Performance of the phonatory deviation diagram in monitoring voice quality before and after voice exercise in individuals with Parkinson's Disease.
Hellen Vasconcelos Silva Leal de Lima, Leonardo Wanderley Lopes, Hilton Justino da Silva and 4 others
PMID 37466502WHAT IT FOUND
A brief vocal exercise improved shimmer and shifted voice diagrams toward normality, but did not change diagram categories.
Most voices remained outside the normal range. Therapists should track visual shifts rather than expecting categorical changes.
Key findings
01Shimmer was the only acoustic parameter that improved significantly after the vocal technique.
02There was no significant difference in the distribution of voice samples across phonatory deviation diagram categories (area, density, quadrant, shape) after the intervention.
03Visual qualitative analysis showed that 70.58% of cases displaced toward the lower-left quadrant, closer to normality, after using the technique.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
Small sample size (n = 30). Retrospective design using secondary data from a previous study. The intervention was a single brief exercise, which may not reflect long-term therapy outcomes. Most participants had mild to moderate disease (Hoehn & Yahr stages I-III), limiting generalizability to advanced cases.
Declared interests
Funded by CAPES and PROPG-UFPE. No other conflicts of interest declared.
The easy way to misread this
Do not interpret the lack of significant change in PDD categories as evidence that the exercise failed. The study found that while categorical thresholds were not crossed, visual displacement toward normality and improved shimmer occurred, suggesting the tool is more sensitive to directional trends than binary classification in this population.