Mixed Dysarthria

Question 0

Neurologic Basis of Mixed Dysarthria

Answer 0

•There is no specific neurologic basis, it depends on the characteristics of dysarthria that the patient exhibits

Neurologic damage crossing anatomical boundaries, affecting various components of motor system

• Any combination of pure dysarthrias
• Prominence of each pure dysarthria within mixed dysarthria varies significantly among individuals
• Prominence of one dysarthria type can change over time (could be flaccid to begin with and over time it changes to a more ataxic dyarthria)- one dysarthria can dominate over the other or they can b 50-50

Question 1

Definitions of Mixed Dysarthria

Answer 1

• Motor speech disorder
• Occurs when neurologic damage extends into two or more parts of motor system
• Characterized by combination of characteristics in single (pure) dysarthria

Question 2

Causes of Mixed Dysarthria

Answer 2

•Caused by various disorders affecting two or more parts of motor system
•Examples include:
–Single or multiple strokes
–Brain tumors
–Traumatic head injuries
–Degenerative diseases
–Infectious diseases

Question 3

Cause of mixed dysarthria

Multiple sclerosis

Answer 3

–Progressive demyelinating disease (body attacks myelin sheath wrapped around the axons)

-Function of myelin sheath: production and transmission of neural impulses - neural impulses travel very fast through an axon with a myelin sheath. Myelin sheath is also protective in function.

–Can occur in brainstem, cerebellum, cerebral hemispheres, and spinal cord

–Can cause any pure or any combination of mixed dysarthria

–Ataxic-spastic dysarthria most commonly seen in multiple sclerosis

1.7 females to 1 male and more prominent in people living in cold climates than tropical climates

100 in every 100,000 people

Question 4

Cause of Mixed Dysarthria

Multisystems atrophy

Answer 4

–Collective term for group of degenerative disorders, many including parkinsonian symptoms (not responsive to dopaminergic treatment (L-Dopa), idiopathic Parkinsonism is)

1. Shy-Drager syndrome (Parkinsonism symptoms most likely seen in this syndrome) • Can occur in brainstem, basal ganglia, and ANS
   • Onset is middle age
   • Does not present dementia
   • Hypo-ataxic and ataxic-spastic most common
2. Progressive supranuclear palsy
   • Very rare (occurs in 1.4/100,000 people)
   • Degenerates neurons in brainstem, basal ganglia, and cerebellum
   • Onset is middle age
   • Fatal after many years; can lead to dementia and dysphasia
   Key feature: restricted voluntary eye movement
   • Hypo-spastic most common
3. Olivopontocerebellar atrophy
   • Degeneration of neurons in the inferior olivary nucleus, pons, and cerebellum
   • Onset is 30s
   • Idiopathic
   • Presents with arm and leg incoordination, gait, tremors, numbness in extremities, occasional muscle spasms, choreic movements, dementia
   • Lifespan once it sets in is ~20 years, then fatal
   • Ataxic-spastic, flaccid and/or hypo most common

Question 5

Cause of Mixed Dysarthria

Amyotrophic lateral sclerosis (ALS)

Answer 5

–Progressive degeneration of any of four areas of motor neurons
–Often progresses from affecting two motor neuron groups to all four
–Mixed dysarthria predominates throughout much of this disorder

Question 6

Amyotrophic lateral sclerosis (ALS)

Answer 6

–Progressive degeneration of motor neurons
–Occurs in about 1.5 per 100,000.
–Median age of onset is 65 years.
–Men: Women ratio – 1.5:1
–It is progressive and fatal

Question 7

•ALS can affect motor neurons in any four areas of the motor system:

Answer 7

• in the spinal nerves at the point where they join the spinal cord
• in the cranial nerves where they join the brainstem
• in the UMN of the corticospinal tracts
• in the UMN of the corticobulbar tracts

Question 8

•Depending on which motor neuron is affected first, patients with ALS may demonstrate one of the four possible clusters:

Answer 8

Spinal nerve involvement – weakness in arms and legs, loss of muscle tone, muscle atrophy, and decreased reflexes

Cranial nerve involvement – flaccid dysarthria, a reduced gag reflex, tongue atrophy, dysphagia, and facial and oral weakness.

UMN of the corticospinal tract involvement – weakness and spasticity of the arms and legs, hyperreflexia, and painful cramps in the extremities

UMN of the corticobulbar tract involvement – spastic dysarthria, hyperactive gag reflex, facial and oral weakness, and dysphagia.

Early in the course of ALS, only one or two of the motor neuron groups will be affected, but as the disease progresses, all four groups are likely to be involved.

Question 9

•Speech characteristics of ALS:

Answer 9

The type of dysarthria presented depends on which motor neurons are affected. Those, with LMN involvement will present with flaccid dysarthria. Those with UMN involvement will present with spastic dysarthria.

•When the disease progresses, flaccid-spastic mixed dysarthria is usually observed.

Question 10

Wilson’s disease

Answer 10

Very rare hereditary disease preventing normal metabolism of dietary copper.

• Small amounts of copper are a necessary nutritional mineral, individuals with Wilson’s disease cannot metabolize copper properly.
• Instead of being excreted, excessive amounts of copper are deposited in the corneas of the eyes, kidneys, liver, and brain (basal ganglia).
• The buildup of copper in these organs results in cognitive, motor, and psychiatric symptoms.

Characteristic feature:Brown-colored ring around cornea
(Kayser-Fleischer ring)

•Penicillamine successful in treating most patients.
•If left untreated, this condition can be fatal.
•Dysarthria one of earliest signs
–Ataxic-spastic-hypokinetic present in many

Question 11

•Friedreich’s ataxia

Answer 11

Rare, inherited, progressive disorder
–Causes neuron degeneration in cerebellum, brainstem, and spinal cord
–Untreatable, fatal
–Death is usually due to heart failure or coma
–Ataxic-spastic dysarthria most prevalent mixed dysarthria

Question 12

Treatment of Mixed Dysarthria

Answer 12

• Treating mixed dysarthria challenging
• Many speech errors
• Difficult to determine where to start

Question 13

•General rule:

Answer 13

first treat component most severely affecting speech production

•Dworkin (1991) suggested when elements of mixed dysarthria affect speech production equally, treat in following order:
–Respiration, resonation, phonation, articulation, prosody
–Rationale: prior speech components foundation for others

Question 14

•Other caveats of treatment:

Answer 14

–Given multiple problems in single component of speech production, treat most severe first
–Patient may have strong preference for what needs to be treated initially (client centered therapy)
–Patient’s attention or memory deficit may make working on one deficit too difficult

Question 15

•Augmentative communication for patients with ALS

Answer 15

–Communicative stages of patient with ALS
–Responsibility of SLP changes within each stage
–Progression variable

Question 16

Communicative stages of patients with ALS:

Answer 16

1. No detectable speech disorder
2. Obvious speech disorders with intelligible speech
3. Reduction in speech intelligibility
4. Residual natural speech and augmentative communication
5. Loss of useful speech

Question 17

Summary

Answer 17

Mixed dysarthria occurs with damage to more than one portion of motor system
•Extent and location of neurologic damage determine combination of pure dysarthrias to be components of mixed dysarthria
•One speech components may be more noticeable
•Many conditions cause mixed dysarthria
–ALS and MS are common degenerative diseases that cause mixed dysarthria
•Treatment sequence is to first treat component contributing most to speech deficits
•If elements equally affected, use sequence of respiration, resonation, phonation, articulation, prosody