Acoustic Change Complex as an Objective Gap Detection Test in Elderly Individuals

Abstract

A decline in temporal resolution abilities or the ability of the auditory system to track fast changes in incoming sounds is one factor thought to contribute to speech understanding difficulties that accompanies aging process.The present study was carried out to find out the minimum gap duration required to elicit the Acoustic Change Complex (ACC). Also the study was carried out across age groups to find out the effect of age on the behavioral gap duration and gap duration required to elicit the electrophysiological responses. ACC and behavioral Gap Detection Test were administered on sixty participants with normal peripheral hearing, divided into four groups including fifteen young adults in Group I (18-28 years) and older adults in Group II (>50-55 years), Group III (>55-60 years) and Group IV (>60-65 years). The results showed that behavioural gap detection thresholds and gap durations required to elicit ACC increased as age increases and major detrimental effects on gap detection is seen after 60 years of age and above. The results also showed that the behavioral gap detection thresholds were lower than the gaps required to elicit ACC . The results of the current study shows that changes in the aging auditory system older adults required higher gap duration compared to young adults in eliciting the cortical responses and also behavioral responses. These results clearly indicate slow temporal processing thus possibly leading to the difficulties faced by older adults in understanding speech in difficult listening situations. The objective test could also help in testing the difficult to test older adults with associated problems.