Dysarthria is a speech articulation impairment affecting intelligibility, particularly through consonant production. It can also disrupt phonation, resonation, and prosody, leading to slurred, effortful speech. Dysarthria is often associated with dysphagia, necessitating careful evaluation of airway protection.
Pathophysiology
- Neuromuscular Disorder: Dysarthria reflects a severe impairment of the neuromuscular control of speech.
- Neural Pathway Involvement:
- Bilateral lesions of neural pathways (corticobulbar and spinal tracts).
- Affected structures include:
- White Matter: Corticobulbar tracts, corona radiata, central semiovale, internal capsule.
- Gray Matter: Persylvian and perirolandic cortices, basal ganglia (putamen, caudate nucleus), thalamus, cerebellum.
Epidemiology
- Cerebral Palsy:
- Affects ~33% of children with CP.
- Spastic and hyperkinetic dysarthria types are most common.
- A quarter of children with CP lack speech entirely, with functional communication correlated with motor functioning
- Communication in Cerebral Palsy:
- The Communication Function Classification System (CFCS) aligns with WHO's ICF to describe functional communication performance.
- Gross motor functioning predicts communication ability at school entry
Types of Dysarthria with Clinical Features and Aetiologies
Flaccid Dysarthria (Lower Motor Neuron Lesion)
- Affects ~20% of children surviving moderate to severe TBI.
- Often accompanied by oromotor deficits, including cranial nerve dysfunction (e.g., facial, hypoglossal, vagus, and trigeminal nerves)
- Commonly accompanied by:
- Oromotor Deficits:
- Facial nerve: Buccal and labial movement.
- Hypoglossal nerve: Tongue strength and coordination.
- Trigeminal nerve: Jaw movements.
- Vagus nerve: Velopharyngeal function.
- Oromotor Deficits: