Classifications
of the
Dysarthrias;
Motor Speech Disorders



​Dysarthria is a term used for a group of speech disorders caused by weakness, paralysis, rigidity, spasticity, sensory loss, or incoordination of muscle groups responsible for speech. Dysarthrias are neurogenic speech disorders that can affect any of the following subsystems necessary to produce speech & language
  • Respiration
  • Phonation
  • Resonance
  • Articulation
  • Prosody

All of the following Speech Disorders are caused by a pathology affecting the nervous system. Most neurogenic speech disorders fit into one of the dysarthria types. Meaning that if this speech disorder is diagnosed, the brain is somehow involved, and it's most likely that we, an SLP, can easily figure out where the SOL (Site of Lesion) is occurring based on the symptoms. Site of Lesion can mean a few different things, so don't rush to judgement and automatically think cancer. It just means, refer to the neurologist first if they have not already been and you are suspecting dysarthria. There are seven (7) main types of Dysarthrias.

Flaccid Dysarthria

​The patient demonstrates weakness and is usually marked by a droop towards one side of the face (mouth open, drooling, etc).

All of the speech CN's are involved 
  • Trigeminal, (CN V)
  • Facial Nerve, (CN VII)
  • Glossopharyngeal ,(CN IX)
  • Vagus Nerve and all three of it's branches; In the vagus nerve we worry about VF peresis or paralysis, and respiratory. -Pharyngeal Branch -Superior Laryngeal Nerve Branch -Reccurrent Laryngeal Nerve (RLN) 
  • CN XII
  • C3 C4 & C5 of the Cranial Nerves

Neuropathology location: LMN
Speech characteristics: depends upon what CN, SN, muscles are involved (motor, sensory)

Hyperkinetic Dysarthria

  • HYPERkinetic Dysarthria is marked by involuntary movements
  • Orofacial stable at rest and involuntary movements, involuntary jerk single or repetitive movements, jerky movements of the velum, tics, chorea, slower movements and slower involuntary movements as well as Spasmodic Dysphonia.
  • In terms of voice disorder, we worry about dyskinesias at the level of the vocal folds

​Neuropathology location: extrapyramidal system
Speech characteristics: dependent upon site of dyskinesias
​

Spastic Dysarthria

  • Spasticity causing harsh & strained voice.
  • Marked by harsh/strained voice.  Speech is slow.
Neuropathology location:  Upper Motor Neuron
​

Ataxic Dysarthria

  • This is the drunk sounding dysarthria (slur)
  • Incoordination & slurred speech

Hypokinetic Dysarthria

  • HYPOkinetic Dysarthria is most associated with Parkinsons' Disease characterized by Rigidity, Masked Face, flat, diminished, monotone speech. Speech mirrors movements. Slow shuffled gait. 
  • SOL is in the Basal Ganglia. 

Apraxia of Speech

  • Automatic speech is fine, prompted speech is difficult - Demonstrates inconsistency 
  • Marked by groping and increasing errors with complex language
  • Articulation & Prosody may be different.
  • AOS is often associated with Broca's Aphasia due to it's location in the brain.
  • There is evidence of AOS also diagnosed in a lot of children.