Background: For many people with Parkinson's disease (PWPD), the long-term maintenance of speech following intensive treatment remains elusive. PD Check-In, a model for supported self-managed maintenance of speech following LSVT LOUD®, was developed and evaluated. Aims: To evaluate the impact of PD Check-In on vocal intensity and level of satisfaction of PWPD and their communication partners (CPs) over 24 months following LSVT LOUD. Methods & Procedures: A repeated-measures study design examined the impact of PD Check-In on the speech of 16 PWPD. Participants received LSVT LOUD followed by PD Check-In at 6 and 12 weeks, and 6, 12 and 24 months after treatment. Outcome measures included acoustic measures of vocal intensity (sound pressure level--SPL) during sustained phonation, functional phrases, reading, and monologue, and satisfaction questionnaires for PWPD and their CPs. Outcomes & Results: A significant treatment effect for time (p < 0.01) was identified for all SPL variables. Planned comparisons showed significant improvements for each variable pre- to post-LSVT LOUD. There was a significant maintenance effect for SPL maximum sustained phonation only, post-LSVT LOUD to 24 months. SPL remained significantly above baseline for functional phrases and maximum sustained phonation at 24 months. Participants' satisfaction with PD Check-In was high, at 93.75% for PWPD and 79.99% for CPs, at 24 months post-treatment. Long intervals between appointments led PWPD to feel less motivated about speech practice but more confident in self-management. Conclusions & Implications: For PWPD and CPs, maintenance of speech following LSVT LOUD encompasses more than acoustic outcomes.