Language disorders beautifully demonstrate the intersection of neuroanatomy and the physical exam. An understanding of both is imperative to being a successful neurologist.
Author: Brian Hanrahan MD, Steven Gangloff MD
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Table of Contents
Disorders of articulation
- Dysarthria: impairment in pronunciation with errors that are consistent and predictable secondary to disturbances in muscle function, whether it be due to weakness, paralysis, or incoordination.
- Apraxia of speech: Articulatory errors are variable and effect the prosody of speech.
Types of dysarthria
Flaccid (bulbar palsy)
- Occurs with lower motor neuron disease/neuromuscular junction disease:
- Commonly seen in patients with bulbar predominant myasthenia gravis.
- Presents with hypernasal speech and imprecise consonants.
Spastic (pseudobulbar palsy)
- Secondary to bilateral lesion in corticobulbar (upper motor neuron (UMN)) tracts.
- Occurs in patients with primary lateral sclerosis (PLS), amyotrophic lateral sclerosis (ALS), progressive supranuclear palsy (PSP), stroke, and other disorders.
- Presents with a harsh, hypernasal, mono-pitched voice, dysarthria, dysphagia, facial and tongue weakness, and emotional lability.
- Jaw jerk reflex will be positive and fasciculations are absent (because UMN affected).
- Presents due to the inaccuracy of muscle movements from cerebellar dysfunction.
- Seen with acute alcohol intoxication but can be irreversible with chronic use.
- Speech can be described as imprecise and scanning, with inconsistent errors in articulation.
- Seen in patients with Parkinson’s disease.
- The speech is described as monotonous and hypophonic.
- Seen with dystonia and chorea which cause hypotonia and incoordination.
Note Patients with ALS who have both upper and lower motor neuron disease can present with either a bulbar or pseudobulbar palsy.