14 Aging: Balance and Vestibular Disorders

Dizziness is a very common complaint among older adults. In the over-60 population, 18.2% of community-dwelling adults have a 1-year prevalence of dizziness sufficient to interfere with activity and require a doctor visit or medication.1 At age 70, 36% of women and 29% of men report a balance problem. This increases to 51% and 45%, respectively, in 88-to 90-year-old individuals.² Among patients more than 75 years old presenting to a physician’s office, dizziness was the most common complaint, and for patients over 85, dizziness accounts for 7% of all visits to primary care physicians.^3,4 Dizziness is associated with an increased risk of falls and associated morbidity and mortality. Moreover, there are multiple insidious effects, such as decreased physical activity due to fear of falling, decreased quality of life, and a high rate of depression.

Age-related decline in vestibular function is referred to by various terms, including presbystasis, presbylibrium, and disequilibrium of aging. Studies have revealed age-related changes in vestibular organs, including changes in the overall cell number and ultrastructure of vestibular hair cells and vestibular ganglia, degeneration of otoconia, decrease in blood flow to the cristae, and decrease in volume of the crista.^5,6,7,8,9,10 Vestibular dysfunction, determined using a modified Romberg test, increases significantly with age.¹¹ Comorbidities, such as decreased visual function and peripheral neuropathy, as well as decreased neuroplasticity and impaired executive control, pose obstacles to successful vestibular compensation in the older patient. While aging is inevitable, it is important to note that even individuals with age-related changes in vestibular function can still benefit from interventions. The misconception that dizziness is a part of aging and is therefore not treatable contributes to delays in diagnosis for older patients with treatable causes of dizziness (i.e., benign paroxysmal positional vertigo [BPPV]).¹²

Older dizzy patients sometimes suffer an inverse version of the tale of the blind men, each feeling a different part of an elephant and declaring the object before them to be a rope, a fan, or a tree branch. Patients are sometimes passed from specialist to specialist, each declaring that the dizziness is “not cardiac,” “not central,” etc., and the patient is left frustrated, without a diagnosis, and without a treatment plan. When the appropriate evaluations do not yield an inner ear source, it is important for the otolaryngologist to go beyond the declaration that the problem is “not peripheral” and to initiate practical interventions (i.e., exercise program, fall risk-reduction program, vestibular physical therapy) aimed at restoring function and reducing the risk of falls. Simple steps, such as asking about falls, can lead to valuable interventions, even if the dizziness is not secondary to inner ear pathology.

Etiology

Studies on the etiology of dizziness in the older patient yield widely varying results, depending on the patient population, whether in the community, in a primary care setting, or in a specialty clinic. A large cross-sectional population study from Australia reveals that nonvestibular sources of vertigo are more common than vestibular sources of vertigo.¹³ In a large study of patients presenting to a primary care clinic in the Netherlands with dizziness, 57% were found to have a cardiovascular disease as the major cause of their symptoms.¹⁴ However, in a large study of patients referred to ENT clinics in Denmark with a chief complaint of dizziness, the majority of patients had BPPV.¹⁵ Within otolaryngology specialty clinics, common causes of dizziness in the general population are also common in the older population (i.e., BPPV). A retrospective review of more than 1,000 patients over 70 years old presenting to a dizziness clinic revealed that 39% had confirmed or strongly suspected BPPV.16 Besides BPPV, other neurotologic diagnoses to be considered include vestibular neuritis, Meniere’s disease, vestibular hypofunction, and vestibular schwannomas. Multisensory deficits (i.e., a combination of vestibulopathy, peripheral neuropathy, and vision loss) are also common causes of disequilibrium in the older population.

Neurologic causes, such as stroke, need to be considered. Vertebrobasilar insufficiency, multiple sclerosis, Parkinson’s disease, cerebellar ataxia, and Arnold-Chiari malformation can present with vertigo, disequilibrium, and/or gait disorder.¹⁷ Migraine-associated dizziness occurs with less frequency in the older population.¹⁶ In patients with cervical disease, cervicogenic dizziness should be considered.¹⁸ There is some evidence that white matter abnormalities (T2 hyperintensities on MRI) may account for symptoms in patients with no other identifiable cause.¹⁹ Cardiovascular issues, such as orthostatic hypotension, are common causes of lightheadedness. Other cardiac issues to consider, particularly in the context of lightheadedness, include arrhythmias (i.e., bradycardia), valvular disease (i.e., aortic stenosis), and other cardiac conditions that result in decreased blood flow to the brain.

Etiologies encountered with greater frequency in the older population include medication side effects, particularly in the setting of polypharmacy. Initiation or change in dosage of antihypertensive medications can lead to postural hypotension and lightheadedness. Other medications often associated with dizziness include anticonvulsants, antidepressants, anxiolytics, sedatives, strong analgesics, muscle relaxants, and anti-arrhythmics.¹⁷ General medical issues, such as anemia or hypoglycemia, must also be considered. Multifactorial etiologies (i.e., multisensory disequilibrium, polypharmacy, and hypoglycemia) are common in older patients. Psychological issues as a primary factor are unusual in the older patient.²⁰

History, Physical, and Laboratory Examination of the Older Dizzy Patient

While the history, physical, and laboratory examination of the dizzy patient are covered extensively in other chapters of this book, there are unique issues that are important to consider when approaching the older patient. While younger patients are often quite concerned about symptoms like vertigo or imbalance, some older patients may not complain of dizziness. They may assume, for example, that it is normal at their age to have some dizziness when turning to get out of bed. A study of patients in a geriatric clinic, none of whom complained of dizziness to their primary care physicians, revealed that 61% had dizziness.²¹ Of the 100 patients who were included in the study, 9% had undiagnosed BPPV. Given the underreporting of dizziness in the older population, symptoms should be solicited with direct questions, such as “Do you get dizzy when you roll over in bed?” or the like.

Polypharmacy is a particularly important issue in the older population, and a detailed review of medications is necessary. It is not uncommon for patients to be placed on vestibular suppressants, such as meclizine, indefinitely and without regard for their effectiveness. Discontinuing the inappropriate use of chronic vestibular suppressants can facilitate vestibular compensation. Particularly when there is memory impairment or cognitive decline, it can be worthwhile to have a family member or friend assist with eliciting the history or filling out a dizziness questionnaire.

Given the high prevalence and underreporting of symptoms, Dix-Hallpike testing should be included in the physical examination of all older dizzy patients. It is also worthwhile to include orthostatic vitals. Observation of gait is vital, as gait deficit is one of the most common risk factors for falls.²²

On oculomotor testing, it is not uncommon to find some degree of bilateral end-gaze nystagmus as well as limitation in upgaze in the older patient. Difficulty with tandem walking can also be expected. Bedside vestibular tests, as well as more formal measures of vestibular function, should be interpreted in light of normative data that is emerging for healthy older adults. A majority of older adults with no self-reported handicap as measured by the Dizziness Handicap Inventory failed a modified Romberg test (standing on a foam pad with eyes closed to eliminate both visual and proprioceptive input).²³ This same population exhibited a high prevalence of abnormal head impulse testing (30–40%), particularly in the plane of the horizontal semicircular canal. Some authors report a modest age-related decline in canal function (as measured using caloric tests) in comparison to a more marked reduction in vestibular evoked myogenic potential (VEMP) responses.²⁴ Others report significant declines in both semicircular canal and otolith function (as measured using head thrust dynamic visual acuity, cervical VEMP, and ocular VEMP) in an age-dependent fashion.²⁵

Benign Paroxysmal Positional Vertigo

The incidence of BPPV increases with age¹⁵ and BPPV is often unrecognized in older adults.²¹ Even with directed questions, the reporting of symptoms is not straightforward. Patients may not recognize that a turn to the side triggered the vertigo and will report the complaint as dizziness when they get out of bed—a symptom that can be mistaken for postural hypotension. Given the very high prevalence of BPPV in the older population,15,16 Dix-Hallpike testing should be included in the assessment of every older dizzy patient.

Decreased neck range of motion, limited trunk mobility, and kyphosis are potential factors that may affect both Dix-Hallpike testing and Epley repositioning maneuvers in the older patient population. The literature is divided on this topic. Some authors did not find a significant association between age and recurrence rate of BPPV.^26,27 Other studies suggest that effectiveness of repositioning maneuvers is age dependent. A study of 86 patients treated for BPPV found that 4% of patients had persistent symptoms after four repositioning maneuvers—all were older women.²⁸ Another study of 47 patients age 70 and above found that 64% of patients improved with Epley repositioning maneuvers. Those who did not improve were referred for vestibular rehabilitation, which boosted the improvement rate to 77%.²⁹

When performing Epley maneuvers in the older patient, an assessment of kyphosis and cervical spine range of motion should precede treatment. It can be helpful to have an assistant in the room. A slow and gentle maneuver, letting the patient recline only as quickly as they are comfortable with, rather than jerking the head back, can still be effective. It is not necessary to hyperextend the neck, since successful repositioning depends on the orientation of the head relative to gravity not relative to the rest of the body. Placing the exam chair in Trendelenburg position can help to overcome anatomic challenges stemming from kyphosis or limited neck range of motion.

Many otolaryngologists provide patients with postrepositioning instructions that include the recommendation to avoid sleeping in a fully reclined position for 24 to 48 hours. However, sleeping in a partially reclined chair or using extra pillows is likely to disturb sleep, and poor sleep presents yet another fall risk.³⁰ Eliminating these positional restrictions does not seem to affect the success rate of the Epley maneuver.^31,32

A prospective study of postural stability (using dynamic posturography) revealed that older patients were less likely to show improvements in postural stability after treatment even though the vertigo resolved. It is unclear whether this is a causative phenomenon or whether there is coexistent vestibular pathology.³³ Others have reported an increased fall risk in patients with BPPV.²¹ Mild horizontal canal BPPV has been implicated as a possible cause of chronic dizziness.³⁴

Meniere’s Disease

De novo presentation at age 65 and above was noted in 9% of patients with definite Meniere’s disease.³⁵ Among 66 older patients with Meniere’s, 41% were found to have reactivation of long-standing disease, as opposed to 59% with de novo appearance of symptoms.³⁵ Drop attacks are noted more commonly in older patients.^35,36

A difficult treatment dilemma arises in the older Meniere’s patient who fails conservative management. There is a dogma that vestibular compensation is impaired in older individuals, raising the concern that older patients may be more prone to experience chronic disequilibrium after vestibular ablation. The older Meniere’s patient with recalcitrant vertigo attacks may be denied chemical or surgical vestibular ablation on this basis. However, there have been challenges to this conventional dogma. It has been demonstrated that older individuals are able to receive the same degree of benefit from vestibular rehabilitation as their younger cohorts.³⁷ Additionally, recent work examining vestibular compensation after acoustic neuroma surgery has revealed that older patients do compensate successfully and that the degree of preoperative physical activity, more so than age, is a predictor of the ability to regain normal balance function.^38,39 It is worthwhile to consider the patient’s “biologic” or functional age rather than their chronologic age. Access to ablative procedures should not be denied purely on the basis of age. Instead, an assessment of comorbidities that present additional insults to equilibrium provides a more useful approach. An otherwise completely healthy 70-year-old is more likely to compensate well than a 50-year-old with peripheral neuropathy and poor vision. It is helpful to have input from a vestibular therapist before ablation, particularly when there are concerns about a patient’s ability to successfully compensate.

Fall Prevention

The fall risk for an individual over 65 is ~ 30%. This increases to 50% in individuals over 80. A fall in an older person is more likely to result in significant injury: 95% of hip fractures are caused by falls. Adjusting for inflation, the Centers for Disease Control and Prevention (CDC) estimate the direct medical costs of falls at $34 billion.^40,41 Individuals who complain of dizziness and demonstrate vestibular dysfunction (abnormal modified Romberg) have an eightfold increase in the odds of sustaining a fall.¹¹ Multifactorial fall risk assessment, as well as exercise programs, have been shown to decrease fall risk.42 Given these figures, providers who evaluate patients with dizziness and vestibular dysfunction are poised to reduce fall risk for their patients. Often, particularly in otolaryngology, training focuses on diagnostics and treatment, and less on prevention. A quick and practical preventative approach aimed at identifying fall risk factors should be included in the assessment of every older dizzy patient (see Box 14.1).

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