Chapter 8 Flashcards
olfactory dysfunctions
destruction of the olfactory bulb, tract, and primary cortex results in ipsilateral anosmia
- damage to the olfactory system can occur from traumatic brain injury, cancer, infection, inhalation of toxic fumes, or neurodegenerative diseases such as Parkinson’s disease and Alzheimer’s disease
clinical tests to detect damage to the olfactory system
- presenting the patient with odors via scratch-and-sniff cards
- by having the patient close their eyes and try to identify common available odors like coffee or peppermint candy
- other diseases that inhibit or eliminate the sense of smell, such as chronic colds or sinusitis, must be excluded before making the diagnosis that there is permanent damage to the olfactory damage
hyposmia
a reduced ability to detect odors
anosmia
the complete loss of the sense of smell
dysosmia
a distorted or altered sense of smell
- includes parosmia and phantosmia
parosmia
a distorted perception of a real odor
phantosmia
the perception of a smell that isn’t actually there (olfactory hallucination)
hyperosmia
rare condition typified by an abnormally heightened sense of smell
olfactory hallucinations
caused by lesions of the uncus or seizures in the uncus
uncus
anterior extremity of the parahippocampal gyrus
clinical tests to detect optic deficits
- Snellen chart tests visual acuity
- Rosenbaum card is a miniature scale version of Snellen chart for testing visual acuity at near
retinal detachment
separates the retinal cells from the layer of blood vessels that provides oxygen and nourishment to the eye
- can lead to blindness
- warning signs may include one or all of the following: reduced vision and the sudden appearance of floaters and flashes of light
testing visual fields and defects
- confrontation method: done with fingers; less precise
- perimetry: done with a computer; more precise
evator palpebrae superioris
upper eyelid muscle
lesions of oculomotor nucleus or nerve results in oculomotor nerve palsy
- ipsilateral lateral (external) strabismus (squint): the eye is down and out (medial rectus and inferior oblique) resulting in diplopia
- ipsilateral mydriasis (dilated pupil): due to involvement of the pupillary muscles (via Edinger-Westphal nerve)
- loss of direct and consensual pupillary light reflexes in the ipsilateral eye
trochlear nerve palsy
when walking downstairs, complaining of diplopia
superior oblique (cranial nerve 4) palsy
- complain of diplopia especially when walking downstairs or reading (requiring eye intorsion)
- tilt head away from the side of lesion (to compensate for the alignment of both eyes and help relive the diplopia)
lesion of abducens cranial nerve (6)
- medial strabismus
- medial rectus muscle is unopposed and pulling the eyeball medially
tests of trigeminal nerve (5)
- sensory functions: pin pricks, vibration, light touch on various areas of the face; moving jaws and asking for direction of movement
- motor functions: biting, looking for position of jaw (is it deviated to one side?)
lesion in facial nerve (cranial nerve 7)
Bell’s palsy
- make quadrant of face and look at where the deficit lies
- ask patient to wrinkle forehead and smile
upper motor neuron deficit
forehead spared
lower motor neuron deficit
forehead weak
lesions of cranial nerve 8 (audition)
- test with sounds
- can look for balance issues
lesions of cranial nerves 9, 10, 11, and 12
- say “ahhh” and watch the uvula (should remain in midline)
- put both hands on shoulder and ask patient to resist
- put one hand on cheek and ask patient to try to turn against the hand
- stick out tongue and see if tongue deviates to the side (of the lesion)
grading muscle strength to test corticospinal tract
- 0 = no movement
- 1 = muscle twitch, no movement of limb
- 2 = muscle contracts but no movement against gravity
- 3 = able to provide minimal resistance
- 4 = able to provide moderate resistance
- 5 = normal strength
grading muscle tone to test corticospinal tract
- normal
- decreased - flaccid
- increased - rigid, spastic, cogwheeling
corticospinal tract (motor system) tests
- grading muscle strength
- grading muscle tone
- look for tendon reflexes
- look for abnormal reflexes (e.g., Babinski sign)
spinal reflex arc (test of corticospinal tract)
- stimulate patellar ligament
- sensory neuron signals
- motor neuron causes tendon reflex
- observe if reflex does not occur, happens too weakly, or happens too strongly
Babinski sign
- normal in babies before 8-9 months
- stimulate sole of foot through stroking
- if toes fan out, this is an indication of a cortex issue
tests of spinothalamic tract
- check for pain and temperature
- pin prick
tests of medial lemniscus and dorsal columns
- check for vibration, discrimination touch, proprioception
- Romberg sign (with eyes closed)