"Does speech in patients with different Parkinson's disease subtypes decline over time?"

Area of Science:

• Neurology
• Speech-Language Pathology
• Biomedical Engineering

Background:

• Parkinson's disease (PD) is a neurodegenerative disorder affecting motor control.
• PD presents with diverse motor subtypes, including tremor-dominant and non-tremor-dominant.
• Speech impairments are common in PD, but their progression across subtypes is not fully understood.

Purpose of the Study:

• To investigate longitudinal speech changes in patients with different motor subtypes of Parkinson's disease (PD).
• To identify acoustic markers that differentiate between tremor-dominant and non-tremor-dominant PD subtypes.

Main Methods:

• A longitudinal study of 60 individuals with PD, classified into tremor-dominant (n=42) and non-tremor-dominant (n=18) subtypes.
• Speech samples collected at baseline, 12 months, and 24 months using diadochokinesis (/pataka/) and monologue tasks.
• Acoustic variables analyzed included syllable number, duration, phonation time, articulation rate, average syllable duration (ASD), and pause ratio.

Main Results:

• No significant differences in speech metrics over time were found when analyzing tremor-dominant and non-tremor-dominant subtypes separately.
• Significant differences between subtypes were observed in diadochokinesis tasks, including syllable number, phonation time, articulation rate, and ASD.
• Trend analysis revealed distinct patterns for monologue and diadochokinesis tasks between the two subtypes.

Conclusions:

• Speech patterns in both tremor-dominant and non-tremor-dominant PD subtypes are stable over a three-year period.
• Articulation time metrics effectively distinguish between PD motor subtypes.
• Diadochokinesis tasks show potential for deriving speech biomarkers for PD subtypes.