Audiogram Estimation by Auditory Brainstem Response with NB CE-Chirp LS stimulus in Normal Hearing Infants.

Area of Science:

• Audiology
• Neuroscience
• Pediatric Medicine

Background:

• The NB CE-Chirp LS stimulus was developed to enhance auditory brainstem response (ABR) threshold estimation in infants and difficult-to-test children.
• Understanding the stimulus's behavior in normal-hearing infants is crucial before evaluating its efficacy across various hearing loss types.

Purpose of the Study:

• To characterize ABR thresholds using the NB CE-Chirp LS stimulus at 500, 1,000, 2,000, and 4,000 Hz in normal-hearing infants.
• To describe the amplitude and absolute latency of ABR thresholds obtained with this stimulus.

Main Methods:

• Auditory brainstem response thresholds were measured using the Eclipse EP25 system.
• The NB CE-Chirp LS stimulus was delivered via ER-3A insert earphones.
• EEG filtering included a 30 Hz high-pass and 1,500 Hz low-pass filter; ABR threshold was defined as the lowest intensity evoking wave V, with absence of response at 5 dB below.

Main Results:

• Eighteen normal-hearing infants were assessed.
• Mean ABR thresholds (dB nHL) were 23.8 (±4.2) at 500 Hz, 14.4 (±5.7) at 1,000 Hz, 6.0 (±5.0) at 2,000 Hz, and 7.0 (±5.9) at 4,000 Hz.
• Mean absolute latencies (ms) ranged from 8.86 (±1.12) to 9.64 (±0.52), and mean amplitudes (nV) ranged from 0.105 (±0.028) to 0.141 (±0.052) across frequencies.

Conclusions:

• The NB CE-Chirp LS stimulus achieves low auditory brainstem response thresholds, particularly at higher frequencies.
• This stimulus yields consistent absolute latencies across frequencies and robust amplitudes.
• The findings increase examiner confidence in ABR threshold results obtained with the NB CE-Chirp LS stimulus.