aging of the human vestibular system.pptx
TRANSCRIPT
10/13/16
1
THE AGING HUMAN VESTIBULAR SYSTEM &
THE SILVER TSUNAMI
CHRIS ZALEWSKI, PH.D. NIH, AUDIOLOGY
“We would accomplish many more things if we did not think of them as impossible” - Vince Lombardi
DISCLOSURES I have relevant financial relationship(s) with: National Institutes of Health
Employed and receives salary.
University of Maryland and Gallaudet University
Employed as adjunct faculty
Washington Hospital Center
Employed as a PRN Clinical Audiologist
I have relevant non-financial relationship(s) with: American Balance Society
Currently on the Board of Directors
American Academy of Audiology Currently on the Board of Directors
10/13/16
2
PRESENTATION OBJECTIVES LEARNER OUTCOMES
1. Getting acquainted with the aging population
2. Epidemiology of falls and dizziness in the elderly
3. Role(s) of the vestibular system in balance
4. Histology associated with aging of the vestibular system
5. Clinical finding associated with an aging vestibular system
THE SILVER TSUNAMI
Who are they? When are they arriving? Are we ready?
10/13/16
3
ADVANCING BABY BOOMER GENERATION
In 2009, the U.S. senior population (65 years and older) was 39.6 million
In 2030, the senior population is expected to balloon to 72.1 million
In 2050, the senior population is expected to peak at 86 million – a greater than 200% increase than the census in 2012
http
://f
ivet
hirt
yeig
ht.c
om/f
eatu
res/
wha
t-ba
by-b
oom
ers-
retir
emen
t-m
eans
-for
-the
-u-s
-eco
nom
y/
https://familyinequality.wordpress.com/2014/10/07/this-word-generation-i-do-not-think-it-means-what-you-think-it-meants/
PROJECTED HEALTH CARE COSTS WITH A RISE IN SENIOR HEALTH CARE
With a near exponential rise in the number of senior citizens, the increase in health care spending is projected to be as much as three times the current cost for areas like Medicare.
When normalized against the overall effect of the aging population, the effective cost for caring for the elderly shows an exponential growth faster than the overall GDP of the United States
Spending on Social Security, Medicare, and Medicaid as a Percentage of GDP, 2005–2050
10/13/16
4
PROJECTED HEALTH CARE NEED
Projected need of 5,600 Audiologist jobs by 2020 to maintain current levels of care
The U.S. Census Bureau estimates that the last of the baby boomers will die in the year 2070, leaving 53 years of potentially intense health care issues related to balance disorders as well as complications arising from this health care epidemic (Overberg, 2000)
https://www.healthit.gov/sites/default/files/chws_bls_report_2012.pdf https://www.healthit.gov/sites/default/files/chws_bls_report_2012.pdf
EPIDEMIOLOGY OF FALLS & DIZZINESS IN THE ELDERLY
A Review of the Literature
10/13/16
5
PREVALENCE OF BALANCE DISORDERS IN THE GERIATRIC POPULATION
At least half of the overall U.S. population is affected by a balance or vestibular disorder sometime during their lives (NIDCD, 1997)
Vestibular / Balance disorders currently impact the daily functional capacity of approximately 12.5 million Americans over the age of 65 (NIDCD, 2002)
When considering only vestibular origins to dizziness, nearly 20% of the general population is affected by a vestibular disorder (Univ of Iowa, 2002)
…MOREOVER An astounding 70% of elderly patients present with some type of dizziness complaint in the primary care setting (Sloan et al, 2001)
The diagnosis of non-specific dizziness (⅓ of patients over 75 years of age) is often very difficult to diagnose, particularly in the elderly in whom it is often secondary to multi-system dysfunction (Univ. of Iowa Health Care, 2002)
It is estimated that 65% of individuals over 60 years of age experience loss of balance or dizziness (Hobeika, 1999)
10/13/16
6
OVERALL IMPACT…FALLS Balance disorders, particularly in the elderly, often leads to falls
Mortality rates following the first fall are often only 1 year
Falls are one of the major complications of dizziness and balance dysfunction that contributes to one of the principal causes of fatal and non-fatal injuries in older adults (Center for Disease Control, 2001)
Every year, one-third to one-half of the population over 65 years of age and older experience falls (Hausdorff et al, 2001).
The elderly represent more than one-third of all hospital injury admissions of which 80% are due to falls
>85% of hip fractures related to falls are in persons 65 years or older
RISING COSTS…
Injurious falls rank as the 6th leading cause of death in the “elderly” population
Medical expenses related to injurious falls amounts to 10-20 billion dollars annually in the U.S., and is projected to climb to 32 billion dollars by the year 2020 (Am Acad Ortho Surg, 2003; CDC, 2001, Bloem, 2003)
Moreover, the cost of medical care associated with simply the treatment of balance problems and medical care associated with vestibular dysfunction exceeds one billion dollars annually (Univ of VA Health System, 2003)
10/13/16
7
AGRAWAL, Y., ET AL. (2009) ARCHIVES OF INTERNAL MEDICINE
Overall Conclusions: Odds of vestibular dysfunction increased significantly
with age
Substantial portion of individuals without a history of self-reported dizziness has evidence of vestibular dysfunction These individuals have a significantly increased odds of falling
Recommendation: Screening for vestibular dysfunction in assisted living or
nursing home facilities could be life saving and cost-effective practice (>$20 billion annually)
AGRAWAL, Y., ET AL. (2009) ARCHIVES OF INTERNAL MEDICINE
10/13/16
8
SHOAIR, O., ET AL. (2011) OTOLARYNGOLOGY CLINICS OF NORTH AMERICA
Medication-related dizziness can be difficult to diagnose, especially in older persons, in whom it can masquerade as a geriatric syndrome.
Geriatric syndromes are difficult to define, but they are characterized as symptoms with multifactorial causes, which become more common with aging and are in fact often mistaken for normal aging.
PHARMACOKINETICS, POLYPHARMACY & PHARMACODYNAMICS
Pharmacokinetics describes the relationship between the dose of the drug administered and the resulting drug concentrations achieved in the systemic circulation. Aging is generally characterized by changes in all
pharmacokinetic processes including absorption, distribution, metabolism, and excretion, although the most clinically important changes are those affecting hepatic and renal drug elimination.
Pharmacodynamics describes the relationship between drug concentrations in the systemic circulation and drug response. Pharmacodynamic changes often result in
increased sensitivity to medications, especially for drugs acting on the central nervous system (CNS).
Polypharmacy refers to the use of multiple medications and/or the administration of more medications than is clinically indicated, representing unnecessary drug use.
* Sloane PD, Coeytaux RR, Beck RS, et al. Dizziness: state of the science. Ann Intern Med 2001;134(9 Pt 2):823–32. Salles N, Kressig RW, Michel JP. Management of chronic dizziness in elderly people. Z Gerontol Geriatr 2003;36(1):10–5.
*
10/13/16
9
AMBROSE, A., ET AL. (2013) MATURITAS
75-80% of falls without injury are not reported
Falls affect 33% over the age of 65 years
Falls affect 50% over the age of 80 years
Injuries (2009) 2.2 million non-fatal injuries requiring ER visits More than 581,000 requiring hospitalization
19,000 deaths related to falls (5th leading cause of death in adults >65 years of age)
AMBROSE, A., ET AL. (2013) MATURITAS
10/13/16
10
Falls are the leading cause of injury and death among older adults
Breakdown of fall-related injuries: 30-50% of falls result in minor lesions such as bruises or lacerations
5-10% of falls result in major injury such as fractures or TBI Falls are the most common cause of TBI in older adults and account for 46% of
fall-related deaths in TBI patients 90% of all hip fractures are fall-related
In the first year following a hip fracture: 25% of older patients will die
76% will have a decline in their mobility 50% will have a decline in their ability to perform daily life activities – setting
up a viscous spiral with further declines in physical fitness, social isolation and depression
22% will move into a nursing home
AMBROSE, A., ET AL. (2013) MATURITAS
Older individuals have an increased susceptibility for fall-injury due to the higher prevalence of comorbidities such as: Older age Prior history of falls Functional impairment Use of a walking aid or assistive device Cognitive impairment or dementia Impaired mobility or low activity level of daily life activities Gait or balance abnormalities Vestibular impairments Dizziness Drop attacks Confusion Postural hypotension Visual disorders Syncope Polypharmacy Reduced strength Depression Poor environmental management (footwear)
AMBROSE, A., ET AL. (2013) MATURITAS
10/13/16
11
ROLE OF THE VESTIBULAR SYSTEM IN BALANCE
VOR & VSR
ANATOMY OF THE PERIPHERAL VESTIBULAR LABYRINTH
Antonio Scarpa, 1789
Aelius Galen (129-216 AD)
During osteological study of the skull, the inner ear reminded him of the Cretan ‘Labyrinthos’. …and hereafter, the term “labyrinth” has been used to describe the inner ear vestibular anatomy.
10/13/16
12
VESTIBULAR SENSORY END ORGANS
Each vestibular system has FIVE distinct sensory end organs 3 Semicircular Canals Horizontal (lateral)
Anterior (superior) Posterior
2 Maculae (Otoliths) Saccule Utricle
Vestibular Nerve • Superior • Inferior
Cochlea
r Nerv
e
Superior Branch
Ante
rior C
anal
Horizontal Canal
Posterior Canal
Utric
le
Sacc
ule Cochlea
to brainstem
VESTIBULAR AFFERENT & EFFERENT PATHWAYS
Central Vestibular Nuclei
Lateral SCC
Anterior SCC
Posterior SCC
Utricle
Saccule
Lateral SCC
Anterior SCC
Posterior SCC
Utricle
Saccule
Rig
ht L
abyr
inth
Le
ft La
byrin
th
Adaptation
Eye Muscles
Skeletal Muscles
Vestibular Ocular Reflex (VOR)
Saccadic System Tracking
System
Optokinetic System Neck
Receptors
Other
Vestibular Spinal Reflex (VSR)
Proprioceptive
Visual
Tactile
Other
- Adapted from Canalis & Lambert, 2000
10/13/16
13
HISTOLOGY OF THE AGING VESTIBULAR SYSTEM
Highlights from the Literature
MERCHANT, ET AL., 2000 ANNALS OF OTOLOGY, RHINOLOGY AND LARYNGOLOGY
10/13/16
14
TOTAL HAIR CELL COUNTS (CRISTAE) MERCHANT ET AL., NORMAL VESTIBULAR HAIR CELL DATA (2000)
Total hair cell counts (density) by age for each of the semicircular canal cristae
Type I versus Type II epithelial densities for each of the cristae
Total counts for all 3 canals show a strong negative correlation with an age-effect that was highly significant (p<0.0001)
No difference observed between any of the 3 canals
Supe
rior
SCC
La
tera
l SC
C
Post
erio
r SC
C
TOTAL HAIR CELL COUNTS (MACULAE) MERCHANT ET AL., NORMAL VESTIBULAR HAIR CELL DATA (2000)
Total hair cell counts (density) by age for each of the otolith maculae
Type I versus Type II epithelial densities for each of the maculae
The mean total hair cell density between maculae at birth were significantly different from each other (p<0.0001) utricle (68 cells per 0.001 mm2) saccule (61 cells per 0.01 mm2)
Total cell counts show a strong negative correlation with an age-effect that was highly significant (p<0.0001) No difference in age-slopes between maculae
Utr
icle
Sa
ccul
e
10/13/16
15
TOTAL HAIR CELL DENSITIES: CENTRAL VS PERIPHERAL END ORGAN (CRISTAE) MERCHANT ET AL., NORMAL VESTIBULAR HAIR CELL DATA (2000)
Total hair cell counts (density) by cristae location for each of the semicircular canals
Hair cell densities were significantly greater at the periphery than at the center (p<0.01) (9/67 normal temporal bones from 0-40 yr age group)
Center (70 cells per 0.01mm2) Periphery (87 cells per 0.01mm2) Density difference between central and peripheral were more marked for type I than for type II hair cells
TOTAL HAIR CELL COUNTS FROM BIRTH TO DEATH MERCHANT ET AL., NORMAL VESTIBULAR HAIR CELL DATA (2000)
10/13/16
16
GENERAL FINDINGS… MERCHANT ET AL., NORMAL VESTIBULAR HAIR CELL DATA (2000)
Density in the cristae and maculae (as expressed as number of cells per 0.01 mm2 of the neuroepithelial surface)
FIRST DECADE OF LIFE: 80-90 cells per 0.01 mm2
NINTH DECADE OF LIFE: 40-60 cells per 0.01 mm2
Rate of cell loss with age was significantly greater for the cristae than for the maculae (p<0.0001) highlighted by a more rapid degeneration rate of type I hair cells located within the central epithelial regions
No differences observed between male and female or between right and left ears
IGARASHI, M., ET AL., (1993) ACTA OTO-LARYNGOLOGICA
10/13/16
17
OTOCONIA VOLUME LOSS FROM AGING
The otonconia volume in senile temporal bones was less than that of young persons.
Utricle-to-Saccule ration of 100:70 in the young age group, that degraded to a ratio of 100:35 in the elderly group. This result suggests for an increased rate of age-related saccular degeneration.
This may be due to saccular orientation or reduced mitigation of calcite seeding (Lim, 1984)
*
2-month old child 58/61 y/o adult
ROSS, M., ET AL., (1976) ANNALS OF OTOLOGY
10/13/16
18
ROSS, M., ET AL., (1976) ANNALS OF OTOLOGY
21 Young Adult (Utricle) 21 Young Adult (Saccule) 21 Young Adult (Utricle)
52 year old early pitting and cavitation
83 year old pitting and fibrous (rough) appearance
65 year old mid-section fracturing and fibrous appearance
65 year old splitting and separation
Aged otoconia bodies are pitted, fissured, fragmented, finely serrated, weaken or broken filaments
VELAZQUEZ-VILLASEÑOR, ET AL., 2000 ANNALS OF OTOLOGY, RHINOLOGY AND LARYNGOLOGY
10/13/16
19
SCARPA’S GANGLION CELL DATA
Highly significant age effect for a strong negative decline in total cell counts (p=0.0001)
Superior division cell loss (37.2/yr) statistically greater than inferior division cell loss (19.6/yr) (p=0.025)
Significant gender effect (independent of age) with male demonstrating a higher cell count than women at any age. However, the age-related rate of decline
failed to reach statistical significance between male (49.9/yr) and female (69.5/yr)
No significance right / left difference
Normal Aging Cell Counts Superior Division vs Inferior Division
Male vs Female Right vs Left
ALVAREZ, ET AL., 2000 MECHANISMS OF AGEING AND DEVELOPMENT
10/13/16
20
ALVAREZ, ET AL., 2000 MECHANISMS OF AGEING AND DEVELOPMENT
Neuronal loss occurs with aging in the descending (DVN), medial (MVN), and lateral (LVN) vestibular nuclei, but not in the superior (SVN).
Neuronal loss could be related with the problems that elderly people have to compensate unilateral vestibular lesions and the alterations of the vestibulospinal reflexes.
The preservation of SVN neurons could, in part, explain why vestibulo-ocular reflexes are compensated after unilateral vestibular injuries. A moderate vestibular dysfunction, that would not to cause problems in a young adult, could produce symptoms
and signs in the elderly, when there are also poor sight and loss of proprioception and neuromuscular function.
SUMMARY OF VESTIBULAR AGING HISTOLOGY 1. Significant age-related deterioration in the number of type I and type II
hair vestibular hair cells in the periphery
2. Significant age-related deterioration of central vestibular sensory neurons in the vestibular nuclei and the cerebellum
3. More rapid degeneration rate of type I vestibular hair cells with a concomitant higher rate of hair cell loss for the cristae than the maculae
4. Greater loss of hair cells in the central epithelial regions of the sensory end organs than the periphery
5. Hair cell loss is most prominent in the 7th to 8th decade of life, which is also the same time that many sexagenarians and septuagenarians begin reporting the onset of unrelenting dizziness and function imbalance
6. Concomitant compensation mechanisms could both mask clinical findings and exacerbate function disabilities in the elderly populations, making prebystasis a difficult “disorder” to clinically segregate and treat.
10/13/16
21
CLINICAL ASSESSMENT OF THE AGING VESTIBULAR
SYSTEM
Highlights from the Literature
REVIEW OF CLINICAL VESTIBULAR MEASURES IN THE AGING
Videonystagmography Ocular Motor Positional
Caloric Irrigation
Rotational Vestibular Assessment
Vestibular Evoked Myogenic Potentials cVEMP oVEMP
Video Head Impulse Testing (vHIT)
10/13/16
22
IRVING, E., ET. AL., (2006) INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
195 subjects aged 3-86 years
Age effects identified on all saccadic parameters; velocity, latency and accuracy (amplitude gain)
After the 50 years of age, saccades greater than 20° had hypometria exceeding 20% and the mean hypometria increases to nearly 40% by the ninth decade.
IRVING, E., ET. AL., (2006) INVESTIGATIVE OPHTHALMOLOGY & VISUAL SCIENCE
10/13/16
23
KANAYAMA, R., ET. AL., (1994) ACTA OTOLARYNGOLOGICA
The relationship between pursuit gain and target frequency in the older groups was similar to that in the young controls through 400/sec, but in advanced age groups pursuit gain decreased more markedly with stimulus frequency
Cerebral cortical atrophy and cerebellar Purkinje cell loss is known to accompany senile changes.
Pursuit gain was lower in groups in their 50’s and 60’s. Therefore, it is important to take patient's age into consideration when evaluating smooth pursuit eye movement.
KANAYAMA, R., ET. AL., (1994) ACTA OTOLARYNGOLOGICA
10/13/16
24
SIMMONS & BÜTTNER (1994) EUROPEAN ARCHIVES OF PSYCHIATRY AND NEUROLOGICAL SCIENCES
SIMMONS & BÜTTNER (1994) EUROPEAN ARCHIVES OF PSYCHIATRY AND NEUROLOGICAL SCIENCES
Maximal OKN velocity decreases with increasing age, particularly above stimulus velocities of 500/sec
10/13/16
25
ZALEWSKI (2015): CALORIC FINDINGS BETWEEN 1974-1990 - SEMINARS IN HEARING
MALLINSON & LONGRIDGE (2004): JOURNAL OF VESTIBULAR RESEARCH
10/13/16
26
MALLINSON & LONGRIDGE (2004): JOURNAL OF VESTIBULAR RESEARCH
Examined the mean of the warm and cool responses from the better-responding ear from 185 individuals
Age range from 9-89 years with no history of frank vestibular disease
No significant correlation for cross-sectional mean peak-caloric response
REVIEW OF CLINICAL VESTIBULAR MEASURES IN THE AGING
Videonystagmography Ocular Motor Positional
Caloric Irrigation
Rotational Vestibular Assessment
Vestibular Evoked Myogenic Potentials cVEMP oVEMP
Video Head Impulse Testing (vHIT)
10/13/16
27
PAIGE, G. (1992) JOURNAL OF VESTIBULAR RESEARCH
PAIGE, G. (1992) JOURNAL OF VESTIBULAR RESEARCH
Mean VOR gain and phase are remarkably similar between young, middle-aged, and elderly groups with the exception of: Significant VOR phase lead for the lowest
two frequencies 0.025Hz and 0.1 Hz between elderly and young
Significant VOR phase lead for 0.025Hz between middle-aged and elderly
Significant lower VOR gain for 0.025Hz between young and elderly
10/13/16
28
PAIGE, G. (1992) JOURNAL OF VESTIBULAR RESEARCH
VOR Linearity:
Mean VOR gain and phase are remarkably similar between young, middle-aged, and elderly groups at 500/sec
VOR gain and phase progressively depart from one another as peak head velocity increases, and becomes very pronounced at 3000/sec
Overall: Age-dependent changes in VOR response
characteristics are amplified as head velocity increases
CHAN, GALATIOTO, AMATO & KIM (2015) LARYNGOSCOPE
10/13/16
29
Youngest group significantly different from all other groups
Lowest frequencies have greatest sensitivity to detect age-related changes
CHAN, GALATIOTO, AMATO & KIM (2015) LARYNGOSCOPE
REVIEW OF CLINICAL VESTIBULAR MEASURES IN THE AGING
Videonystagmography Ocular Motor Positional
Caloric Irrigation
Rotational Vestibular Assessment
Vestibular Evoked Myogenic Potentials cVEMP oVEMP
Video Head Impulse Testing (vHIT)
10/13/16
30
JANKY, K. & SHEPARD, N. (2009) JOURNAL OF THE AMERICAN ACADEMY OF AUDIOLOGY
Controlled for SMC activation using a BP cuff, conducted cVEMPS using 250 Hz, 500 Hz, 750 Hz, 1000 Hz, and click stimuli
Identified significant mean differences between the youngest age group (20-29 years) and all other age groups for a decrease in P1 latency (250, 750 &1000 Hz) and a lower cVEMP threshold (500 & 1000 Hz)
JANKY, K. & SHEPARD, N. (2009) JOURNAL OF THE AMERICAN ACADEMY OF AUDIOLOGY
10/13/16
31
PIKER, E., ET. AL. (2011) JOURNAL OF THE AMERICAN ACADEMY OF AUDIOLOGY
Age groups: Youngest (<18 years; n=20) Middle-aged (18-49 years; n=58) Oldest (≥50 years; n=22)
100% subject <50 years had a recordable oVEMP
Only 77% of subjects ≥50 years had a recordable oVEMP
Significant amplitude decrease and threshold increase in the oldest group compared to the two younger groups
Significant correlation identified for oVEMP amplitude (r2=0.139) and threshold (r2=0.105)
PIKER, E., ET. AL. (2011) JOURNAL OF THE AMERICAN ACADEMY OF AUDIOLOGY
10/13/16
32
PIKER, E., ET. AL. (2015) OTOLOGY & NEUROTOLOGY
Sample: 895 patients with cVEMP data 297 patients with oVEMP data 20-87 years of age segregated by 3rd to 9th decade 500 Hz 125 dB pkSPL AC stimuli
Results: 798 present cVEMP; 97 absent cVEMP (10.8%) 173 present oVEMP; 124 absent oVEMP (41.8%) 22.7x odds ratio of absent cVEMP response in 70’s 54.2x odds ratio of absent cVEMP response in 80’s 6x odds ratio of absent oVEMP response in 40’s, 50’s, & 60’s 13x odds ratio of absent oVEMP response in 70’s Age alone was a significant predictor for presence/absence of response
PIKER, E., ET. AL. (2015) OTOLOGY & NEUROTOLOGY
* significant
* significant
10/13/16
33
HARUN, OH, BIGELOW, STUDENSKI & AGRAWAL (2016) OTOLOGY & NEUROTOLOGY
These data corroborate an emerging literature establishing a link between vestibular and cognitive function. Individuals with dementia had poorer function of both the saccular and utricular otolith organs relative to controls, with relative preservation of horizontal canal function. Moreover, analysis of MCI versus AD compared with age-matched controls, revealed significantly poorer vestibular function among AD patients specifically.
HARUN, OH, BIGELOW, STUDENSKI & AGRAWAL (2016) OTOLOGY & NEUROTOLOGY
10/13/16
34
REVIEW OF CLINICAL VESTIBULAR MEASURES IN THE AGING
Videonystagmography Ocular Motor Positional
Caloric Irrigation
Rotational Vestibular Assessment
Vestibular Evoked Myogenic Potentials cVEMP oVEMP
Video Head Impulse Testing (vHIT)
MANTIÑO-SOLER, E., ET AL. (2014) OTOLOGY & NEUROTOLOGY
10/13/16
35
212 adults 5-95 years of age
Identified stable VOR gain, regardless of head impulse velocity, through 70 years of age
Progressive decrease in VOR gain for those over 70 years of age but only for higher head impulse velocities with a greater number of re-fixation saccades
Decrease in VOR gain for all head velocities >90 years of age
MANTIÑO-SOLER, E., ET AL. (2014) OTOLOGY & NEUROTOLOGY
LI, C., ET AL. (2015) OTOLOGY & NEUROTOLOGY
10/13/16
36
109 elderly adults 26-92 years of age
Relatively stable vHIT VOR gain between 26-79 years of age
Eight-fold decrease in obtaining vHIT VOR gain greater than 0.80 relative to those less than 80 years of age
No other significant associations were identified as a contributing factor including cardio-vascular risk factors
LI, C., ET AL. (2015) OTOLOGY & NEUROTOLOGY
MCGARVIE, MACDOUGALL, HALMAGYI, BURGESS, WEBER & CURTHOYS (2015) FRONTIERS IN NEUROLOGY
10/13/16
37
Velocity was significant at every age group with a decrease in VOR gain as head velocity increased
For all canals, there was minimal decrease in VOR gain with age, at least up to the 80’s such that age was not a significant factor with the exception of a weakly significant decrease in gain for the posterior canal
MCGARVIE, MACDOUGALL, HALMAGYI, BURGESS, WEBER & CURTHOYS (2015) FRONTIERS IN NEUROLOGY
CLINICAL ASSESSMENT OF THE AGING VESTIBULAR
SYSTEM SUMMARY
10/13/16
38
It just may be that the power to segregate a presbystasis phenotype may be more difficult than realized.
Applying wide variances for normative reference ranges are often employed due to the lumping of all age groups
However, when viewing the variances across age groups, tight variances for younger age groups are clearly evident. Unfortunately, use of these stratified age ranges will only assist in increasing the diagnostic power for younger individuals – not the elderly.
CLINICAL SUMMARY ON AGING
FINAL THOUGHTS….
10/13/16
39
AN AGING POPULATION… Concomitant with the aging of the population and the dawn of the baby boomer generation reaching 65 years of age, the need for better management of balance disordered patients is essential over the next few decades.
LIN & BHATTACHARYYA (2011) LARYNGOSCOPE NATIONAL AMBULATORY MEDICAL CARE SURVEY
“There will be an estimated 650,000 additional annual clinic visits by the elderly to all medical specialties for an otologic complaint by 2020.”
10/13/16
40
LIN & BHATTACHARYYA (2011) LARYNGOSCOPE NATIONAL AMBULATORY MEDICAL CARE SURVEY
“As the number of Americans older than 65 years of age steadily increases with a potential to gradually over-whelm the number of clinicians trained to provide for both their basic and complex healthcare needs, the medical community and the United States government must prepare for an imminent crisis in the national health-care system.
With American population demographics hurriedly moving toward an inverted pyramid scheme generated by a growing and aging baby boomer cohort benefiting from medical advances that extend life expectancy and quality, the nation’s healthcare system is currently ill-prepared to meet and manage the many medical and social challenges an escalating geriatric population is predicted to present in the coming decades.
Maintaining effective delivery of healthcare to a rapidly growing segment of the population already faced with high rates of comorbidities, frailty, and polypharmacy will require a considerable workforce and financial initiatives specifically aimed at augmenting the number of healthcare providers trained in geriatric medicine and improving access to these resources.
With the percentage of the American population older than 65 years of age predicted to rise to 20% and double in number from 35 million to 71million by the year 2030, the report concludes that the healthcare workforce is currently anticipated to be much too undersized and grossly unprepared to meet the coming needs of the growing elderly population. “
SO HERE WE STAND AT THE PRECIPICE…
10/13/16
41
…LOOKING OVER AN IMPENDING “EPIDEMIC” WITH TWO FUNDAMENTAL CHALLENGES...
Steve Ackley Memorial Conference; Jerry Northern, Ph.D.; November 14, 2014
…WE THINK TO OURSELVES: “ARE WE READY?”
10/13/16
42
AUDIOLOGY DOCTORAL GRADUATES & PROJECTED ATTRITION
Approximately 600 new graduates per year
(American Academy of Audiology Member Survey, 2012)
Steve Ackley Memorial Conference; Jerry Northern, Ph.D.; November 14, 2014
…WE THINK TO OURSELVES: “ARE WE READY?”
Steve Ackley Memorial Conference; Jerry Northern, Ph.D.; November 14, 2014
10/13/16
43
…HOW ARE WE TO EFFECTIVELY SEGREGATE AGING “PATHOLOGY”? “The majority of clinical studies investigating the age-related decline in vestibular physiology have been unable to demonstrate any strong correlation to the histologic reports identifying an obvious decline in sensory hair cell counts, particularly prior to 60-70 years of age.”
“When abnormalities are present, age-related differences are usually subtle, often fall within the lower range of normal limits, and/or exhibit larger variances making statistically discernable differences from younger or middle-aged groups difficult.”
“As medical diagnoses broaden to include dizziness as its own geriatric syndrome, our approach to discovering the underlying etiology must also broaden. Cross-disciplinary medical care will be imperative to effectively diagnose and treat such a multi-factorial and obscure condition as geriatric dizziness”
“…it is clear that advancements and alternatives to our current battery of vestibular tests and stimuli are critically needed to better segregate and identify age-related vestibular changes. As we stand on the brink of a rapidly aging population, it is abundantly clear that a tremendous chanllenge lies ahead”
…THANK YOU
“I cannot teach you anything….all I can make you do is think.” - Socrates