Lombard's effect's implication in intensity, fundamental frequency and stability on the voice of individuals with Parkinson's disease

"Lombard Effect" and Voice Changes in Adductor Laryngeal Dystonia: A Pilot Study

OBJECTIVES

The aim was to describe the acoustic, auditory-perceptive, and subjective voice changes under the Lombard effect (LE) in adductor laryngeal dystonia (AdLD) patients.

METHODS

Subjective perception of vocal effort (OMNI Vocal Effort Scale OMNI-VES), Maximum Phonation Time (MPT), and the perceptual severity of dysphonia (GRBAS scale) were assessed in condition of stillness and under LE in 10 AdLD patients and in 10 patients with typical voice. Speakers were asked to produce the sustained vowel /a/ and to read a phonetically balanced text aloud. Using the PRAAT software, the following acoustic parameters were analyzed: Mean Pitch (Hz), Minimum and Maximum Intensity (dB), the Fraction of Locally Unvoiced Frames, the Number of Voice Breaks, the Degree of Voice Breaks (%), the Cepstral Peak Prominence-Smoothed (CPPS) (dB).

RESULTS

Under LE, the AdLD group showed a decrease of both G and S parameters of GRBAS and subjective effort, mean MPT increased significantly; in the controls there were no significant changes. In both groups under LE, pitch and intensity of the sustained vowel /a/ significantly increased consistently with LE. In the AdLD group the mean gain of OMNI-VES score and the mean gain of each parameter of the speech analysis were significantly greater than the controls' ones.

CONCLUSION

Auditory feedback deprivation obtained under LE improves subjective, perceptual-auditory, and acoustics parameters of AdLD patients. These findings encourage further research to provide new knowledge into the role of the auditory system in the pathogenesis of AdLD and to develop new therapeutic strategies.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:3754-3760, 2024.

Behavioral Management of Respiratory/Phonatory Dysfunction for Dysarthria Associated With Neurodegenerative Disease: A Systematic Review

PURPOSE

This systematic review represents an update to previous reviews of the literature addressing behavioral management of respiratory/phonatory dysfunction in individuals with dysarthria due to neurodegenerative disease.

METHOD

Multiple electronic database searches and hand searches of prominent speech-language pathology journals were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards.

RESULTS

The search yielded 1,525 articles, from which 88 met inclusion criteria and were reviewed by two blinded co-investigators. A large range of therapeutic approaches have been added to the evidence base since the last review, including expiratory muscle strength training, singing, and computer- and device-driven programs, as well as a variety of treatment modalities, including teletherapy. Evidence for treatment in several different population groups-including cerebellar ataxia, myotonic dystrophy, autosomal recessive spastic ataxia of Charlevoix-Saguenay, Huntington's disease, multiple system atrophy, and Lewy body dementia-were added to the current review. Synthesis of evidence quality provided strong evidence in support of only one behavioral intervention: Lee Silverman Voice Treatment Program (LSVT LOUD) in people with Parkinson's disease. No other treatment approach or population included in this review demonstrated more than limited evidence, reflecting that these approaches/populations require urgent further examination.

CONCLUSION

Suggestions about where future research efforts could be significantly strengthened and how clinicians can apply research findings to their practice are provided.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24964473.

Laryngeal Aerodynamics in Healthy Older Adults and Adults With Parkinson's Disease

PURPOSE

The present study compared laryngeal aerodynamic function of healthy older adults (HOA) to adults with Parkinson's disease (PD) while speaking at a comfortable and increased vocal intensity.

METHOD

Laryngeal aerodynamic measures (subglottal pressure, peak-to-peak flow, minimum flow, and open quotient [OQ]) were compared between HOAs and individuals with PD who had a diagnosis of hypophonia. Increased vocal intensity was elicited via monaurally presented multitalker background noise.

RESULTS

At a comfortable speaking intensity, HOAs and individuals with PD produced comparable vocal intensity, rates of vocal fold closure, and minimum flow. HOAs used smaller OQs, higher subglottal pressure, and lower peak-to-peak flow than individuals with PD. Both groups increased speaking intensity when speaking in noise to the same degree. However, HOAs produced increased intensity with greater driving pressure, faster vocal fold closure rates, and smaller OQs than individuals with PD.

CONCLUSIONS

Monaural background noise elicited equivalent vocal intensity increases in HOAs and individuals with PD. Although both groups used laryngeal mechanisms as expected to increase sound pressure level, they used these mechanisms to different degrees. The HOAs appeared to have better control of the laryngeal mechanism to make changes to their vocal intensity.

Speech and language therapy versus placebo or no intervention for speech problems in Parkinson's disease

BACKGROUND

Parkinson's disease patients commonly suffer from speech and vocal problems including dysarthric speech, reduced loudness and loss of articulation. These symptoms increase in frequency and intensity with progression of the disease). Speech and language therapy (SLT) aims to improve the intelligibility of speech with behavioural treatment techniques or instrumental aids.

OBJECTIVES

To compare the efficacy of speech and language therapy versus placebo or no intervention for speech and voice problems in patients with Parkinson's disease.

SEARCH METHODS

Relevant trials were identified by electronic searches of numerous literature databases including MEDLINE, EMBASE, and CINAHL, as well as handsearching of relevant conference abstracts and examination of reference lists in identified studies and other reviews. The literature search included trials published prior to 11(th) April 2011.

SELECTION CRITERIA

Only randomised controlled trials (RCT) of speech and language therapy versus placebo or no intervention were included.

DATA COLLECTION AND ANALYSIS

Data were abstracted independently by CH and CT and differences settled by discussion.

MAIN RESULTS

Three randomised controlled trials with a total of 63 participants were found comparing SLT with placebo for speech disorders in Parkinson's disease. Data were available from 41 participants in two trials. Vocal loudness for reading a passage increased by 6.3 dB (P = 0.0007) in one trial, and 11.0 dB (P = 0.0002) in another trial. An increase was also seen in both of these trials for monologue speaking of 5.4 dB (P = 0.002) and 11.0 dB (P = 0.0002), respectively. It is likely that these are clinically significant improvements. After six months, patients from the first trial were still showing a statistically significant increase of 4.5 dB (P = 0.0007) for reading and 3.5 dB for monologue speaking. Some measures of speech monotoni city and articulation were investigated; however, all these results were non-significant.

AUTHORS' CONCLUSIONS

Although improvements in speech impairments were noted in these studies, due to the small number of patients examined, methodological flaws, and the possibility of publication bias, there is insufficient evidence to conclusively support or refute the efficacy of SLT for speech problems in Parkinson's disease. A large well designed placebo-controlled RCT is needed to demonstrate SLT's effectiveness in Parkinson's disease. The trial should conform to CONSORT guidelines. Outcome measures with particular relevance to patients with Parkinson's disease should be chosen and patients followed for at least six months to determine the duration of any improvement.

Vocal responses to perturbations in voice auditory feedback in individuals with Parkinson's disease

BACKGROUND

One of the most common symptoms of speech deficits in individuals with Parkinson's disease (PD) is significantly reduced vocal loudness and pitch range. The present study investigated whether abnormal vocalizations in individuals with PD are related to sensory processing of voice auditory feedback. Perturbations in loudness or pitch of voice auditory feedback are known to elicit short latency, compensatory responses in voice amplitude or fundamental frequency.

METHODOLOGY/PRINCIPAL FINDINGS

Twelve individuals with Parkinson's disease and 13 age- and sex-matched healthy control subjects sustained a vowel sound (/α/) and received unexpected, brief (200 ms) perturbations in voice loudness (±3 or 6 dB) or pitch (±100 cents) auditory feedback. Results showed that, while all subjects produced compensatory responses in their voice amplitude or fundamental frequency, individuals with PD exhibited larger response magnitudes than the control subjects. Furthermore, for loudness-shifted feedback, upward stimuli resulted in shorter response latencies than downward stimuli in the control subjects but not in individuals with PD.

CONCLUSIONS/SIGNIFICANCE

The larger response magnitudes in individuals with PD compared with the control subjects suggest that processing of voice auditory feedback is abnormal in PD. Although the precise mechanisms of the voice feedback processing are unknown, results of this study suggest that abnormal voice control in individuals with PD may be related to dysfunctional mechanisms of error detection or correction in sensory feedback processing.