Voice assessment in patients with amyotrophic lateral sclerosis: Association with bulbar and respiratory function

Abstract

Abstract Patients with amyotrophic lateral sclerosis (ALS) face respiratory and bulbar dysfunction causing profound functional disability. Speech production requires integrity of bulbar muscles and good breathing capacity, being a possible way to monitor such functions in ALS. Here, we studied the relationship between bulbar and respiratory functions with voice characteristics of ALS patients, at the convenience of using a simple smartphone for voice recordings. For voice assessment we considered a speech therapists’ standardized tool – Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V); and an acoustic analysis toolbox (for both time and frequency domains). The bulbar subscore of the revised ALS Functional Rating Scale (ALSFRS-R) was used; and pulmonary function measurements included forced vital capacity (FVC%) and maximum expiratory and inspiratory pressures (MIP% and MEP%, respectively). Correlation coefficients and both linear and logistic regression models were applied. A total of 27 ALS patients (12 males; 61 years mean age; 28 months median disease duration) were included. Patients with significant bulbar dysfunction revealed greater CAPE-V scores in overall severity, roughness, strain, pitch, and loudness. They also presented slower speaking rates, longer pauses, and higher jitter values in acoustic analysis (all p < 0.05). The CAPE-V’s overall severity and sub-scores for pitch and loudness demonstrated significant correlations with MIP% and MEP% (all p < 0.05). By contrast, acoustic metrics (speaking rate, absolute energy, shimmer, and harmonic-to-noise ratio) were significantly correlated with FVC% (all p < 0.05).The results provide supporting evidence for using smartphone-based recordings in ALS patients for CAPE-V and acoustic analysis as good correlates of bulbar and respiratory function.