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Balance and Falls

The Balance and Falls Center at UCSF is designed to evaluate and treat various causes of vertigo, dizziness, and balance problems. The center believes in the multidisciplinary approach, where experts from different fields (including audiology, otolaryngology, neurology, and physical therapy) collaborate together to help determine the best treatment for your dizziness. State of the art diagnostic testing is performed, including videonystagmography (VNG), Rotary Chair Testing, VEMP testing, and Video Head Impulse Testing. Common treatments involve use of the canalith/particle repositioning maneuvers (like the Epley maneuver) for treating benign paroxysmal positional vertigo, and vestibular physical therapy. However, with our team-based multidisciplinary approach, we are able to offer the full range of diagnostic and treatment services for different causes of dizziness.

For an overview of vertigo, please read this article on page 10 by Dr. Jeff Sharon, published in San Francisco Medicine magazine.


 

 

 

 

 

 

 

 

 

Vestibular Testing

Videonystagmography (VNG)

VNG is a technique designed to evaluate how the inner ear is functioning. Since one of the main functions of the balance system is to keep our visual world steady during head movements, the eyes and the inner ears are connected through a reflex arc known as the vestibulo-ocular reflex. Therefore, every time the inner ear senses a head movement, the eyes move in an equal and opposite direction. Because of this feature, we are able to use eye movements as a window to study the inner ear. Eye movements can be measured in a variety of ways, including by using electrodes to measure electrical changes associated with movement (ENG, or electronystagmography), or with infrared goggles and computer software that tracks the position of the pupil (VNG). The test is non-invasive, and involves several parts. First, the patient is asked to visually track targets that will either jump around (saccades), or move continuously (smooth pursuit). This part tests the oculomotor system, which is the neural network that controls eye movements. Second, positional nystagmus is assessed, with placing the patient into certain positions that may cause dizziness. This is important to see if the dizziness is related to BPPV. Finally, caloric testing is performed, which involves placing hot and cold air or water into each ear to stimulate the inner ear (mostly the horizontal semicircular canals). The speed of the resulting eye movements (specifically the slow phase of the nystagmus) is then measured. This test is helpful for determining if the inner ears are functioning properly, or if one or both are damaged (vestibular hypofunction). While this test may sometimes cause nausea, almost all patients get through the test with minimal to no discomfort.

Rotary Chair Testing

Rotary chair testing is also used to assess the functioning of the inner ear. It is different than VNG because instead of using temperature changes to stimulate the inner ear, whole body rotations are used instead. This is done in a mechanical chair that is situated within a dark chamber. Eye movements are again recorded with infrared goggles. When the chair is rotated, the inner ear senses the rotation, and moves the eyes in the opposite direction. Several different types of rotations are used as a stimulus. In the first, sinusoidal (back and forth) movements of the chair are used at different frequencies (similar to speed, this is the number of rotations per second). A second stimulus that is used is called step velocity testing, or impulse testing. In this part, the chair is rotated at a set velocity for enough time for the nystagmus to taper off (usually 1-2 minutes). By measuring certain variables, such as gain (ratio of eye movements to head movements), phase (how long it takes the eyes to move relative to the head movement), asymmetry (the difference in response between the two ears), and time constant (how long it takes the nystagmus speed to decay to 37% of its original value), these tests can help us determine if the inner ears are functioning properly, or if one or both of the inner ears are weak. In additional, optokinetic nystagmus is Anchortested as well, which measures how the eyes move in response to a moving visual field. This test can be abnormal is certain central conditions, and with bilateral vestibular loss.

Vestibular Evoked Myogenic Potentials (VEMP)

Vestibular Evoked Myogenic Potentials (VEMP) testing is used to assess the otolith organs: the utricle and saccule. Both of these organs are located in a part of the inner ear called the vestibule. The utricle is oriented in the horizontal plane, and senses horizontal linear acceleration (like accelerating in a car), and head tilt. The saccule is oriented in the vertical plane, and therefore senses vertical acceleration (like going up and down in an elevator). Because these organs may have originally been used for sound or vibration detection, they do have some sound sensitivity, which can be measured. Therefore, the test involves placing sound in the ears, and then measuring certain muscle responses to that sound. In a cVEMP (cervical VEMP), sound is delivered to the ear and activates the saccule, which then inhibits some muscles in the neck, including the SCM (sternocleidomastoid) muscle. Because the signal that gets sent to the muscle is inhibitory, the test is done with the muscle contracted, which can be achieved by having the patient lift their head up off the bed during the testing. Normally, the evoked response (electrical change in muscle activity) can only be seen with pretty loud sounds (stimulation levels above 80 dB), but with superior canal dehiscence syndrome, responses are seen at lower levels (60-70 dB). The test can fail to show a response in a variety of conditions, including conductive hearing loss, poor muscle tone, and conditions that damage the saccule like Menière’s disease. Another type of VEMP is the oVEMP (ocular VEMP). This tests the utricle, and sound delivered to the utricle results in excitation of the contralateral eye muscles. Therefore, electrodes placed under the eye, while the patient looks up, are used to measure evoked potentials in the inferior oblique muscle (an eye muscle close to the skin surface). Loss of responses may indicate conductive hearing loss or utricular damage, whereas responses with Anchorabnormally high amplitudes (the degree of response) can indicate 3rd window physiology, as occurs with superior canal dehiscence syndrome.

Video Head Impluse Testing (vHIT)

Head impulse testing is used to measure the responses of the three semicircular canals to quick head rotations. The semicircular canals are the part of the inner ear that sense head rotation, and since the inner ears wants to be able to measure rotation in any direction, we have 3 canals in each ears, oriented at 90° to each other. Quick head movements (also called impulses), result in eye movements in the opposite direction. By using a video camera and computer software, we are able to measure quick eye movements that are difficult to see with the naked eye. By rotating the head quickly in the same plane as the semicircular canal being tested, we are able to separately assess each of the six semicircular canals. This test is important for determining if there has been any damage to each of the six semicircular canals, and also for assessing the central compensation that occurs after damage has been done.

 

 

 

Common Causes of Dizziness

Benign Paroxysmal Positional Vertigo (BPPV)

One of the most common forms of vertigo, Benign Paroxysmal Positional Veritgo (BPPV) occurs when loose “crystals” from the one parts of the inner ear (the utricle) break off and end up in another part of the inner ear (typically the posterior semicircular canal). The “crystals”, aka otoconia, are composed of calcium carbonate, and help the utricle sense head tilt and acceleration by acting as a weight that will slide relative to the hair cells with head position changes. They can be displaced from the utricle for a variety of reasons, including aging, trauma, inflammation (neurititis), Menière’s disease, and surgery. Since the semicircular canals are designed to sense fluid movement (via the crista ampullaris) as part of their job in sensing head rotations, when the loose otoconia end up in the semicircular canals, they can mimic fluid movement, sending a false signal to the brain that you are moving quickly, when in reality you are not. This produces dizziness, nystagmus (rhythmic eye movement in same plane as the canal being stimulated), and nausea. Most cases involve the posterior semicircular canal, due to the fact that it is the most dependent portion of the inner ear (similar to why debris collects in the U-bend under a sink). However, the other two semicircular canals (the horizontal canal and the superior canal) can be affected as well, although this is much rarer. Treatment is aimed at moving the otoconia back into the vestibule, where it won’t cause problems (and is likely reabsorbed but no one really knows). This is usually accomplished with the Epley maneuver for posterior canal BPPV, although occasionally other maneuvers (Semont, Brant-Daroff, Log Roll, Gufoni, etc.) are needed. Surgery can be considered in very rare cases where particle repositioning maneuvers are not effective, but this is very uncommon.

To learn more, please visit our BPPV Videos Page

Vestibular Migraine

Vestibular migraine (aka MAV- migraine associated vertigo) is one of the most common and least appreciated causes of dizziness. Migraine is a complex neurological disorder, and while headache is the most common manifestation, dizziness is another very common symptom and it does not have to occur with headaches. Patients are often very sensitive to multiple stimuli, including lights, sounds, smells, touch, and motion during episodes. A prior personal history of migraines, and/or a family history of migraines, is common, but sometimes if enough “migrainous” features occur with the dizziness (such as headache, light or sound sensitivity, or aura), a diagnosis can be made without a previous history of migraine. Migraines are incredibly common, affecting ~30 million Americans, and ~1/3 of those will experience dizziness at some point. While many patients will experience episodic dizziness, where symptoms come and go, some patients will experience constant symptoms, with a sense of imbalance that is there all the time. Treatment is first aimed at lifestyle changes, including avoiding foods that can trigger migraines, stress reduction, and promoting good sleep. Patients who are still experiencing dizziness despite those measures will often need a medication as well to help prevent dizziness, and the specific choice of medication depends on several factors, including the patient’s health, other medications that they are taking, their blood pressure, and whether or not they have any co-existing psychiatric conditions such as anxiety or depression.

Menière’s Disease

Menière’s disease is named after a French neurologist, Prosper Meniere, who in 1861 argued that vertigo could be caused by diseases of the inner ear. Menière’s disease causes hearing loss, tinnitus, vertigo, and ear fullness, usually occurring together in discreet episodes. Progressive damage to the inner ear can occur over time, resulting in permanent hearing loss and balance impairments. While the cause of Menière’s disease is currently unknown, histologic studies have consistently shown “endolymphatic hydrops”, which refers to a swelling of a portion of the inner ear called the endolymphatic space. Treatment is aimed at reducing the incidence and severity of vertigo episodes, providing symptomatic relief during attacks, and hearing rehabilitation. Common treatments involve use of a low salt diet, a diuretic (“water pill”), or steroids (which can be given by mouth or directly injected into the ear through the eardrum). If these treatments don’t work, then others are considered, such as betahistine (commonly used in Europe, not commonly used in the US), the Meniett device (after placement of an ear tube, pulses of air pressure are delivered to the ear), and endolymphatic sac surgery. The efficacy of all these treatment options is controversial, however they are all considered “non-ablative”, meaning that they don’t cause damage to the ear. Ablative therapies, such as gentamicin injection into the ear, labyrinthectomy (surgical ablation of the inner ear), or vestibular nerve section (surgical division of the balance nerve) are all very effective at reducing vertigo, but they carry risks to hearing and to the balance system. By damaging the remaining ear function they can cause oscillopsia - the sense of the world bobbing or jumping with head movement. Vestibular physical therapy is often very helpful in reducing imbalance after these treatments. We believe in a comprehensive and stepwise approach to managing Menière’s disease, with an emphasis on rehabilitation and symptomatic relief from vertigo.

For further information, we highly recommend reading our patient-centered guide to Meniere’s disease. This guide, which is freely available through the link below, was written by Dr. Jeffrey Sharon and Laura Kirk, PA, and is a comprehensive evidenced-based review designed to help patients figure out a treatment plan for Meniere’s disease.

Patient’s Guide to Meniere’s Disease (PDF).

Vestibular Neuritis/Labyrinthitis

Inflammation of the balance nerve (vestibular neuritis) causes the nerve to stop functioning properly. Since our sense of being stationary depends on a balanced input from both inner ears, if the balance nerve on one side (the wire between the brain and the ear) stops functioning, this creates the perception of rotation to the healthy ear (i.e. vertigo). This vertigo will last several days, but steadily improve over time as the brain readapts (adjusts to the condition). It has been shown in clinical trials that oral steroid therapy is helpful in limiting the damage done by the nerve inflammation. In certain cases, central (brain) adaptation is slow or incomplete, and in these cases vestibular physical therapy, along with treatment of BPPV if present and discontinuation of vestibular suppressant medications (like valium or meclizine) can be helpful. Inflammation of the inner ear (as opposed to the balance nerve) is called labyrinthitis, and this causes hearing loss in addition to vertigo.

Multifactorial Causes

Our sense of balance is a complex process that depends on many different systems, including the inner ear, vision, proprioception (our sense of our own position in space), muscle strength, and sensation. Given the many different factors that comprise a functioning sense of balance, it’s no wonder that many balance problems are due to a combination of problems, including poor vision, poor muscle strength and coordination, medications that cause sedation and low blood pressure, poor sensation (especially on the feet), and impaired proprioception (like not being able to tell if your toe is being held up or down). Multifactorial causes of dizziness are especially common in the elderly. Furthermore, disorders of blood pressure regulation, heart disease, and some neurological diseases will cause us to feel lightheaded, like we are going to pass out (pre-syncope), and this sensation is also commonly called “dizziness” as well (although its usually treated by primary care doctors, neurologists, and cardiologists). Therefore, we believe that a dizziness evaluation must take into account not only the inner ear, but the whole body as well, with referrals as needed to other physicians such as ophthalmologists, cardiologists, geriatricians, physiatrists, neurologists, and orthopedists. Physical therapy aimed at the inner ear, general balance, muscle strength, and coordination is also very helpful for multifactorial causes of dizziness. In additional, patients with multifactorial causes of dizziness are at increased risks of falls, and there are several common-sense interventions that can reduce the risks of falls. These include making the home safe (removing anything on the floor that can cause tripping, ensuring adequate handrails on stairs and in the bathroom, removing all clutter, and ensuring proper lighting), wearing proper footwear, strength training/physical therapy, treatment of any vision problems, and vitamin D supplementation when indicated.Anchor

Persistent Postural Perceptual Dizziness (also called Chronic Subjective Dizziness)

PPPD (Persistent Postural Perceptual Dizziness) refers to constant sense of imbalance or dizziness that is worse with motion and visual stimuli. It commonly occurs after an inciting event, such as vestibular neuritis or BPPV, leading some to conjecture that PPPD reflects a central maladaptation to the inciting event in susceptible individuals (anxiety, depression, and obsessive-compulsive personality are all common with PPPD). Diagnosis is made after a thorough evaluation and workup to make sure that other causes of dizziness are not present. Treatment involves medications (typically SSRIs or SNRIs), vestibular physical therapy, and treatment of co-existing conditions that may be contributing to symptoms. Since patients with PPPD seem to be overly Anchor“sensitized” to motion, part of the therapy is aimed at “habituation”, or getting the patient used to regular motion by repeated exposure in a safe environment.

Uncommon Causes of Dizziness

Superior Canal Dehiscence Syndrome (SCDS)

Superior canal dehiscence syndrome (SCDS) was first described by Dr. Lloyd Minor in 1998. Normally, the entire inner ear (a fluid filled space deep within the temporal bone) is encapsulated in dense bone called the otic capsule. In two areas, the oval window (where the stapes sits), and the round window, the inner ear is covered with membranes instead of bone. This design allows for the transmission of sound energy from the ear bones (ossicles) to the inner ear via the oval window, with the round window acting as a low resistance outlet to permit sound energy to vibrate the fluids and membranes of the hearing part of the inner ear- the cochlea- which is a spiral offshoot located between the oval and round windows. Because of this anatomy, the balance part of the inner ear, which is also contiguous with the cochlea, does not experience any fluid vibrations, because it’s not located along this path of least resistance between the oval and round windows. In SCDS, for unknown reasons, bone is absent over the superior semicircular canal (one of the balance organs that senses head rotations in the vertical plane). Since this opening (dehiscence) is the third opening of the otic capsule bone (after the oval and round windows), it’s called a 3rd window. Functionally, this results in two problems. Firstly, pressure transmissions, from either sound or pressure changes (like coughing, straining, or sneezing) can travel between the oval window and the dehiscence, activating the superior canal along the way, resulting in the sensation of movement (vertigo) with sound or pressure changes. Secondly, the 3rd mobile window changes the impedance of the inner ear, making it easier for sounds coming from the body to be heard. This results in several curious symptoms, such as autophony (hearing one’s voice abnormally loudly), pulsatile tinnitus (hearing your heartbeat or pulse in your ear), and hearing other bodily sounds (such as your eyes moving or your neck muscles creaking). Testing for SCDS involves imaging (CT scan), VEMP testing, audiometry (hearing test), and a physical exam. Treatment Anchorinvolves surgery, with plugging and/or resurfacing of the dehiscent (open) canal.

Mal Du Debarquement Syndrome (MDDS)

MDDS involves a persistent sense of motion, which is usually described as rocking or swaying that occurs after an inciting event (typically a boat trip such as a cruise). Its name is French for “the sickness of disembarking”. While most people will take a few days to feel completely back to normal after a long voyage, MDDS sufferers can have persistent symptoms for months or even years. Paradoxically, symptoms can improve during passive motion, such as being in the back of a car. Vestibular and audiometric testing is usually normal with MDDS. Treatment consists of medications (like SSRIs), stress reduction, vestibular physical therapy, and treatment of co-existing disorders that can contribute to symptoms (e.g. migraine or anxiety). Promising new Anchortreatments for patients who don’t respond to the usual treatments involve transcranial magnetic stimulation, and modulation of the VOR (vestibulo-ocular reflex).

Vestibular Hypofunction

With vestibular hypofunction, the balance part of the inner ear is not working properly. This can occur on one side (unilateral hypofunction), or on both sides of the head (bilateral hypofunction). Unilateral hypofunction can occur after damage from a variety of causes, including vestibular neuritis, vestibular schwannoma/treatments for vestibular schwannoma, and Meniere’s disease/treatments for Meniere’s disease. Bilateral hypofunction can occur after damage to the inner ear/balance nerve from a variety of causes, including exposure to aminoglycoside antibiotics (which are toxic to the inner ear), neurofibromatosis type II, CANVAS syndrome (cerebellar ataxia, neuropathy, and vestibular areflexia), autoimmune disease, congenital problems, trauma, superficial siderosis, and idiopathic causes. Both unilateral and bilateral vestibular hypofunction are diagnosed with VNG (showing absent/diminished inner ear responses to thermal changes on one or both sides), rotary chair testing (showing decreased gain, phase leads, and decreased time constant on the affected side), and head impulse testing (showing that the eyes slip off the target during a rapid head movement, and then quickly correct, known as a catch-up saccade). Hypofunction of the inner ear produces symptoms related to a loss of the normal balance reflexes- therefore patients can have oscillopsia (movement or bobbing of the visual world with head movement due to loss of the vestibulo-ocular reflex), dizziness, and postural instability. Both unilateral and bilateral vestibular hypofunction are treated with vestibular physical therapy. In unilateral hypofunction, treatment is aimed at promoting central compensation and relies on the other ear (the normal side) to perform most of the inner ear functions. In bilateral hypofunction, vestibular physical therapy can still be helpful, but therapy is often longer and more difficult, as the Anchorabsence of all inner ear function means that you have to rely on other systems (such as the COR- cervical-ocular reflex) to sense head movements.

Acoustic Neuroma (also called Vestibular Schwannoma)

Acoustic neuroma, synonymous with vestibular schwannoma, is a benign tumor of the balance nerve (the 8th cranial nerve). While hearing loss is the most common symptom that leads to diagnosis (through an MRI of the brain), dizziness can occur as well, and dysfunction of the balance nerve is common. Since these tumors are benign (non-cancerous), but located in an important and hard to reach area deep in the head, treatment is tailored for each patient. Treatment decisions depend on many factors, including: overall health status, hearing status, symptoms like dizziness, size of the tumor, tumor characteristics, and patient preferences. Currently, treatment options include observation (serial MRI scans to follow the tumor), stereotactic radiation, and microsurgical resection. Surgery can be accomplished by taking several different routes to the tumor, including retrosigmoid (aka suboccipital), translabyrinthine, and middle fossa (aka Anchorsubtemporal) approaches.

Vertebrobasilar Insufficiency/Stroke

The inner ear depends on a small artery, called the labyrinthine artery, for its blood supply. This artery typically branches off another artery, called the AICA (anterior-inferior cerebellar artery). Both of these arteries are part of a larger network of arteries called the “posterior circulation”, which supplies blood to the brainstem and cerebellum. Similar to other TIAs (transient ischemic attacks) or strokes (damage to brain tissue as a result of impaired blood flow), when blood flow to the vestibular system is interrupted, dizziness ensues. It can also cause other symptoms, including facial weakness, speech and swallowing problems, facial numbness, vision changes, confusion, lethargy, extremity weakness or numbness; all depending on which other parts of the brainstem or cerebellum have interrupted blood supply. Risk factors are similar to other stroke risk factors, including high blood pressure, high cholesterol, obesity, vascular disease/atherosclerosis, heart arrhythmias, and diabetes. Vertebrobasilar insufficiency (VBI) is diagnosed when there is transient and reversible changes in blood supply, and is usually treated with an antiplatelet agent (like aspirin or clopidogrel). Sometimes VBI can be provoked with certain neck positions (like turning the head far to one side). A posterior circulation stroke is a life-threatening medical emergency, Anchorand treatment is usually managed by a stroke neurologist after stabilization in the emergency room.

Perilymphatic Fistula

The fluids of the inner ear are normally separated from the air-filled middle ear cavity by two membranes: the oval window (where the stapes sits), and the round window. It is hypothesized that a tear in either membrane can cause a leakage of perilymph (one of the inner ear fluids) into the middle ear cavity (the space behind the ear drum). This leakage is called a “perilymphatic fistula”, or PLF. It is thought to cause fluctuating sensorineural hearing loss (SNHL), and dizziness with pressure changes (such as sneezing, coughing, or straining). While it seems clear that this can occur after surgical opening of these membranes (such as during a stapes surgery), whether or not a PLF can occur spontaneously is controversial. It is generally agreed upon that the incidence of PLF was overestimated in the past. Treatment is aimed at closing the fistula, with surgical reinforcement of the round and oval windows with autologous materials (such as fat, fascia, or Anchorperichondrium harvested during the surgery).

Vestibular Paroxysmia

Another very rare cause of dizziness is vestibular paroxysmia. In this condition, it is thought that nearby arteries pulsate against the balance nerve, causing brief interruptions in functioning, resulting in intense episodes of vertigo lasting seconds. While it is well established that this proposed mechanism can cause dysfunction of other cranial nerve as they traverse a space in the head called the cerebellopontine angle (such as the facial nerve, i.e. hemifascial spasm), it’s more controversial if it can cause vertigo. Symptoms can be precipitated by hyperventilation, and workup includes an MRI, as certain heavily T2 weighted sequences can show a blood vessel compressing the 8th cranial nerve in the CPA (cerebellopontine angle) or the IAC (internal auditory canal). However, care must be taken in interpreting these scans, as up to 1/3 of normal individuals will have these findings as well. Balance testing (ENG, VEMP), and hearing testing (ABR, audiometry) may show subtle abnormalities. Treatment is usually medical, with agents that are thought to calm irritable nerves, such as oxcarbazepine or carbamazepine. In recalcitrant cases, microsurgery can be considered, with separation of the 8th nerve (the balance nerve) from the offending blood vessel.

Vestibular Physical Therapy

Vestibular physical therapy is a specific branch of physical therapy that is designed to help patients with problems with dizziness and imbalance. We are fortunate at UCSF to work with a group of physical therapists who have special expertise in this area. To understand why someone has imbalance or dizziness, they will perform a comprehensive assessment, looking at all the various factors that are required for good balance, including sensory input (from the eyes, inner ear, and skin/joint sensation), muscle strength, posture, gait, ability to recovery from loss of balance, and cognitive function. That will allow a therapist to from a treatment plan, that can address any weaknesses. Specific areas that they may want to focus on include:

Gaze Stability Excercises

These exercises are important when one or both of the inner ears have been damaged, resulting in a loss of vestibular function. In addition to dizziness and imbalance, people with a loss of vestibular function can have trouble seeing clearly- especially when they are moving. To them the world may appear jumpy. To address this problem, pateints are prescribed exercises to teach the brain how to focus clearly again using other body systems to make up for lost function. The key ingredients are maintaining a clear focus, quick head movements, and progressive difficulty. The therapist is essential for guiding patients on how to monitor their symptoms, performing the exercises accurately, and progressing them appropriately.

Gait and Balance training

Exercises help with balance, walking, and recovery strategies when balance is lost. If the patient has a high fall risk and severe balance loss, learning to use an assistive device may be necessary.

Habituation

This refers to repeated exposure to stimuli that can be bothersome, like quick head movements. The goal of this is to get someone more used to things that they need to do in order to function well, but have been avoiding because of discomfort. The concept is that certain avoidance behaviors can be maladaptive in the long run, and therefore must be carefully rehabilitated.

General conditioning

In some cases, it’s also necessary to work on general muscle strength, endurance, and physical health, all in order to improve functioning.

Particle repositioning exercises

In one form of dizziness, called BPPV (benign paroxysmal positional vertigo), loose crystals in the inner ear cause vertigo when someone moves into certain positions (typically rolling over in bed). This is treated with repositioning maneuvers, and our team of physical therapist are all experienced with treating BPPV in this way.

For a great overview of the vestibular system, please watch this video of the vestibular rap- written and performed by Erica Pitsch, PT, MPT, DPT, NCS.