Medbrige pathomechanics

Question 1

What does vertigo mean?

Answer 1

false sense of motion (rotational or linear)

Question 2

What does dizziness mean?

Answer 2

Disturbed spatial orientation without a sense of self motion

Question 3

What is Oscillosia

Answer 3

Gaze instability

Question 4

What is unsteadiness

Answer 4

instability, disturbed postural control

Question 5

what is pulsion

Answer 5

imbalance with a tendency to fall in a particular direction

Question 6

what is presyncope

Answer 6

feeling of faintness

Question 7

what medications are typically used to treat vertigo

Answer 7

Benzodiazipines: indicated for acute vertigo, addition is possible and contraindicated for liver and kidney trouble
- diazepma (valium) and lorazepam (ativan)
Antihistamies (motion sickness and chronic vertigo)
- meclinzine (antivert), dimenhydrinate (dramamine), promethazine (phenergan)

Question 8

What makes up the vestibular system

Answer 8

1. vestibule (sensory organ)
2. 8th cranial nerve (vestibular-cochlear)
3. brainstem bestibular nuclei
4. cerebellar pathway
5. VOR - vestibular occular
6. VCR - vestibular cervical (collic)
7. VSR - vestibular spinal

Question 9

What are the different parts of the vestibular system?

Answer 9

1. Canals (posterior, anterior, horizontal), sensory part of the canals at the terminals ends containing cupla
2. Vestibule made up of the otoliths a- utricle, b- saccule
3. cochlea

Question 10

Describe the orientation of vestibular organ

Answer 10

45 degrees towards the mid line

• anterior - 45 degree in front of ear in line with opposite posterior
• posterior - 45 degree behind ear in line with opposite anterior
• horizontal - sits in the horizontal plane

Question 11

How do the canals collect their sensory information

Answer 11

• the endolymph and the cupula have the same specific gravity therefore gravity and head position don’t influence the organ
• head angular acceleration moves the fluid through the canal and displaces the cupula triggering the sensory signals

Question 12

How do to the otolith work

Answer 12

otoconia at the end of the hair cells within the vertical sacula and the horizontal utrical have a greater specific gravity than the endolymph and are therefore gravity sensitive
- sensitive to linear acceleration of the head

Question 13

How does age impact the otolith

Answer 13

otoconia change with age

• increased variability in size
• hypertophy
• fragmentation
• fissures
• pitted
• weakening of linkages

Question 14

Desribe the vascular supply of the vestibular organ

Answer 14

1. Originates from the basilar artery (posterior circulation)
2. Anterior vestibular artery - nourishes anterior and horizontal canals and utricle
3. Posterior vestibular artery - nourishes posterior canal and saccule

Question 15

Describe the innervation of the vestibular organ

Answer 15

1. superior portion of the vestibular nerve innervates anterior and hrz canal and utricle
2. interior portion of the vestibular nerve innervates the posterior canal and saccule

Question 16

What eye motion does the horizontal canal regulate

Answer 16

1. right - creates left horizontal eye motion

2. left - creates right horizontal eye motion

Question 17

What eye motion does the superior canal regulate

Answer 17

1. right - creates vertical with left torsion

2. left - creates vertical with right torsion

Question 18

What eye motion does the posterior canal regulate

Answer 18

1. right - creates inferior with left torsion

2. left - creates inferior with right torsion

Question 19

what is nystagmus

Answer 19

Repetitive, uncontrolled eye movement that quickly reset of the eye towards the visual target
- sustained end range positions can trigger

Question 20

what is the optokinetic response

Answer 20

corrective saccades - a combination of a slow-phase and fast-phase eye movements. It is seen when an individual tracks (pursuit movement) a moving object with their eyes, which then moves out of the field of vision at which point their eye moves back to the position it was (saccade movement) in when it first saw the object

Question 21

Describe the relationship between the cerebellum and eye movement

Answer 21

1. midline (vermal) region of the cerebellum regulate balance and eye movement with midline lesions resulting in unsteady gait and impaired eye movement
2. overall the cerebellum plays a central role in fine tuning ocular motor reflexes with the intent of maximizing visual performance