1

Introduction

Patients’ descriptions of their symptoms are one of the most critical factors in establishing the cause of dizziness . Thus, asking patients to describe their symptoms is crucial step in evaluating patients with dizziness. Dizziness caused by changes in head or body position is called positional dizziness (PD) . Orthostatic dizziness (OD) is defined as dizziness provoked by orthostatic positional change, such as upright standing from a supine or sitting position. Both PD and OD are considerably common conditions in dizziness clinic, and are important symptoms for diagnostic evaluation of the dizziness.

Orthostatic dizziness is found in 2–19% of elderly population and 4.8% of the adult population > 20 years of age . It can be caused by orthostatic intolerance (OI), which is a subcategory of dysautonomia. Dizziness in this condition is resulted from abnormal changes in blood pressure, heart rate, and cerebral blood flow in response to upright posture. Orthostatic intolerance was further classified as orthostatic hypotension, orthostatic tachycardia, or orthostatic hypertension . In general, OD is considered as a typical manifestation of orthostatic hypotension, thus most studies for orthostatic effect on dizziness via cardiovascular system involvement have been focused on orthostatic hypotension . Only a few studies have been conducted on the rate of OI and its subtypes in patients with OD .

The causes of PD vary widely because any disease that affects the vestibular system can cause PD. Among the various dizziness eitologies that are associated with positional changes, benign paroxysmal positional vertigo (BPPV) is the characteristic condition associated with typical symptom-provoking positions. The primary symptom of BPPV is rotational vertigo characterized by a sudden attack that is triggered by changes in head position in a specific direction, such as looking upward, bending forward, or rolling over in bed, depending on the semicircular canal involved. However, it was reported that a small group of BPPV patients experienced an unspecific sensation of dizziness, such as oscillopsia, imbalance, and nausea . Also, in more than half of patients, symptoms of BPPV can be provoked by rising up from supine position . This may complicate the diagnostic impression because dizziness caused by upright position is usually considered as a typical manifestation of OI. Reverse nystagmus and otolith organ dysfunction may account for OD in BPPV patients .

In this study, we aimed to evaluate (1) the ratio of OI and its subtypes in patients with dizziness which is associated with orthostatic positional change (OD), and (2) the disease entities for the group of simple OD and for the group with combined form dizziness (dizziness is associated with orthostatic position as well as changes in head position).

2

Patients and methods

The protocol of this retrospective study was approved by the Institutional Review Board of Incheon St. Mary’s Hospital (approval No. OC09FZZZ0037). The study included 102 patients whose dizziness was induced or aggravated by orthostatic positional change. Patients who could not tolerate orthostatic vital sign measurement test (OVSM) because of acute, severe vertigo and subjects who could not understand the questionnaire were excluded from the study.

All subjects were asked to independently complete a questionnaire prior to an interview with the physician. The questionnaire consisted of 13 items regarding the effect of various positional changes on their dizziness. First six items were taken from the Dizziness Handicap Inventory , and the last seven items were composed by the authors ( Table 1 ). Questions 1–11 pertained to specific head position changes that aggravated dizziness, whereas questions 12 and 13 referred to the effect of orthostatic positional changes on dizziness (OD). The subjects were divided into two groups according to their answers to the questionnaire. Patients who answered “yes” to either 12 or 13 and “yes” to any of questions 1–11 were placed in group PO (combined OD; PD as well as OD). Subjects who answered “yes” to only items 12 and 13 were placed in group O (simple OD).

Thorough medical histories were taken and a complete physical examination, including the head and neck area and vestibular and neurological examinations, was performed on the patients. The tests included serology, electrocardiogram, audiometry, vestibular tests, and hematology. Vestibular assessment included an eye-movement examination, positioning tests, and caloric testing using video-nystagmography. Posterior canal BPPV was diagnosed by observation of torsional upbeating nystagmus following Dix-Hallpike test. Horizontal nystagmus induced by supine roll test was considered as diagnostic sigh for lateral canal BPPV. Anterior canal BPPV is diagnosed when Dix-Hallpike positioning produces a down-beating nystagmus with torsional component . Brain imaging study was performed for cases in which an etiology of central origin was suspected.

All patients underwent OVSM using an automatic sphyngomanometer (Omron 10 Series™, Omron Healthcare, Kyoto, Japan), which is performed by a nurse. After a rest period in a quiet room, blood pressure and heart rate were measured with the patient’s arm placed at heart level in a sitting position. The patient was then placed in the supine position on the bed, and blood pressure and heart rate were recorded after a 2-min of rest period. Finally, the patient was instructed to stand up with the forearm placed on a table at the height of the patient’s heart level (4th intercostal space). Vital signs were measured 2 and 5 min after assuming the standing position. When the patient is intolerable to the orthostatic challenge, the procedure is immediately discontinued. Criteria for positive orthostatic hypotension were defined as a decrease in systolic or diastolic blood pressure greater than 20 or 10 mmHg, respectively, or both at the standing position. Orthostatic tachycardia was defined as an increase in HR of at least 30 bpm, or a maximum of 120 bpm was obtained in the upright position without profound hypotension; orthostatic hypertension was defined as systolic BP increase ≥ 20 mmHg with orthostatic position .

Statistical differences among groups were determined using analysis of variance (ANOVA) and the chi-square test. P values < 0.05 were determined to indicate statistical significance. All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS; SPSS, Inc., Chicago, IL).

2

Patients and methods

The protocol of this retrospective study was approved by the Institutional Review Board of Incheon St. Mary’s Hospital (approval No. OC09FZZZ0037). The study included 102 patients whose dizziness was induced or aggravated by orthostatic positional change. Patients who could not tolerate orthostatic vital sign measurement test (OVSM) because of acute, severe vertigo and subjects who could not understand the questionnaire were excluded from the study.

All subjects were asked to independently complete a questionnaire prior to an interview with the physician. The questionnaire consisted of 13 items regarding the effect of various positional changes on their dizziness. First six items were taken from the Dizziness Handicap Inventory , and the last seven items were composed by the authors ( Table 1 ). Questions 1–11 pertained to specific head position changes that aggravated dizziness, whereas questions 12 and 13 referred to the effect of orthostatic positional changes on dizziness (OD). The subjects were divided into two groups according to their answers to the questionnaire. Patients who answered “yes” to either 12 or 13 and “yes” to any of questions 1–11 were placed in group PO (combined OD; PD as well as OD). Subjects who answered “yes” to only items 12 and 13 were placed in group O (simple OD).

Thorough medical histories were taken and a complete physical examination, including the head and neck area and vestibular and neurological examinations, was performed on the patients. The tests included serology, electrocardiogram, audiometry, vestibular tests, and hematology. Vestibular assessment included an eye-movement examination, positioning tests, and caloric testing using video-nystagmography. Posterior canal BPPV was diagnosed by observation of torsional upbeating nystagmus following Dix-Hallpike test. Horizontal nystagmus induced by supine roll test was considered as diagnostic sigh for lateral canal BPPV. Anterior canal BPPV is diagnosed when Dix-Hallpike positioning produces a down-beating nystagmus with torsional component . Brain imaging study was performed for cases in which an etiology of central origin was suspected.

All patients underwent OVSM using an automatic sphyngomanometer (Omron 10 Series™, Omron Healthcare, Kyoto, Japan), which is performed by a nurse. After a rest period in a quiet room, blood pressure and heart rate were measured with the patient’s arm placed at heart level in a sitting position. The patient was then placed in the supine position on the bed, and blood pressure and heart rate were recorded after a 2-min of rest period. Finally, the patient was instructed to stand up with the forearm placed on a table at the height of the patient’s heart level (4th intercostal space). Vital signs were measured 2 and 5 min after assuming the standing position. When the patient is intolerable to the orthostatic challenge, the procedure is immediately discontinued. Criteria for positive orthostatic hypotension were defined as a decrease in systolic or diastolic blood pressure greater than 20 or 10 mmHg, respectively, or both at the standing position. Orthostatic tachycardia was defined as an increase in HR of at least 30 bpm, or a maximum of 120 bpm was obtained in the upright position without profound hypotension; orthostatic hypertension was defined as systolic BP increase ≥ 20 mmHg with orthostatic position .

Statistical differences among groups were determined using analysis of variance (ANOVA) and the chi-square test. P values < 0.05 were determined to indicate statistical significance. All statistical analyses were performed using the Statistical Package for the Social Sciences (SPSS; SPSS, Inc., Chicago, IL).