Dysarthria in amyotrophic lateral sclerosis: A review

Abstract

Dysarthria is a motor disorder of speech characterized by abnormalities of the articulation and intelligibility of speech. Phonation and the rate of facial movements may also be affected. Understanding the nature and course of dysarthria in amyotrophic lateral sclerosis (ALS) is important because loss of communication prevents patients from participating in many activities, may lead to social isolation, and reduces the quality of life. The goal of management of dysarthria in ALS patients is to optimize communication effectiveness for as long as possible.

The information about dysarthria in ALS is dispersed in physiological, pathological, speech therapy, otorhinolaringological and neurological publications. This review summarizes the current state of knowledge on the clinical features, differential diagnosis, pathophysiology, investigations and management of dysarthria in ALS patients. There is a need to compare the different methods used to assess dysarthria and for controlled clinical trials to assess therapeutic strategies.

• ALS
• MND
• dysarthria
• bulbar palsy

Notes

*Acoustic cues in speech are: fundamental frequency, vowel formants, noise bursts, transitions. A formant is a peak in an acoustic frequency spectrum that results from the resonant frequencies of the vocal tracts. Distinguishing between vowels can be quantitatively demonstrated by the frequency content of the vowel sounds. The formant with the lowest frequency is called F1; the second F2 is the next highest. These two formants are primarily determined by the position of the tongue. The second formant (F2) is well known to be important to intelligibility.