Motor Speech Disorders Overview

Motor Speech Disorders

• Motor speech disorders are a collection of speech production deficits caused by abnormal functioning of the motor system.
• These disorders involve seven types of dysarthria and one type of apraxia.
• Motor refers to the part of the motor system controlling motor movements.
• Speech is communication through the use of vocal symbols in physical production.
• Disorders are abnormalities of function.

Dysarthria

• Dysarthria is impaired speech production due to disturbances in muscular control of the speech mechanism.
• It's characterized by a "disordered utterance."
• Dys- (disordered or abnormal) and -arthria (Greek for "to utter distinctly")
• A misconception is that dysarthria is always slurred speech.
• Dysarthria can impact articulation, respiration, prosody, resonance, and phonation.

Apraxia

• Apraxia is a deficit in the smooth sequencing of speech-producing movements of the tongue, lips, jaw, and other parts of the speech mechanism.
• It's associated with 'a' (absence of) and 'praxia' (Greek for "performance of action").
• Apraxia primarily affects articulation and prosody.
• It often results from damage to the left hemisphere of the brain.

Historical Review

• Examining early reports is crucial for understanding historical context.
• Ancient medical writers often displayed "modern" approaches.
• Taking an analytical approach to understanding medicine has evolved over time.

Case Reports (Ancient Greece)

• Early written accounts of speech and language disorders appear in the Hippocratic Corpus.
• Writings describe speechlessness, recovered tongue use, and tongue paralysis.

Case Reports (Middle Ages and Renaissance)

• Descriptions from case reports during the Middle Ages and Renaissance include instances of omitted/added syllables in speech and speech attempts filled with babble.

Two Early Theories on Localization of Reason

• The four cerebral ventricles (ancient times to 16th century) were believed to be important for reasons.
• The meninges had a role in sensations and movement during this time.

From the Nineteenth Century to Today

• Case reports and medical descriptions became more specific during the 1800s.
• Examples included "Shaking palsy" and "Slow drawling manner."

From the Nineteenth Century to Today (continued)

• Liepmann accurately described apraxia of speech in 1900.
• Wernicke described nonverbal oral apraxia in 1906.

Summary

• Speech motor disorders are a collection of speech production deficits stemming from abnormal motor system functioning.
• The disorders involve seven types of dysarthria and one type of apraxia.

Summary (continued)

• Historical accounts include the Hippocratic Corpus and the Middle Ages and Renaissance.
• Two theories of localization and reasoning—four cerebral ventricles and meninges-controlled senses and movement—were proposed in earlier times.

Summary (continued)

• The 19th century and beyond saw Liepmann describe apraxia of speech and Wernicke characterize nonverbal oral apraxia.