Auditory late potentials in normal-hearing adult subjects with Down's syndrome.

Objective: Several studies have demonstrated that adult subjects with Down's syndrome (DS) and hearing impairments show significantly delayed latencies in auditory late potentials (ALPs). The aim of this study was to investigate whether the differences were still present in ALPs in an adult DS population with normal hearing, taking into consideration sex, handedness, and head size. Study Design: Prospective study. Setting: Audiology unit of the hospital Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy. Patients: Sixteen normal-hearing adult DS subjects referred to the health monitoring program for DS patients of Vivi Down Onlus Association in Milan, Italy (7 male subjects with a mean age of 26 +/- 7.74 yr and 9 female subjects with a mean age of 28 +/- 8.63 yr) and 16 controls (7 male subjects with a mean age of 26 +/- 7.74 yr and 9 female subjects with a mean age of 28 +/- 8.86 yr) matched for sex, age, and handedness. Main Outcome Measure: The 2 negative peaks, N1 and N2, and the 2 positive peaks, P1 and P2, of ALP. Results: ALP N1 and P2 components were well defined in all subjects. The P1 and N2 components were less evident than the others. There were significant delayed latencies in the DS group with respect to the control subjects for P1, N1, P2, and N2 components. Conclusion: Our study demonstrated that ALP longer latencies are present in adult DS participants even when they have a normal hearing threshold, regardless of handedness and head size.