Summary: Tongue range motion is reduced while lower lip and jaw motion is increased in people who suffer dysarthria associated with ALS. The findings may help develop new therapies to help those with ALS improve their speech, researchers say.
Source: Penn State.
New clues may help improve speech for people with dysarthria, a type of speech disorder commonly found in patients with amyotrophic lateral sclerosis (ALS).
Findings in a study led by Jimin Lee, assistant professor of communication sciences and disorders at Penn State, could aid patients with dysarthria. Dysarthria can cause slurred speech, slowed speech, abnormal pitch and rhythm, changes in voice quality and limited tongue, lip or jaw movement, according to the American Speech-Language-Hearing Association. Dysarthria has the highest prevalence rate among all types of acquired neurogenic communication disorders.
By analyzing the size of the space used by each articulator (tongue, lip and jaw) while study participants read a paragraph that includes all sounds in American English, Lee found that in people with more severe dysarthria due to ALS, tongue range of motion is reduced, while range of motion for the lower lip and jaw both increase.
This measurement could be useful for estimating speech dysfunction and determining treatment to improve speech in patients with ALS or other neurological conditions, such as Parkinson’s disease, cerebral palsy and multiple sclerosis.
“This highlights the importance of range of motion for speech production, and indicates that if we change range of motion in people with the disorder, if we ask them to expand their overall work space for speech production, then we may see more understandable speech,” Lee said.
“The difference in range of motion in people with dysarthria has been largely assumed, but had not been directly tested. It is exciting to provide empirical evidence based on the movement of articulators. Additionally, the study provides important evidence regarding the different amount of impairment across articulators as well as its high sensitivity to the severity of dysarthria. This has values for both intervention and diagnosis of dysarthria.”
The study, which included 22 ALS patients, is an extension of a previous study that involved 14 people with ALS. The American Journal of Speech-Language Pathology published the latest findings online this week.
Researchers conducted both studies using an instrument to analyze patients’ speech disorders, which measures the movement of tongue, lips and jaw using an electromagnetic field while simultaneously recording acoustic signals. The instrument is a 3-D, portable electromagnetic articulograph — also called the Wave system.
Sensors are attached to a patient’s tongue to trace its movement during speech production. Patients are asked to read a specific set of words and sentences. The tool also is connected to a microphone and computer, which stores the data.
“The ultimate goal is to develop effective intervention for people with dysarthria. In order to help people with ALS use their speech as long as possible, we will continue to identify what types of movement will generate speech signals that are easier to understand,” Lee said.
“The majority of people with ALS lose their speech during the progression of the disease. Their tongue function deteriorates fast but the jaw function is relatively preserved, and these two articulators work together for speech production. Thus, we are trying to find a way to enhance their speech intelligibility by looking at tongue and jaw movement characteristics simultaneously.”
Source: Jennifer Cruden – Penn State
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is in the public domain.
Original Research: Abstract for “Articulatory Range of Movement in Individuals With Dysarthria Secondary to Amyotrophic Lateral Sclerosis” by Jimin Lee; and Michael Bell in American Journal of Speech-Language Pathology. Published May 24 2018.
Articulatory Range of Movement in Individuals With Dysarthria Secondary to Amyotrophic Lateral Sclerosis
Purpose The current study examined overall articulatory range of movement (ROM) in individuals with amyotrophic lateral sclerosis (ALS). Differential involvement of articulators was also tested using articulatory working space in individuals with varying degrees of dysarthria severity and in typically aging individuals. A strong association between overall articulatory ROM and severity measures among individuals with ALS was hypothesized. In addition, it was hypothesized that differential involvement of articulators would be detected using overall articulatory ROM measures.
Method Twenty-two speakers with dysarthria secondary to ALS and 22 typically aging speakers participated. Speech intelligibility and speaking rate were used as indices of severity. Movement range and overall articulatory working space area (convex hull) of the tongue, lower lip, and jaw were each measured by electromagnetic articulography while the speakers produced the Rainbow Passage.
Results Tongue convex hull size was significantly correlated with both indices of severity. A significant interaction between articulators and groups was observed. Individuals with severe dysarthria had reduced tongue convex hull size and exaggerated lower lip convex hull size. ROM in the anterior–posterior dimension showed a more notable differential involvement pattern than ROM in the superior–inferior dimension. Results in the area under a receiver operating characteristic curve analysis revealed group-specific ROM sensitivity.
Conclusions The findings indicate that tongue ROM is reduced in individuals with more severe dysarthria when estimated using a standardized paragraph containing all American English phonemes. The articulatory working space measure could be useful for estimating speech dysfunction in ALS. ROM of the tongue decreases, but ROM of the lower lip and jaw each increase in individuals with severe dysarthria. Differential involvement of the articulators in the anterior–posterior dimension needs to be further investigated.