Acquired Motor Speech Disorders

Acquired Motor Speech Disorders

What is an Acquired Motor Speech Disorder?

Motor Speech Disorders (MSD) are a group of speech and voice disorders that occur as a result of damage to the brain or other parts of the nervous system. The severity of a MSD may range from very mild to very severe.

What Causes MSDs?

There are many different causes of an acquired MSD, including progressive neurological conditions such as;

  • Multiple Sclerosis 
  • Muscular Dystrophy
  • Myasthenia Gravis
  • Parkinson's Disease
  • Motor Neurone Disease
  • Dementia

Or a MSD may occur suddenly as a result of an acute trauma to the nervous system, for example;

IASLT Communication Card for people with Dysarthria


Motor Speech Disorder or MSD is an umbrella term to describe dysarthria and apraxia of speech

Types of MSD

There are two main types of MSDs;

  • Apraxia of Speech

Apraxia of speech (AOS)  is a disorder that affects the pathways in the brain involved in planning and sequencing speech. A person with AOS has trouble saying what they want to say correctly and consistently. The person knows what they want to say, but cannot properly plan and sequence the speech sound movements they need e.g. the lip and tongue movements. 

  • Dysarthria of Speech

Dysarthria is a group of disorders caused by weakness, slowness, or lack of coordination in the muscles involved in producing speech, including the muscles of the jaw, tongue, lips, voice and breathing system. Dysarthria can alter a person's speech clarity, naturalness, speed, volume, pitch and resonance.

The speech and language therapist’s role in the management of MSDs

The SLT plays an important role in the diagnosis and treatment of people with MSDs. A person may have both dysarthria and AOS, which makes the diagnosis and the treatment of the two disorders more difficult. The SLT’s role may include;

  • Screening people with a possible MSD and determining those who need further speech assessment and/or referral to other services.
  • A full assessment of all speech subsystems when indicated.
  • Diagnosing a MSD and determining the severity, characteristics, and real-life impact of the disorder. 
  • Setting personal and meaningful goals for people with MSDs along with the person, their family and other multidisciplinary team members.
  • Referring to and collaborating with, other healthcare professionals when appropriate. 
  • Rehabilitation of speech, where appropriate, with the aim to improve and restore function, with the aim of increasing a person’s communication effectiveness, social integration and overall quality of life.
  • Communication-based therapy focused on using the person’s strengths to compensate for their speech disorder, with the aim to increase communication effectiveness, social integration, and overall quality of life. Some people with a MSD may not be able to effectively communicate using their speech and may need the assistance of alternative and augmentative communication methods.
  • Educating and supporting others, including family members, carers and other healthcare professionals, to facilitate effective communication with the person across a wide range of social contexts and environments. 
  • Providing support and advice to people with MSDs and their care-givers, directing them toward available support groups, resources, and other professional services when appropriate.
  • Facilitating people with MSDs in decision-making and in assessments of capacity, supporting and enabling them to make important decisions relating to different aspects of their own care, including advanced care planning decisions.