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Flaccid dysarthria (bulbar palsy) - Coggle Diagram
Flaccid dysarthria (bulbar palsy)
Caused by Lesions
Motor cranial nerves, spinal nerves
Reflect problems in: nuclei, axons or neuromuscular jns of motor units in final common pathway
Final common pathway: synapse w actual cells w/i muscle systems, stimulates muscle contraction, mvm. Includes: paired cranial nerves that supply muscles of phonation, resonance, articulation, paired spinal nerves invl in respiratory activities. Other motor divisions act thru it
Effects of LMN lesion
loss, reflexive, automatic, voluntary control of muscles
flaccid, low tone muscles
muscle weakness, dulled muscle reflexes
HALLMARK: fasciulations (aryhtmic twitching), atrophy (shrinkage, wastage of muscle), fibrilations (X see, spontaneous contractions of muscle fibres that are not normal)
Affects: speed, range, accuracy of mvm
Muscles
All muscles in speech mechanism (except respiratory) are innervated by motor cranial nerves arising from bulbar region (pons, medulla oblongata)
Flaccid paralysis of muscles supplied by nerves from bulbar region-damage in bulbar region of brain
Vagus nerve lesions
Lateral medullary syndrome
Not common
Bcos of CVA-occlusion of posterior inferior cerebellar artery, vertebral artery or lateral medullary artery
Ipsilateral palatal, pharyngeal, laryngeal weakness
Dysarthria-characterised by dysphonia, hypernasality
Hallmark: Dysphagia, nausea, vomitting
Phrenic, intercostal nerve lesions
Respiratory hypofunction-decreased tidal volume, vital capacity, impaired control of expiration
Speech abnormalities -short phrases, decreased pitch, loudness given that respiratory drive influences laryngeal control
Aetiologies
Disorders of cranial nerves
Polyneuritis (inflammation of nerves)
compress/damage to cranial nerves bcos of trauma, tumour
Idiopathic paralysis of CN7 (Bell's palsy)
Guillan Barre syndrome
Disorders of CN nuclei, and/or anterior horns of spinal cord
Brainstem CVA (stroke),
progressive bulbar palsy,
amytrophic lateral sclerosis,
neoplasm (tumour, cancerous growth)
Disorders affecting transmission nerve impulse across N-M junction
Myasthenia gravis (autoimmune disease)
Botulism
Disorders affecting speech muscles themselves
Muscular dystrophy
Polymyositis-inflammation of muscles
Case studies
Case 1
Mild flaccid dysarthria- left facial weakness including upper, lower facial quadrants but speech is intelligible
"Open your jaw just a bit more"
Left eyebrow is lower, unable to raise eyebrows, X close L eye
Case 2
Severe flaccid dysarthria-multiple subsystems impaired
Hypernasal
No obvious facial weakness