Single Word Intelligibility of Individuals with Parkinson's Disease in Noise: Pre-Specified Secondary Outcome Variables from a Randomized Control Trial (RCT) Comparing Two Intensive Speech Treatments (LSVT LOUD vs. LSVT ARTIC).

Katherine Freeman,Alan Sharpley,Angela Halpern,Geralyn Schulz,Lorraine Ramig,Ira Panzer,Jennifer Spielman

doi:10.3390/brainsci11070857

Abstract

The majority of people with Parkinson’s disease (PD) experience both prosodic changes (reduced vocal volume, reduced pitch range) and articulatory changes (imprecise articulation) that often limit speech intelligibility and may contribute to significant declines in quality of life. We conducted a randomized control trial comparing two intensive treatments, voice (LSVT LOUD) or articulation (LSVT ARTIC) to assess single word intelligibility in the presence of background noise (babble and mall). Participants (64 PD and 20 Healthy) read words from the diagnostic rhyme test (DRT), an ANSI Standard for measuring intelligibility of speech, before and after one month (treatment or no treatment). Teams of trained listeners blindly rated the data. Speech intelligibility of words in the presence of both noise conditions improved in PD participants who had LSVT LOUD compared to the groups that had LSVT ARTIC or no treatment. Intensive speech treatment targeting prominent prosodic variables in LSVT LOUD had a positive effect on speech intelligibility at the single word level in PD.

Highlights

It has been estimated that approximately 6.1 million people are living with Parkinson’s disease (PD) globally [1,2]
90% of people with PD have prosodic and articulatory signs, including reduced vocal loudness and difficulty with articulation. These changes in communication lead to a reduction in speech intelligibility, which has been reported to contribute to significant declines in functional communication, communicative participation, and quality of life
Our PD participants had significantly reduced single word intelligibility in both background noise conditions compared to healthy age-matched controls

Summary

Introduction

It has been estimated that approximately 6.1 million (range of 5.0–7.3 in 2016) people are living with Parkinson’s disease (PD) globally [1,2]. The two most salient speech signs include disorders of prosody (reduced vocal loudness; monopitch, and monoloudness; a breathy or harsh voice) [6,7,8,9,10,11,12,13], and disorders of articulation (imprecision of consonant and vowel production) [6,14,15,16,17,18,19,20,21,22,23,24,25]. Reduced vocal loudness (a prominent prosodic feature), is often the first speech sign noticed in people with PD [6,8]; voice is described as weak, hoarse, and breathy [26,27,28]. More recent studies have demonstrated abnormalities in central sensory processing (reduced awareness of soft voice), internal cueing (difficulty self-generating increased loudness), and self-monitoring of speech output that may play a causal role in the reduced vocal loudness of PD [35,36,37,38,39,40,41,42,43,44,45]

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