Predicting Early Bulbar Decline in Amyotrophic Lateral Sclerosis: A Speech Subsystem Approach.

Panying Rong,Jordan R Green,Jun Wang,Yana Yunusova

doi:10.1155/2015/183027

Abstract

Purpose. To develop a predictive model of speech loss in persons with amyotrophic lateral sclerosis (ALS) based on measures of respiratory, phonatory, articulatory, and resonatory functions that were selected using a data-mining approach. Method. Physiologic speech subsystem (respiratory, phonatory, articulatory, and resonatory) functions were evaluated longitudinally in 66 individuals with ALS using multiple instrumentation approaches including acoustic, aerodynamic, nasometeric, and kinematic. The instrumental measures of the subsystem functions were subjected to a principal component analysis and linear mixed effects models to derive a set of comprehensive predictors of bulbar dysfunction. These subsystem predictors were subjected to a Kaplan-Meier analysis to estimate the time until speech loss. Results. For a majority of participants, speech subsystem decline was detectible prior to declines in speech intelligibility and speaking rate. Among all subsystems, the articulatory and phonatory predictors were most responsive to early bulbar deterioration; and the resonatory and respiratory predictors were as responsive to bulbar decline as was speaking rate. Conclusions. The articulatory and phonatory predictors are sensitive indicators of early bulbar decline due to ALS, which has implications for predicting disease onset and progression and clinical management of ALS.

Highlights

Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease defined by the degeneration of both upper and lower motor neurons in the brain and spinal cord
Bulbar motor deterioration due to ALS was investigated using a data-driven approach based on commonly used clinical measures of speech decline and instrumentation-based measures of the four major speech subsystems
The findings showed that the subsystem measures that captured articulatory and phonatory dysfunction were affected prior to the presence of speech intelligibility deficits and the substantial slowing of speaking rate

Summary

Introduction

Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease defined by the degeneration of both upper and lower motor neurons in the brain and spinal cord. Bulbar ALS, which affects speech and swallowing, is characterized by the eventual loss of speech intelligibility and ability to swallow [2,3,4]. The current standard assessment of bulbar function includes clinician-based estimates of speech intelligibility and speaking rate. The slowing of speaking rate to 120 WPM marks the onset of the rapid decline phase of speech intelligibility (i.e., intelligibility < 85%). In contrast to the normal speech phase (i.e., intelligibility ranged within 100∼97%) and the slow decline phase (i.e., intelligibility ranged within 96%∼86%), which correspond to minimal or slow declines in intelligibility, the rapid decline phase is characterized by precipitous declines in intelligibility and the eventual loss of speech communication within a short time span [3, 4]

Methods

Results

Discussion

Conclusion