Effects of Tailored Singing on Voice Traits in Parkinson’s Disease and Controls: Intra- and Intergroup Analysis with Sex Stratification

Hypokinetic dysarthria affects up to 90% of individuals with Parkinson’s disease (PD), impairing communication and quality of life. This pilot study evaluated the effects of a tailored singing intervention on acoustic and biomechanical voice traits in PD and age-matched controls, hypothesizing improvements in phonatory function. Eight PD participants (4 men, 4 women, aged 60-81, Hoehn & Yahr ≤3) and 5 controls (3 men, 2 women, aged 63-82) completed ≥8 weekly 60-minute individualized singing sessions. BioMet®Phon assessed 11 voice traits, including F0, jitter, shimmer, biomechanical imbalances, and tremors. Pre- and post-intervention changes were analyzed using Wilcoxon signed-rank tests with Bonferroni correction (p<0.005). In PD, 68.2% of traits improved or stabilized (23.9% significant, p<0.05), notably body mass unbalance (-75.0%), cover mass unbalance (-73.4%), and cover stiffness unbalance (-73.1%); non-normative traits decreased from 40.9% to 30.7% (p=0.0386). Controls showed 83.6% improvement or stability (10.9% significant), particularly in shimmer (-21.1%) and body mass unbalance (-66.7%), with non-normative traits minimally reduced (14.5% to 12.7%, p=1.0). IQR reductions (72.7% in PD, 65.5% in controls) indicated enhanced phonatory consistency. PD males improved more than females; control females outperformed males. Individualized singing shows promise for improving voice traits in PD, with potential as a complementary therapy to LSVT. Larger trials are needed to confirm efficacy and explore long-term effects.