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CHAPTER 9
Chapter Overview
Hyperkinetic dysarthria is a group of various motor speech disorders, each associated
with a hyperkinetic movement disorder. The dysarthria is caused by involuntary
movements that interfere with voluntary attempts at speech. These disorders mostly
seem to be caused by dysfunction in the basal ganglia, and they all produce involuntary
movements that interfere with normal speech production. Hypokinetic means “too much
movement”, as these movement disorders are characterized by excessive involuntary
movements of various body parts. Chorea, myoclonus, tics, dystonia, and essential
tremor are all examples of hyperkinetic movement disorders. When these involuntary
movements interfere with speech production, the result is hyperkinetic dysarthria. The
neurological basis for hyperkinetic dysarthria is damage to the basal ganglia or its control
Chorea is a movement disorder distinguished by random involuntary movements of the
limbs, trunk, head, and neck, appearing dancelike, smooth, and coordinated but actually
unpredictable, purposeless, jerky, and abrupt. Disorders that include chorea as a
symptom include Sydenham’s chorea and Huntington’s disease. Stroke can cause
chorea when it affects the basal ganglia or nearby subcortical structures such as the
thalamus. Tardive dyskinesia, caused by taking certain antipsychotic drugs over a period
of months or years, can also cause chorea, as well as cerebral anoxia, carbon monoxide
poisoning, and although rare, pregnancy and the use of oral contraceptives. The degree
of chorea influences how severely speech is affected. The variety of errors are based on
two factors: the movements of chorea may affect many different muscle groups; and the
movements of chorea are unpredictable, affecting any number of muscle groups at any
Motor Speech Disorders, Second Edition
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Myoclonus is a hyperkinetic movement disorder distinguished by involuntary and brief
contractions of part of a muscle, a whole muscle, or a group of muscles in the same area
of the body, with the contractions occurring singly, in a repeating irregular pattern, or
rhythmically. It can appear as part of kidney failure, epilepsy, cerebral anoxia, strokes,
traumatic head injury, and some progressive neurologic disease such as Alzheimer’s and
Creutzfeldt-Jakob’s disease. Tic disorders are characterized by tics, rapid movements
that can be controlled voluntarily for a time, but nevertheless performed frequently
because of a compulsive desire to do so. Essential (or organic) tremors are the most
common hyperkinetic movement disorder, with tremors faster than the parkinsonian
tremor. Dystonia is another hyperkinetic movement disorder, with movements typically
having a slower, more sustained quality than those seen in chorea. One muscle, a single
group of muscles, or multiple groups of muscles may be affected. It is categorized
according to the number of affected body parts. Sensory tricks (simple, idiosyncratic
Key evaluation tasks for hyperkinetic dysarthria include vowel prolongations, alternate
motion rates (AMRs), conversational speech and reading, and careful observation of the
associated involuntary movements. Treatment of hyperkinetic dysarthria is based on
medical and behavioral interventions. Most medical treatments are pharmacologic, with
drugs that suppress the involuntary movements that cause speech deficits. The most
successful has been Botox injections. Deep brain stimulation is also used. Behavioral
treatment for Huntington’s involves speech-language treatment based on the stage of the
disease. Behavioral treatment for dystonia includes sensory tricks, bite blocks, and easy
onset of phonation. Behavioral treatment for tic disorders includes relaxation therapy and
other related treatments, such as mental imagery and habit-reversal procedures.
Study Questions and Answers
1. Define hyperkinetic dysarthria in your own words.
effects of each disorder on speech production are different.
Motor Speech Disorders, Second Edition
iii
2. Why is it appropriate to describe hyperkinetic dysarthria as actually being a
collection of separate dysarthrias?
3. What is one reason why the function of the basal ganglia is not well
understood?
4. How are the involuntary movements of chorea different from those of
dystonia?
5. What are the symptoms of Huntington’s disease?
6. Why do individuals with chorea sometimes have voice stoppages,
unexpected inhalations, and sudden exhalations?
7. Describe fully the cause of tic disorders.
8. What is the most common hyperkinetic movement disorder?
9. What are sensory tricks, and with which hyperkinetic movement are they
most closely associated?
10. How are most hyperkinetic movement disorders treated?
