Oral Mobility a Good Indicator of Disease Progression in Patients with Advanced FA, Study Says

An individual’s ability to control facial muscles might be better than other tools commonly used to measure disease progression among patients with advanced Friedreich’s ataxia (FA), a study says.

The findings in “Oral mobility reflects rate of progression in advanced Friedreich’s ataxia,” were published recently in the Annals of Clinical and Translational Neurology.

FA is a rare, genetic, progressive disease that affects the nerves and muscles. Initially, patients notice an unusual loss of balance that gradually progresses to a complete inability to control body movements, a medical condition known as ataxia.

“Later-stage patients are often too severely impaired to be assessed using most measures of arm and leg function and the measurement of dysarthria [weakness of the muscles that control speech] has been suggested to be useful for annual follow-up of changes but has not yet been tested longitudinally,” the investigators wrote.

A group of researchers from Sorbonne University in Paris, France, set out to look for a new marker of FA progression that could be used to detect changes in the voice and speech of patients with advanced FA.

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Forty FA patients (20 men and 20 women) recruited from the Pitié‐Salpêtrière University Hospital in Paris were enrolled into the prospective, longitudinal study (NCT02069509).

All patients were asked to perform a battery of tests to evaluate their decline in speech, voice, and auditory function, and in their ability to move their mouth and control their facial muscles (oral motor mobility) over the course of one year.

At baseline, 26 patients were already wheelchair-bound and 13 had auditory impairments of varying degrees of severity (eight had mild impairments, three had moderate impairments and two wore hearing devices).

After one year of follow-up, none of the remaining patients enrolled in the study developed hearing problems, and none of those who already had auditory impairments at the beginning of the study experienced an aggravation of their symptoms. No significant correlations were found between the severity of patients’ hearing impairments and the scores of their voice tests.

Conversely, patients’ total oral motor mobility significantly decreased after one year of follow-up, both among individuals who already had oral motor impairments at baseline, and among those who did not. Analyses also revealed that tongue mobility was severely affected during the follow-up period, while the mobility of the cheeks and lips remained stable.

In addition, they found no significant differences in voice or speech test scores after one year of follow-up.

Finally, they found that over the course of one year, the standardized response mean (SRM) was high (1.26) for oral motor mobility and low (0.12) for the Scale for the Assessment and Rating of Ataxia (SARA). That suggested  oral mobility might be more suitable than SARA to assess disease progression in FA patients at more advanced stages of the disease.

Of note, the SRM is a statistical measure used to calculate responsiveness to a given parameter; SARA is a standard tool used to assess FA patients’ physical impairments

“Oromotor measurement was feasible, even in advanced FA, as the test took less than 5 minutes. Furthermore, it can be used independently of language or age. In addition, oromotor function is a good indicator of functional vocal handicap. [It] could, therefore, be a sensitive marker in therapeutic trials,” the investigators wrote.

“Further studies are needed to assess the responsiveness of oromotor function in earlier stages of the disease,” they said.