pathophysiology of the motor system

Question 1

what are the symptoms of a frontal lobe lesion

Answer 1

-Difficulty with executive functions: hard to manage his daily plans, decision-making problem, not organized…etc.
-Change in personality and behavior: more aggressive, less compassion, social isolation…etc.

Question 2

upper motor neuron lesion (site of lesion, m. weakness, m. tone, m. atrophy, fasciculation, tendon reflex, plantar reflex)

Answer 2

-site of lesion: cortex, brainstem, spinal cord
-m. weakness: yes (plegia)
-m. tone: increased (spasticity)
-m. atrophy: disuse atrophy
-fasciculation: no fasciculations
-tendon reflex: hyperreflexia
-plantar reflex: positive babinski sign

Question 3

lower motor neuron lesion (site of lesion, m. weakness, m. tone, m. atrophy, fasciculation, tendon reflex, plantar reflex)

Answer 3

-site of lesion: ant horn, roots, nerves, neuromuscular junction
-m. weakness: yes (myopathy)
-m. tone: decreased (hypotonia)
-m. atrophy: denervation atrophy
-fasciculation: fasciculations
-tendon reflex: hyporeflexia
-plantar reflex: negative babinski sign

Question 4

what kind of lesion causes hyporeflexia: absence or weak extension of the leg

Answer 4

lower motor neuron lesion

Question 5

what kind of lesion causes hyperreflexia: strong extension of the leg

Answer 5

upper motor neuron lesion

Question 6

upper motor neuron lesion causes _____ on the reflex circuit

Answer 6

lack of control

Question 7

what does the distribution of facial weakness provide

Answer 7

important localizing clues indicating whether the underlying injury involves the lower motor neuron (LMN) or the upper motor neuron (UMN)

Question 8

injury to the primary motor cortex causes a weakness of what facial m.
what input is lost and intact

Answer 8

contralateral inferior facial muscles:
Ø Input to inferior facial muscles from the UMN in primary motor cortex is lost.
Ø Input to superior facial muscles from the UNM in the premotor areas (cingulate gyrus) remains intact.

Question 9

injury to the corticobulbar tract causes a weakness of what facial m.
what input is lost and intact

Answer 9

contralateral inferior facial muscles:
Ø Input to inferior facial muscles from the UMN in primary motor cortex is lost.
Ø Input to superior facial muscles from the UNM in the premotor areas (cingulate gyrus) remains intact bc this input projects bilaterally

Question 10

injury to the facial motor nucleus or its n. causes a weakness of what facial m.
what input is lost and intact

Answer 10

all m. of facial expression on the same side of the lesion:
Ø Input to inferior and superior facial muscles from the LMN is lost.

Question 11

what is aphasia

Answer 11

Aphasia is a disorder in the comprehension and/or expression of language

Question 12

what are the 2 diff types of aphasia

Answer 12

-Broca’s (motor) aphasia: loss of the ability to produce language.
-Wernicke’s aphasia: difficulty understanding speech.

Question 13

why is broca’s aphasia also called non-fluent aphasia

Answer 13

Characterized by the loss of the ability to produce language,

Question 14

why is broca’s aphasia also called motor aphasia

Answer 14

Lesion in the Broca’s area: the posterior inferior frontal gyrus (inferior part of the motor cortex)

Question 15

what is broca’s aphasia mostly caused by

Answer 15

stroke

Question 16

what does the severity of broca’s aphasia varies from and what does it depend on

Answer 16

The severity of the problem varies from the complete loss of the ability to speak to struggle to speak depends on the size of the affected area.

Question 17

is there a possibility of recovery w broca’s aphasia

Answer 17

yes, Possibility of recovery by speech therapy.

Question 18

what is multiple sclerosis

Answer 18

an immune-mediated inflammatory disease that causes the demyelination of the nerves of central nervous system

Question 19

what happens w multiple sclerosis when it affects motor neurons, sensory neurons or optic fibers

Answer 19

motor neurons: m. weakness
sensory neurons: loss of sensation
optic fibers: visual disturbances

Question 20

what is myasthenia gravis

Answer 20

a neuromuscular disease that causes weakness in the muscles (e.g. drooping of eyelids, difficulty swallowing, shortness of breath)

Question 21

what happens with myasthenia gravis

Answer 21

-Acetylcholine (Ach) receptors blocked (or destroyed) by antibodies (autoimmune disease).
-Reduced transmission of Ach in the muscle.
-Impaired muscle contraction.

Question 22

what is the treatment for myasthenia gravis

Answer 22

Cholinesterase inhibitors: inhibit the metabolism of Ach by the cholinesterase enzyme (i.e., keep more Ach in the synaptic cleft), Thus, boost signals between nerves and muscles to improve muscle strength

Question 23

parkinson’s disease is the degeneration of what neurons

Answer 23

substantia nigra’s neurons (loss of dopaminergic neurons)

Question 24

what does parkinson’s cause

Answer 24

igidity, tremor and akinesia (i.e. inability to initiate and stop movement)

Question 25

what is the 2 most common neurodegenerative diseases

Answer 25

1-alzheimer’s
2-parkinson’s

Question 26

what are the treatment options of parkinson’s disease

Answer 26

-Dopamine-based medication : L-Dopa (dopamine precursor).
-Deep Brain Stimulation

Question 27

what entails deep brain stimulation for parkinson’s treatment

Answer 27

-Insertion of an electrode deep into the brain
-Repetitive and regular electrical stimulation.
-targeted structures: subthalamic nucleus, globus pallidus internal.

Question 28

degeneration of caudate and putamen neurons is associated with what disease

Answer 28

huntington’s

Question 29

what movement disorder does huntington’s cause

Answer 29

hyperkinesia (rapid and jerky motions with no clear purpose)

Question 30

in ataxia what does dysfunction of the Cerebrocerebellum cause

Answer 30

Lack of voluntary coordination of muscle movements (e.g.,failure to predict motor movement, patients will overshoot intended target)

Question 31

in ataxia what does dysfunction of the vestibulocerebellum cause

Answer 31

Loss of balance and gait difficulty

Question 32

cause of ataxia

Answer 32

genetic disease