cochlear implantation program among nigerians (black...

Pakistan Journal of Otolaryngology 2013; 29 : 62-66 Case Series

INTRODUCTION: Practicing otologists among theblack Africans have over the years been helpless inachieving meaningful rehabilitation of the profoundlydeaf who form a major part of their clinic as many ofsuch patients over the years return home with theirparents or guardians without any definite hope ofrestoration of their hearing or meaningfulrehabilitation within reach. Such was the commonexperience at the dedicated deaf clinic of our centerprior to the year 2008 as most sessions with patientsand parents end up with them crying out ofdisappointment. Worldwide, the journey out offrustration for the profoundly deaf started as early as1957, when Djourno and Eryies observed thatactivation of the auditory nerve with an electrifieddevice provides auditory stimulation in a patient1.Doyle and Doyle’s early experiments of 1963, on thescala tympani preceded the first House/3M singlechannel implant of 19722. Blair Simmons in 1964 atCalifornia succeeded in the surgical placement of a 6-electrode array in the modiolus of a human volunteer3.In 1984, the US food and drug administration (FDA)approved the use of the House-3M single-channelimplant, then the multichannel Nucleus 22-channelimplant for adults and then children in 1985 and 1990respectively. A multichannel cochlear implant consistsof two parts, a receiver stimulator implanted in thetemporal bone consisting of a receiver coil with anelectrode array inserted into the cochlea, and anexternal device. The three main components of theexternal device are the microphone, speech processorand a transmitter coil conveying signals from theprocessor across the skin to the electrode array (Figure

1). The microphone picks up sounds and transfersthem to the speech processor. These sound signals areanalyzed and converted to a form suitable fortransmission by the processor. In most devices thesetransformed signals reach the electrodes by radio-frequency transmission from the transmitter coilresting on the head to the implanted receiver coil.Profound deafness in the majority of cases resultsfrom damage to the sensory cells in the 'Organ of Corti'in the inner ear, due to various causes. CI helps thisgroup of patients since it bypasses the damaged partof the auditory pathway and stimulates the survivingspiral ganglion cells directly with electrical signals.The aim of this was to simulate the activity of normalcochlea, by stimulating the tonotopically arrangedsurviving neural elements resulting in a significantimprovement in the speech perception capability. Thevarious efforts made to improve on the multichannelimplant have led to the development of this fullspectrum implant used in this series. The cochlearimplant is the only medical intervention that canrestore hearing to a totally deaf person, as of April2009, approximately 188,000 people worldwide hadreceived cochlear implants4. In the United States,about 40,000 adults and over 30,000 children arerecipients5. Whereas, in the sub-Saharan Africa thereis no documentation of any cochlear implantationcompletely programmed locally until this report. Manyreasons can be adduced for this, ranging frommanpower, the technical skills, as well as the cost.The cost of implant device alone, excluding surgeryand rehabilitation, is priced between US $15,000 andUS $35,000 depending on the implant type and the

Cochlear Implantation Program Among Nigerians(Black Africans)

Otorhinolaryngology Department, College of Health Sciences, Obafemi Awolowo University, Ile-Ife, Nigeria.

ABSTRACT: OBJECTIVE: We report the first ever Cochlear Implantation (CI) program among theNigerians (black Africans), using the short electrode implant and the minimal access surgery technique,the peculiar challenges encountered as a developing country are also discussed. PLACE AND DURATIONOF STUDY: Department of Otorhinolaryngology, College of Health Seiences, Obafemi Awolowo University,Ile-Ife, Nigeria, during Jun 2008 and May 2011. PATIENTS & METHODS: We retrospectively reviewedthe case notes of the eight patients who had CI followed by speech rehabilitation between 2008 and 2011in our centre. We obtained information on demography, socioeconomic status, source of funding for theimplant, clinical presentation, aetiology, high resolution petromastoid computerized tomography (HRCT),surgery, outcome of surgery, and rehabilitation. RESULTS: Eight patients were implanted in this study,onset and etiology of the deafness varied. All had a successful implantation with no major postoperativecomplication noted and they developed environmental sound awareness and speech discrimination witha variable degree of expressive language where applicable. Outcome in the postmeningitic deafness wasalso impressive despite minimal cochlear fibrosis. CONCLUSION: Our CI was effective for auralrehabilitation of profound sensorineural hearing loss caused by all the etiological agents in this review.We had various challenges ranging from logistics, facilities, manpower, others related to our poor resourcesetting. As cochlear implant technology evolves and surgical techniques continue to improve, our centerwill continue its efforts to provide effective hearing.Key Words: : Cochlear implant, Short electrode, Black Africans, Challenges.

Y.B. Amusa, A.O. Adeniji, J.A.E. Eziyi, T.O. Olarinoye, A.O. Adeyemo, Grace Ogunniyi

Cochlear Implantation Program Among Nigerians (Black Africans)

(OAE), Auditory Brainstem Evoked Response (ABR),high resolution petromastoid computerized tomography(HRCT) to establish the patency of the cochlea6,implant type, surgical procedure, outcome of surgery,complications and speech rehabilitation from thepatients’ case files. The outcome after speechrehabilitation was divided into six depending onwhether the patients did not respond to sound,responded to sound at low frequencies only, respondedto sound at high frequencies only, responded to soundacross all frequencies, developed reasonable speech,did not develop speech. Data regarding the age andaetiology of deafness of the study group are as shownin Table 1.THE DEVICE: The cochlear implants are surgicallyimplantable electronic devices for stimulating thespiral ganglion via the cochlea in hearing impairedpatients. They are manufactured by a few companiesworldwide and are in Australia, Austria, France, SouthKorea, Spain and United States of America. The cost-effectiveness of the device and the surgery remainsthe major factor considered in determining who amongthe many potential candidates get implanted. The CItype ienjoysound(ies)-250 manufactured by MaterialSolutions Technology Co., Ltd. of South Korea wasimplanted in all the patients. It is simple, cost-effective;it has a short electrode and provides a full spectrumof hearing as well as the preservation of residualhearing of the patient. The relatively simple techniqueof implantation makes it easier for relatively youngerotologists with less experience in inner ear surgeries.Presence of after sale service also made it morereassuring to us. The products are approved by CE,KFDA and ISO.THE TEAM: Our CI team comprised of the ENTsurgeon, Audiologist/ Speech therapist, Psychologist,Social workers, Radiologist, Pediatricians, Teachersfor the deaf, Psychiatrists, Neurologist, Anesthetist,and Implant nurses. Our team had to bear severalburdens but majorly resting upon the surgeon and thespeech therapist. Absence of the diagnostic facilitiesnecessary for the preoperative assessment of theimplant patient was an initial task for the patientsand the team. Fund was as always a major problemwe had to contend with. The team was headed by theHead of Ear, Nose and Throat Surgery; an Otologist,supported by other ENT surgeons and resident doctors.All surgeons had earlier repeated refresher coursesin temporal bone dissection anchored by local andinternational faculties, so as to get more acquaintedwith middle and inner ear anatomy, and surgicaltechniques. Our audiologist who performed the speechtherapy had special overseas training course forrehabilitation of the cochlear implant patients. Othermembers of the team were encouraged to participatefully, especially the social worker for follow up of thepatients. We had a robust technical support by themanufacturer especially at the initial period.INTERVENTION:(A) PRE-OPERATIVE EVALUATIONS. This includedthe Pure tone audiometry, Free field audiometry,Otoacoustic emission (OAE), Auditory brain stemresponse (ABR) testing were ordered as required.Complete medical history and physical examination

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specific market. Arguably due to this high cost,majority of the beneficiaries are in the advancedcountries of the world. Presently cochlear implantprogram is already in Egypt, Republic of South Africaand recently Nigeria which we now report.According to the World Health Organization (WHO),more than 80% of the world’s 120million people whohave disabling hearing difficulties live in developingcountries. With a personal average annual income ofwell below US $2,000, the present cochlear implantis virtually unavailable for deaf people in developingnations especially the black Africans. This articledocuments the Nigerian experience (the black Africans)with the cochlear implantation program as a resourcechallenge country without any previous national policyfor this program.PATIENTS AND METHODS: We retrospectivelyreviewed the case file of the 8 patients who had cochlearimplantation done followed by rehabilitation in ourcentre. The study period was between June 2008 andMay 2011.We obtained information on the patients’bio data, clinical presentation, diagnosis, Pure ToneAudiometry, Tympanometry, Otoacoustic emission

Figure 1: Cochlear implant.

Figure 2: During and after surgery.


but, via a minimal postauricular incision, with raisinga tympanomeatal flap followed by mobilizing thefibrous annulus of the tympanic membrane out of thetympanic sulcus. From here the promontory isidentified and using the skeeter drill, the cochleostomyperfomed and from here only about 6mm of the tip ofthe electrode of the cochlear implant is inserted (shortelectrode insertion). Both the technique of the surgeryand the technology of the implant are simpler, andposes no danger to the facial nerve and preservesresidual hearing of the patient because only a shortportion of one electrode is implanted into the base ofthe cochlea using the iES 250 device.RESULTS : Eight patients had cochlear implantationfollowed by rehabilitation over the study period. Agerange at implantation was between 14 months and 19years (see Fig. 3). mean age was 8 years. There were5 males and 3 females; sex ratio was 5:3 (Fig. 4). Themale preponderance in this study is consistent withprevious similar studies in West Africa10. Onset ofdeafness: Pre, Peri and Post lingual is depicted in Fig.5.AETIOLOGY: The predominant causes of deafnesspreventable causes as 7 out of the 8 patients who hadthe implantation had acquired deafness. Workers inthis environment had earlier found acquired deafnessto be the most predominant11. Measles was the causein 12.5% of our patients and this is comparable witha figure of 19.3% in the causes of childhood deafnessin Nigeria12 and more recently 13.9%13. Meningitis isstill a major cause of preventable deafness as it is saidthat 15% of patients who survive acute bacterialmeningitis develop neurological sequelae, andpermanent sensorineural hearing loss account forapproximately 75% of these cases11,14.POST IMPLANT RESPONSE: Implantation of thedevice is usually followed by its switch on and mappingafter a period of 6weeks, however ‘switch on’ wasdone within 24 hrs- 5days post-operatively in all ourpatients and it was successful in all the patients, thisis because of the simple nature of the procedure withminimal raising of flap and therefore less oedema overthe internal device. The ‘switch on’ was followed by afinal ‘hook on’ and mapping This is then followed bythe auditory verbal training which is given by thespeech therapist intensively. At the initial switch onand the final hook on and mapping, response was100% as all the patients responded to sound. The

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were performed to ensure that the patient was fit foranaesthesia and to rule out other congenital anomalies.A full head and neck examination was also carriedout to rule out the presence of an active middle eardisease. Examination of all other systems especiallythe eye was done in the congenital deafness and thecerebral palsy. Computerized tomography scan wasdone to image the structure of the cochlea and identifyany abnormalities or malformation. It had been saidthat severe abnormalities may present surgicalchallenges but do not necessarily preclude patientsfrom CI surgery. One case of cochlear fibrosis wasfound in the patient with meningitis. Psychologicalevaluation was also carried out to assess the child’scognition function to rule out factors other than hearingimpairment which may be inhibiting child’s auditorydevelopment such as learning disorder. Neurologicalevaluation was also done by the other members of theteam. The patients and relations were adequatelycounseled on expectation and a specially prepared andadministered informed consent document was obtainedbefore surgery.(B) SURGERY: The hypotensive general anaesthesiawas employed in all the cases as widely used7. Theconventional cochlear implantation procedure involveseither a cortical mastoidectomy and facial recessapproach8, or a cortical mastoidectomy and hypo-tympanotomy approach9 to access the promontory,this however usually necessitates raising of a largescalp flap, also the facial nerve is at risk of damage.One of the unique features of this implant is that thesurgical procedure for the implantation was by thesimplified and less invasive minimal access techniquein which neither of the usual approaches were used

Males

Females

Figure 3: Age at implantation (Yrs). Figure 4: Sex distribution.

Figure 5: Onset of deafness.


these patients who had post meningitic deafness, hisunderstanding of speech did not occur as fast as heexpected and he wanted to sit for the post universityexamination interview, he was however promptlyattended to by the other members of the team, in thesecond patient it appeared to be constitutional. Twoof the patients were not complying with rehabilitationappointments; this still occurred despite usingacceptable standards for our candidacy. Externalauditory canal flap necrosis occurred in one of thepatients necessitating a supervised sterile clinic auraltoileting leading to re-epithelialisation within a fewweeks. Functioning of the implant (battery) was poorin one of the paediatric patient, and this was probablydue to erratic power supply for charging the implantbattery or the use of direct current (generator) tocharge the implant battery, or both and this had beenreplaced the company. There was no case needing re-implantation. The simple nature of the procedure;avoiding mastoidectomy, good candidate selection,preoperative preparation coupled with meticuloussurgery may be responsible for the good outcome andabsence of major complications. However, it is alsotrue that the relatively small number of our seriesmay also contribute. Post implant CT scan was alsodone in two of the patients and the implant was foundto be in place.CANDIDACY: Our criteria used for selecting patientsare similar to those obtained worldwide with slightmodification and emphasis on funds and good socialsupport, and this included that : None of our patientswas less than 12 months, confirmed diagnosis ofprofound sensory neural hearing loss, with an intacteight nerve function demonstrable by ABR, with apatent cochlea. There was however partial cochlearossification in one of the patients demonstrated onthe HRCT scan, in this patient, the etiology was themeningitis, the procedure was however successful buthe had deficiency in hearing at high frequency. Thereshould also be no contraindication to elective surgeryand general anaesthesia.CHALLENGES ENCOUNTERED: During the processof commencement of the OAUTHC CI programs someof the challenges encountered included:Logistics: Absence of facility the ABR, OEA was amajor challenge for which we had to make arrangementfor our patient to go to Lagos (about 250kilometersaway) for the tests. Vaccination: Meningococal vaccinewhich was given to all the patients in which it wasrequired had to be source from the Northern part ofNigeria a distance of more than 400kilometers as itwas not readily available.COST OF IMPLANTS: This was by far one of the mostimportant challenges we faced. The number of patientsattending the dedicated deaf clinic of our center waswell over four hundred and only a few of theseprospective candidates could afford the cost of theimplant.REHABILITATION: Facilities for Rehabilitation wasnot fully available as our audiology room also doubledas the speech therapy clinic. We did not have adedicated speech therapist for the auditory verbaltraining but through our motivation and overseastraining our audiologist was able to perform the

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auditory verbal training was generally doneintensively, and patients had to stay in or close to thehospital for the first 6 weeks, following this the patientswere given appointments monthly, then 3 monthly,then twice in a year depending on how well they wereresponding. Our rehabilitation was howeverindividualized to cater for the needs of each of thepatients, the patient from the neighboring Africancountry was discharged a week after the switch onand mapping. The care givers were also educated onthe rehabilitation.POST REHABILITATION: The outcome after speechrehabilitation was divided into six depending onwhether the patients had responded to sound and atwhich frequencies, as well as speech development.One of the patients was however not available forassessment at the time of putting up the paper, thispatient was the one who was brought in from theneighboring African country. There was a goodresponse to sound across all frequencies in mostpatients, there was however poor perception in thehigh frequency range for the post menigitic deafnessin the initial period (this is explainable by theaffectation of the basal turn of the cochlea by thefibrosis), this however gradually improved over time.Audiological evaluation was also challengingoccasionally in the post cerebral palsy and the samepatient had a poor speech development despite evidencethat he perceived sound (Table 2). Overall, all thepatients responded to sound, while those above 4 yearswere already making simple sentences within 12months of commencement of the therapy. The starpatient was the 19year old with post meningiticdeafness, he attended the national conference of theOtolaryngologists (ORLSON) of our country about8months after the implant surgery and there he wasable to jot down notes!COMPLICATIONS: There was no major complicationin our report. The report by MRC institute of HearingResearch on the evaluation of the national cochlearimplant program confirmed that the occurrence ofmajor complications was acceptably low15. In our series,two patients had psychological breakdown, in one of

AetiologyCongenitalPost MeaslesPost TraumaticPost MeningitisPost febrile illnessPost Cerebral palsyUncertain

Table 1: Showing the age at implantation and aetiology of deafness ofthe patients implanted.

S/N1234567

Age (yrs)9412193

1.28

No. of Patients1111211

Table 2: Table showing response of patients.

Outcome Measure

No response to soundResponded to sound at low frequencies onlyResponded to sound at high frequencies onlyResponded to sound across all frequenciesDeveloped reasonable speechHas not develop speech

No of Patients

None (0%)None (0%)None (0%)8 (100%)5(62.5%)1 (12.5%)

WORKSHOP AT TRIBUVAN UNIVERSITY TEACHING HOSPITALKATHMANDU-NEPAL

HANDS-ON TERMPORAL BONE DISSECTION WORKSHOPOctober 28th - 31st, 2013

HANDS-ON CADAVERIC HEAD AND NECK DISSECTION WORKSHOPDecember 29th 2013 to 1st, January 2014

Info : Dr. PabinaEmail : [email protected]

Dr. Kunjan AcharyaEmail : [email protected]


establishing the Nigerian Cochlear Implant Group.We thank all the ENT specialists in Nigeria for theirsupport and positive criticisms of our program. Manythanks also to the entire members of the CochlearImplant team for their invaluable help in this program.REFERENCES:1. Djourno A, Eryies C. Prosthese auditive par excitation electrique

a distance du nerf sensoriel a l'aide d'un bobinage inclus a demeure.[Auditory prosthesis by means of a distant electrical stimulationof a sensory nerve with the use of an indwelling coil]. Presse Med.1957; 65: 1417.

2. Doyle J, Doyle D. Electrical stimulation of the nerve deafness.Bulletin of the Los Angeles Neurological Society. 1963;28:148-50.

3. Simmons FB. Electrical stimulation of the auditory nerve in man.Arch. Otolaryngol. 1966; 84: 2-54.

4. Jennifer Davis (2009-10-29). ‘‘Peoria’s first cochlear implant surgeryhas grandfather rediscovering life’’. Peoria’s Journal Star.http://www.pjstar.com/features/x876590686/Peoria-s-first-cochlear-implant-surgery has-grandfather-rediscovering- l i fe .

5. Mary Brophy Marcus (2009-08-17). ‘’Eyeing smaller, faster, smarterear implants’’. USA Today. http://www.usatoday.com/news/health/2009-08-16-cochlear-implant_N.htm.

6. Phelps PD, Anis JAD, Robinson P J. Imaging for cochlear implants.Br J Radiol 1990; 63: 512-6.

7. G John, JG Toner. Cochlear Implantations in Northern Ireland:An overview of the first five years. The Ulster Medical Journal.1999; 68: 12-6.

8. House WF. The cochlear implant. In Braekmann D. E (ed):Neurological surgery of the ear and Skull Base. New York: RavePress, 1982.

9. Michelson RP, Schindler RA: Multichannel cochlear implant:Prelimnary result in man. Laryngoscope1981;91:38-42.

10. Ologe and Akande. Pattern of disabilities in a residential schoolfor the handicapped in Ilorin, Nigeria. Nigerian PostgraduateMedical Journal 2003;10(4):208-10.

11. McPherson B, Holborow CA. A study of deafness in West Africa:the Gambian Hearing Health Project. International Journal ofPaediatric Otorhinolaryngology 1985;10:115-35.

12. Holborow C, Martinson FD, Anger NA study of deafness in WestAfrica. International Journal of Pediatric Otorhinolaryngology.1982;4: 107-32.

13. AD Dunmade, S Segun-Busari, TG Olajide, FE Ologe. ProfoundBilateral Sensorineural Hearing Loss in Nigerian Children: AnyShift in Etiology? J. Deaf Stud. Deaf Educ. 2007;12 (1): 112-8.

14. Brobby G.W Causes of congenital and acquired total SensorineuralHearing Loss in Ghanaian children. Tropical Doctor 1988;18: 30-2.

15. Summerfield AQ, Marshall DH. Cochlear implantation in the UK1990-1994. Report by the MRC institute of hearing research onthe evaluation of the national cochlear implant program. 1995;63:89,171-85.

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auditory verbal training for our patients .FUNDING: This was a big problem throughout theprogram. Skepticisms from the people: This wasexpressed initially by some of the patient’s relativesand even some members of the medical communitysince this is a very new introduction in Nigeria medicalpractice.CONCLUSION: The CI program of our center amongthe black Africans is very successful despite manyodds against it. The simple nature of the implantationtechnique, the advanced nature of the technologycoupled with the relatively cheaper cost makes it theimplant of choice in any part of the world. The mainreport by the MRC institute of hearing research onthe evaluation of the national cochlear implantprogram in UK confirms with relevant data the benefitsof cochlear implants for the rehabilitation of deafpatients15. At this phase of CI program in Nigeriawhich serves the entire black Africans it is highlybeneficial to the patients and is therefore a welcomedevelopment, but is faced with myriads of challengesranging from social, financial, manpower, to policyissues and others related to a poor resource setting.We recommend institutionalization of NigerianCochlear Implant Group (NCIG) which has alreadybeen kick started by the OAUTHC CIG, establishmentof Ear health commission under the Federal and Stategovernments and that, funding for cochlearimplantation and rehabilitation must be provided bythis body following a positive assessment by thespecialist cochlear implant centre. There is need forequipping the several otolaryngology centers with upto date audiological facilities to aid in hospital diagnosisand help in community hearing screening. Theavailability of these facilities will help to improve ourmanagement outcome further. In addition, werecommend this implant type with its surgicaltechnique for patients in whom it is indicated due toits numerous advantages. It is also hoped thatinternational non-governmental organizations willcome to the aid of the deaf in the black Africancountries.ACKNOWLEDGEMENT: The authors thank DrMiklu Senapati for his efforts and support in practically

cochlear implantation program among nigerians (black...

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