VOICE LOUDNESS, SELF-ASSESSMENT, AND SENSORY FEEDBACK IN PARKINSON’S DISEASE VOICE PRODUCTION

Parkinson’s disease (PD) is frequently associated with reduced voice loudness, potentially linked to atypical sensory feedback processing in voice production. Individuals with PD (IwPD) often do not notice their voice difficulties, limiting self-assessment. Prior electrophysiological studies using Motor-Induced Suppression (MIS) and event-related potentials (ERPs; N1, P2) indicated alterations associated with loudness regulation (Emmendorfer et al., 2021; Abur et al., 2018; Li et al., 2021). We examined loudness, self-perception, and sensory feedback in IwPD using PROMs and ERPs. In Study 1, self-perceived voice function was assessed with patient-reported outcome measures (PROMs) in 27 IwPD (61–79 years), 25 individuals with general voice disorders (GVD; 57–83 years), and 28 healthy controls (HC; 60–80 years). Group differences were tested with univariate and multivariate analyses. In Study 2, ERPs were recorded during voice playback in three conditions: vocalizing at +15 dB, passive listening to +15 dB voice playback, and a motor only condition (button-press)(100 trials/condition). IwPD reported lower awareness of voice problems than GVD and HC despite slightly higher PROM scores than HC. A principal component analysis indicated a distinct group separation in perceived loudness and total scores. Further, IwPD showed altered voice perception, including N1 differences to unexpected loudness increases during passive listening. These findings indicate that reduced voice awareness co-occurs with impaired perception of voice loudness at the neural level in PD. These results support targeted voice assessment and therapy that address both perceptual and neurophysiological factors.