final exam comprehensive Flashcards
ABR findings with conductive HL
an increase with absolute latencies
ABR findings with SNHL
higher wave latencies with early waves disappearing as the intensity decreases
ABR findings with retrocochlear pathologies
presence of wave 1 only
ABR findings with ANSD
a flattened sum curve, flipped condensation and rarefaction curves
ABR findings with a schwannoma
wave 5 increases and therefore interwave latency also increases
OAE findings with PE tubes
reduced or obliterated
OAE findings with negative ME pressure
variable responses
OAE findings with ANSD
present unless blood supply is impacted
neuroglial cells
the supporting cells of the brain
-astrocytes : nerve cells and functions as an insulator
-oligodendrocytes : myelin sheath for central nerve fibers
-microglia : activated with inflammation/degeneration in CNA
-ependymal cells : line CSF filled cavities and spinal cord
neoplasms
abnormal mass of tissue, can be benign or malignant
-a disorder of the cell cycle in which they prey on the host
classification of neoplasms
intracranial, benign, malignant, intra-axial and extra-axial
intracranial neoplasms
brain tumor that includes :
-benign and malignant tumors
-masses within brian
-tumors of meninges
-tumors from structures near brain tissue
benign neoplasm
slow growing with well defined borders
-generally not life threatening
-does not metastasize
malignant neoplasms
tends to grow faster and causes invasion and destruction of structures
-can become life threatening
-able to metastasize to other areas of the body
intra-axial tumors
originating within the brain tissue
extra-axial tumors
originating from tissue that is not originated from the brain
vascular tumors
most found within the temporal bone and are benign
-messy and difficulty to remove due to them becoming involved with blood supply
-typically presenting with symptoms in the 3rd decade of life
two types of vascular tumors
hemangiomas and vascular malformations
hemangiomas
initial rapid growth with decreasing growth rate
vascular malformations
grows in proportion with the body growth without regression
-more common than hemangiomas
site of lesion for vascular tumors
IAC or the geniculate ganglion of the 7th nerve
-can also arise from ME cavity
symptoms of vascular tumors
CN 7 dysfunction, hemifacial spasm, tinnitus and vertigo (occurs when CN 8 is impacted)
diagnosis of vascular tumors
case Hx and presentation of symptoms, high resolution CT scan, MRI with contrast (geniculate lesions may be difficult to view)
what type of MRI is useful with vascular tumors?
T2 weighted image as the fluid is brighter