Patients with late-onset Pompe disease demonstrated a deterioration in voice quality over a period of three years, but early treatment may stop this progressive impairment, a study reports.
The study, “Follow-up analysis of voice quality in patients with late-onset Pompe disease,” was published in the Orphanet Journal of Rare Diseases.
Pompe disease is a progressive metabolic disorder caused by a deficiency in an enzyme known as alpha-glucosidase, which plays a role in degrading a large molecule known as glycogen.
As a result, glycogen accumulates in the body — mainly in the muscles — where it causes progressive impairment.
Patients with Pompe disease can have either the infantile form (classic form) or the late-onset form, which can occur in both juveniles and adults.
Those with late-onset Pompe disease (LOPD) can develop dysfunction of the voice apparatus, which leads to both speech and voice difficulties.
These impairments include problems with articulation, consonant substitutions, consonant omissions, mild to moderate hypernasal resonance, hoarseness, dysphonia (disorder of voice), glottic insufficiency (vocal cords cannot close), and tense voice.
To date, only one study has assessed voice quality dysfunction in patients with LOPD.
Therefore, researchers conducted a study to evaluate and compare changes in voice quality over a period of three years in 15 LOPD patients who were first examined in 2014 and then re-examined in 2017.
Voice quality assessment of patients was carried out using acoustic analysis and electroglottography, a tool for analyzing the voice source in speech and singing.
The LOPD patients, whose ages ranged between 15 and 57, came from 10 different families. They were all being treated with enzyme replacement therapy (ERT).
In 2014 and then again in 2017, these 15 LOPD patients underwent perceptual assessment of voice quality on the German Roughness-Breathiness-Hoarseness (RBH) scale, electroglottographic recordings, and acoustic recordings.
In 2014, the patients were found to have voice quality disorders, the symptoms of which included dysphonia, glottic insufficiency, tense voice, voice pitch fluctuation, and variation within the same phonation (the process by which the vocal folds produce certain sounds).
Three years later, in 2017, the LOPD patients demonstrated a deterioration in voice quality.
In particular, the researchers noted that there was a statistically significant increase in glottic insufficiency and a shift toward tense voice.
However, the clinical condition of patients did not change significantly between 2014 and 2017.
Interestingly, two out of three patients who had been treated with ERT before their symptoms appeared demonstrated stable voice quality compared with 2014.
This suggests that early identification and treatment of Pompe disease can help patients retain their voice quality.
“Changes in voice quality in LOPD patients were demonstrated, with deterioration in voice quality observed three years after the 2014 study. The changes in patients included increases in both tense voice and glottic insufficiency,” the authors concluded.