The Effects of LSVT®LOUD on Monopitch of Speech for Oral Reading and Monologue in Japanese-Speaking Patients with Parkinson's Disease

Abstract

Monopitch is one of the speech features frequently observed in patients with Parkinson's disease (PD). The systematic voice therapy program LSVT®LOUD (LOUD) is known to increase loudness of speech in PD patients and to have effect on monopitch in English-speaking patients. The aim of the current study was to examine whether LOUD would alter monopitch in Japanese-speaking patients with PD. Thirty-five patients (mean age: 66) and twenty-nine normal controls (mean age: 68) were included in this study. Speech signals for oral reading and monologue tasks were recorded, and acoustic-perceptual analyses were conducted. Speaking pitch range (SPR) in semitones (st) increased significantly (p<0.01) comparing pre-treatment (10.5st) with post-treatment (13.1st), relevant to the level of the normal controls (13.4st). The grade of monopitch, speech intelligibility, and speech naturalness all improved significantly (p<0.05). Increased vocal loudness was also observed after the treatment (p<0.01). Our findings suggest that LOUD has positive effects on not only vocal loudness but also pitch range, which are preferred as normal prosodic features, in Japanese-speaking patients with PD.