An investigation of auditory memory for tonal and nonword stimuli in adolescents with Williams syndrome

This study sought to investigate auditory memory in participants with Williams syndrome (WS) while considering the relation between phonological memory and hearing status. Participants were 17 adolescents with WS (13.17 to 20.33 years) and 17chronological age and gender control matches from the general population (CTR). Estimated behavioral hearing thresholds, phonological processing measures, and electrophysiologic responses were recorded. Results replicate previous findings that hearing loss is significantly more common among adolescents with WS than among adolescents in the general population. Further, phonological memory testing indicated that the WS group performed significantly worse than the CTR group on digit recall but not on nonword repetition. Event-related potentials (ERPs) including N100 and P300 for tonal and nonword stimuli in single-deviant and two-deviant oddball conditions confirm auditory processing differences between the two groups. ERP results for tonal stimuli indicated that the WS group differed from the CTR group in amplitude of the N100 response, suggesting a reduction in orienting to changing stimuli. Further, the WS group displayed increased latency of P300 responses relative to the CTR group, even after controlling for IQ differences. There was not, however, a corresponding reduction in amplitude. Additionally, the WS group displayed poorer performance on P300 target latency in the presence of a distracter stimulus. These differences in P300 responses for tonal stimuli were not present for nonword stimuli. The WS group displayed a differing topography of response for the nonword stimuli than did the CTR group, with an increased latency occurring at posterior electrodes. The electrophysiologic responses provide further support that there may be differing mechanisms for processing tonal sounds and speech-like stimuli in individuals with WS.