Acoustic change complex for assessing speech discrimination in normal-hearing and hearing-impaired infants

•Acoustic change complex (ACC) to low-, mid-, and high-frequency speech stimuli can be recorded in awake infants with normal hearing and infants using hearing aids.•ACC can be used to predict speech discrimination capacity in individual infants.•ACC is positively correlated with parent-reported functional performance of infants in everyday life. This study examined (1) the utility of a clinical system to record acoustic change complex (ACC, an event-related potential recorded by electroencephalography) for assessing speech discrimination in infants, and (2) the relationship between ACC and functional performance in real life. Participants included 115 infants (43 normal-hearing, 72 hearing-impaired), aged 3–12 months. ACCs were recorded using [szs], [uiu], and a spectral rippled noise high-pass filtered at 2 kHz as stimuli. Assessments were conducted at age 3–6 months and at 7–12 months. Functional performance was evaluated using a parent-report questionnaire, and correlations with ACC were examined. The rates of onset and ACC responses of normal-hearing infants were not significantly different from those of aided infants with mild or moderate hearing loss but were significantly higher than those with severe loss. On average, response rates measured at 3–6 months were not significantly different from those at 7–12 months. Higher rates of ACC responses were significantly associated with better functional performance. ACCs demonstrated auditory capacity for discrimination in infants by 3–6 months. This capacity was positively related to real-life functional performance. ACCs can be used to evaluate the effectiveness of amplification and monitor development in aided hearing-impaired infants.