Dysarthria

CLINICAL DIAGNOSTIC MANUAL

Dysarthria is a speech disorder caused by weakness, paralysis, or incoordination of the muscles used for speaking. It is characterised by poor articulation of words, resulting in slow, slurred, or unclear speech.

Dysarthria can result from neurological injuries affecting the motor areas of the brain, cranial nerves, or muscles responsible for speech. It is important to differentiate dysarthria from other speech disorders, such as aphasia, which affects the ability to understand or formulate language.

Condition	Clinical Symptoms and Signs	Suspected Diagnosis	Confirmatory Diagnosis
Cortical brain lesion	Dysarthria, focal muscle weakness, seizures, personality changes	History of stroke, traumatic brain injury	MRI or CT showing lesion in the motor cortex area
Internal capsule brain lesion	Dysarthria, hemiparesis, facial paralysis, contralateral body weakness	History of stroke, intracerebral haemorrhage	MRI or CT showing lesion in the internal capsule
Upper motor neuron lesion	Spastic dysarthria, exaggerated reflexes, spasticity	History of amyotrophic lateral sclerosis, multiple sclerosis	MRI showing lesions in corticobulbar tracts
Lower motor neuron lesion	Flaccid dysarthria, muscle atrophy, fasciculations, severe muscle weakness	History of neuromuscular disease, such as myasthenia gravis, Guillain-Barré syndrome	EMG and nerve conduction studies
Extrapyramidal dysarthria	Monotonous speech, low voice, rigidity, bradykinesia	History of Parkinson’s disease or other movement disorders	Clinical evaluation, MRI showing basal ganglia atrophy
Cerebellar lesion	Slow, slurred speech, ataxia, dysmetria, nystagmus	History of cerebellar disease, hereditary ataxia	MRI showing cerebellar atrophy or focal lesion
Toxic effects	Dysarthria, confusion, ataxia, systemic symptoms such as nausea or vomiting	History of exposure to toxic substances, medication use	Blood and urine tests for toxins, medication history review