This page was based on a review of the Valsalva Maneuver published by Cherchi and Hain (2010).
The Valsalva test consists of "straining" to increase pressure in the thorax or middle ear, which is transmitted into the inner ear.
The maneuver is most commonly performed by having the patient “bear down”. To employ this maneuver in the diagnosis of pressure sensitivity, have the patient wear video Frenzel goggles while sitting upright. Then have the patient “bear down” for 10 seconds. When people "bear down", generally their head and body shakes slightly, and this can be seen on the Frenzel goggles. Alternative methods involve having the patient squat or do a partial sit-up.
Observe the eyes in complete darkness looking for nystagmus during or following the Valsalva maneuver. Practically, we don't think that you can do this test productively without magnification -- i.e. a video-frenzel system with a good enough focus that you can see torsion. Another method is to use an examining microscope focused on the sclera. We are less enthused about this technique as it is hard to keep the sclera in view while the patient is undergoing a maneuver.
There are two variants -- glottis open and glottis closed.
Here things are more complicated. This is the "nose pinched" Valsalva. Pressure also is increased in the spinal fluid, but also (potentially) increased in the middle ear. Depending on which pathway is more salient, pressure may be exerted outward (ear to spinal fluid), or inward (spinal fluid to inner ear. This ambiguity seem to us to provide the potential for considerable confusion.
In this version, the subject is told to block pressure in their throat (glottis). Sometimes it helps to say "Bear down". Here pressure does not get into the upper airway but is confined to the thorax. Pressure is increased in the spinal fluid. In SCD, there is a pressure differential across the inner ear, which is connected to the spinal fluid less directly.This technique avoids changing middle ear pressure, but retains the effect on intrathoracic pressure.
Here we will be discussing the Valsalva with the glottis closed, but the reader should be aware that the term “Valsalva maneuver” is used for two distinct techniques. We generally do not use the “nose pinched” version of the Valsalva maneuver because it is more likely to introduce the uncertainties.
The Valsalva maneuver was first described by Antonio Maria Valsalva who lived from 1666 to 1723. He wrote the “Treatise on the Human Ear” and detailed the anatomy of the eustachian tube (Bluestone, 2005). The maneuver originally described by Valsalva was a method of inflating the middle ear by forced nasal expiration with the nose and lips closed. For this technique, there is increased intrathoracic pressure as well as increased upper airway pressure. In later years, the method of doing the “Valsalva maneuver” as originally described was modified so that it was performed with a closed glottis.
The increased intrathoracic pressure, increased systemic arterial pressure, and decreased venous return that accompany the Valsalva maneuver result in an increase in intracranial pressure (Hamilton et al. 1936; Ng et al. 2004; Williams 1981). The transient increase in intracranial pressure can be transmitted to the ear, and in certain disorders, induce dizziness.
The Valsalva maneuver is most widely known for its effects on heart rate, cardiac stroke volume, systemic arterial pressure, and venous return. These effects result primarily from changes in intrathoracic pressure (Looga 2005).
There are several conditions in which there are abnormal openings between the perilymph compartment of the inner ear and another space such as the middle ear or dura. In this situation, pressure differentials across the opening may induce dizziness.
In persons with perilymphatic fistula, there is an opening in either the oval or round window. While pressure changes may be troublesome to the patient, the nystagmus provoked by Valsalva or other pressurization procedures in perilymphatic fistula is generally unreliable and weak (Hain and Ostrowski 1997). In this situation, pressure differentials may be across the cerebrospinal fluid compartment or related to movement of the stapes.
In persons with bony fistulae of the labyrinth, such as persons with a cholesteatoma eroding into the lateral canal, or who have had the obsolete “fenestration” operation for otosclerosis (Niyazov et al. 2000), the Valsalva maneuver causes nystagmus in the plane of the opened canal. This is generally horizontal.
Supplemental material : Movie of nystagmus elicited by Valsalva in person with fenestration
Superior Canal Dehiscence (SCD) -- follow this link for much more material.
In superior canal dehiscence (SCD), there is an opening in the roof of the superior semicircular canal. During the Valsalva maneuver (closed glottis), intracranial pressure is transmitted to the superior canal via the meninges and via the perilymph of inner ear through the cochlear aqueduct (Tilikete et al. 2004; Younge et al. 2003). Here a brief vertical and torsional nystagmus is encountered that aligns with the orientation of the superior canal (Cremer et al. 2000).
In SCD, Valsalva against a closed glottis may produce upbeating nystagmus and nystagmus beating with the torsional fast phase in the opposite direction (CW for right ear, CCW for left ear). We ourselves prefer the Valsalva against a closed glottis.
For those familiar with posterior canal BPPV, the vector relationships between vertical and torsional components is reversed so that the upbeating nystagmus beats away from the "bad" ear, and downbeating, towards the "good" ear. More commonly, however, no nystagmus at all is produced by either maneuver. In persons with lateral canal fistulae (which are rare and usually confined to persons with cholesteatoma or after fenestration surgery), horizontal nystagmus can be produced (see example below). In persons with window fistulae, generally very little nystagmus is produced by Valsalva or for that matter, any maneuver.
The "too-long stapes prosthesis" is either due to a surgical misadventure, or due to "migration" of the prosthesis years later. These people have pressure sensitivity. In the “too-long-stapes prosthesis syndrome,” the utricle can be stimulated by the prosthesis, which may move as the position is altered by the Valsalva maneuver. This can produce a nystagmus at the onset and offset of the maneuver (Huttenbrink 2003).
In persons with an Arnold-Chiari malformation, as well as in some normal subjects, Valsalva can induce a low amplitude downbeating nystagmus (Russell et al. 1992). In this case, it is likely that nystagmus is produced via a transient pressure on the cerebellar tonsils rather than an effect on the inner ear.
There are a number of other likely associations where there are abnormal inner ear fluid dynamics (e.g. other dehiscence syndromes, hydrops) that may eventually be reported as people become more familiar with the video-frenzel goggle technology.
The main utility of the Valsalva maneuver for dizziness is in evaluating superior canal dehiscence. It may also elicit strong nystagmus in patients with other canal fistulae such as those due to cholesteatoma or “fenestration” surgery. Weaker nystagmus may be seen in craniocervical junction abnormalities (such as Arnold-Chiari malformations) and in persons with perilymphatic fistulae. In persons with cardiovascular disorders the Valsalva maneuver may induce faintness without nystagmus.
No studies have formally investigated the sensitivity of Valsalva-induced nystagmus. Our clinical observations suggest that it is sensitive to superior canal dehiscence as well as post-stapedectomy pressure sensitivity. It is insensitive to perilymphatic fistulae.
Similarly, no studies have investigated the specificity of Valsalva-induced nystagmus. In our clinical observations, we have found the appearance of a brief torsional nystagmus during the Valsalva maneuver to be highly specific for superior canal dehiscence. A strong horizontal nystagmus is suggestive of a horizontal canal fistula such as might result from a cholesteatoma or fenestration surgery.
Questions for further study (as of end of 2014)
- Many patients have a small amount of nystagmus post valsalva. Is this due to asymmetries in pressure transmission ? Due to hydrops ? Does it correlate with any particular patient group ?
- Occasional patients have suppression of ongoing nystagmus during the valsalva maneuver. What does this mean ?
- It would not be that difficult to control pressure during the valsalva - -such as have patients blow up a "standard balloon". Would this improve the sensitivity/specificity of the valsalva test ?
The Valsalva maneuver (and related maneuvers) is extremely useful when evaluating a patient with pressure sensitivity. It is of relatively minor general use since the conditions where it is positive are rare.