PRESBYCUSIS/PRESBYSTASIS—-DANIEL TODD, MD
SENILE DEGENERATION OF THE AUDITORY SYSTEM
A POST MIOTIC CELL LINE
RARELY FAMILIAL
GENERALLY IDIOPATHIC—USUALLY OVER 65, NO FHx, NO OTHER ETIOLOGY FOUND
CONTRIBUTING FACTORS: CARDIOVASCULAR Dz, NOISE EXPOSURE, OTOTOXIC SUBSTANCES, Fhx, DIET, HTN, DEMENTIA, DEPRESSION, ESTROGEN, THYROID FUNCTION, DIABETES
SENSORY PRESBYCUSIS—-BY FAR THE MOST COMMON TYPE
OUTER HAIR CELL LOSS IN THE BASAL TURN OF THE COCHLEA
ABRUPTLY DOWNSLOPING AUDIO
SYMMETRIC
HIGH FREQUENCY
OFTEN SPARRING THE SPEECH FREQUENCIES (300-3000HZ)
GOOD SDS
SLOWLY PROGRESSIVE-INSIDIOUS
(CAN BE NOISE RELATED)
NEURAL PRESBYCUSIS
DEGENERATION OF THE COCHLEAR NEURONS AND ATROPHY OF THE SPIRAL GANGLION
POOR SDS
PHENOMIC REGRESSION=SDS LOSS DIPROPORTIONATE TO THE PTA
FLAT TO SLIGHTLY DOWNSLOPING AUDIO
STRIAL (ATROPHY) OR METABOLIC ATROPHY
STRIAL ATROPHY CAUSED BY MICROVASCULAR Dz
THE MAJOR CAUSE OF LOW FREQUENCY SNHL
GOOD SDS
FEMALE > MALE
FLAT AUDIO
BEST CANDIDATES FOR AMPLIFICATION
MECHANICAL PRESBYCUSIS=COCHLEAR CONDUCTIVE PRESBYCUSIS
A POST MORTEM Dx=BASOPHILIC DEPOSITS IN THE BASILAR MEMBRANE
STIFFNESS AND IMPAIRED MECHANICAL-ELECTRICAL TRANSDUCTION OF ENERGY FROM THE BASILAR MEMBRANE
SYMMETRIC
GOOD SDS—INVERSELY RELATED TO THE SLOPE OF THE SNHL
PRIMARILY AFFECTS THE BASAL TURN OF THE COCHLEA
FLAT-DOWN SLOPING (HIGH FREQUENCY) AUDIOGRAM
PRESBYSTASIS
ANATOMIC-INNER-DEGENERATION OF HAIR CELLS AND SUPPORTING NETWORK OF VESTIBULAR END ORGANS EAR-DECREASE OF NUMBER OF MYELINATED NERVE FIBERS IN THE VESTIBULAR NERVE
-OTOCONIA DEGENERATION
-DECREASED SYNAPTIC PATHWAYS CENTRALLY
GENERAL—BALANCE IS A COMPLEX INTERACTION OF VESTIBULAR, VISUAL, AND PROPRIOCEPTIVE SYSTEMS WITH DEFICITS IN ANY AREA POSSIBLE CAUSING CLINICAL DZ
DIZZINESS-PERIPHERAL DZ ETIOLOGY IN 50% OF ELDERLY AND RELATED TO BPPV
-CEREBROVASCULAR DZ ETIOLOGY IN 25% AND IF PRESENT USUALLY HAS OTHER NEUROLOGICAL DEFICITS RELATED TO VERTEBROBASILAR SYSTEM
TESTING-MAY SHOW GENERALIZED WEAKNESS BUT NO SPECIFIC CHANGES ASSOCIATED WITH AGE-RELATED DIZZINES
TREATMENT-VESTIBULAR REHABILITATION WITH POSSIBLE SHORT COURSE OF VESTIBULAR SUPPRESSANTS AS NEEDED
-SURGERY IS APPROPRIATE IN CERTAIN PATIENTS DEPENDING ON THE DIAGNOSIS AND SEVERITY OF SYMPTOMS