CURRENT CONCEPTS ON COMPLEX ISSUES
CUTTING EDGE COCHLEAR IMPLANTS AND IMPLANTABLE HEARING DEVICES —William M. Luxford, MD, House Ear Clinic, Los Angeles
| Middle ear implants: many mechanical problems with devices over last 5 yr; Symphonix Vibrant SoundBridge—most commonly used in United States; similar to cochlear implant, with external transmitter, internal transmitter, and implanted receiver attached by electrodes to incus with floating mass transducer; electrical input stimulates ossicular chain directly, depositing information in inner ear; now made in Europe; newer devices available in United Sates in 2005 |
| Indications for SoundBridge: moderate sensorineural loss; higher number indicates worse hearing; 100 decibels (dB) indicates profound loss; older individuals have trouble with high-frequency loss; older hearing aids had difficulty in selectively amplifying higher frequencies; using SoundBridge did not affect residual hearing but improved sound quality (compared to “regular hearing aid”); device popular because it decreased feedback and occlusion effect of having hearing aid in ear |
| Electroacoustic device: hybrid of cochlear implant and hearing aid; cochlear implant stimulates higher frequencies, hearing aid stimulates lower frequencies; shorter electrode of cochlear implant does not damage inner ear and preserves lower frequencies |
| Bone-anchored hearing aid (BAHA): used for single-sided deafness, chronic ear problems, or malformations; stimulates same side through abutment of stimulator; for patients with single-sided deafness, BAHA transforms into bone-anchored cochlear stimulator; placed on deaf side and stimulates cochlea on opposite side; requires “very good” hearing on opposite side; eliminates head shadow effect, occlusion, and feedback; patients prefer device; different from cross-aid device, where microphone attaches on nonhearing side, signal crosses head to hearing ear, and sound has no directionality |
| 3M/House single-channel implant: used in patients with bilateral deafness; now called single-channel ALLHear device |
| Cutting-edge advances: neural response telemetry and neural response imaging—reduce time for fitting device, especially in infants and young children; enhance “real-time fitting,” so signal processor fitted during surgery, enabling patient to use device immediately; smaller surgical incision, less distance between external transmitter and internal receivers allow quicker setup times; bilateral cochlear implants—provide improved sound localization, speech understanding in noise; requires same make and model of implants to combine stimulation; age for implanting cochlear implants has decreased to 1 yr (from ≥2 yr); in special cases (eg, meningitis), electrode implanted at <1 yr; younger implantees do better; study comparing hearing outcomes in 6-mo to 12-mo infants vs 18-mo to 2-yr olds; some hearing aid information suggests that patients receiving hearing aid at 6 mo do better; bilateral implantation occurring in infants in European programs; questions whether this creates negative or positive effect on hair cell regeneration (eg, will it cause cochlear receptivity problem with future scientific advancements; will electrode stimulation enhance hair cell viability and allow drug delivery to cochlea); totally implantable hearing aids and cochlear implants—will depend on battery and microphone technology; at present, magnetic resonance imaging (MRI) cannot be used because of magnet; magnet can be surgically removed before MRI, then replaced; auditory brain stem implant (ABI)—initially for patients with neurofibromatosis type 2 (NF2), advanced from single- to multichannel surface to multichannel penetrating electrode (investigational); hope that penetrating probe will provide access to areas for high, middle, and low sounds; ABI safe, patients receive input similar to single-channel cochlear implant (have sound awareness); some patients receive benefits similar to multichannel implant and have more than sound awareness |
| HEREDITARY HEARING LOSS —Rick A. Friedman, MD, PhD, Clinical Professor, Department of Otolaryngology, Keck School of Medicine of the University of Southern California, Los Angeles and House Ear Clinic |
| Hearing loss: most common sensory deficit in world; 50% of octogenarians suffer some degree of sensorineural hearing loss; 50% of loss in children environmental (eg, ototoxic drugs, acoustic trauma, bacterial and viral infections); other 50% genetic (30% syndromic, 70% nonsyndromic); understanding molecular level of disease results in earlier testing, preventive health care, and ability to attack problems at biochemical level |
| Genetic annotations: DFNA—dominant nonsyndromic hearing loss that affects only ears and nothing else in body; DFNB—autosomal recessive nonsyndromic forms of hearing loss; x-linked—annotated DFN; mitochondrial (maternally) inherited hearing impairment |
| Environmental causes: Toxoplasma, rubella, cytomegalovirus (CMV), and herpes simplex virus major causes of congenital hearing loss; meningitis (formerly number one reason for cochlear implantation, now less common); congenital CMV causes variable and fluctuating hearing loss (adequately diagnosed only in neonatal period using IgM titers) |
| Genetic causes: determined by history; autosomal dominant pedigree—vertical transmission, affects every generation; autosomal recessive—more common, but more difficult to delineate genetic basis; x-linked hearing impairment—uncommon; males affected, females obligate carriers |
| Genetic mapping: must have ≥10 affected members in family; marker analysis (involves several hundred markers) enables identification of region of genome where disease gene lies; DFNA—51 genes mapped; functions involved include potassium homeostasis (important for endocochlear potential), gap-junction formation, unconventional myosins; DFNB— 39 genes mapped; more difficult to map because of geographically isolated populations (eg, India, Bali); overlapping genes—gene mutation in one region causes dominant inheritance, and mutation in another area causes recessive inheritance |
| Clinical significance: DFNA—postlingual and progressive (often to deafness); does not affect children; affects people in their 20s, 30s and 40s; DFNB—congenital and profound; children deaf; x-linked—variable; mitochondrial (maternally) inherited disorders 㪧/55 mutation makes people susceptible to aminoglycoside ototoxicity; 15% of US cases of aminoglycoside ototoxicity caused by this disorder; syndromic hearing loss—≈400 syndromes associated with hearing loss |
| Autosomal dominant syndromic disorders: Waardenburg syndrome type 1—dystopia canthorum hallmark; patients have wide-set canthi, white forelock, heterochromia ( 1 or 2 bright, Caribbean blue eyes); Waardenburg’s syndrome type 2—same as type 1 but without dystopia canthorum; 3 other Waardenburg’s syndromes—genetic testing available, but diagnosis clinical; branchio-oto-renal syndrome—responsible for 2% to 3% of childhood hearing impairment; genetic testing available; affects development of outer, middle, and inner ears, branchial clefts, and kidneys; Jervell and Lange-Nielsen syndrome—make diagnosis with electrocardiography (ECG); involved in potassium metabolism; involves 2 genes; associated with cardiac conduction abnormalities and sudden death in infants; NF2—schwannomin gene involved in growth control of Schwann cells; genetic testing available and useful when another affected family member has been tested and mutation known; otherwise, difficult to identify new gene mutation and provide accurate molecular diagnostic testing; MRI with contrast diagnostic |
| Autosomal recessive disorders: Pendred’s syndrome—euthyroid goiter and hearing loss; sulfate ion transporter; Usher’s syndrome type 1—congenital; profound hearing loss with abnormal vestibular function; type 2—congenital; mild to severe hearing loss with normal vestibular function; type 3—progressive hearing loss with progressive vestibular dysfunction; retinitis pigmentosa generally appears in second decade; early ophthalmologic evaluation with electroretinal potentials critical; fundoscopic examination not diagnostic until second decade; most common cause of deafness and blindness |
| Common forms of hereditary hearing loss: enlarged vestibular aqueduct—most common abnormality seen on high resolution CT of temporal bone; genetic basis in ≈50% of cases; same gene that causes Pendred’s syndrome, but different phenotype caused by mutation in different location; genetic testing available but positive in only 50% of cases |
| Autosomal recessive nonsyndromic hearing loss: most common form of genetic hearing loss; most common gene associated is DFNB1 (connexin 26); presents as prelingual deafness, sometimes with mild-to-profound hearing loss; no vestibular or radiographic abnormalities; fair amount of intrafamilial variability; caused by mutations in gap junction protein GJB2 (connexin 26); gene expressed in spiral ligament and spiral limbus, areas critical for potassium metabolism and recirculation to maintain endocochlear potential; in United States, mutations most commonly caused by deletion at position 35 (35deltaG); 3% carrier rate in United States; has surpassed cystic fibrosis as most common genetic disease carrier; distribution of deafness severe-to-profound or profound; hearing impairment not progressive; no sex difference because disease autosomal; intrafamilial variability (eg, if child has mild-to-moderate hearing loss, subsequent sibling with same mutation has 66% chance of having same phenotype, 34% chance of having profound hearing loss; if child has severe-to- profound hearing loss, affected sibling also more likely to have severe-to-profound loss); significant residual hearing; 40% of children with unexplained sensironeural hearing loss connexin 26-positive; deafness usually severe-to-profound, but many children have some preserved hearing; genetic testing available in United States for 35deltaG; degree of preserved hearing highly familial; children without preserved hearing do very well with cochlear implants (auditory nerve healthy) |
| Research conducted in speaker’s lab: otosclerosis—speaker believes measles not involved; 6 genes associated with disease; linkage analysis mapped to chromosome 16 |
| Diagnostic algorithm for unexplained hearing loss in children: history (eg, prematurity, toxic exposure, metabolic abnormalities, syndromic hearing loss), physical examination, and audiologic testing help characterize most children; for idiopathic unilateral hearing loss, high resolution CT of temporal bone recommended; study showed that as many as 40% had enlarged vestibular aqueduct; significant because 70% bilateral, and those children at risk for losing hearing after minor head trauma (eg, during soccer, baseball); speaker does not perform CT on young children because of need for sedation; speaker does not recommend contact sports for children with bilateral enlarged aqueducts and hearing; with unilateral enlarged aqueduct, trauma can lead to hearing loss in affected ear; all children with bilateral mild, moderate, severe, or profound sensironeural hearing loss deserve connexin 26 testing; test readily available, alleviates parental stress and need to conduct further testing; if results positive, refer to genetic counselor; informative Web sites include <geneclinics.org> and National Institutes of Health (NIH) Web site |
| RHINOGENIC HEADACHE —Michael Setzen, MD, Clinical Assistant Professor of Otolaryngology, New York University School of Medicine, New York City |
| Headaches: commonplace (70%-80% of population); $50 billion annual expenditure; responsible for 1% of annual patient visits; 30 million have migraines, 37 million have rhinosinusitis; “sinus headache” may be due to other conditions (eg, deviated septum, turbinate problems, concha bullosa); otolaryngologists often evaluate patients because of “sinus headache” complaints, headaches unresponsive to treatment, or nasal problems related to headache; majority of headaches migraine, although patients believe headaches sinus-related |
| Rhinologic causes: acute rhinosinusitis; anatomic variations (contact-type) cause headaches directly or in conjunction with sinusitis by blocking sinus ostia; variations include huge septal spur pressing against middle or inferior turbinate, concha bullosa, prominent ethmoid bullae, agger nasi cells, abnormally bent uncinate process; any of these can cause facial pain or headache; many studies have shown that medical and/or surgical intervention relieved symptoms |
| History: ask about congestion, drainage, facial pain, anosmia, fever, cough, ear fullness, precipitating factors; treatment by neurologist, temporomandibular joint (TMJ) specialist, or allergist? recommendations? effectiveness? headache history—location, duration, precipitating and relieving factors; visual aura? relation to stress |
| Diagnosis: nasal endoscopy, CT of sinuses; facial pain important factor in sinus disease, while headache minor factor; International Society of Headache characterization—purulent nasal drainage, abnormal x-ray findings, pain over one sinus simultaneously with headache; headache location important |
| Migraine headache: lasts 4 to 72 hr; unilateral, pulsating, moderate-to-severe intensity; may have associated symptoms of nausea, vomiting, and photophobia; may have nasal complaints (congestion, postnasal drip); pain caused by vasodilation of blood vessels in dura and cholingeric stimulation of nerve endings in nose; triggers—stress, fatigue, caffeine, alcohol, menses, altitude change |
| Examination: palpate sinuses (elicit tenderness); nasal endoscopy; if patient has pain at time of examination, resolution of pain after injection of vasoconstrictor in region of contact point provides useful information (eg, contact spur); routine examination not sufficient; must look at osteomeatal complex for sinus disease (eg, purulence, retroverted middle turbinate, septal spur, concha bullosa); inform patient that surgical correction of anatomic defect may resolve headaches; do not guarantee headache resolution |
| Treatment: aggressive treatment of infection or allergy; consider treating migraine; consult specialists; mild migraine—ibuprofen; moderate-to-severe migraine—triptans (safe in patient without cardiac disease); give one tablet, then another if no relief in 1 to 2 hr; key is to treat patient as soon as symptoms occur; if medical therapy fails and physician thinks contact points cause of problem, inform patient of risks, benefits, and alternatives, and perform septoplasty and/or correction of other anatomic abnormalities; endoscopic sinus surgery controversial |
Educational Objectives
| The purpose of this program is to provide the listener with information on use of implantable hearing devices, the nature and management of hereditary hearing loss, and rhinogenic headache. After hearing and assimilating this program, the clinician will be better able to: |
 | 1. List and discuss the indications for cochlear implants and other implantable hearing devices. |
| 2. Cite some recent advances in hearing devices. |
| 3. Review the causes, clinical significance, and manifestations of genetic hearing loss. |
| 4. Summarize the etiology of rhinologic headaches. |
| 5. Describe the examination and treatment of the patient with rhinologic headaches. |
Discussed on This Program
Botulinum toxin type A [Botox, Botox Cosmetic, Dysport] Eletriptan HBr [Relpax] Frovatriptan succinate [Frova] Naratriptan HCl [Amerge] Rizatriptan benzoate [Maxalt, Maxalt-MLT] Sumatriptan succinate [Imitrex] Zolmitriptan [Zomig]
Suggested Reading
Bitner-Glindzicz M: Hereditary deafness and phenotyping in humans Br Med Bull 63:73, 2002; Chorbachi R et al: Cochlear implantation in Jervell and Lange-Nielsen syndrome Int J Pediatr Otorhinolaryngol 66:213, 2002; Cui B et al: Refinement of the locus for non-syndromic sensorineural deafness (DFN2) J Genet 83:35, 2004; Del Castillo I et al: Prevalence and evolutionary origins of the del(GJB6-D13S1830) mutation in the DFNB1 locus in hearing-impaired subjects: a multicenter study Am J Hum Genet 73:1452, 2003; Felisati G et al: The role of the ear, nose and throat specialist in diagnosing headaches Neurol Sci 2:s83, 2005; Finsterer J, Fellinger J: Nuclear and mitochondrial genes mutated in nonsyndromic impaired hearing Int J Pediatr Otorhinolaryngol 69:621, 2005; Gantz BJ et al: Preservation of hearing in cochlear implant surgery: advantages of combined electrical and acoustical speech processing Laryngoscope 115:796, 2005; Kelly et al: Electrophysiological and speech perception measures of auditory processing in experienced adult cochlear implant users Clin Neurophysiol 116:1235, 2005; Khan AM et al: Histopathology of human cochlear implants: Correlation of psychophysical and anatomical measures Hear Res 205:83, 2005; Kiss JG et al: Neural response telemetry in cochlear implant users Int Tinnitus J 9:59, 2003; Lainez MJ et al: Effects on productivity and quality of life of rizatriptan for acute migraine: a workplace study Headache 45:883, 2005; Liu XZ et al: Audiological Features of GJB2 (Connexin 26) Deafness Ear Hear 26:361, 2005; Mafong DD et al: Use of laboratory evaluation and radiologic imaging in the diagnostic evaluation of children with sensorineural hearing loss Laryngoscope 112:1, 2002; Mauer J et al: Reliability of cochlear implants Otolaryngol Head Neck Surg 132:746, 2005; Mesolella M et al: Connexin 26 mutations in nonsyndromic autosomal recessive hearing loss: speech and hearing rehabilitation Int J Pediatr Otorhinolaryngol 68:995, 2004; Mir A et al: Mapping of a novel autosomal recessive nonsyndromic deafness locus (DFNB46) to chromosome 18p11.32-p11.31 Am J Med Genet A 133:23, 2005; Nolle C et al: Cochlear implantation after acoustic tumour resection in neurofibromatosis type 2: impact of intra- and postoperative neural response telemetry monitoring ORL J Otorhinolaryngol Relat Spec 65:230, 2003; Otto SR, Shannon RV: The multichannel auditory brain stem implant: performance in twenty patients Otolaryngol Head Neck Surg 118:291, 1998; Piazza V et al: Functional analysis of R75Q mutation in the gene coding for Connexin 26 identified in a family with nonsyndromic hearing loss Clin Genet 68:161, 2005; Ramadan HH: Nonsurgical versus endoscopic sinonasal surgery for rhinogenic headache Am J Rhinol 13:455, 1999; Scarupa MD et al: Rhinitis and rhinologic headaches Allergy Asthma Proc 25:101, 2004; Uyguner O et al: Frequencies of gap- and tight-junction mutations in Turkish families with autosomal-recessive non-syndromic hearing loss Clin Genet 64:65, 2003.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial relationship with the manufacturer or provider of any commercial product or service discussed. For this issue Dr. Luxford has disclosed that he is a consultant for the Medical Advisory Board of Cochlear Corp. and Advanced Bionics Corp. Dr Setzen has disclosed that he is a consultant for Gyrus ENT, BrainLab, Aventis , GlaxoSmithKlein, and Merck.
Drs. Luxford and Friedman addressed Clinical Frontiers in Otolaryngology, held January 21-22, 2005, in Los Angeles, sponsored by the Research Study Club of Los Angeles. Dr. Setzen addressed the New York Rhinology Update, held April 8-9, 2005, in New York, sponsored by New York University School of Medicine and Albert Einstein College of Medicine. The Audio-Digest Foundation thanks the speakers and sponsors for their cooperation in the production of this program.
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