ACOUSTIC STAPEDIAL REFLEX THRESHOLD IN NORMAL HEARING PARTICIPANTS IN SULAIMANI CITY

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Background Acoustic stapedial reflex threshold (ASRT) is an objective, important test that can be included in a test battery along with behavioural pure tone audiometry and otoacoustic emissions to differentiate among middle ear, cochlear, and retro cochlear sites of the lesion. It can be used as a cross-check with a behavioural audiogram to increase confidence in the diagnosis. In most people with normal hearing thresholds and middle ear function, the acoustic stapedial reflex will be present at all frequencies and within an intensity range of 70-90 dB HL above the behavioural hearing threshold. Objectives To measure ASRT in participants with normal hearing thresholds in Sulaymaniyah city and to observe the effect of different parameters on the threshold. Patients and Methods The study was conducted on 200 participants (400 ears) who met inclusion criteria (110 males and 90 females); data were collected through visiting five different places with different age groups within three months duration. Participants were divided into three age groups (6-12 years), (13-18 years), (19 years and above).Only participants with normal otoscopic examination, normal pure tone audiometry, normal tympanogram, undergone through stapedial reflex threshold measurement, and the reflexes were elicited and recorded bilaterally by using tympanometer (Impedance meter) MAICO MI34 brand, single frequency 226 Hz of German-made model 2011. Results Mean ASRT measured in both ears was within the normal range of 70-90 dB HL above hearing threshold in both ipsilateral and contralateral pathways as Right ipsilateral (74.5 dB HL), right contralateral (76.9 dB HL), left ipsilateral (74.6 dB HL), and left contralateral (76.8 dB HL) above hearing thresholds. There was no significant difference between right and left ears according to ASRT (P-values > 0.05). There was no gender effect on ASRT (P-values > 0.05), while there was a significant effect of age on ASRT, especially in the adult population (P-values < 0.05). Conclusion A stapedial reflex threshold in normal hearing subjects was within normal range, different parameters as the side of ear and gender did not affect the threshold. In contrast, with advancing age amount of intensity needed to elicit the reflex increased.