Superior canal dehiscence syndrome (SCDS)
Superior canal dehiscence syndrome (SCDS) is a rare condition of the inner ear, first described in 1998 by Dr.Lloyd Minor of Johns Hopkins University, Baltimore, USA, leading to hearing and balance disorders in those affected. The symptoms are caused by a thinning or complete absence of the part of the temporal bone overlying the superior semi circular canal. This may result from slow erosion of the bone or physical trauma to the skull and there is evidence that the defect or susceptibility is congenital.
• Autophony – Patients with SCDS-related autophony report hearing their own voice as a disturbingly loud and distorted sound deep inside the head as if relayed through “a cracked loudspeaker.” Additionally they may hear the creaking and cracking of joints, the sound of their footsteps when walking or running, their heartbeat and the sound of chewing and other digestive noises. A distinctive feature of this condition almost exclusively associated with SCDS is hearing the sound of the eyeballs moving in their sockets (e.g. when reading in a quiet room) “like sandpaper on wood”.
• Tullio phenomenon, another of the more identifiable symptoms leading to a positive SCD diagnosis is sound-induced loss of balance. Patients showing this symptom may experience vertigo, a feeling of motion sickness or even actual nausea, triggered by normal everyday sounds. Although this is often associated with loud noises, volume is not necessarily a factor. Patients describe a wide range of sounds that affect balance: a telephone ringing; a knock at the door; music; the sound of children playing and even the patient’s own voice are typical examples of sounds that can cause a loss of balance when this condition is present, although there are countless others. For such persons, a visit to the concert hall or to a noisy playground may seem like being at the epicenter of an earthquake. A change of pressure within the middle ear (for example when flying or nose-blowing) may equally set off a bout of disequilibrium or nystagmus.
• Low-frequency conductive hearing loss is present in many patients with SCDS and is explained by the dehiscence acting as a “third window.” Vibrations entering the ear canal and middle ear are then abnormally diverted through the superior semi circular canal and up into the intracranial space instead of being registered as sound in the hearing center, the cochlea. This hearing loss being greater in the lower frequencies and may initially be mistaken for otosclerosis.
• Pulsatile tinnitus is yet another of the typical symptoms of SCDS and is caused by the gap in the dehiscent bone allowing the normal pulse-related pressure changes within the cranial cavity to enter the inner ear abnormally. This pressure change thus becomes audible and an existing tinnitus will be perceived as containing a pulse-synchronized “wave” or “blip” which patients describe as a “swooshing” sound.
• Brain fog and fatigue are both common SCDS symptoms and are caused by the brain having to spend an unusual amount of its energy on the simple act of keeping the body in a state of equilibrium when it is constantly receiving confusing signals from the dysfunctional semicircular canal.
• Headache and migraine are also often mentioned by patients showing other symptoms of SCDS. A direct causal link has yet to be proven.
In approximately 2.5% of the general population the bones of the head develop to only 60-70% of their normal thickness in the months following birth. In SCDS the section of temporal bone separating the superior semicircular canal from thecranial cavity, normally 0.8 mm thick, shows a thickness of only 0.5 mm, making it more fragile and susceptible to damage through physical head trauma or from slow erosion.
The presence of dehiscence can be detected by a high definition (0.6 mm or less) coronal CT Scan of the temporal bone, currently the most reliable way to distinguish between superior canal dehiscence syndrome (SCDS) and other conditions of the inner ear involving similar symptoms such as Meniere’s disease and Perilymph fistula. Other diagnostic tools include the VMPtest, CENG (Computerized ElectroNystagmography) or VNG, electrocochleography (ECOG) and the rotational chair test. An accurate diagnosis is of great significance as unnecessary exploratory middle ear surgery may thus be avoided. Several of the symptoms typical to SCDS (e.g. vertigo and Tullio) may also be present singly or as part of Ménière’s disease, sometimes causing the one illness to be confused with the other. There are reported cases of patients being affected by both Ménière’s disease and SCDS concurrently.
Once diagnosed, the gap in the temporal bone can be repaired by surgical resurfacing of the affected bone or plugging of the superior semicircular canal. These techniques are performed by accessing the site of the dehiscence either via a middle fossa craniotomy or via a canal drilled through the transmastoid bone behind the affected ear.
- MBBS (University of Mumbai, India)
- DORL (Diplomate of the College of Physicians & Surgeons, Mumbai)
- FCPS (Fellow of College of Physicians & Surgeons, Mumbai, by examination)
- MS (Master of Surgery [ENT], University of Mumbai, India
- DLO (Diplomate by examination in 2 parts of the Royal College of Surgeons (London)
- FRCS (Edinburgh) – Fellowship by examination in 2 parts of the Royal College of Surgeons
Dr. A. K. Chaudri graduated from the University of Mumbai, India
He had advanced post graduate training in the ENT speciality and in Plastic surgery at the K.E.M.Hospital, and the L.T.M.G. Hospital,Mumbai . He then proceeded for super specialization to the U.K. where he had extensive training in the more advanced aspects of the speciality for 5 years.
He passed the Diploma in E.N.T. Examinations – both parts at first appearance DLO of the Royal College of Surgeons (London)
He became a fellow of the Royal College of Surgeons of Edinburgh ie FRCS ( Edinburgh) after successfully passing the primary and final parts of the FRCS at first appearance in both examinations.
He has done an advanced course in hearing and vertigo testing at the Institute of Sound and Vibration Research, University of Southampton, England. He has undergone special training in ear surgery with Dr. IanThorburn, well known Ear Surgeon, for 1 year at Blackpool, England.
He has attended several courses at Gray’s Inn Road E.N.T Hospital, King’s Cross, London, the well recognised Centre of E.N.T. learning
Back in India he has participated in several camps in ear surgery at Nashik and Dhule, in Maharashtra and in Dahanu with the Rotary Club of Mumbai South of which he was the Medical Chairman. He has worked with well known Ear surgeons Dr. Gadre, Dr. Tepan, Dr. Karnik and Dr. Anklesaria. He has performed free examination of school children in hundreds.
After his initial training abroad, in the U.K., he has been travelling extensively to learn personally from world renowned ENT surgeons in their fields of expertise. He has visited the authorities in the European subcontinent – Professor Tauno Palva at the Korrva Klinika in Helsinki, Finland, Professor Plester at the University of Tubingen, West Germny, Prof. Jean Marquet in Belgium, Prof Claus Jannsen in West Germany, Professor Claus Claussen, Professor of NeuroOtology a world renown authority on vertigo at Bad Kisengen in West Germany.
Commitment to Excellence
Dr. Chaudri has a special interest in ear pathologies, ear surgery, hearing assessment and fitting of hearing aids, treatment for ear drum perforations andcholesteatoma, sino-nasal pathology and allergy management.
As ear problems are extremely common in the Indian sub continent, he has vast experience in the surgical treatment of these conditions.
Commitment to Community
Dr. Chaudri is actively serving the medical profession at various levels.His special ability and interest lies in explanatory talks on medicaltopcs to laymen, students and doctors alike. He has been an invitee at various Rotary clubs, Giants clubs etc.
He is on Advisory Panel of some magazines and is often sought for his views and opinions about ENT conditions by both English and local newspapers. He has appeared on TV and he gives talks on medical related topics
He participates in community events such as deafness screening of senior citizens and free examination of hundreds of school children.
Commitment to Positive Thinking and Healthy Living
Being a firm believer of lifelong learning, he is a regular reader of medical books and magazines, devoted to research activities, regularly recording endoscopic clips of E.N.T. disease and presenting them as interesting case studies for laymen and the medical profession.
This form of migraine was previously known as Basilar Artery Migraine (BAM). Under the International Headache Society’s International Classification of Headache Disorders, 2nd Edition, the new designation for this form of Migraine is Basilar-Type Migraine (BTM). It has also been called Bickerstaff syndrome, brainstem Migraine, and vertebrobasilar Migraine.
The term Basilar-Type Migraine is actually a bit misleading as it implies that the Migraine attack is vascular in origin due to spasm of the basilar artery and the subsequent ischemia.
Since the time when the term Basilar came into use, however, it has been shown that Migraine is a genetic neurological disease, and BTM, as other types of Migraine are neural in origin.
As with all Migraine, there is a vascular component once the Migraine begins, but the origin is neurological. Early literature (Bickerstaff 1962) suggested that BTM was most common in adolescent females. However, presently it is seen to affect all age groups and both male and female.
BTM does exhibit the same female predominance seen overall in Migraine; three times as many female sufferers as male. A Basilar-Type Migraine is a Migraine that has aura symptoms originating from the brainstem and/or affecting both hemispheres of the brain at the same time, but with no motor weakness.
The aura of BTM usually lasts less than 60 minutes, but in some cases can be more extended. Many Migraineurs who have BTM also report Migraine with typical aura. The aura of BTM can include temporary blindness, which is one reason they can be quite terrifying. However,
BTM is actually essentially Migraine with aura with the aura localized to the brainstem. Still, because of that localization, Migraine-specific medications such as the triptans and ergotamines are contraindicated for BTM. Of the preventive medications, it’s recommended that beta blockers be avoided in cases of BTM.
Because of the medication contraindications, I highly recommend that Migraineurs who experience BTM wear some kind of medical identification at all times. Diagnosis of BTM requires at least two attacks meeting the following criteria:
Aura consisting of at least two of the following fully reversible symptoms, but no motor weakness:
Dysarthria (impairments or clumsiness in the speaking of words due to diseases that affect the oral,
lingual, or pharyngeal muscles)
hypacusia (impaired hearing)
diplopia (double vision)
visual symptoms simultaneously in both temporal and nasal fields of both eyes
decreased level of consciousness
simultaneously bilateral paresthesias (abnormal or unpleasant sensation often described as numbness
or as a prickly, stinging, or burning feeling)
At least one of the following:
at least one aura symptom develops gradually over five or more minutes and/or different aura
symptoms occur in succession over five or more minutes
each aura symptom lasts five or more and 60 minutes or less headache meeting criteria Migraine
without aura begins during the aura or follows aura within 60 minutes
Migraine experts caution that when there is motor weakness, great care be taken to arrive at the proper
diagnosis as there are times when it can be difficult to differentiate between Basilar-Type Migraine and
Hemiplegic Migraine. The IHS criteria also note that if motor weakness is present, the disorder should
be coded as Familial Hemiplegic or Sporadic Hemiplegic Migraine.
Another reason great care must be taken in diagnosis is that many of the symptoms of BTM are also
Basilar-Type Migraine presents symptoms that can mimic other, far more serious conditions. It is
essential that the diagnosis be definitive and correct. An imaging study such as a CT scan or MRI
should be performed to rule out other causes for the symptoms, and an EEG is often performed to
rule out seizure disorders. If the doctor making the diagnosis is hesitant about it, definitely seek a second
opinion from another doctor. Since BTM is not common, seeing a Migraine specialist is advisable when
possible. It is also important to continue medical treatment as advised by your doctor and not skip follow-
Some other conditions that should be ruled out in diagnosing BTM are:
space-occupying lesions of the brain
brainstem Arteriovenous Malformation (AVM): a congenital defect consisting of a tangle of abnormal
arteries and veins with no capillaries in between. The blood pressure in the veins is higher than
normal and may result in a rupture of the vein and bleeding into the brain.
As with other forms of Migraine, BTM can be disabling. Because of the neurological symptoms that can
occur during Basilar-Type Migraine aura, it can present a larger hurdle than Migraine with aura because
the aura itself is debilitating and can last longer. This can mean special problems for people in the
traditional work force or trying to care for young children. If they are in an environment where others are
not educated about Migraine disease, it is particularly important that efforts be made to educate those
Basilar-Type Migraine is one of the most frightening of head pain disorders, but the symptoms are
usually more frightening than harmful.
However, as with other forms of Migraine, if the pain is extreme, it is best to seek emergency care. BTM
does increase the risk of stroke slightly more than Migraine with aura and Migraine without aura, so
additional care should be taken. Once diagnosed with BTM, it is important (as with any form of
Migraine) to consult your doctor if your symptoms or Migraine pattern change. Without consulting a
doctor, it’s impossible to be sure that new symptoms or changes in pattern are attributable to BTM, and
that no other condition is present. While BTM isn’t cause to panic, it is more than reason to be sensible
and take good care of yourself.
In basilar migraine and in other migraine equivalent vertigos the otological aspect is subsidiary to the
main disease. Investigation fails to reveal a primary labyrinthine disorder and treatment is the province of medical or neurological specialties.
Meniere’s disease is a disease of the inner ear that causes episodes of vertigo, noises in the ear (tinnitus), a feeling of fullness or pressure in the ear and fluctuating hearing loss. It is named after a french physician who first described it in 1861.
A typical attack is preceded by fullness in one or both ears, hearing fluctuation or tinnitus (ringing sounds in the ears). The attack involves severe vertigo (spinning sensation), nausea, vomiting, sweating in severe cases. An attack usually lasts from minutes to a few hours. The episodes may occur as several attacks in a short time or in other cases, months or even years may pass between episodes. Between the acute attacks, most people are free of symptoms or experience only mild imbalance and tinnitus. In 75 percent of cases, the disease is confined to one ear, in the rest, both ears may be involved. In most cases a progressive hearing loss occurs in the affected ear. Though acute attacks are incapacitating, the disease itself is not fatal.
Mechanism of symptoms of Meniere’s disease
The inner ear serves the body’s functions of hearing and balance. It is a system of hollow coiled tubes containing fluid (endolymph) and suspended in fluid (perilymph). The hearing and balance are in continuityanatomically and ohysiologically. In a normal ear, the endolymph is maintained at a constant volume. An acute attack of Meniere’s disease is believed to result from from fluctuating pressure of the endolymph fluid within the inner ear. The underlying cause of Meniere’s disease is unknown
Diagnosis of Meniere’s disease
The diagnosis is based on history, findings at clinical examination and results of hearing tests like Audiometry and Impedance Bridge studies and vestibular (balance) tests like Electronystagmography (E.N.G.), the gold standard by which the function of the balance organ is measured.. Rarely an M.R.I. brain scan may be required to exclude a rare tumour of the nerve of balance. (Ac neuroma) which presents with symptoms of Meniere’s disease. See vertigo testing Click
Management of an acute attack
During an acute attack, one must lie down on a firm surface. Do not move till the severity of vertigo subsides, then get up slowly. The eyes must be kept open and fixed on a stationary object. Do not drink water. It may cause vomiting.. If the vomiting and vertigo persist, send for the family physician . If relief is still not obtained, an E.N.T. specialist has to be consulted.
How does one cope up with the symptoms?
Avoid maneuvers involving neck twisting, Be extra careful during crossing roads, avoid sitting on two wheelers, avoid dangerous heights, etc. From now on, you will have to rely more on the two other modalities for maintenance of balance – namely – vision and proprioception (sensations from the peripheral sensory inputs of skin, muscle and joint sense. It is advisable to tell colleagues at work what to do if an acute attack occurs.
What can be done to reduce the symptoms?
Between attacks, different medications and different types of Vestibular rehabilitation exercises may be prescribed to help to encourage coordination between ears, eyes, cervical spine and stance and gait.
Salt restriction during the acute attack helps prevent water logging within the internal ear and helps early recovery. A permanent tinnitus (ringing in the ears) or a progressive hearing loss may be the consequence of a long term Meniere’s disease. In severe cases not responding to medication, surgery may be advised to block the transmission of information from the affected ear to the brain. The surgical methods available can be discussed with doctor when the need arises.
For Vestibular rehabilitation exercises Click
Vestibular neuronitis / neuritis Vestibular neuritis is The secondmost common cause of vertigo arising from a disorder of thelabyrinth is caused by inflammation of the vestibular nerve, thenerve that connects the balance portion of the inner ear to the brain.It is manifested by a sudden attack of rotatory vertigo often associated with nausea, vomiting, and sweating.
What are the causes? (Aetiology and pathology)
Vestibular Neuritis is thought to be caused by a viral infection of the balance nerve that runs from the inner ear to the brain. Various theories have been proposed to account for the cause of vestibular neuritis including inflammation of the vestibular nerve and ischemia of the labyrinth. Many of the histological features of vestibular neuritis when evalu¬ated in postmortem studies are similar to those observed in other sensory epithelia in known viral disorders. Herpes simplex virus type 1 (HSV -1) DNA has been detected on autopsy with the use of polymerase chain reaction in 66% of human vestibular ganglia. Reactivation of a latent infection with HSV -1 is presumed to account for the occurrence of vestibular neuritis.
The condition chiefly affects adults between the ages of 30 and 50 years without preference for sex.
Vestibular neuritis affects the superior division of the vestibular nerve more commonly than the inferior division. The superior division has a longer course through bone than does the inferior division and is therefore more liable to affection from ischemia, injury and entrapment.
Because of the association of the disorder with reactivation of HSV-l, the condition is also referred to as vestibular neuronitis.
Some patients will report having an upper respiratory infection (common cold) or a flu prior to the onset of the symptoms of vestibular neuritis, others will have no viral symptoms prior to the vertigo attack.
What are the symptoms?
The main symptom of vestibular neuronitis is vertigo, which appears suddenly, often with nausea and vomiting. Vertigo usually lasts for several days or weeks. It can come as a single attack or as a series of attacks of vertigo or a constant sense of balance carrying on for two to four weeks before diminishing. It may follow an upper respiratory tract infection. The cochlea (hearing portion) of the inner ear is unaffected and therefore the patient’s hearing function is normal.
Onset:- (The Acute phase) Vertigo is the leading symptom. The onset is sudden with, in some cases, transient paroxysms of vertigo accompanied by black-outs or drop-attacks, in others a feeling of imbalance, especially when walking or standing, aggravated by movements of the head indicating a sudden and partial or complete loss of vestibular function on one side,. Vertigo may be accompanied by nausea or vomiting but never by tinnitus or deafness. The presence of hearing loss in the affected ear may indicate labyrinthitis, an acute Meniere disease attack or infarct of the brainstem or cerebellum (often in the territory of the ante¬rior inferior cerebellar artery).
The patient should be made to walk, however difficult it may be, as severe gait ataxia strongly points to a central cerebrovascular event such as cerebellar infarction – especialli in the territory of the poste¬rior inferior cerebellar artery (PICA). Magnetic resonance imaging (MRI) with diffusion weighted images should be performed when indicated based upon clinical suspicion of an infarct.
Later:- (The Subacute phase) The intense vertigo of acute vestibular neuri¬tis can last from hours to days and rarely weeks. This phase is characterized by imbalance and disequilibrium that noticeably improves over this time. Patients will have sensitivity to motion and may avoid head turns and rapid movements.
They may develop brief attacks of vertigo that are not as intense as the initial attack. Vestibu1ar rehabilitation during this phase may speed recovery.
At the end of the subacute phase the patient will be near their baseline balance function but may notice small disturbances of equilibrium with rapid motions or in challenging environ¬ments. If evaluated for dizziness at this late stage, a diagnosis of vestibular neuritis is based largely on a suspicious history of severe vertigo within the prior months to year. Additional test¬ing, as described below, may also demonstrate a unilateral weakness confirming an insult to the inner ear. Commonly in this stage anxiety plays a major role in the patients perception of their debility. A significant portion of patients with acute vertigo will develop anxiety regarding their balance and potential for having recurring ver¬tigo. They will often limit activities such as driving, withdraw socially and become intensely fixated on any abnormal sensation of equilibrium. A psychological consultation in any vestibular neuritis patient with a dependent or insecure personality type is advisable.
In rare cases it can take months to go away entirely. Vestibular neuronitis does not lead to loss of hearing. One may notice that vision is disturbed or jumpy on looking to a particular side.
How is the diagnosis confirmed?
Pure tone Audiometry, Impedance bridge studies and vestibular (balance) tests – Electronystagmography is the gold standard by which the function of the balance organ is measured. A C.T.Scan or M.R.I.Scan of the brain is not required immediately and usually turns out to be normal.
Evaluation and Diagnostic Testing
Physical Examination. Findings on physi¬cal examination will generally depend upon the stage of vestibular neuritis. In the acute phase, the examiner will note spontaneous nystagmus the eyes move in the plane of the affected semicircular canal(s).
The nystagmus will increase in amplitude with gaze toward the horizontal fast phase component, which is usu¬ally toward the nonaffected ear. The nystagmus should suppress with visual fixation but may be of such intensity as to be reduced in amplitude but remain noticeable. Direction changing nys¬tagmus and lack of visual suppression should raise the suspicion of a central event and prompt imaging for stroke evaluation. The presence of ataxia is also suggestive of central vestibular dys¬function or, rarely, a drug reaction.
Hearing should be checked during the acute phase A hearing loss is inconsis¬tent with vestibular neuritis, and the practitioner should consider labyrinthitis, Meniere disease, perilymphatic fistula, or acute otitis media among otologic causes of acute cochleovestibular symptoms.
The spontaneous nystagmus has usually resolved in the subacute phase although nys¬tagmus may be observed with gaze toward the unaffected ear
Electronystagmography Objective testing can be used to identify the unilateral vestibular hypofunction characteristic of vestibular neuritis. Caloric test¬ing showing an asymmetry is consistent with a history of unilateral vestibular insult. This test is more sensitive than either head thrust or head shake for identifying such an asymmetry. The ENG battery of tests can also be used to assess for the presence of.BPPV which occurs often after vestibular neuritis. In the acute and subacute phases, ENG can identify and document spontaneous and gaze evoked nys¬tagmus as well as determine their direction thus helping to identify the affected side. The ENG is important to distinguish a PICA thrombosis (in which ENG is normal) from Vestibular neuronitis in which it is always abnormal.
Imaging. The acute phase of vestibular neu¬ritis is of such severity and duration that clini¬cal examination alone may not be sufficient to rule-out central vascular events. Thus, computed tomography (CT) scan is the initial imaging test of choice to look for an acute hemorrhage involving the brainstem or cerebellum. MRI of the internal auditory canals during an acute phase of vestibu¬lar neuritis may show subtle enhancement of the superior vestibular nerve at the region of Scarpa ganglion. Beyond the acute phase, MRI with gadolinium enhancement is most useful for eval¬uating for other intracranial lesions that could account for an attack of vertigo or prolonged vestibular dysfunction. Tl-weighted images with contrast can demonstrate the presence of vestib¬ular schwannoma. Sudden vertigo is the initial presenting sign for vestibular schwannoma in approximately 15% of cases. It is rare in isolation and usually accompanies hearing loss. The presence of Chiari I malfor¬mation, cerebellar tumor, cerebellopontine angle arachnoid cyst, old brainstem infarct, or vascular loop can also be identified with MRI.
Management. Supportive treatment should also be given during the acute phase of vestibular neuritis.
Acute phase – Combination treatment of Methylprednisolone in a dosage of 48 mg. daily for the first 3 days tapered by 16 mg every 3 days for a total treatment time of 20 days and
Va1cyclovir admiistered as 1,000 mg three times per day for 1 week.
Patients should be hydrated if they are having significant vomiting and provided antiemetics.
Vestibular suppressants can also be prescribed to attenuate the severity of the attack. The treatment of vestibular neuronitis is medical, and depends entirely upon the severity of symptoms. Some patients’ will be so disabled as to require a period of rest in bed, others will be able to continue to get about, but all will probably require labyrinthine sedation to tide over the period of activity of the disease. As in Meniere’s disease promethazine theoclate (Avomine) or dimenhydrinate (Dramamine) tablets are useful drugs for suppressing the symptoms of vertigo and nausea.
Low dose valium is an effective vestibular suppressant, and mini¬mally sedating dosages of 2 mg every 6 hours as needed can be provided. Attempts should be made to wean the patient off of vestibular suppressants as soon as possible to allow central compensation of the unilateral hypofunction.
Once the patient has entered the subacuate phase of their attack, vestibular rehabilitation exercises should be recommended VOR exercises can speed central compensation for the unilateral weakness Patients experiencing chronic daily disequililibrium should be evaluated for psychogenic dizziness trigered by the initial neurotologic disorder. Additionally, an attack of vestibular neuritis may exacerbate underlying psychiatric or anxiety disorders.
The condition pursues a benign although sometimes protracted course and symptomatic recovery is the rule. Reassurance that recovery is confidently to be anticipated. Even when vertigo has been initially severe and immobilizing the recovery period does not often exceed 3 weeks.
Caloric responses generally remain permanently abnormal.
D.D. In Meniere’s disease deafness is always present, a feature which should immediately eliminate a diagnosis of vestibular neuronitis
Other forms of labyrinthitis, toxic, vascular or infective, may at times be difficult to differentiate, but if it is remembered that the diagnosis of vestibular neuronitis requires the stringent double verification of abnormal caloric reactions and normal cochlear audiograms.
How is an acute attack managed?
During an acute attack, lie down on a firm surface. Stay as motionless as possible and keep your eyes open and fixed on a stationery object in front of you. Do not try to sip or drink water as this may cause vomiting. Stay like this till the severity of vertigo subsides. Avoid the position causing the vertigo.
How is it treated?
Medical treatment based on results of investigations by a vertigo specialist usually involves a combination of medication and vestibular rehabilation therapy and course of exercises is advised. Also special exercises help to come back to normal early.
Appropriate Vestibular Rehabilitation Excersies help to recover quickly.
Anatomy and Physiology of the Ear Click here
Causes of a Tumour of the nerve of balance
An acoustic neuroma arises from the fibrous sheath of the nerve of balance (vestibular nerve) within the internal auditory canal.
The initial symptom of an acoustic neuroma is tinnitus (noise in the ear). Deafness appears later and so does vertigo. Occasionally the presentation is by a sudden deafness. The vertigo is usually a constant sense of imbalance. As the tumour grows in size, it presses on adjoining areas – cerebellum and brain stem. Pressure on the Cerebellar causes increasing imbalance, increasing tinnitus and increasing heraing loss. Pressure on the Brainstem causes various neurological problems.
Confirmation of the diagnosis
Pure tone Audiometry, Impedance bridge studies and vestibular (balance) tests. Electronystagmography is the gold standard by which the function of the balance organ is measured. An M.R.I.Scan of the brain will show a suspicious shadow occupying the internal audiitory canal and cerebello pontine angle.
How is it treated?
Early diagnosis is extremely important as the treatment is surgical removal of the tumour. Every case of noise in th ear should be properly investigated by Pure tone Audiometry, Impedance bridge studies and vestibular (balance) tests. Electronystagmography. The sooner this is done, the better, since this the tumour grows in a closed space, next to vital brain stem structures responsible for cardiac function and respiration and the larger it is, the more difficult it is to remove. There is no place for medical treatment.
Vestibular Rehabil Exercises Click here
Precautions during vertgo attacks Click here
Results of Audio – Vestibular investigations of a patient with Right Acoustic Neuroma
Pure Tone Audiogram showing a moderately severe to severe sensori neural hearing loss in the Right ear
Electro Nystagmography recordings of a patient with a Right Acoustic Neuroma
Recordings of the Caloric test
Right ear warm stimulus
Right ear cold stimulus
Left ear warm stimulus
Left ear cold stimulus
Recordings of right and left ear caloric responses for frequency calulations
Cerebello Pontine Angle / Internal Auditory Canal Mass Lesions
Acoustic Schwanomma – The most common CPA-IAC mass
Meningioma of CPA – 2nd most common CPA-IAC mass
- 2nd most common primary intracranial tumour (15 –25 %)
Meningioma - intracanalicular may mimic AS
Facial Nerve Schwannoma confined to CPA / IAC may mimic AS
Metastasis & Lymphoma
Idiopathic Hypertrophic Pachymeningitis (rare)
Epidermoid cyst 3rd common
Benign cystic neoplasm – cystic meningioma, cystic ependymoma and cystic schwannoma
Malignant cystic neoplasm – Ependymoma pedunculating from brainstem
- Astrocytoma pedunculating from 4th ventricle
Aneurysm of PICA, VA, AICA
Labyrinthine Ossificans following meningitis
Inner Ear Schwannoma – Intra Vestibular, Cochlear, Vestibulo-Cochlear, Translabyrinthine
Facial Nerve Schwannoma with Secondary Erosion Into Inner Ear
Endolymphatic Sac Tumour
Cerebellopontine Angle Lesions:
1. Acoustic schwannoma
* most common mass in the CPA, up to 75% of cases
* usually arises from the superior vestibular nerve
* usually a solid space-occupying mass with a tail in the internal acoustic meatus/ canal that uniformally enhances with contrast; can cause compression of the pons and cerebellar peduncles
* surgical approaches- A. Suboccipital retrosigmoid (Figure 1)
Figure 1: T1 -weighted coronal view (with contrast) of a left cerebellopontine angle lesion showing enhancement. The lesion is predominately in the posterior fossa with a tail in the internal acoutic canal. This lesion was excised through a suboccipital/ retrosigmoid approach.
B. Trans-labyrinthine presigmoid (Figure 2)
Figure 2: A: T1-weighted coronal view (with contrast) of a right cerebellopontine angle lesion showing uniform enhancement. This lesion is mostly in the internal acoustic canal and was excised through a translabyrinthine approach. The patient had no useful hearing preoperatively and had preservation of the facial nerve postoperatively.
B: Intraoperative of the tumor resection. The tumor is carefully dissected away from the cranial nerves in the porus acousticus.
C: Note the preservation of the cranial nerves after complete resection of the tumor.
C. Middle Fossa (Figure 3)
Figure 3: T1-weighted axial view (with contrast) of a small intracanalicular left acoustic tumor (arrow). The patient had useful hearing preoperatively and thus this lesion was resected through a middle fossa approach. The patient had preserved hearing and facial function postoperatively.
* second most common lesion, up to 10% of cases
* uniformally enhancing mass; dural tail
3. Ectodermal inclusion tumors: Epidermoid (Figure 4)- also known as ‘congenital cholesteatoma”; 5-7% of cases in the CPA; cystic space-occupying, non-enhancing lesion
Figure 4: T2-weighted axial view showing a hyperintense lesion in the left cerebellopontine angle. This is a typical appearance for an epidermoid lesion.
5. Paraganglioma- “glomus jugulare tumor” arising in the jugular foramen and extending into the CPA; incidence: 2-10%
6. Other schwannomas: 2-5% incidence; trigeminal and facial nerves are probably the most common sites of nonacoustic schwannomas. Other cranial nerves involved are: VI, IX, X, XI and rarely XII.
7. Vascular lesions (2-5% incidence)
* dolichobasilar ectasia: 3-5%
* aneurysm: 1-2%
* vascular malformation: 1%
8. Choroid plexus papilloma: 1%; primary in the CPA or extension via the lateral foramina of Luschka
9. Ependymoma: 1%; extension from the 4th ventricle
10. Rare lesions: incidence <1%
* arachnoid cyst
* lipoma (CPA is the 2nd most common site in brain)
* exophytic brain stem or cerebellar astrocytoma
* osteocartilaginous tumors
Cranial Nerves at the Internal Acoustic Meatus (Figure 5):
Figure 5: A diagrammatic view of the cranial nerves at the internal acoustic meatus. Taken from Surg Neurology 8:388,1977.
* there are five nerves in the meatus: nervus intermedius (sensory component of the VIIth nerve), facial motor root, cochlear nerve, inferior and superior vestibular nerves.
* position of the 5 nerves is most constant in the lateral portion of the meatus, which is divided into a superior and an inferior portion by a horizontal ridge (transverse or falciform crest): facial and superior vestbular nerves (SVN) are superior to the crest; facial nerve is anterior to the SVN and is separated from it at the lateral end of the meatus by a vertical ridge of bone (Bill’s bar); nervus intermedius (NI) is between the facial motor root and the SVN (it may be adherent to the SVN); cochlear nerve and the inferior vestibular nerve (IVN) run below the transverse crest with the cochlear nerve located anteriorly.
FACIAL NERVE: Anterior-superior
COCHLEAR NERVE: Anterior-inferior
*because acoustic neurinomas most frequently arise in posteriorly placed vestibular nerves, they usually displace the VIIth nerve anteriorly (facial nerve is stretched around the anterior half of the tumor capsule).
*because the facial nerve enters the facial canal at the anterior-superior quadrant of the lateral margin of the meatus, it is usually easiest to locate it here after the posterior lip of the meatus has been removed, rather than at a more medial location where the degree of displacement of the nerve is more variable, depending on the site of origin and growth characteristics of the tumor.
*while the posterior meatal lip is removed, mastoid air cells that extend into the lip may be opened, and must then be sealed carefully to prevent CSF leak or meningitis.
*during removal of the posterior meatal wall, care is taken to avoid the posterior semicircular canal, which is lateral to the posterior wall of the meatus- to avoid this semicircular canal, bone lateral to the tranverse crest should not be removed.
*labyrinthine arteries and their branches typically lie below the nerves- are the sole supply to the membranous labyrinth.
The LSUHSC Skull Base Team (Neurosurgery, Otolaryngiology, Plastic Surgery, Neuroradiology, Neurophysiology departments) routinely deals with CPA lesions, especially acoustic tumors. In 1999, 10 acoustic tumors were removed at LSU: 4 suboccipital; 3 translab; 3 middle fossa
What is BPPV? (Benign Paroxysmal Positional Vertigo)
BPPV is a disease of the balance organ in the inner ear (vestibule) which results from the altered function of the utricle and posterior semi circular canal.. Small crystals of calcium carbonate (“otoconia”) normally present in the utricle, drop into the posterior semi circular canal during head movement. The crystals can lodge in the posterior semi circular canal (Commonest) (Canalithiasis) or in the Cupula of the posterior canal (Cupulolithiasis) The vertigo occurs in sudden brief episodes and is short lived (paroxysmal); it is positional because the symptoms are precipitated by head movement. Some people feel it when the head is taken back to look up, while others feel it if they lie down suddenly or get up suddenly.
BPPV is a common cause of dizziness. About 20% of all dizziness is due to BPPV. In the elderly, about 50% of dizziness is due to BPPV
What causes it?
BPPV can be due to simple infections like common colds, and degeneration of the inner ear as in ageing. However, BPPV may rarely occur for no known reason.
The most common cause of BPPV in people under age 50 is head injury with damage to the utricle. There is also an association with migraine. In older people, the most common cause is degeneration of the vestibular system of the inner ear. BPPV becomes much more common with advancing age. In half of all cases, BPPV is called “idiopathic,” which means it occurs for no known reason. Viruses affecting the ear such as those causing vastibular neuritis, minor strokes such as those involving anterior inferior cerebellar artery (AICA Syndrome, and Meniere’s disease are unusual causes. Occasionally BPPV follows surgery. The cause b in such cases could be a combination of a prolonged period of supine positioning, or ear trauma when the surgery is to the inner ear.
How is the diagnosis confirmed?
Positional testing by the Hallpike maneuvers help identify the specific positions provoking the vertigo.
Pure tone Audiometry, Impedance bridge studies and vestibular (balance) tests – Electronystagmography is the gold standard by which the function of the balance organ is measured. A C.T.Scan or M.R.I.Scan of the brain is not required immediately and usually turns out to be normal. Low blood pressure can give rise to positional vertigo. However in these cases the giddiness is only on sitting up (postural hypotension) and never on lying down.
How is an acute attack managed?
During an acute attack, lie down on a firm surface. Stay as motionless as possible and keep your eyes open and fixed on a stationery object in front of you. Do not try to sip or drink water as this may cause vomiting. Stay like this till the severity of vertigo subsides. Avoid the position causing the vertigo.
How is it treated?
The specific positions provoking the vertigo are identified by the vertigo specialist and avoided and a combination of medication and vestibular rehabilation therapy and course of exercises is advised. Also special exercises help to come back to normal early. The Eppley-Semont manoeuvres are effective in helping the symptoms subside.
Certain modifications in your daily activities may be necessary to cope with your dizziness. Use two or more pillows at night. Avoid sleeping on the “bad” side. In the morning, get up slowly and sit on the edge of the bed for a minute. Avoid bending down to pick up things, and extending the head, such as to get something out of a cabinet. Be careful when at the dentist’s office, the beauty parlor when lying back having ones hair washed, when participating in sports activities and when you are lying flat on your back.
The specific positions provoking the vertigo are identified by the E.N.T Surgeon and avoided and a combination of medication and vestibular therapy is advised. Labyrinthine sedatives, vasodilators. Also special exercises help to come back to normal early. The Eppley-Semont manoeuvre performed by an E.N.T Surgeon are effective in helping the symptoms subside.
Balance is maintained by 3 sources of input to the brain – Inner, ear, the main balance organ, eyes – vision to information received from your feet, ankle and legs assist you in keeping your balance and moving around.
Modifications in the daily activities will help you cope with your dizziness.
The exercises aim at helping one Dependance on vision.- on the information received from the eyes.
Because of this you should take special precautions in situations where clear, normal vision is not available to you to avoid injury in case you fall. At home, when walking through dark rooms, keep lights or night lights on all the time. Eliminate slippery floor surfaces, maintain clear a path to your bathroom and move away objects that could injure you, should you have a fall. Do not drive your car at night, during stormy weather or when visibility is poor. Do not carry large objects which obstruct the view in front.
Dependance on inputs from awareness of contact with the floor through the skin, joint position awareness, muscle tone awareness
Take great care when walking on soft rugs, carpeted floors, sand or loose gravel and other uneven surfaces. Make sure, the floors at home are free from obstructions. Maintain a clear path to your bathroom and move away all objects along the floor that could entangle your feet or injure you, should you have a fall. Most important, do not place yourself in a situation where you might lose your balance and be at risk of falling and serious injury; stay off chairs, stools, ladders, roofs. Exercise special care in the kitchen, near an open flame. Take extra care crossing roads, avoid sitting on two wheelers and avoid heights.