The Acoustic Voice Quality Index (AVQI) in People with Parkinson's Disease Before and After Intensive Voice and Articulation Therapies: Secondary Outcome of a Randomized Controlled Trial.

Voice quality was a secondary outcome; the trial was powered on sound pressure level, so the AVQI analysis was not the primary question the study was designed to answer. Neither participants nor treating clinicians were blinded to which treatment was delivered, which is inherent to speech therapy trials but means expectation effects cannot be ruled out. No significant difference was found between the Parkinson's group and healthy controls at pre-treatment for either AVQI or SPL, which the authors attribute to age-matching and the smaller sample of phonation used for analysis. Two LSVT LOUD participants and two untreated participants were excluded from analysis after a later diagnosis of atypical parkinsonism or severe palilalia. All participants were from the Denver, Colorado area, and the study was conducted at a single site.

The parent RCT was funded by the NIH-NIDCD. No industry funding or commercial conflicts of interest are declared in the supplied text.

Do not read the LSVT ARTIC follow-up improvement (d = 0.83) as evidence that articulation treatment improves voice quality in Parkinson's disease. The pre-to-post change did not reach significance (p = 0.087), and the group's scores remained above the dysphonia threshold of 2.43 at every time point, meaning these voices were still classified as dysphonic.