Lecture 14; Movement disorders 3 Flashcards
What is the incidence of spinal cord injuries in the US?
Most frequent injury of CNS
- 10,000 year
- 50% quadriplegic
- 75% 16-30
- 250,000 confined to wheelchairs
What is the relationship of the spinal column and trauma?
The spinal column although protective can dislodge and cause trauma.
What can hemisection of the spinal cord result in?
Brown sequard syndrome
What is the brown sequard syndrome?
In example, if the spinal cord is lesioned at t8 on the left. The resulting symptoms follow;
- Paralysis of the LEFT (Descending LMN tracts)
- Dorsal column (Tactile) loss on the LEFT (As decussation occurs at Brain stem)
- Loss of Pain and Temperature sensation on the RIGHT hand side (spinothalamic tract decussates at the spinal cord)
summery;
- Paralysis left side
- Loss of tactile sensation left side
- Loss of pain and temp right side
What is a condition that arises briefly following complete spinal cord lesion
Spinal shock
Describe spinal shock;
Areflexia (no reflexes) lasts 1-3 days because of loss of descending inputs
This initial period following spinal cord lesion is also accompanied by; (at T8 lesion)
- Paraplegia
- Total anaethesia to lower bod
- areflexia to lower bod
- BP drop and Blood vessel dilation
- Absence of sweating in lower bod
- Bowels and bladder atonic
Lower bod is hot and dry
Describe the role of the RVL in BP drop;
Lesion of the presympathetic fibres in the spinal cord extending from the rostral ventral lateral medulla oblongata results in loss of sympathetic innervation.
What happens after the 3 days?
Partial recovery; (and additional symptoms)
- Stretch reflexes recover and become hyperactive
- Flexor withdraw symptoms recover
- Reflex emptying of bladder and bowel
- BP increases
- Parethesias (burning sensation in absence of stimulus)
What is the mechanism of recovering after the first three days?
Sprouting of axon terminals and formation of new synapses (reprogramming of remaining synapses (plasticity))
or
Denervation supersensitivity (increased receptor expression, trafficking)
What is a device that may be necessary for some paraplegic patients?
Those with high lesions that result in loss of phrenic nerve motor neuron innervation will need breathing pacemakers (i.e the phernic nerve itself is fine but the descending rhythmic pathways are lesioned)
Rhythmic pattern of breathing driven by brainstem resp center
Lungs dont cope well in the presence of positive pressure
Breathing pacemaker can be used to provide respiration with an intact phrenic nerve.
What are three new systems that have been developed to assist paraplegic people?
Parastep
Rex bionics
Rewalk
What is parastep?
Microcomputer system that evokes coordinated muscle contractions in paraplegic patients
Controller sends coordinated electrical activation to muscle electrodes to generate coordinated muscle contraction
What is rex bionics;
Robotic legs
Heavy system
Not very good at balance
What is rewalk?
Exoskeleton developed in isreal
Robotic legs
Could nerve grafts be effective?
- Peripheral nerves have the correct trophic factors expressed by supporting schwann cells to regenerate
- CNS cells do not as schwann cells arent present and oligiodendrocytes oppose regeneration
- Central axons can be regenerated if certain conditions are met
Experimentation has been done where a peripheral nerve was added to optic nerve and function was gained / axons regenerated as schwann cells were present (lesioned optic nerve)
