Hearing Infants.
OBJECTIVE
To study normative thresholds and latencies for click and tone-burst auditory brainstem response (TB-ABR) for air and bone conduction in normal infants and those discharged from neonatal intensive care units, who passed newborn hearing screening and follow-up distortion product otoacoustic emission. An evoked potential system (Vivosonic Integrity) that incorporates Bluetooth electrical isolation and Kalman-weighted adaptive processing to improve signal to noise ratios was employed for this study. Results were compared with other published data.


METHODS
One hundred forty-five infants who passed two-stage hearing screening with transient-evoked otoacoustic emission or automated auditory brainstem response were assessed with clicks at 70 dB nHL and threshold TB-ABR. Tone bursts at frequencies between 500 and 4000 Hz were used for air and bone conduction auditory brainstem response testing using a specified staircase threshold search to establish threshold levels and wave V peak latencies.


RESULTS
Median air conduction hearing thresholds using TB-ABR ranged from 0 to 20 dB nHL, depending on stimulus frequency. Median bone conduction thresholds were 10 dB nHL across all frequencies, and median air-bone gaps were 0 dB across all frequencies. There was no significant threshold difference between left and right ears and no significant relationship between thresholds and hearing loss risk factors, ethnicity, or gender. Older age was related to decreased latency for air conduction. Compared with previous studies, mean air conduction thresholds were found at slightly lower (better) levels, while bone conduction levels were better at 2000 Hz and higher at 500 Hz. Latency values were longer at 500 Hz than previous studies using other instrumentation. Sleep state did not affect air or bone conduction thresholds.


CONCLUSIONS
This study demonstrated slightly better wave V thresholds for air conduction than previous infant studies. The differences found in the present study, while statistically significant, were within the test step size of 10 dB. This suggests that threshold responses obtained using the Kalman weighting software were within the range of other published studies using traditional signal averaging, given step-size limitations. Thresholds were not adversely affected by variable sleep states.
1Communication Sciences Research Center, Division of Audiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; 2Physical Acoustics Laboratory, Boys Town National Research Hospital, Omaha, Nebraska, USA; 3National Center for Rehabilitative Auditory Research, Portland, Oregon, USA; 4Department of Otolaryngology, Oregon Health & Science University, Portland, Oregon, USA; 5Department of Audiology, Pacific University, Forest Grove, Oregon, USA; and 6Department of Rehabilitation and Physical Therapy, Good Samaritan Hospital of TriHealth, Inc., Cincinnati, Ohio, USA.
Alaaeldin M
AM
Elsayed
Lisa L
LL
Hunter
Douglas H
DH
Keefe
M Patrick
MP
Feeney
David K
DK
Brown
Jareen K
JK
Meinzen-Derr
Kelly
K
Baroch
Maureen
M
Sullivan-Mahoney
Kara
K
Francis
Leigh G
LG
Schaid
D000161:Acoustic Stimulation; D001309:Auditory Threshold; D001844:Bone Conduction / Q000502:physiology*; D001330:Electronic Data Processing; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015997:Neonatal Screening; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology; D012016:Reference Values; D059629:Signal-To-Noise Ratio