Effects of different acoustic stimulu on acoustic stapedial reflex properties

The aim of this study is to evaluate how acoustic stimuli with different characteristics affect the Acoustic Stapedial Reflex (ASR) features and to examine the reflexive responses of the acoustic reflex system to various types of acoustic stimuli. The study included 30 adult volunteers (16 females, 14 males) aged between 18 and 50 years with normal hearing. Evaluations were conducted using Wideband Tympanometry. During tympanometric assessment, acoustic stapedial reflex (ASR) and reflex decay (RD) threshold values were measured using 250 Hz, 500 Hz, 1000 Hz, narrowband, and speech stimuli. Descriptive and comparative statistical analyses were performed. According to the findings, ASR and RD threshold values obtained especially at 250 Hz, 500 Hz, and 1000 Hz frequencies showed statistically significant differences compared to the narrowband and speech stimuli (p<0.05). Additionally, the 1000 Hz stimulus produced the highest mean ASR (78.33 dB) and RD (82.92 dB) threshold values. In contrast, the narrowband and speech stimuli were notable for producing lower reflex threshold values. These results suggest that the type of stimulus may have a significant effect on acoustic stapedial reflex thresholds and reflex decay thresholds, and that speech stimuli, in particular, may produce clinically distinct results due to their lower threshold levels. This indicates that the choice of stimulus used in audiological assessments can directly influence test outcomes. In future studies, stimulus types used in reflex measurements can be compared using larger sample sizes, and the clinical implications of stimulus selection can be examined in more detail. The diagnostic contribution of speech stimuli may also be investigated across different populations.