Auditory function in raised intracranial pressure

Asymmetry and tuning shift of the cervical vestibular evoked myogenic potential indicate saccular dysfunction in idiopathic normal pressure hydrocephalus

OBJECTIVE

The purpose of this study was to investigate the effects of excessive cerebrospinal fluid (CSF) retention on the peripheral vestibular function and the inner ear fluid in patients with idiopathic normal pressure hydrocephalus (iNPH).

METHODS

In 25 patients with iNPH (14 females, age 65-88 years), cervical vestibular evoked myogenic potential (cVEMP) was measured before the spinal tap test. The asymmetry ratios (ARs) and tuning properties in 500 Hz and 1,000 Hz short-tone burst stimuli of cVEMP were evaluated. Furthermore, cVEMP was measured in an age-matched control group of 12 non-iNPH patients.

RESULTS

Seven (28%) iNPH patients exhibited a cVEMP asymmetry (AR > 33%). cVEMP tuning was significantly shifted to a higher frequency in the iNPH group than in the age-matched control group.

CONCLUSIONS

One-fourth of patients with iNPH had obvious saccular dysfunction. A high rate of a shift in cVEMP tuning in the iNPH group indicated that excessive CSF accumulation propagated to the endolymph and perilymph.

SIGNIFICANCE

Saccular dysfunction might be one of the possible causes of imbalance in iNPH, and the shift in cVEMP tuning may be a determining factor in the diagnosis and treatment strategy.

Positional nystagmus in middle ear cholesteatoma with labyrinthine fistula

Chronic otitis media with cholesteatoma can cause erosion of the dense labyrinthine bone overlying the inner ear organs, and this labyrinthine fistula allows pressure or mass-induced motion of the underlying perilymphatic and endolymphatic compartment, evoking vestibular symptoms. While the mechanism of a positive fistula test, which is conducted by increasing or decreasing the external auditory canal pressure, has been well established, the mechanism underlying positional nystagmus in labyrinthine fistula has not been discussed yet. In the present study, we propose a new hypothesis accounting for positional nystagmus in labyrinthine fistula involving the lateral semicircular canal (LSCC), i.e., the change in intracranial cerebrospinal fluid pressure by position change is transmitted to the perilymphatic space, causing ampullopetal (excitatory) or ampullofugal (inhibitory) deflection of the LSCC cupula.

Vertigo Induced During Coitus

Objectives: The aim of this study was to describe the clinical features of vertigo developed during sexual intercourse. Methods: We retrospectively reviewed the clinical and laboratory findings of seven patients who reported recurrent vertigo during sexual intercourse. Results: All the patients reported spinning sensation for a few minutes to 1 h, which developed during the coitus. Most patients (6/7, 86%) reported associated auditory symptoms including tinnitus (n = 4), ear fullness (n = 2), autophony (n = 1), hearing impairment (n = 1), or hyperacusis (n = 1). Four patients reported the vertigo to occur exclusively during sexual intercourse or masturbation while the other three patients also experienced vertigo during other physical activities. Underlying disorders included Meniere's disease (n = 3), superior canal dehiscence (n = 1), and high jugular bulb anomaly (n = 1) while the remaining two patients had no identifiable causes. Conclusions: Various disorders may cause coital vertigo probably due to disruption of the mechanism that normally refrains the increased intracranial pressure from being directly transferred to the peripheral vestibular organs.

Asymmetric hearing loss and chronic dizziness in a patient with idiopathic normal pressure hydrocephalus

We report a case of a 54-year old female patient, complaining for chronic dizziness, hearing loss, tension headaches without aura, postural instability and gait dysfunction. The patient referred having these symptoms from 1992, but the last few months she experienced a noticeable aggravation of the symptoms. A magnetic resonance imaging test revealed a triventricular hydrocephalus, not associated with signs of intracranial hypertension decompensation. The ENT-Audiology evaluation revealed a bilateral sensorineural hearing loss with a conductive component, video-nystagmography resulted in an areflexia of the right ear and a reduced vestibular activity for the left ear. Auditory brainstem response test was also carried out and showed pathologic findings for the latencies of the waves I-III, III-V and I-V bilaterally but more significant in the right ear. On January 2016 the patient had endoscopic third ventriculostomy. On the follow up the patient referred an important subjective improvement regarding instability and gait dysfunction. In this paper we study the correlation between hydrocephalus, hearing loss and vestibular dysfunction.

Acute Deafness: A Rare Complication of Shunting

BACKGROUND

Mild hearing loss following shunting has been described; however, severe auditory impairment associated with ventriculoperitoneal (VP) shunt is an uncommon, rarely reported phenomenon. Treatment options and pathophysiologic considerations are discussed in this case report.

CASE DESCRIPTION

A 27-year-old man who was treated for an eighth cranial nerve schwannoma with complete resection and a VP shunt 10 years previously presented to the emergency department with acute severe hearing loss and headache. Imaging showed diminished size of the ventricles and dural contrast enhancement. The previous shunt was replaced with a programmable antisiphoning VP shunt. The patient's hearing and headache improved 48 hours later, as demonstrated in serial audiograms.

CONCLUSIONS

Hearing loss is an underestimated complication of shunting that in some cases may progress to severe impairment and deafness. Patients with a VP shunt who experience hearing loss should undergo further evaluation and possibly adjustment of shunt settings.

Resolution of bilateral sensorineural hearing loss following ventriculoperitoneal shunt and literature review

OBJECTIVE

The purpose of this study is to highlight the relationship between obstructive hydrocephalus, changes in intracranial pressure, and sensorineural hearing loss.

METHODS

A case of a 10-month old infant with sensorineural hearing loss secondary to obstructive hydrocephalus is reported. A literature review, with a focus on sensorineural hearing loss in the setting of changes in intracranial pressure, was performed.

RESULTS

The authors report the case of a 10-month old infant with metopic and bicoronal craniosynostosis who presented with bilateral moderately severe sensorineural hearing loss after failing newborn hearing screening. Imaging subsequently demonstrated obstructive hydrocephalus, which was treated with the insertion of a VP shunt. The patient had immediate improvement of her hearing post-operatively, with repeat hearing tests showed resolution of her hearing loss.

CONCLUSION

Sensorineural hearing loss is a rare complication of hydrocephalus, but changes in intracranial pressure should be considered in the differential diagnosis. We put forth a flow diagram illustrating the hypothesized relationship between intracranial pressures, alterations in the levels of cochlear fluid, and hearing.

A new possible mechanism of hearing loss after microvascular decompression for hemifacial spasm

OBJECTIVE

Hearing loss is a well-known complication that may occur during microvascular decompression (MVD) for hemifacial spasm (HFS). Cause and risk factors are highly variable. We present cases of hearing loss induced by saline overinfusion after MVD.

STUDY DESIGN

Retrospective review in a tertiary referral center.

INTERVENTION

Three hundred thirty-one patients with HFS underwent MVD from March 2009 to October 2010.

MAIN OUTCOME MEASURES

Brain stem auditory evoked potential (BAEP) was monitored during the surgery. Before completion of the dural closure, the surgical field was routinely filled with warm saline to avoid postoperative pneumocephalus and epidural hematoma.

RESULTS

Seven patients experienced a change in wave V amplitude and latency after the dural closure. In 2 patients, the amplitudes decreased by less than 50%, and latencies were delayed by less than 1.0 ms, ipsilaterally in 1 patient and contralaterally in the other. In 1 patient, decreased amplitude and delayed latency appeared bilaterally with more severity on the operated side, accompanied by delayed ipsilateral permanent hearing loss. In 4 of the 7 patients, an ipsilateral response of BAEP was completely absent. Of these 4 patients, 2 experienced permanent hearing loss, and another 2 patients who underwent dural reopening and saline drainage had restoration of their normal hearing.

CONCLUSION

Intradural compression due to overinfusion of saline may lead to postoperative hearing loss, although the incidence is low, and immediate decompression by drainage may be required.

Modified brain stem auditory evoked potentials in patients with intracranial mass lesions

The authors report their experience utilizing a recently described rapid rate, binaural click and 1000-Hz tone burst modification of the brain stem auditory evoked potentials (BAEP), modified (MBP), in 27 symptomatic patients with non-brain stem compressive space-taking cerebral lesions (22), hydrocephalus (4), and pseudotumor cerebri (1).  Many presented with clinical signs suggestive of increased intracranial pressure (ICP) and focal neurological deficits. The cerebral lesions, mostly large tumors with edema, had very substantial radiological signs of mass effect. Fourteen patients were also studied following surgical decompression. A number of significant changes in the wave V and Vn latency/intensity and less so amplitude/intensity function was found in the 27 patients, compared to normal volunteers, as well as those studied pre- and postoperatively. Similar MBP changes had been noted in normal volunteers placed in a dependent head position. Possible mechanisms to explain these findings are discussed.  The MBP methodology shows promise and further development could make neuro-intensive care unit monitoring practical.

Cerebrospinal fluid shunting and hearing loss in patients treated for medulloblastoma

OBJECT

Cerebrospinal fluid shunting has previously been associated with hearing loss. Although the mechanism for this is unclear, it is thought that changes in CSF pressure can affect cochlear physiology via endolymph expansion in the setting of a patent cochlear aqueduct. Patients undergoing radiation and cisplatin chemotherapy are at risk for hearing loss. The authors hypothesized that the incidence and severity of hearing loss in patients undergoing radiation and chemotherapy for medulloblastoma would be greater in those with shunts than in those without shunts.

METHODS

Baseline and longitudinal audiology data were collected in 33 patients with medulloblastoma who were receiving radiation and cisplatin chemotherapy. Additional data included age, sex, details of shunt placement and revision, and details of chemotherapy and radiation. Hearing sensitivity and peripheral auditory function measures included pure tone audiometry, immittance audiometry, and distortion product evoked otoacoustic emissions. Ototoxicity was determined according to the American Speech-Language-Hearing Association criteria. Severity of hearing loss was determined using the Brock hearing loss grades. Incidence of hearing loss and association with shunting was determined.

RESULTS

Thirteen (39.4%) of the 33 patients evaluated had undergone shunt placement. Hearing loss occurred in 14 (70%) of 20 patients without shunts and in 13 (100%) of 13 patients with shunts. The difference between the rates of hearing loss in patients with shunts versus those without the devices was highly significant (p = 0.0008). The odds ratio for hearing loss in patients with a CSF shunt compared with those without a shunt was 23.49 (95% CI 4.21-131.15). Age, side of shunt, evidence of dissemination, diameter of cochlear aqueduct, and treatment protocol did not have a significant effect on shunt-related ototoxicity.

CONCLUSIONS

This study suggests an independent association between CSF shunting and hearing loss in children undergoing treatment for medulloblastoma, laying the foundation for a prospective study evaluating hearing loss in children with shunts who are not treated with ototoxic therapy.

Resolution of hydrocephalus-associated sensorineural hearing loss after insertion of ventriculoperitoneal shunt

The authors present a pediatric patient with severe hearing loss due to communicating hydrocephalus. This is the first clearly documented case of de novo sensorineural deafness caused by hydrocephalus, with subsequent improvement in hearing after shunt insertion. The patient initially presented with otitis media and was found to have hearing loss. After reporting ongoing headaches, he received a diagnosis of communicating hydrocephalus, which was treated with the insertion of a ventriculoperitoneal shunt. Formal hearing tests showed dramatic improvement postsurgery; his hearing was normal at 2 months. At 3 years postsurgery the patient's hearing remains within normal limits. Hearing loss is a rare complication of hydrocephalus. Based on this case, the authors suggest that the diagnosis of hydrocephalus be considered as a cause of unexplained hearing loss, and conversely, that patients with hydrocephalus might benefit from hearing assessment.

High-temperature, but not high-pressure, conditions alter neuronal activity

We describe the effect of high pressure and high temperature on neuronal activity. Increased intracranial pressure is generally a pathological sign observed in intracerebral hemorrhage, brain edema, and brain tumor, yet little is known about how the hyperbaric pressure per se affects neuronal activity. Using a pressure/temperature-changeable perfusion chamber, we carried out functional multineuron calcium imaging to record spontaneous spiking activity simultaneously from about 100 neurons in hippocampal slice cultures. High-pressure conditions (up to 100 mmHg) did not alter the network excitability, whereas high-temperature conditions (up to 40 degrees C) increased synchronized network activity. Thus, neurons are sensitive to feverish conditions, but the acute hyperbaric circumstance itself is unlikely to exert a detrimental effect on neuronal function.

Disappearance of Hemifacial Spasm After Ventriculoperitoneal Shunting in a Patient With Achondroplasia-Case Report-

A 15-year-old boy with achondroplasia developed right hemifacial spasm associated with headache, vomiting, and hearing disturbance. Computed tomography showed hydrocephalus. A ventriculoperitoneal shunt was placed. His hydrocephalus subsequently resolved, the hemifacial spasm and headache disappeared, and his hearing disturbance improved. The episodes of hemifacial spasm were probably related to a small posterior cranial fossa volume, the so-called crowding of the posterior fossa. Increased intracranial pressure due to hydrocephalus apparently contributed to further reduction in the posterior cranial fossa volume and led to the hemifacial spasms. In addition, his hearing disturbance may have been the result of dysfunction of the cochlear nerve due to the increase in intracranial pressure caused by hydrocephalus.

Reversible hearing loss associated with a malignant pineal germ cell tumor. Case report

In patients with pineal tumors, clinical symptoms are due to direct compression of adjacent structures. The most common signs include increased intracranial pressure (80%) caused by obstruction of the sylvian aqueduct, and Parinaud syndrome (50%) caused by direct compression of the superior colliculi. Hearing loss is rare in patients with tumors in this location. The authors report on the case of a 12-year-old boy in whom a malignant pineal germ cell tumor was found together with the unusual occurrence of severe hearing loss due to direct bilateral compression of the inferior colliculi. This condition resolved completely after tumor regression.

Pineal region tumor manifesting initially as hearing impairment

An 18-year-old male presented with a pineal region germinoma with hearing impairment as the chief complaint. Magnetic resonance image demonstrated a well-enhanced multi-cystic tumor extending into the upper fourth ventricle and wall of the bilateral lateral ventricles. Audiometry revealed bilateral mild hearing impairment in the low frequencies. Auditory brainstem response recording showed low amplitudes in all waves (IV-V/I ratio < 1) with prolong latencies (I-V and III-V) on the right but no discernable wave at 60 dB clicks on left. Hearing impairment and audiometric findings were improved after ventriculoperitoneal shunt operation. The hearing impairment appeared to be a mixed (conductive and sensorineural) type. The tumor was responsible for the sensorineural deafness because of invasion and compression of the central auditory structures. The inferior brachium was maximally compressed anterolaterally by the dilated bilateral lateral ventricles and posteromedially by the tumor. Hydrocephalus caused conductive deafness by halting or arresting the footplate of stapes movement, as a consequence of high-pressure transmission through the cochlear aqueduct.

Late dissemination of fourth ventricle ependymoma: a case report

Dissemination of benign ependymoma is relatively rare, especially when a local tumor is under control. The majority of the failures take place within a few years after surgery. However, we experienced a case in which multiple spinal cord dissemination was found 13 years after resection of the fourth ventricle ependymoma without a local failure. A 38-year-old man had undergone a subtotal resection of the fourth ventricle ependymoma and radiation therapy to the posterior fossa when he was 25 years old. Follow-up MR imaging repeated once every one or two years detected no recurrence until he began to complain of lumbago and numbness of the right foot 13 years after the surgery. MR imaging revealed multiple nodules along the whole spinal cord. Examination of the cerebrospinal fluid detected tumor cells with ependymal cell features. He underwent radiation therapy to the whole spine, and remained stable at 18 months after the therapy. This case alerts us to the necessity for long-term radiological follow-up including the spinal cord even in benign ependymomas, although it is still not certain for how long and how often we should do it.

Analysis of hearing loss after shunt placement in patients with normal-pressure hydrocephalus

OBJECT

Following shunt placement for treatment of normal-pressure hydrocephalus (NPH), several patients suffered hearing loss. The authors undertook a study to analyze this outcome.

METHODS

Sixteen patients in whom NPH was diagnosed were treated by placement of a ventriculoperitoneal shunt. Their hearing was assessed pre- and postoperatively by using pure tone audiometry. Two thirds of the ears tested showed a postoperative hearing loss of more than 10 dB. Recovery of the hearing loss occurred 6 to 12 weeks after shunt placement in 75% of the ears examined.

CONCLUSIONS

Although shunt insertion for treatment of NPH results in a decrease in hearing, most of the loss can be recovered.

Why monitor perilymphatic pressure in Menière's disease?

A cohort of 39 patients with confirmed raised intracranial pressure was investigated. Of these patients, 24 (62%) complained of tinnitus and 11 (28%) suffered from paroxysmal rotary vertigo. Intracranial hypertension can occur without the usual headache and visual symptoms. In such cases, the patient may be referred to the otolaryngological clinic and the condition may be mistaken for Menière's disease or a labyrinthine disorder. The Tympanic Membrane Displacement (TMD) technique now provides a non-invasive method of monitoring the intracranial and perilymphatic pressures. This study provides recommendations for the use of TMD techniques in the otolaryngological clinic for screening, diagnosing and monitoring treatment of patients presenting with raised perilymphatic pressure.

Bilateral cavernous sinus thrombosis causing Korsakoff's amnesic syndrome

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Cochlear and cerebrospinal fluid pressure: their inter-relationship and control mechanisms

The patency of the cochlear aqueduct is a key factor in intra-cochlear hydromechanics. If patent, the cerebrospinal fluid (CSF) provides the reference pressure for the perilymph and also to a large extent the endolymph, since Reissner's membrane can only withstand a relatively small pressure differential. The aqueduct often becomes sealed as a natural process of ageing. In this instance the reference pressure is from a source, its position unknown, within the boundaries of the cochlea itself. Relatively large and rapid changes in the cerebrospinal fluid pressure may result from everyday events such as coughing (ca. 175 mm saline) and sneezing (ca. 250 mm saline). The resistive nature of the cochlear aqueduct and the mechanical compliance of the cochlear windows are probably important factors in limiting the amount of stress, and therefore possible damage, which may occur to the cochlea and cochlear windows for a given pressure change within the CSF system. A narrow aqueduct and compliant cochlear windows reduce the risk of structural damage. In practice, this should mean that the risk of structural damage will be increased by any process which reduces the compliance of one or both of the cochlear windows, for example, extremes of middle ear pressure perhaps brought about by Eustachian tube dysfunction or rapid barometric pressure changes. Techniques are now available which provide non-invasive indirect measures of perilymphatic pressure and CSF-perilymphatic pressure transfer. The tympanic membrane displacement measurement technique has been used to provide reliable measures of perilymphatic pressure and CSF-perilymphatic pressure transfer on an individual subject basis.(ABSTRACT TRUNCATED AT 250 WORDS)

The relationship between intracranial pressure and tympanic membrane displacement

Transmission of intracranial pressure (ICP) to the perilymph of the cochlea may occur via the cochlear aqueduct and possibly other routes. Indirect measurement of perilymphatic pressure may be investigated by observing tympanic membrane (TM) displacement during stapedial reflex contraction. In a previous study we investigated the effects of changes in ICP on perilymphatic fluid pressure in three patients who underwent ventriculo/lumbar-peritoneal shunt operations. The TM displacement technique proved extremely sensitive and revealed marked changes in cochlear fluid pressure brought about by changes in ICP (Marchbanks et al., 1987). The study has been extended to 58 patients with hydrocephalus, intracranial tumours and other neurological conditions associated with abnormal ICP. Significant differences in the TM displacement were found between patients with raised and normal ICP. We have shown that changes in ICP can affect the hydrostatic pressure of the cochlea and influence the peripheral auditory system. The finding that ICP can be correlated with TM displacement strengthens the association between an abnormal TM displacement and abnormal cochlear hydrostatic status, irrespective of cochlear aqueduct patency. We suggest that the TM displacement technique provides a useful non-invasive method for the assessment of perilymphatic fluid pressure.

Otologic manifestations of benign intracranial hypertension syndrome: diagnosis and management

Benign intracranial hypertension (BIH) is a syndrome characterized by increased intracranial pressure (IIP) without focal signs of neurological dysfunction. The diagnosis is essentially made by exclusion of various causes of IIP. The classic presenting symptoms of BIH are headache and/or visual disturbances. Otologic manifestations of this syndrome have not been described in detail. In this thesis, 20 BIH patients with associated otologic symptoms were thoroughly studied over a 5-year period. The author concludes that 1. objective pulsatile tinnitus and low frequency hearing loss can be the major or only manifestation of this syndrome; 2. diagnosis is established by lumbar puncture and elimination of other causes of IIP; 3. medical management is very effective with surgery reserved for patients with deteriorating vision or with disabling tinnitus.

Intracranial pressure and auditory evoked responses of the cat

Auditory evoked responses (AERs) were recorded from the primary cortex, medial geniculate body (MG), inferior colliculus (IC) and cochlear nucleus (CN) of the cat anesthetized with sodium pentobarbitone to examine the effects of increased intracranial pressure (ICP) on neural activity in the different levels of auditory centres. ICP was increased by injecting saline solution into the intracranial space and a tone burst was used for activating the auditory centres. Cortical response (ACR) began to decrease in amplitude from about 30-40 mmHg of ICP. A decrease in amplitude of MG response and that of IC response followed in the order with a further increase in ICP. CN response was most resistant and usually remained even when ACR and MG responses were totally abolished. Recovery of the AERs followed a release of the increased pressure in the reversed order to the decrease in the AERs. When an increase was repeated with a short interval of pressure release such as 5 to 10 min, recovery of ACR became much slower and no recovery was sometimes observed 30-60 min after the release of ICP increased to a level below 100 mmHg. A discussion was conducted on the origin of the changes in AERs in response to increased ICP. We concluded from the results that the higher auditory centres are more susceptible to an increase in ICP to suppress the neural activities without apparent influence on the lower centres. A clinical test of ABR may be available to predict the prognosis of the auditory disorders.

Otologic symptoms and findings of the pseudotumor cerebri syndrome: a preliminary report

Pseudotumor cerebri or benign intracranial hypertension is a syndrome characterized by increased intracranial pressure without focal signs of neurologic dysfunction. The clinical manifestations of this syndrome are usually headache and/or disturbance of vision. Although tinnitus, hearing loss, and vertigo have been described in association with intracranial hypertension, otologic symptomatology as the presenting manifestation of this syndrome has not been previously reported. In this article we report the otologic symptoms and findings of two pseudotumor cerebri patients, one of whom presented with pulsatile tinnitus. The pathogenesis of the otologic symptoms, diagnostic workup, and management of these patients are discussed.

The effect of intracranial hypertension on cochlear blood flow

The cochlear blood flow was investigated in rabbits with the microsphere method before and during an induced increase of intracerebral and intracochlear pressures. The increase was accomplished by infusing Ringer solution into the lateral cerebral ventricles. The cochlear blood flow was found to autoregulate in response to decreases in perfusion pressures down to 5-6 kPa. This finding is discussed in relation to known effects of intracochlear and intracranial pressure on hearing.

Békésy audiometry in evaluation of hearing in cases of raised intracranial pressure

The paper reports findings in a Békésy audiometry study on 50 ears of 27 patients with raised intracranial pressure. The Békésy audiometry was done both preoperatively and after operation when the raised intracranial pressure had been controlled. The study showed a significant hearing loss in Békésy audiometry due to raised intracranial pressure. However, only low frequencies of 125-250-500 Hz showed a reversal of hearing loss which was statistically significant. The type II pattern of Békésy audiometry changed to type I after control of the raised intracranial pressure. The type IV and V patterns had a tendency to change to Békésy I or II, on control of the raised intracranial pressure.