Researchers at the University of Kansas have found that slowing down speech may be a more effective strategy than speaking clearly for individuals with amyotrophic lateral sclerosis (ALS) to improve their speech rhythm and be better understood. This research, published in the Journal of Speech, Language, and Hearing Research, offers new insights into how neurodegenerative diseases affect speech and could pave the way for more personalized therapies. The study analyzed a public dataset that used X-ray microbeams to record the detailed speech organ movements of healthy speakers and those with ALS, providing a comprehensive look at the physical mechanics of speech production.
The core of the research lies in its potential to improve the early detection and monitoring of progressive communication disorders in people with neurodegenerative diseases. By understanding the subtle changes in the rhythm control of speech, clinicians can better tailor interventions to individual patients. This work is part of a broader effort at the University of Kansas to enhance brain health. The findings suggest that a one-size-fits-all approach to speech therapy may not be the most effective, and that interventions should be based on a detailed analysis of an individual’s specific speech deficits. This is especially important for a condition like ALS, which has a wide variety of symptoms and progression rates.
A New Model for Speech Communication
The study, titled “An Explanatory Model of Speech Communication Centered on Multiscale Rhythmic Modulation: Implications for Motor Speech Assessment and Intervention for Individuals With Amyotrophic Lateral Sclerosis,” was authored by Panying Rong, an associate professor in the University of Kansas Department of Speech-Language-Hearing: Sciences & Disorders, and her former graduate student, Erin Liston. Their research utilized a public dataset that employed X-ray microbeam technology to capture the precise movements of the tongue, lips, and jaw during speech. This allowed for a detailed comparison of the rhythmic characteristics of speech between healthy individuals and those with ALS across different speaking styles.
Three Speaking Styles Analyzed
The researchers examined three distinct speaking styles: habitual, slow, and clear. The habitual style was the participants’ normal way of speaking. For the non-habitual styles, participants were instructed to either speak more slowly or more clearly than they normally would. These two non-habitual styles are common intervention strategies used by clinicians to manage motor speech disorders. Rong noted that previous experiments have shown that these strategies can be effective in improving speech intelligibility for some individuals but not for others, and the reasons for these inconsistencies have not been well understood.
Unraveling the Rhythmic Disruptions of ALS
The study aimed to understand exactly how ALS disrupts speech rhythms and to determine whether common intervention strategies can improve these rhythmic characteristics. The analysis was conducted at various levels of speech production, from individual sounds to syllables and words. By matching the data from the participants’ physical mouth movements to their recorded speech, the researchers were able to gain a deeper understanding of the subclinical changes in rhythmic characteristics. Rong explained that her lab is developing a rhythmic modulation framework to characterize how the brain modulates speech rhythms in different speaking styles, which could help explain the effectiveness of various intervention strategies.
Effectiveness of Slow Speech
A key finding of the study was that speaking slowly appears to be a more effective strategy for most people with ALS to improve rhythm control and, consequently, their speech intelligibility. This is a significant insight, as it provides a data-driven basis for recommending certain speech therapy techniques over others. The researchers hope that by relating these physiological changes at subclinical levels to the functional alterations resulting from these intervention strategies, they can help clinicians identify the most effective strategy for each patient.
Advancing Personalized Medicine in Speech Therapy
The ultimate goal of this research is to translate these findings into clinical practice, enabling more personalized and effective speech therapy for individuals with neurodegenerative diseases. Rong emphasized that because ALS is a progressively debilitating condition with substantial variability in symptom presentations and progression rates, there is a strong need for personalized medicine. This means delivering the right intervention to the right person at the right time to optimize outcomes. The study represents a novel effort to facilitate the translation of personalized medicine into the care for progressive communication disorders in neurodegenerative diseases.
Broader Implications for Neurodegenerative Diseases
While this study focused on ALS, its findings have broader implications for other neurodegenerative diseases that affect speech, such as Alzheimer’s, Frontotemporal Dementia, and Vascular Dementia. Speech and language impairments are a prominent symptom in many of these conditions, and they can manifest in various ways, including difficulty with name generation, single-word comprehension, and changes in speech rate and timing. For example, patients with dementia have been found to produce shorter speech and more pauses than healthy older adults. Similarly, individuals with logopenic variants of primary progressive aphasia or Alzheimer’s disease tend to pause more frequently or for longer durations.
Speech as a Biomarker
Speech is considered an excellent biomarker for neurodegenerative diseases because it is non-invasive and its analysis is rapid and economical. Subtle changes in speech, such as alterations in duration, fluency, and intensity, can be indicative of an underlying neurodegenerative process. In some cases, these changes may be present even in the preclinical stages of a disease, offering an opportunity for early diagnosis and intervention. For example, in individuals with mild cognitive impairment that is likely to progress to Alzheimer’s, changes in speech duration and an alteration in rhythm rate and intensity have been identified as differentiating parameters.
