1.  Define mixed dysarthria
Mixed dysarthria is a combination of two or more of the pure dysarthria types.

2.  What is the neurological basis of a mixed dysarthria?
When neurological damage due to strokes, head injuries, degenerative and infectious diseases, tumors affect various components (upper motor, lower motor neurons) of the motor system simultaneously.  The individual with mixed dysarthria will demonstrate at least some speech characteristics of the pure dysarthrias that compose the mixed dysarthria.

3.  What dysarthria’s can co-occur?  Nearly any combination of the pure dysarthrias can comprise a mixed dysarthria.

4.  How frequent are mixed dysarthrias? Explain. Clinicians see more cases of mixed dysarthrias than dysarthrias of the pure form. With a brain stem stroke upper and lower motor neurons are close approximation.  Progressive disorders and TBI can affect the motor system diffusely.

5.  What determines the relative prominence of one dysarthric component over another?
The prominent component is determined by the severity and extent of damage in one area of the nervous system over the other.  The dysarthria can change over time as the disease begins to affects another area of the body with its progression until all components are equally pronounced.

6.  Is it difficult to make a correct diagnosis for mixed dysarthria? Why?
Yes.  Because of the many speech components which are affected.

7.  Describe some etiologies of some of the more prominent causes of mixed dysarthria.

 Multiple Sclerosis (MS):
 **a.  It is the most common of the demyelinating diseases.
 b.  Appears around 30; women more than men.
 c.  Etiology is unknown but some evidence that it is an immunological disorder triggered by a virus.
 d.  the destruction of the myelin affection function of the nerve by slowing it or stopping its ability to conduct neural impulses.
 e.  demyelination can occur in the brainstem, cerebellum, cerebral hemispheres, and spinal cord (almost anywhere in the CNS)
 **f.  the most common complaints are
  a. vision difficulties (double vision, color perception, decreased acuity and impaired central vision.
  b.  chronic feeling of tiredness and weakness in the limbs
  c.  dysarthria
  d.  sensory disturbances (numbness, burning, itching, tingling)
 g.  speech characteristics:
  a.  Most do not have dysarthria or if some minimal
  b.  for those with dysarthria the most common complaint is
   loudness control, harshness, impaired articulation
  c.  The two most common pure dysarthrias in MS are ataxic and spastic dysarthrias, but has the potential for consisting of numerious types of dysarthrias.

Multisystem atrophy (know the name is associated with mixed dysarthria)

1.  Shy-Drager syndrome:
 a.  degenerative affecting the brainstem, basal ganglia, and autonomic NS (blood pressure regulation, bowel and bladder dysfunction). Usually fatal after several years. No dementia. Cause unknown.
 *b. Parkinsonlike symptoms (bradykinesia, akinesia, rigidity) but without tremor.  Drugs don’t help alleviate the symptoms.
 c.  Most common pure dysarthrias that comprise Shy-Drager are
spastic-ataxic-hypokinetic and hypokinetic-attaxic and ataxic-spastic dysarthria.

2.  Progressive Supranuclear Palsy:
 a.  Rare progressive disease causing degeneration of neurons in the brainstem, basal ganglia and cerebellum; cause unknown; fatal in several years.
 b.  Most obvious: gradual restriction of voluntary eye movements (vision difficulties)
 c.  Parkinsonian symptoms
 d.  several types of dysarthria are associated with supranuclear palsy: hypokinetic, spastic, or mixed the most common

3.  Olivopontocerebellar Atrophy
 a.  gradual deterioration of neurons in the inferior olivary nucleaus (collection of neuron cell bodies in the brainstem near the cerebellar peduncles), pons, and cerebellum.
 b.  rare and cause is unknown, hereditary, fatal
 c.   ataxic disturbances of balance, uncoordinated movements, tremor, muscle spasms, bowel and bladder control and dysarthria; choreic movements and dementia
 d.  dysarthria: ataxic, spastic, flaccid, hypokinetic

**4.  Amyotrophic Lateral Sclerosis
 *a.  disease that results in the progressive degeneration of motor neurons
 b.  cause unknown; median age 65; fatal (pneumonia & respiratory failure)
 c.  can affect motor neurons in any of four areas
  a.  spinal nerves at spinal cord
  b.  cranial nerve at brainstem
  c.  UMN of cortiospinal tract
  d.  UMN of corticobulbar tract
 *d.  initially has the symptoms of the area attacked first
  a.  spinal nerve: Muscular weakness in arms and legs, loss of tone, atrophy, decreased reflexes
  b.  cranial N: flaccid dysarthria dyspahgia, tongue atrophy, reduced gag, facial and oral weakness
  c.  UMN corticospinal: weakness and spasticity; increased reflexes; muscle cramps
  d.  UMN corticobulbar tract: spastic dysarthria, hyperactive gag, facial, oral weakness, dysphagia
  e.  Speech characteristics of ALS- Flaccid-Spastic Dysarthria
     imprecise consonants, hypernasality, harsh vocal quality

Wilson’s Disease
 *a.  rare hereditary; prevents the normal metabolism of dietary copper.
 b.  copper build up in various parts of the body and in the basal ganglia
 c.  dysarthria may be one of the earliest signs of Wilson’s: reduced stress, monopitch, monoloudness
 d.  cognitive, motor and psychiatric problem
 d.  parkinson’s like, ataxia, dementia, dysphagia, dysarthria
 *e.  treatment available to reduce copper deposits

Friedreich’s Ataxia
 a.  inherited, progressive disorder causing neuron degeneration in the cerebellum, brainstem and spinal cord; fatal usually a result of heart failure or coma
 b.  ataxia is he most common dysarthria associated with the disease.

Treatment of Mixed dysarthria

Rule of thumb:  treat the component that is most severely affecting speech production or is the most prominent first.

When elements of a mixed dysarthria are equally affecting speech production, treatment should be sequenced with respiration errors first, resonation, phonation, articulation and then prosody (Dworkin)

Listen to the person and determine what can I treat that would affect intelligibility the most.

Augmentative Communication for ALS
Stages of ALS
1.  no detectable speech disorder: begin introduction of the ACC; learn what is available and the basics of the devices
2.  Obvious disorder with intelligible speech: introduce measures that facilitate ability to understand individuals (quiet room, amplification); Initiate selection of AAC system
3.  Reduction in speech intelligibility: treat dysarthria with behavioral treatment; AAC should be in place
4.  Residual natural speech and AAC supplements residual intelligibility; assess adequacy of the system for the person; train others in communicating with person with the AAC device.
5.  Loss of useful speech: Teach person and caregivers other techniques to facilitate communications:  yes/no communication, eye pointing, eye blinks