Retrospective Study
Transcranial Doppler Ultrasonography measuring of
patients with chronic dizziness
Principle Investigator

Dr Dov Gefel (MD) Head of Internal Medicine C Department
Collaborating Investigators/Physicians:


Dr Gur Alexander, M.D.
Dr Anna Gelfand
Site
Barzilai Medical Center, Ashkelon.
Background
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 (1-3). In the primary care
setting, dizziness increases in frequency as a presenting complaint; as many as 7% of
elderly patients present with this symptom (4-5). Dizziness is a term used to describe
everything from feeling faint or lightheaded to feeling weak or unsteady.
Classification of dizziness by subtype (vertigo, pre-syncope, 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. Moreover, two-third of the dizzy patients
experience persistent or recurrent dizziness for at least six months. The chronic dizzy
patient may pose a challenge because of the wide range of underlying conditions. As
dizziness may have multiple causes, it is often impossible to identify a specific
etiology. No diagnosis can be made in 20-40% of all patients presenting with
dizziness in general practice(6).Even if specific diseases are revealed, these cannot
always be treated effectively. The diagnostic approach to dizziness is often difficult:
dizziness is a subjective complaint, refers to various abnormal sensations of body
orientation in space, and may be caused by a wide range of benign and serious
conditions that may or may not co-exist in an individual patient. Investigators would
benefit from the use of specific criteria to describe the symptoms of dizziness and
establish diagnosis. Investigation of the effects of testing and treatment should focus
on diagnoses that are life threatening or may lead to significant morbidity. One such
condition is dizziness or vertigo associated with impaired blood flow to specific brain
areas as seen in stroke or transient ischemic attack in the anterior or posterior brain
circulation. This may be suspected when dizziness is accompanied by other signs and
symptoms of acute focal neurological deficit, However, it has recently become
evident that dizziness or vertigo may be the sole manifestation of cerebral vascular
events.
Transcranial Doppler (TCD) ultrasonography is a non-invasive ultrasonic technique
measuring local blood flow velocity and direction in the proximal portions of large
intracranial arteries. Ultrasound waves are used to measure the velocity of blood flow
in the basal arteries of the brain. These waves are transmitted through the relatively
thin temporal bone, foramen magnum or orbit. When these waves encounter moving
red blood cells, they are emitted at a different frequency through the brain and skull
back to a detector. The change in frequency as blood cells move toward or away from
the ultrasound transmitter and detector is an expression of the Doppler effect and is
related to the velocity and direction of flow(7, 8) .TCD flow velocity is most
commonly and easily measured in the middle cerebral and internal carotid arteries,
but may also be measured in other vessels including the anterior cerebral, anterior
communicating, posterior cerebral, posterior communicating, vertebral and basilar
arteries. TCD allows for the evaluation of autoregulation and hemodynamics in the
basal intracranial arteries (9, 10). The value of TCD ultrasonography in assessing
patients with dizziness is uncertain. We sought to determine the contribution of TCD
ultrasonography to the evaluation of patients with dizziness and to determine whether
flow disturbances and narrowing of intracranial vessels may be associated with the
common symptom of chronic dizziness.
Purpose/ Goals
To assess the value of TCD in evaluation of patients with dizziness by comparison
between blood flow velocities in the main intractanial artery and clinical symptoms of
the dissiness via retrospective files.
Materials & Methods
The TCD results of the 25 patients with chronic dizziness (lasting more than 3
months) and TCD results of 25 individuals without dizziness matched for age, sex
and weight, studied by TCD ultrasonography at the Department of Neurology,
Barzilai Medical Center during the last two years , Ashkelon.
Peak systolic and end-diastolic blood flow velocities values, pulsatility, and
resistance indexes will be obtained in the middle cerebral, vertebral and basilar
arteries. Presence or absence of dizziness will be based on medical history. The
results of the patients with history of stroke and vertigo will be excluded from the
study. TCD findings, Epidemiological and clinical factors associated with dizziness
will be determined.
Sample Size
The determination of the sample size (50 patients; 25 patients study group and 25
patients control group) was based on the 95% confidence level, 19 confidence
interval and population of the Ashkelon estimated to complain on dizziness.
Inclusion Criteria
1. Women and men aged 18-60 with chronic dizziness
2. The patients referred from the LOR clinic for TCD test at department of
neurology in the Barzili Medical Center during the lat two years.
Exclusion Criteria
1. Pregnant women
2. Patients with severe neurological disability and after stroke
3. Patients with severe somatic disorder
4. patients with vertigo
Statistical Analysis
Using Chi-square test of "matched pairs, an estimation the results of the 25 patients
will be needed for the study in each group. Overall, about 50 results of the TCD
examination that have been perfermed at Barzilai hospital during the last two years
(6/11-6/13).
References:
1. Colledge N, Wilson JA, Macintyre CCA, MacLennan WJ: The prevalence and
characteristics of dizziness in an elderly community. Age & Ageing 1994, 23:117120.
2. Jonsson R, Sixt E, Landahl S, Rosenhall U: Prevalence of dizziness and vertigo in
an urban elderly population. J Vestib Res 2004, 14:47-52.
3. Sloane P, Blazer D, George LK: Dizziness in a community elderly population. J
Am Geriatr Soc 1989, 37:101-108.
4. Tinetti ME, Williams CS, Gill TM: Dizziness among older adults: A possible
geriatric syndrome. Annals of Internal Medicine 2000, 132:337-344.
5. Maarsingh OR, Dros J, Schellevis FG, van Weert HC, Bindels PJ, van der Horst
HE: Dizziness reported by older patients in family practice: prevalence, incidence,
and clinical characteristics. BMC Fam Pract 2010, 11:2.
6. loane PD, Coeytaux RR, Beck RS, Dallara J: Dizziness: State of the science.
Annals of Internal Medicine 2001, 134:823-832.
7. AaslidR, Markwalder TM, Nornes H. Noninvasive transcranial Doppler
ultrasound recording of flow velocity in basal arteries. J Neurosurg 1982;57:769-74.
8.Werner C, Kochs E, Hoffman WE, Blanc IF, Schulte AM, Esch J. Cerebral
blood flow and cerebral blood flow velocity during angiotensin-induced
arterial hypertension in dogs. Can J Anaesth 1993;40:755-60.
9. Homburg AM, Jacobsen M, Enevoldsen E. Transcranial Doppler
recordings in raised intracranial pressure. Acta Neurol Scand 1993;87:48893.
10. Rainov NG, Weise JB, Burkert W. Transcranial Doppler sonography in adult
hydrocephalic patients. Neurosurg Rev 2000;23: