Acoustic and Perceptual Markers of Dysarthria in Amyotrophic Lateral Sclerosis (ALS)

ALS is a motor neuron disease characterized by a progressive degeneration of motor neurons in the brain, brainstem, and spinal cord. Degeneration of the upper and lower motor neurons (UMN and LMN) leads to spasticity, impaired reflexes, muscle fatigue, muscle weakness and atrophy. PLS is a motor neuron disease involving exclusively the UMN system and Kennedy's disease is a genetic condition involving the LMN system. Those three different motor neuron diseases can lead to a dysarthria. Affected individuals with ALS vary significantly in the locus of disease onset, presentation at diagnosis and rate of progression. Regardless of the site of onset, most patients with ALS will experience bulbar motor deterioration that will lead to a dysarthria. According to Darley's classification of dysarthrias, dysarthria in ALS is grossly described as "mixed" (both spastic, due the UMN deterioration, and flaccid, due to the LMN deterioration). However, at the onset of bulbar signs, when the dysarthria is still mild, dysarthric profiles and bulbar clinical signs can vary within individuals. Perceptual and acoustic features of dysarthria in ALS have been studied but they have not been studied in dysarthric patients with PLS and KD. This study was motivated by the need to better understand the dysarthria in ALS and it's management in speech therapy. The goals of this study is to question the impact of the degeneration of the UMN system versus the LMN system on the speech motor system and see if the investigators can identify acoustic and perceptual markers related to UMN degeneration on one side and LMN degeneration on the other side. The investigators will compare acoustic and perceptual features between the recorded speech of different clinical groups. Clinical groups will be made according to clinical signs and EMG. The clinical signs for UMN involvement in the bulbar region are: gag reflex, jaw clonus, pseudobulbar features (lability). The clinical signs for LMN involvement are: lingual atrophy and fasciculation. The population will be composed by groups of ALS-LMN patients, ALS-UMN patients , PLS patients and KD patients and a control group already recruited by the LPP (Laboratoire de Phonétique et de Phonologie) team (CNRS...) which permitted to establish the standards of the "MonPaGe" tool that the investigators will use to analyse patients recorded speech. This tool is based on a multidimensional and quantified assessment of voice and speech, by a set of targeted acoustic and perceptual criteria.