Benign Paroxysmal Positional Vertigo and Time of Day
Benign Paroxysmal Positional Vertigo and Time of Day
Vertigo is one of the most common complaints physicians encounter both in the office and in the emergency room (ER).Vertigo, an illusory sensation of motion (usually spinning), is a vestibular symptom.Many patients have a difficult time describing their symptoms as more than ‘dizziness’, which is a non-specific term that encompasses vertigo, light-headedness, imbalance, and spatial disorientation. By asking patients specifically if they feel a sensation of motion when they are actually still, the physician may be able to narrow this symptom down to true vertigo.This may reflect disease in the inner ear, the vestibular nerve, or the brainstem, but very rarely is it due to pathology in the cortex.
For most patients, vestibular symptoms are episodic and are not continuous.The factors that precipitate symptoms may provide important clues as to the etiology of the attacks.Vertigo brought on by lying supine and turning to one side is typical of benign paroxysmal positional vertigo (BPPV). Other typical precipitating positions for BPPV include looking underneath a low object (like a sink), or reaching up to a high shelf. Lightheadedness brought on by getting up quickly from a lying or sitting position is typical of orthostatic hypotension; however, patients with BPPV may also have brief vertigo and nystagmus on sitting up quickly. Vertigo when rolling over in bed is so common in BPPV that if the patient denies it the diagnosis of BPPV is unlikely.
Definitive identification of BPPV at the bedside is of great value because it does not require further work-up such as imaging studies,1 it is not associated with central nervous system (CNS) disease,2 which reassures patients, and it can be treated quickly and effectively in the office or ER.3 The diagnosis is made by observing the characteristic nystagmus.
With the head hanging back below the supine position and turned to one side, the ampulla of the posterior semicircular canal faces directly upwards toward the otolith organs. Otoconia not firmly attached to the maculae may enter the posterior canal, eliciting vertigo and nystagmus characteristic of BPPV.The Dix–Hallpike (DH) test is a positioning maneuver intended to stimulate the vertical semicircular canals.4 With the head turned 45 degrees to one side, moving the patient from a sitting to a supine position results in rotation in the plane of the canal pair. In the normal patient, no nystagmus occurs following this maneuver. In patients with BPPV, when the affected ear is undermost, mixed torsional and vertical nystagmus is seen typically after a short latency. The upper pole of the eye beats toward the undermost ear and there is an upbeating component. This nystagmus decays (habituates) in less than a minute and typically in less than 15 seconds. CNS lesions may result in nystagmus with little or no latency in the DH maneuver.This nystagmus may not habituate and lasts as long as the patient’s head is hanging back.
The leading theory of the cause of BPPV is that it is caused by free-floating debris in the semicircular canals.1,2 Barany 3 and then Dix and Hallpike 4 noted that repeated provocative maneuvers carried out in a short period of time result in a diminished response (fatigability). Epley explained fatigability along with other key features of BPPV with the theory of debris particles forming a ‘leaky piston’ that displaces endolymph as it is pulled by gravity.5,6 He postulated that with repeated head movements the particles tend to disperse.That model correlates with the observation that as the day progresses and patients make repeated head movements, symptoms decrease.7,8 This suggests that the DH maneuver would be less likely to be positive later in the day, making its reliability dependant on the time of day.To investigate whether time of day affects the outcome of the DH maneuver, a chart review was performed of all the electronystagmograms (ENGs) performed at the JFK Medical Center during a 25-month period starting in January 2001, in which the result and time of day of the test were noted.
Methods
Audiologists took histories and performed and analyzed the ENGs. An otoneurologist reviewed the results. For the purpose of this study, the history was considered consistent with BPPV if it included ‘dizziness’ induced by head movements with respect to gravity. Dizziness was not further defined. ENGs were performed using video-oculography recording horizontal and vertical eye movements. A DH was considered positive if it induced up-beating nystagmus after the maneuver and the nystagmus decayed in less than 30 seconds. If the patient refused the DH, the test was termed ‘not completed’. Test time was determined by adding 45 minutes to the appointment time and then rounding up to the nearest hour.
- Epley J M, “New dimensions of benign paroxysmal positional vertigo”, Otolaryngol Head Neck Surg (1980);88(5): pp. 599–605.
- Parnes L S, McClure J A,“Free-floating endolymph particles: a new operative finding during posterior semicircular canal occlusion”, Laryngoscope (1992);102(9): pp. 988–992.
- Barany R, “Diagnose von Krankheitserscheinungen im Bereiche des Otolithenapparates”, Acta Otolaryngol. (1921);2: pp. 334–437.
- Dix M R, Hallpike C S, “The pathology, symptomatology and diagnosis of certain common disorders of the vestibular system”, Ann Otol (1952);61: pp. 987–1,016.
- Epley J M, “Particle repositioning for benign paroxysmal positional vertigo”, Otolaryngol Clin North Am (1996);29: pp. 323–331.
- Epley J M, “The canalith repositioning procedure: for treatment of benign paroxysmal positional vertigo”, Otolaryngol Head Neck Surg (1992);107: pp. 399–404.
- Troost B T, Pattom J M,“Exercise therapy for positional vertigo” Neurology (1992);42: pp. 1,441–1,444. (Published erratum appears in Neurology (1992); 42: p. 2059).
- Baloh R W,“Benign positional vertigo”, in: Baloh R W, Halmagyi G M (eds), Disorders of the Vestibular System, New York: Oxford University Press (1996): pp. 328–339.
