The impact of Lee Silverman Voice Treatment (LSVT LOUD®) on voice, communication, and participation: Findings from a prospective, longitudinal study

•LSVT LOUD® decreased voice handicap.•LSVT LOUD® improved communicative participation and communicative effectiveness.•There was a strong correlation between patient- and partner-ratings.•The Communicative Participation Item Bank was sensitive to treatment changes.•LSVT LOUD® may reduce social isolation risk by facilitating social participation.