- Thought to be a result of a combination of genetic, infectious, environmental and autoimmune factors
- Trigger protein, the antigen, is activated, producing autoimmune, cytotoxic effects in the brain.
- Immune system responds by triggering production of T-lymphocytes, macrophages, and immunoglobulins.
- BBB is ineffective in blocking the myelin sensitive T-cells from entering and attacking the myelin sheath.
- Demyelination, local inflammation disrupt nerve transmission.
- Initially oligodendrocytes are not effected so remyelination can occur.
- As the disease progresses, remyelination can not keep up with destruction
- Gliosis (scar tissue)ultimately occurs as repair becomes impossible. Plaques result and further disrupt transmission.
- Weakness and muscle atrophy: extraoccular muscles are spared until later in progression
- Muscle cramping and fasciculations
- Alterations in gait, reflexes and tone
- Bulbar symptoms: dysphagia, dysarthria, dysphonia and respiratory changes
- Patients will have either limb-onset or bulbar onset ALS
- Rarely affects bowel and bladder, even more rarely affects senses
- Recent studies have shown that cognitive effects are possible depending on where the damage occurs.
- Hyperreflexia, increased/spastic tone, no fasciculations/atrophy, + Babinski
- Hyporeflexia, decreased/flaccid tone, fasciculations/severe atrophy, - Babinski
UMN: descending motor system ((corticospinal and corticobulbar)
• Cortical input to rubospinal, vestibulospinal, reticulospinal
• Lesions: CVA, MA, Huntington's, TBI, Parkinson's
LMN: alpha motor neuron in the spinal cord out to the periphery
• Not including sensory afferents coming in, only outgoing efferents
• Lesions: Bell's Palsy, carpal tunnel, trauma, GBS, Herpes Zoster
I. No Response- coma, sleeping
II. Generalized Response - some stimuli elicits response
III. Localized Response- may/may not respond to stimuli
• Bizarre acting
• Combative, annoyed
• Non-purposeful, low attention, impulsive, helmet
• Follow simple commands
• Still inappropriate, distractible, can start becoming social
• Sexually inappropriate
• Goal oriented behavior
• Still confused, no orientation
• Become robotic
• Follow commands, carry out tasks, very machine like
• Highest TBI, can learn, aware, responsive, appear relatively normal
• Cannot handle high stress situation, no higher level judgment