I. Apraxia-an inability to perform volitional learned motor acts in the presence of normal comprehension, muscle strength, sensation, attention, and coordination. Results from a lesion disconnecting Broca’s area from the motor association area responsible for organizing intentional actions.

A. Ideational Apraxia- an inability to carry out a hierarchical complex motor plan as the result of bilateral cerebral injury (e.g., making a bed). The patient appears to have lost an overall concept of how to proceed to complete the motor task.

4. Apraxia of Speech-an impaired ability to execute voluntarily the appropriate movements for articulation of speech in the absence of paralysis, weakness, or incoordination of the speech musculature. Errors are inconsistent, involuntary speech is better than voluntary speech, errors include substitution, repetition, simplification, distortion, and addition. The errors increase with complexity and word length.

• Phonemic errors are prominent: omissions, substitutions, distortions, additions, repetitions of phonemes.
• Some errors appear to be perseverative, others anticipatory.
• Errors are seemingly off-target approximations of the desired production made in an effortful groping for the correct position or sequence of positions.
• Errors are highly inconsistent.
• Errors vary with the complexity of the articulatory adjustment.
• Errors increase as words increase in length.
• There is a discrepancy between the articulatory accuracy displayed in automatic-reactive speech performance and the inaccuracy displayed in volitional-purposive performances.
• Imitative responses are particularly poor.
• The speaker is usually aware of his or her errors but is typically unable to anticipate or correct them.
• Monitoring of speech in anticipation of errors leads to prosodic disturbances: slowed rate, even stress, even spacing.
• Oral apraxia is often, but not always, observed in association with apraxia of speech.

• Substitution errors are more frequent than other error types.
• Error sounds are more likely to differ from the target by one phonetic dimension than by two, three, or four.
• Errors are most likely errors of place, followed by errors of manner, voicing, and oral-nasal.
• Voiceless-for-voiced substitutions are more frequent than voiced-for-voiceless substitutions.
• Some errors are anticipatory, some perseverative, and some metathetic with anticipatory errors probably predominating.
• Errors are more likely on consonant clusters than on singleton consonants.
• Apicoalveolar and bilabial sounds are more often correct than sounds produced at other places.
• Affricates and fricatives tend, as classes, to be more often in error than plosives, laterals, nasals, and vowels, although order varies with the position in utterance.
• Consonant errors are more likely than vowel errors; however, some patients may make no more consonant errors than vowel errors.
• Many substitutions appear to be of more "difficult" combinations for "easier" ones.

• Within narrow limits, articulator accuracy is better for automatic-reactive than for volitional-purposive speech.
• Articulatory accuracy may be better with auditory-visual stimulation than with auditory or visual (reading) alone.
• Watching verbal production in a mirror has no effect on the accuracy of single word production.
• Imitative accuracy, unless influenced by the test stimuli, is better than spontaneous accuracy.
• Some patients improve if given more than one consecutive attempt at a production.
• Motivating instructions, within very narrow limits, have no influence on articulatory accuracy.
• Response delay intervals of 0, 3, and 6 seconds do not significantly influence articulatory accuracy.
• Binaural masking probably has no facilitating effect on articulation for most patients.
• Delayed auditory feedback (DAF) may have a detrimental effect on articulatory accuracy.

II. Assessment-

a complete assessment would include an aphasia battery, oral mechanism exam, and an apraxia assessment.

1. Open your mouth.

2. Stick out your tongue.

3. Blow.

4. Show me your teeth.

5. Pucker up your lips.

6. Touch your nose with your tongue.

7. Bite your lower lip.

8. Whistle.

9. Lick your lips.

10. Clear your throat.

11. Move your tongue in and out.

12. Click your teeth together.

13. Smile.

14. Click your tongue in top of mouth.

15. Chatter your teeth as if you were cold.

16. Touch your chin with your tongue.

17. Cough.

18. Puff out your cheeks.

19. Wiggle your tongue from side to side.

20. Hum.

• Failure to perform appropriately in brain-injured adults suggests a diagnosis of oral apraxia.

III. Treatment for Apraxia of Speech-dependent upon severity of apraxia and accompanying aphasia. The more severe the impairment, the poorer the prognosis is for recovery.

• Limited repertoire of speech sounds.
• Speech may be limited to a few meaningful or unintelligible utterances.
• Imitation of isolated sounds may be in error, and errors may be limited in variety.
• Errors may be highly predictable.
• Automatic speech may not be better than volitional speech.
• Error responses may approximate target if stimuli are chosen carefully.
• Muteness may be present, but rarely persists for more than 1 or 2 weeks if other speech, language, or cognitive deficits are not present.
• Usually accompanied by sever aphasia, but can occur in the absence of aphasia.
• Usually accompanied by nonverbal oral apraxia.

National Institute of Neurological Disorders and Stroke
National Aphasia Association
National Stroke Association
American Academy of Neurology 
Stroke Support Information
Dana Brain Web
 

Bibliography

Brookshire, R. (1992). An introduction to neurogenic communication disorders, 4th edition. St. Louis, MO: Mosby Year Book.

Davis, G. (1993). A survey of adult aphasia and related language disorders 2nd edition. Englewood Cliffs, NJ: Prentice-Hall.

Duffy, J. (1995). Motor speech disorders: Substrates, differential diagnosis, and management. St. Louis, MO: Mosby Year Book.

Haynes, W., Pindzola, R., & Emerick, L. (1992). Diagnosis and evaluation in speech pathology, 4th edition. Englewood Cliffs, NJ: Prentice-Hall.

Love, R., & Webb, W. (1986). Neurology for the speech-language pathologist. Boston, MA: Butterworth Publishers.

Skelly, M. (1979). Amer-Ind gestural code based on universal American Indian hand talk. New York, NY: Elsevier.

White, P. (1997). Pocket reference of diagnosis and management for the speech-language pathologist. Boston, MA: Butterworth-Heinemann.