Purpose: The primary purpose of this study was to evaluate the effect of three different types of speech amplification devices on spontaneous speech intelligibility of people with hypophonia secondary to Parkinson's disease or parkinsonism. Method: Twenty-one individuals with hypophonia described pictures aloud to their primary communication partner in four device and two noise conditions. Device conditions included no device, a portable wired speech amplifier, a wireless stationary amplifier, and a one-way personal communication system. Noise conditions included quiet and 65-dB multitalker background noise. Speech intelligibility was evaluated from the perspective of two listener groups, familiar communication partners and naive listeners, as a function of device type and noise. Results: Overall, all three devices were associated with improved intelligibility, especially in noise and for longer utterances for both listener groups. Intelligibility was highest for the personal communication system and lowest for the portable wired amplifier. These results for spontaneous speech patterned similarly to those for read sentences reported for these same talkers and listeners in Knowles et al. (2020) . Conclusions: Speech amplification devices demonstrate measurable improvements in intelligibility of spontaneous speech in individuals with hypophonia. Findings add to a growing body of evidence of the potential effectiveness of speech amplification as a management tool for hypophonia. Supplemental Material: https://doi.org/10.23641/asha.31834960
Knowles et al. (Thu,) studied this question.