title: Speech-sound discrimination in school-age children: psychophysical and neurophysiologic measures.
abstract: This study measured behavioral speech-sound discrimination and a neurophysiologic correlate of discrimination in normal school-age children (ages 6 to 15) to determine if developmental effects exist. Just noticeable differences (JNDs) and mismatch responses (MMNs) were assessed for synthetic syllables that differed in third-formant onset frequency (/da-ga/) and formant transition duration (/ba-wa/). These stimuli were selected because children with learning problems often find it difficult to discriminate rapid spectrotemporal changes like /da-ga/, whereas the ability to distinguish /ba-wa/ is relatively unimpaired. Results indicate that JNDs for /da-ga/ show no developmental effects and that JNDs for /ba-wa/ decrease slightly with age (although likely for task-related reasons). MMNs elicited by two /da-ga/ stimulus pairs (onset frequency differences = 20 Hz, 280 Hz) and three /ba-wa/ stimulus pairs (transition duration differences = 3, 5, 15 ms) showed no systematic or significant differences for onset latency, duration, or area as a function of age. Normative JND and MMN data are provided. These norms provide a metric against which children with suspected central auditory processing difficulties or auditory-based language disorders can be compared.
authors.affiliation: Communication Sciences and Disorders, Neurobiology and Physiology, Otolaryngology, Northwestern University, Evanston, IL 60208, USA. nkraus@nwu.edu
authors.forename: N
authors.initials: N
authors.lastname: Kraus
authors.forename: D B
authors.initials: DB
authors.lastname: Koch
authors.forename: T J
authors.initials: TJ
authors.lastname: McGee
authors.forename: T G
authors.initials: TG
authors.lastname: Nicol
authors.forename: J
authors.initials: J
authors.lastname: Cunningham
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002540:Cerebral Cortex / Q000502:physiology; D002648:Child; D004594:Electrophysiology; D005260:Female; D006801:Humans; D007859:Learning Disabilities / Q000175:diagnosis; D008297:Male; D009434:Neural Pathways / Q000502:physiology; D009482:Neurophysiology; D010468:Perceptual Disorders / Q000175:diagnosis; D010700:Phonetics; D011601:Psychophysics; D012727:Sex Characteristics; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*; D013788:Thalamus / Q000502:physiology