Dysarthria

Clinic

• Dysarthria is a motor speech disorder
• Dysarthria is difficulty in articulating words due to a CNS problem = Poor articulation of phonemes = Difficult to pronounce words
• It is completely different from Aphasia, although someone can have both
• Any of the speech subsystems (Respiration, Phonation, Resonance, Prosody and Articulation) can be affected, leading to impairments in Intelligibility, Audibility, Naturalness, and Efficiency of vocal communication.
• Anarthria = Total Speech Loss is advanced phase of Dysarthria

• Neurological injury due to damage in the central or peripheral nervous system may result in weakness, paralysis, or a lack of coordination of the motor–speech system, producing dysarthria.
• These effects in turn hinder control over the tongue, throat, lips or lungs; for example Dysphagia are also often present in those with dysarthria.

Pathophysiology

Cranial nerves	Brain areas
Trigeminal nerve's motor branch (V) Facial nerve (VII) Glossopharyngeal nerve (IX) Vagus nerve (X) Hypoglossal nerve (XII)	Motor or somatosensory cortex Corticobulbar pathways Cerebellum Basal nuclei (Putamen, gGobus pallidus, Caudate nucleus, Substantia nigra etc.), Brainstem (From which the cranial nerves originate) Neuromuscular junction (Myasthenia gravis)

Causes

• Degenerative diseases : Parkinsonism,  ALS, MS, Huntington's disease, Niemann-Pick disease and Friedreich's ataxia
• Toxic and metabolic conditions: Wilson's disease, Hypoxic encephalopathy such as in drowning, and central pontine myelinolysis
• Viral infection: CJD, FFI, GSS, NVCJD

Subypes

Flaccid	Lower motor neuron system and/or muscle (Damage to the peripheral nervous system) (PNS). Hallmarked by difficulty pronouncing consonants.	Nasal speech Flaccid Paralysis	PLV
Spastic	Upper motor neuron involvement Speech issues alongside muscle weakness Abnormal reflexes.	Dysarthria Hyper Reflexia Paralysis Spastic	GSS
Ataxic	Cerebellar control unit. Slurred speech Lack of coordination.	Cerebellar Ataxia Dysarthria Ext, Incoordination	CJD MMP
Hypokinetic	Problem in Basal ganglia control unit such as Parkinson’s and Huntington’s Quiet, breathy, or monotone voice Difficulty initiating sentences Stutter or slurred speech Struggles pronouncing consonants Rigidity or lacked movement in the face and neck Dysphagia that can result in drooling and tremors or muscle spasms	Dysarthria ِDysphagia Rigidity	CJD
Hyperkinetic	Problem in basal ganglia control unit Slurred or slow speech Shaky voice Shortness of breath or fatigue while speaking Muscle spasms and tremors Involuntary twitchy or flailing movements Atypical muscle tone	Spasm Tremor Twitching Irregular Respiration ChoreAthetosis Myoclonous Hypertonia	FFI NVCJD
Unilateral upper motor neuron	Upper motor neuron system	Hyper Reflexia Spasticity / Hypertonia Reflexes, Primitive	NVCJD
Mixed	Variety blend of dysarthria types (for example spastic-ataxic; flaccid-spastic)
Undetermined	observed features are in line with a dysarthria but do not clearly place into any of the identified dysarthria types.

Related disease

• Bulbar palsy
• Brain tumor
• Cerebral palsy
• Guillain–Barré syndrome
• Lyme disease
• Stroke
• Idiopathic intracranial hypertension (formerly known as pseudotumor cerebri)      
• Tay–Sachs disease and late-onset Tay–Sachs disease (LOTS)