Dizziness is one of the most challenging symptoms in

Investigating Selected Symptoms Dizziness: State of the Science Philip D. Sloane, MD, MPH; Remy R. Coeytaux, MD; Rainer S. Beck, MD; and John Dallara, MD Dizziness is prevalent in all adult populations, causing considerable morbidity and utilization of health services. In the community, the prevalence of dizziness ranges from 1.8% in young adults to more than 30% in the elderly. In the primary care setting, dizziness increases in frequency as a presenting complaint; as many as 7% of elderly patients present with this symptom. Classification of dizziness by subtype (vertigo, presyncope, disequilibrium, and other) assists in the differential diagnosis. Various disease entities may cause dizziness, and the reported frequency of specific diagnoses varies widely, depending on setting, patient age, and investigator bias. Life-threatening illnesses are rare in patients with dizziness, but many have serious functional impairment. Dizziness can be difficult to diagnose, particularly in elderly persons, in whom it often represents dysfunction in more than one body system. Given the relatively underdeveloped state of the empirical literature on dizziness, investigators would benefit from use of consistent criteria to describe dizziness symptoms and establish diagnoses. Investigation of the effects of testing and treatment should focus on diagnoses that are life threatening or lead to significant morbidity. In the elderly, a function-oriented approach should be studied and compared with current diagnosis-focused strategies. Alternative therapies for chronic and recurrent dizziness also merit investigation. Ann Intern Med. 2001;134:823-832. For author affiliations and current addresses, see end of text. www.annals.org Dizziness is one of the most challenging symptoms in medicine. It is difficult to define, impossible to measure, a challenge to diagnose, and troublesome to treat. The word dizziness is used to mean various sensations of body orientation and position that are frequently difficult for patients to describe (1, 2). Dizziness can be caused by a wide range of benign and serious conditions, many of which are not well understood. For most patients, the symptom resolves spontaneously, but an important minority of patients develop chronic, disabling symptoms, and a few have a life-threatening condition (3 5). Most of those with chronic symptoms are not relieved by medical treatment (6). The past decade has seen an increasing focus on evidence-based practice in medicine (7). In this context, a series of steps develop an empirical approach to a symptom such as dizziness (Figure). First, the symptom must be defined and its subtypes delineated in a consistent, widely accepted format. Second, these definitions must be used in epidemiologic studies across many clinical settings, so that the clinical epidemiology of the symptom can be appreciated. Third, the conditions that the symptom may represent must be clearly delineated, with diagnostic criteria. Fourth, the diagnostic criteria must be used in epidemiologic studies to elucidate the clinical picture of the symptom and its diagnoses. Certain life-threatening or potentially remediable diagnoses that practicing physicians need to rule in or out should be targeted. For each of these diagnoses, data should be gathered on clinical diagnostic maneuvers and tests (sensitivity, specificity, and likelihood ratios) and the effectiveness of treatment. Once these steps have been completed, we will have adequate data for development of empirically based practice guidelines, clinical pathways, and other methods of ensuring quality, consistency, and cost-effectiveness in medical practice. We review current knowledge about dizziness by following the steps outlined in the Figure and make recommendations for clinical practice and further research. DEFINING AND DESCRIBING DIZZINESS Dizziness refers to various abnormal sensations relating to perception of the body s relationship to space (8). In a classic paper, Drachman and Hart (1) described four subtypes: vertigo, presyncopal lightheadedness, disequilibrium, and other dizziness. Nearly 30 years later, this typology remains the basis of dizziness definition and classification, having long since displaced the narrower definition ( vertigo ) used in earlier studies (9, 10). The dizziness subtypes are described in Table 1. Vertigo is a false sensation that the body or the environment is moving (usually spinning). It suggests a disturbance of the vestibular system, although psychological states, such as panic disorder, can also produce it (11). Presyncope is a feeling of lightheadedness that is often described as a sensation of an impending faint. It is episodic and usually results from diffuse temporary cerebral ischemia. Disequilibrium is a sense of imbalance (postural instability) that is generally described as involving the legs and trunk without a sensation in the 2001 American College of Physicians American Society of Internal Medicine 823

Investigating Selected Symptoms Dizziness: State of the Science Figure. Steps in the development of a scientific database for medical management of a symptom. head. Isolated symptoms of disequilibrium are generally attributed to neuromuscular problems; imbalance that accompanies other types of dizziness is generally a secondary symptom. Other dizziness is typically described as vague or floating, or the patient may have difficulty describing the sensation. Such dizziness is generally present much of the time and is most often caused by psychological disturbances (1). It is often accompanied by other somatic symptoms, such as headache and abdominal pain (1, 9). In the category of other dizziness are also two distinct though rare forms of dizziness: ocular dizziness due to rapid vision change, as after cataract surgery or a change in a corrective prescription (12), and dizziness described as a tilting of the environment, which is generally attributed to an otolith problem (13, 14). This typology is not without problems. Many patients, particularly elderly ones, cannot place their dizziness in one category; approximately half of older persons describe two or more subtypes (2, 15). This is largely because disequilibrium often accompanies other kinds of dizziness in older persons who do not have intact compensatory systems, making it necessary to distinguish between the primary symptom and the secondary disequilibrium. In addition, the causes of presyncope almost completely overlap those of syncope (9, 16), so from the standpoint of differential diagnosis, the differentiation of one from the other is probably artificial. Finally, distinguishing between acute and chronic dizziness may be important because increased symptom duration is a risk factor for functional impairment (4). No consensus exists, however, on the dividing line between acute and chronic dizziness. EPIDEMIOLOGY OF DIZZINESS Many studies have described the epidemiology of dizziness in the community and in primary care settings (3, 6, 15, 17 21). Although the studies have been inconsistent in their definition of dizziness, the accumulated evidence indicates that 1) dizziness is common in all adult age groups and is more common in women than in men and 2) the prevalence of dizziness increases modestly with age in the community and markedly with age in medical practice (Table 2). In both the primary care and the referral setting, dizziness symptoms often involve more than one dizziness subtype, especially in the elderly, and dizziness is more often reported to be episodic rather than continuous (2, 5). In recent decades, several studies have reported that dizziness in older persons is associated with an accumulation of cardiovascular, neurosensory, and psychiatric 824 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) www.annals.org

Dizziness: State of the Science Investigating Selected Symptoms conditions and with use of multiple medications (1, 3, 15, 18, 22, 23). These findings led Tinetti and colleagues (15) to suggest that dizziness in older persons may constitute a geriatric syndrome a final common pathway resulting from the interplay of multiple impairments. Such a viewpoint would support the idea of approaching dizziness from a functional point of view rather than trying to define a symptom subtype, a single mechanism, and a unifying diagnosis. Such an approach is untried, but several recently developed instruments could provide a framework (Table 3) (24 27), and research in this area should be encouraged. Caution is warranted, however. As Drachman noted (28), calling dizziness in the elderly a geriatric syndrome runs the risk of implying that it is due to old age and therefore not treatable, whereas it is usually possible to identify... one or more underlying disorders or diseases. The prognosis of dizziness is generally benign. In one study (4), nearly three quarters of patients who presented with dizziness to primary care offices reported no effect on their lives 3 months later, and two populationbased outcome studies (3, 23) suggested that dizziness is not an independent predictor of institutionalization, death, or functional decline. However, it should be noted that most epidemiologic studies of dizziness have oversampled persons with chronic dizziness and underrepresented persons with acute forms of dizziness, who would be most likely to have life-threatening illnesses. Further, many persons with dizziness and a benign prognosis report great impairment of daily activities, depressed mood, and symptom-related fears (4, 23, 24, 27). Nevertheless, the fact that most dizziness-related conditions are self-limited suggests that 1) seeking out unreported dizziness in community populations and asking about dizziness on a routine symptom review may not be warranted and 2) other symptoms may have greater specificity in screening for serious disease. DIAGNOSING DIZZINESS Effective clinical decision making uses data on which diagnoses are common and, therefore, most likely in a given patient (29). Data on the frequency of diagnoses in similar settings are particularly useful in the evaluation of symptoms, like dizziness, that have a broad range of diagnostic possibilities. Table 4 summarizes 11 studies reporting diagnoses for patients with dizziness (1, 2, 5, 30 37). Peripheral vestibular problems constitute a sizeable minority of diagnoses. Acute labyrinthitis (or vestibular neuronitis) is the most common peripheral vestibular disorder seen in primary care offices (30). In referral settings, recurrent peripheral vestibular disorders, such as benign paroxysmal positional vertigo, recurrent vestibulopathy (38), and Ménière disease (39), predominate (1, 2, 35, 36). Table 1. Approach to the Differentiation of Dizziness Subtypes Dizziness Subtype Type of Sensation Temporal Characteristics Other Specifications Vertigo Presyncope A feeling that one or one s surroundings are moving (typically, spinning) A lightheaded, faint feeling, as though one were about to pass out Disequilibrium A sense of unsteadiness that is 1) primarily felt in the lower extremities, 2) most prominent when standing or walking, and 3) relieved by sitting or lying down Other dizziness: anxiety-related, ocular, tilting environment, other A feeling not covered by the above definitions. May include swimming or floating sensations, vague lightheadedness, or feelings of dissociation. May be difficult for the patient to describe Episodic vertigo occurs in attacks that last seconds to days Continuous vertigo is present all or most of the time for at least a week Typically occurs in episodes lasting seconds to hours Usually present, although it may fluctuate in intensity Usually present all or most of the time for days or weeks, sometimes years Descriptions of episodic vertigo should include the characteristics, duration, and date of the first episode; length of episodes; and exacerbating factors The following questions should be answered: 1) Has syncope ever occurred during an episode? 2) Do episodes occur only when the patient is upright, or do they occur in other positions? 3) Are episodes associated with palpitations, medication, meals, bathing, dyspnea, or chest discomfort? Identify whether symptom occurs in isolation or accompanies another dizziness subtype; describe exacerbating factors The following questions should be answered: 1) Is dizziness associated with anxiety or hyperventilation? 2) Was change in vision connected with dizziness onset? 3) Is dizziness a sensation that the environment is tilting sideways (suggests an otolith problem)? www.annals.org 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) 825

Investigating Selected Symptoms Dizziness: State of the Science Table 2. Prevalence of Dizziness in Selected Studies Variable Studies in Community-Dwelling Adults Study (reference) Yardley et al., 1988 (17) Colledge et al., 1994 (18) Kroenke and Price, 1993 (19); Sloane et al., 1989 (3) Study sample Age 18 64 years; recruited Age 65 years; recruited from Age 18 years; representative from age/sex registers of age/sex registers of five British sample drawn from five U.S. four British group practices group practices communities Tinetti et al., 2000 (15) Age 72 years; probability sample drawn from New Haven, CT Sample size, n 2064 893 13 538 1087 Study definition of dizziness Vertigo, giddiness, lightheadedness, wooziness, feeling faint, unsteadiness/ imbalance Lightheadedness, unsteadiness, vertigo, and other Not specified Dizzy, unsteady, as though spinning or moving, lightheaded, or faint Duration of study 1 month Not specified Lifetime 2 months Reported prevalence, %* 16 in men age 18 35 years 22 in men age 65 69 years 23 in all adults 28 in adults age 72 years 29 in women age 18 35 years 18 in men age 36 64 years 25 in women age 36 64 years 28 in women age 65 69 years 28 in men age 70 74 years 36 in women age 70 74 years 28 in men age 75 79 years 30 in women age 75 to 79 years 30 in men age 80 years 35 in women age 80 years 34 in adults age 60 years * Values are for both sexes if sex is not specified. Prevalence not reported; incidence, 5.5%. Central vestibular causes, such as brain tumors, cerebellar atrophy, migraine, multiple sclerosis, and seizure disorders, are rare or unreported in most studies; of 4536 patients from various settings, 0.7% had brain tumor and 1.2% had other central vestibular causes (39). Most patients with dizziness have nonvestibular diagnoses, and the relative frequencies of specific diagnoses vary widely across settings. In primary care, infections, metabolic problems, and adverse effects of drugs are relatively common. Almost any patient with a systemic viral or bacterial infection can present with dizziness, which is presumably due to postural hypotension (30). Metabolic disturbances reported to cause dizziness include hypoglycemia, hyperglycemia, electrolyte disturbances, thyrotoxicosis, and anemia (39, 40). A wide variety of medications may lead to dizziness (see the Appendix Table, available on the Annals Web site at www.annals.org) (41 44). Benign positional vertigo, other vestibular problems, and psychiatric disorders predominate in patients with chronic dizziness (1, 31, 35), except for older patients, in whom cardiovascular disease and cervical spine disease also seem common (2, 32, 37). As Table 4 shows, published clinical studies vary markedly in the reported prevalence of many diagnoses, even when the study samples were drawn from similar settings. This variation may in part reflect true differences across samples, but a more prominent likely cause is bias caused by investigators tending to diagnose conditions that they know about or are interested in, a phenomenon reminiscent of the blind men and the elephant (45). For example, Lawson and coworkers (32) gave all patients a battery of tests for carotid sinus disease and, not surprisingly, found an unusually high prevalence of this condition. Similarly, Colledge and associates (37), who performed magnetic resonance imaging of the head and neck of elderly patients with dizziness, reported a far higher prevalence of cerebrovascular and cervical spine disease than had been previously identified. The very existence of some diagnostic entities is disputed, most notably perilymphatic fistula (46, 47) and disabling positional vertigo due to vascular compression of the eighth cranial nerve (39, 48 50). CRITICAL DIAGNOSES As noted in the Figure, one way to focus evaluation of an undifferentiated symptom is to identify critical 826 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) www.annals.org

Dizziness: State of the Science Investigating Selected Symptoms Table 2 Continued Studies in Office Practice Sloane, 1989 (20) Kroenke and Mangelsdorff, 1989 (21) Kroenke et al., 1990 (6) All ages; national sample of Adults presenting to a general internal medicine clinic Adults presenting to a general internal medicine clinic general internists, family and general practitioners, and pediatricians 17 498 1000 410 Vertigo-dizziness, room spinning, falling sensation, giddiness, lightheadedness, loss of equilibrium as one of up to three presenting complaints of office visit Presenting complaint of dizziness (definition unspecified) noted on medical record any time during 3-year period 3 years 0.2 in patients age 0 14 years 17 0.7 in patients age 15 24 years 1.8 in patients age 25 34 years 1.8 patients age 35 44 years 2.4 in patients age 45 54 years 2.0 in patients age 55 64 years 3.4 in patients age 65 74 years 4.0 in patients age 75 84 years 6.7 in patients age 85 years Dizziness (definition unspecified) reported to be major problem on one-time survey Unspecified diagnoses that clinicians should not overlook. Such diagnoses should be associated with great morbidity, and effective interventions should exist. They should be targets of clinical evaluation and research, and diagnostic criteria should be developed. Often, clinical practice guidelines center around such diagnoses. The management of chest pain, for example, focuses on identifying and treating one mustn t miss diagnosis acute myocardial infarction. Identification of these target diagnoses is especially important for dizziness and other conditions in which most patients have a benign prognosis and the cost of diagnostic testing can be great (51). Unfortunately, identifying critical diagnoses is far more difficult in dizziness than in chest pain. Rather than a single entity, a wide range of diagnoses must be considered, including potentially life-threatening diseases (which tend to be rare) and chronic, non lifethreatening conditions that produce significant disability (Table 5). Potentially life-threatening conditions include transient ischemic attack, stroke, cardiac arrhyth- Table 3. Standardized Instruments for Evaluating the Severity and Effect of Dizziness on Quality of Life Instrument (Reference) Domains Items, n Scalability Dizziness Handicap Inventory (24) Dizziness Handicap Inventory Short Form (25) UCLA Dizziness Questionnaire (26) Vertigo-Dizziness-Imbalance Questionnaire (27) Activities that bring on or worsen dizziness; effect of symptoms on daily activities; emotional effect of dizziness (isolation, depression, fear) Activities that bring on or worsen dizziness; effect of symptoms on daily activities; emotional effect of dizziness (isolation, depression, fear) Frequency and severity of dizziness; effect on daily activities and quality of life; fear of becoming dizzy Characterization of dizziness; associated symptoms; effect on quality of life 25 One overall scale (range, 0 to 50) and three subscales (functional, emotional, and physical) 13 One scale (range, 0 to 13) 5 Not reported 36 Two scales: symptoms (range, 0 to 100) and health-related quality of life (range, 0 to 100) www.annals.org 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) 827

Investigating Selected Symptoms Dizziness: State of the Science Table 4. Reported Frequency of Causes of Dizziness in Selected Clinical Studies Variable Madlon-Kay, 1985 (30) Sloane et al., 1994 (5) Kroenke et al., 1992 (31) Lawson et al., 1999 (32) Setting Primary care office Primary care office Primary care office Primary care office Study sample All adult patients with dizziness All adult patients with dizziness Adult patients with persistent dizziness Persons age 60 years with severe dizziness only Participants, n 121 144 100 50 Diagnoses, % Peripheral vestibular disease 33 Labyrinthitis or vestibular neuronitis 11 3 24 Benign paroxysmal positional vertigo 7 16 8 Other recurrent vestibulopathy 4 14 2 Infection 21 Viral syndrome 9 Otitis media, otitis externa, or sinusitis 2 Other infection 4 Psychiatric conditions, including hyperventilation 4 11 17 Cardiovascular conditions 18 Cerebrovascular conditions, including migraine 1 8 Cardiac disease, such as arrhythmia or congestive heart failure 6 4 Vasovagal conditions 1 42 Hypertension Adverse effects of drugs, including alcohol 4 Metabolic or endocrine conditions 5 Anemia, including gastrointestinal bleeding 7 Diabetes 2 Neurologic conditions, excluding cerebrovascular conditions 10 Central neurologic conditions 2 10 Cervical spondylosis 4 Head injury Other conditions 5 Multiple conditions 13 None 37 0 26 * Percentages total more than 100 because some patients were given more than one diagnosis. Percentages total less than 100 because only the more common diagnoses were listed. Including orthostatic hypertension and carotid sinus hypersensitivity. Includes cardiac, endocrine, and drug-related conditions. mia, acute ischemic heart disease, acute infection, gastrointestinal bleeding, intracranial tumor (such as acoustic neuroma), and carbon monoxide poisoning. In addition, numerous conditions are generally not life threatening but are treatable sources of morbidity: physical deconditioning, anxiety (including panic disorder), otitis media, sinusitis, adverse effects of drugs, migraine, and possibly eighth nerve vascular compression and perilymphatic fistula. Almost all critical diagnoses identified in Table 5 can present without dizziness. So, although each condition has an extensive body of literature, usually in specialty journals, empirical data are sparse on the most efficient and effective methods of screening when dizziness is the presenting complaint. Most existing data were developed on small samples and lack validation (52, 53). More data are available on the effectiveness of treatment, although randomized, controlled trials remain rare. CONCLUSIONS AND RECOMMENDATIONS The literature indicates that we have far too little empirical data to support the development of evidencebased clinical practice guidelines for the broad spectrum of patients with dizziness. Rather than attempt the Herculean task of developing a database to support comprehensive dizziness guidelines, researchers could focus on developing guidelines for critical, well-defined diagnoses from the list in Table 5. One example would be a guideline for evaluating the likelihood of stroke in persons with dizziness. Others include guidelines for evaluating the likelihood of cardiac arrhythmia in persons with pre- 828 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) www.annals.org

Dizziness: State of the Science Investigating Selected Symptoms Table 4 Continued Skiendzielewski et al., 1980 (33) Herr et al., 1989 (34) Drachman and Hart, 1972 (1) Nedzelski et al., 1986 (35) Sloane and Baloh, 1989 (2) Katsarkas, 1994 (36) Colledge et al., 1996 (37) Emergency department Emergency department Dizziness clinic Dizziness clinic Dizziness clinic Dizziness clinic Community Adult patients Adult patients All adult patients All adult patients Patients age 70 Patients age Volunteers age years 70 years 65 years 106 125* 104* 2222 116* 1194 149* 10 44 10 3 8 2 4 12 17 23 39 18 16 16 7 3 8 5 17 11 33 21 9 32 21 10 5 4 19 6 70 4 1 5 2 2 9 5 9 7 1 4 1 2 2 8 6 2 6 66 6 6 22 6 1 9 41 1 13 2 0 86 5 10 9 19 14 27 4 syncopal dizziness and for diagnosing and managing anxiety disorders in persons presenting with dizziness. This approach would, however, leave most patients who have dizziness without empirical guidelines. Management of such patients will continue to rely, as it does today, on experience and on inference from case series and comparative outcome studies. Given the complexity of dizziness and its broad differential diagnosis, flexible diagnostic strategies and an ability to tolerate uncertainty are necessary. Indeed, for most patients, problemsolving approaches, such as pattern recognition, hypothesis testing, and an extended diagnostic process over time, are more appropriate than algorithmic methods (54, 55). Data suggest that primary care clinicians are efficient and effective in applying these strategies (5). Both clinicians and researchers should seek to describe dizziness symptoms systematically (Table 1) and apply standard criteria to diagnosis (Figure). For too many patients with dizziness, however, a precise definition of the symptom and a specific diagnosis on which to base treatment cannot be established. This is especially true for patients with chronic, disabling forms of dizziness, where multiple factors interplay and primary diagnoses are elusive. As Tinetti and colleagues suggest (15), real progress in managing such patients may require a different paradigm from that in the Figure. Given the relatively benign prognosis of acute and chronic dizziness, clinical management should extend beyond preventing death and hospitalization to improving function and quality of life. Even when a primary diagnosis can be identified, other risk factors and contributing factors should be sought to maximize the patient s ability to function (Table 5). The effect of dizziness on the patient s physical and psychological state www.annals.org 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) 829

Investigating Selected Symptoms Dizziness: State of the Science Appendix Table. Medications That Often Cause Dizziness Class of Medication Probable Mechanism Example 1 -Adrenergic antagonists Orthostatic hypotension Prazosin Alcohol Hypotension, osmotic effects Wine, cough syrups Aminoglycosides Ototoxicity Gentamicin Anticonvulsants Orthostatic hypotension Carbamazepine Antidepressants Orthostatic hypotension Desipramine Anti-Parkinsonian medication Orthostatic hypotension Levodopa Antipsychotics Orthostatic hypotension Olanzapine -Blockers Hypotension or bradycardia Atenolol Calcium-channel blockers Hypotension, vasodilation Verapamil Class Ia antiarrhythmics Torsades de pointes Procainamide Digitalis glycosides Hypotension Digoxin Diuretics Volume contraction; vasodilation Hydrochlorothiazide Narcotics Central nervous system depression Morphine, propoxyphene Oral sulfonylureas Hypoglycemia Tolazamide Vasodilators Hypotension, vasodilation Hydralazine Table 5. Critical Diagnoses in the Evaluation of the Patient with Dizziness Conditions that can be life threatening Acute ischemic heart disease Acute infection (such as pneumonia) Cardiac arrhythmia Gastrointestinal bleeding Intracranial mass lesion (such as acoustic neuroma or subdural hematoma) Neurosyphilis Stroke Transient ischemic attack Toxin exposure (such as carbon monoxide poisoning) Treatable conditions that can cause considerable morbidity Adverse drug reaction Anxiety or panic disorder Benign paroxysmal positional vertigo Carotid sinus syndrome or vasovagal conditions Cervical osteoarthritis Deconditioning Depression Eighth nerve vascular compression Hypertension Hypoglycemia Migraine Otitis media Orthostatic hypotension Perilymphatic fistula Sinusitis Stroke Visual impairment should be evaluated to identify the degree of disability and monitor interventions. Four instruments are available to quantify the functional effect of dizziness (Table 3): the Dizziness Handicap Inventory long form (24), the Dizziness Handicap Inventory short form (25), the UCLA Dizziness Questionnaire (26), and the Vertigo- Dizziness-Imbalance Questionnaire (27). Instead of defining and categorizing symptom subtypes and specific diagnoses, clinicians and researchers may benefit from a management-oriented approach, as has been useful in acute back pain (56). For example, regardless of the diagnosis, patients with chronic, disabling dizziness may benefit from a battery approach aimed at identifying and managing treatable conditions, whether etiologic or contributory. Such a treatment-oriented approach might include correcting visual impairment; improving muscle strength; adjusting medication regimens; identifying and treating psychological comorbidity, such as anxiety or depression (57); and instructing patients on vestibular exercises (58). In addition, nontraditional remedies should be considered and scientifically evaluated, such as acupuncture (59), gingerroot (60), and rocking chair therapy (61). One alternative, the Epley procedure, has become standard therapy for benign paroxysmal positional vertigo (62, 63). For the clinician, a function-oriented approach would complement clinical guidelines for specific diagnoses. For the clinical research community, the challenge is to set priorities that will help fill the key gaps in knowledge about diagnosis and management of patients with dizziness. One important step would be refinement of diagnostic criteria, as has been done for headache (64), including information on how often patients with particular diagnoses present with dizziness as a primary complaint. Wide acceptance of diagnostic criteria would allow better comparability of epidemiologic, diagnostic, and treatment studies. Another important step would be epidemiologic studies in large populations, perhaps as part of a research initiative on symptoms in primary 830 1 May 2001 Annals of Internal Medicine Volume 134 Number 9 (Part 2) www.annals.org

Dizziness: State of the Science Investigating Selected Symptoms medical practice that is incorporated into existing health care databases (65). Such studies would help clarify the epidemiology of dizziness subtypes and of associated diagnoses, elucidate the prognosis of various dizziness states, and identify risk factors for rare yet critical diagnoses. A third step would be studies to determine the sensitivity, specificity, and likelihood ratios associated with selected data from the history, physical examination, and clinical laboratory for critical diagnoses. Research should also identify effective approaches to persons with chronic, multifactorial dizziness. It should determine how to best implement effective, efficient means of identifying functional deficits that are correctable and providing therapy that is effective and safe. All of this should be guided by generalist clinicians in consultation with selected specialists, so that research does not stray too far from the issues of greatest importance to the practicing clinician and to persons with dizziness. From University of North Carolina at Chapel Hill, Chapel Hill, and Duke University, Durham, North Carolina. Grant Support: Dr. Sloane is the recipient of National Institute on Aging Academic Award K08-AG00341. Requests for Single Reprints: Philip D. Sloane, MD, MPH, Department of Family Medicine, C.B. 7595, University of North Carolina, Chapel Hill, NC 27599; e-mail, psloane@med.unc.edu. Current Author Addresses: Dr. Sloane: Department of Family Medicine, C.B. 7595, University of North Carolina, Chapel Hill, NC 27599. Dr. Coeytaux: Robert Wood Johnson Clinical Scholars Program, University of North Carolina, Chapel Hill, NC 27599-7105. Dr. Beck: AHCPR/NRSA Post-Doctoral Fellowship, Cecil G. Sheps Center for Health Services Research, University of North Carolina, Chapel Hill, NC 27599-7590. Dr. Dallara: Department of Emergency Medicine, Box 3096, Duke University Medical Center, Durham, NC 27710. References 1. Drachman DA, Hart CW. An approach to the dizzy patient. Neurology. 1972;22:323-34. [PMID: 0004401538] 2. Sloane PD, Baloh RW. Persistent dizziness in geriatric patients. J Am Geriatr Soc. 1989;37:1031-8. [PMID: 0002809049] 3. Sloane P, Blazer D, George LK. Dizziness in a community elderly population. J Am Geriatr Soc. 1989;37:101-8. [PMID: 0002783432] 4. Bailey KE, Sloane PD, Mitchell M, Preisser J. Which primary care patients with dizziness will develop persistent impairment? Arch Fam Med. 1993;2:847-52. [PMID: 0008111514] 5. Sloane PD, Dallara J, Roach C, Bailey KE, Mitchell M, McNutt R. Management of dizziness in primary care. J Am Board Fam Pract. 1994;7:1-8. [PMID: 0008135132] 6. Kroenke K, Arrington ME, Mangelsdorff AD. 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