Peripheral hearing, brainstem auditory responses, and P300 potentials in Parkinson's disease: A cross-sectional study with one-year follow-up.

BACKGROUND: Auditory dysfunction and cognitive impairment are increasingly recognized as non-motor features of Parkinson's disease (PD), but longitudinal data integrating peripheral hearing, brainstem auditory responses, and cortical auditory-cognitive processing are limited. This study compared pure-tone audiometry, brainstem auditory evoked responses, and auditory P300 potentials between patients with PD and healthy controls at baseline and one year. METHODS: This cross-sectional study with one-year follow-up evaluated pure-tone audiometry, Brainstem Evoked Response Audiometry (BERA), and auditory P300 event-related potentials in 50 patients with PD and 28 healthy controls who completed both assessments. Clinical and neuropsychological measures were assessed. RESULTS: Patients with PD had lower Montreal Cognitive Assessment (MoCA) scores than controls at baseline and one year, higher anxiety scores at both assessments, and higher depression scores at one year. Motor severity remained stable, whereas levodopa equivalent daily dose increased. Peripheral hearing impairment at baseline was more frequent in PD. Selected BERA latencies, particularly left-ear wave IV latency, showed nominal between-group differences, but no BERA parameter survived false discovery rate correction. Baseline Cz-P300 amplitude was higher in PD and remained independently associated with PD status after adjustment for age, sex, education, and hearing status. Cz-P300 parameters were not independently associated with MoCA scores in PD-only models. CONCLUSION: Peripheral hearing impairment was more frequent in PD, whereas only the baseline Cz-P300 amplitude remained significant after correction for multiple testing and multivariable adjustment. These findings suggest that auditory electrophysiological measures may capture aspects of sensory-cognitive dysfunction in PD, although their clinical significance requires further clarification.