Corresponding author: Ufuk Derinsu Ph. D., Sub-department of Audiology, Department of Otorhinolaryngology, School of Medicine, Marmara University, Istanbul, Turkey
Tel: +90 216 327 10 10 / 245 +90 216 327 19 08 E-mail: uderinsu@hotmail.com
Marmara Medical Journal 2004;17(2);84-88
CASE REPORT
COCHLEAR IMPLANTATION IN A PATIENT WITH LARGE VESTIBULAR
AQUEDUCT SYNDROME: A CASE REPORT
Ufuk Derinsu, Ayça Çiprut, Sezer Külekçi, Ferda Akdaş
Sub-department of Audiology, Department of Otorhinolaryngology, School of Medicine, Marmara University, Istanbul, Turkey
ABSTRACT
Large vestibular aqueduct syndrome (LVAS) is a distinct clinical entity characterized by fluctuative sensorineural hearing loss associated with isolated enlargement of the vestibular aqueduct. In this report, we present our experience with cochlear implantation in a patient with LVAS.
Keywords: Coclear implant, large vestibular aqueduct syndrome, enlarged vestibular aqueduct, hearing loss
GENİŞ VESTİBÜLER SENDROMLU HASTADA KOKLEAR
İMPLANTASYON
ÖZET
Geniş Vestibüler Kanal Sendromu, vestibüler kanalın genişlemesine bağlı olarak ortaya çıkan dalgalanmalı işitme kaybı ile karakterize bir klinik olgudur. Bu çalışmada, koklear implantasyon yapılan LVAS'lı bir hastamızdan elde edilen bulgular sunulmuştur.
Anahtar Kelimeler: Koklear implantasyon, Geniş Vestibüler Kanal Sendromu, İşitme kaybı
INTRODUCTION
The association of congenital sensorineural hearing loss with enlarged vestibular aqueducts was initially determined from histopathologic studies of inner ear malformations 1,2. The large vestibular aqueduct syndrome (LVAS) was named by Valvassori and Clemis in 1978, when they described radiologic detection of this anomaly 3. Vestibular aqueduct is defined as “large” if the anteroposterior diameter is larger than 1.5mm. 4. LVAS often associates with profound, nonprogressive sensorineural hearing loss 5.
Sudden sensorineural hearing loss attacks and fluctuative hearing loss have been reported in some cases 5-7. The incidence of sudden hearing loss was found to be rare in other reports 5,8. Hearing loss is found to be generally sensorineural but Jackler and De la Cruz found a conductive component in 27% of the ears 8.
Hearing level may be from normal to profound deafness. Only a few patients were reported to have normal hearing with LVA 9.
There is no treatment to prevent hearing loss in patients with LVAS. Avoidance of head trauma is important, and hearing aids are symptomatic treatment 5,6,10.
The following case report describes a patient with LVAS who received a cochlear implant. A review of the patient’s audiological assessments before and after the cochlear implantation will be presented.
CASE REPORT
The patient is a 21-year-old female with LVAS. The family suspected hearing loss at the age of 3, she had an audiological evaluation elsewhere and fitted a hearing aid on the left ear.
She was a 9-year-old girl with normal speech development when referred to our clinic. She was the product of a full term pregnancy without any complication. There is no consanguity between the parents but there is a history of hearing loss. Her sister also has hearing loss and benefits from hearing aids.
The patient’s first audiological evaluation demonstrated profound sensorineural hearing loss in the right ear, and moderate to severe mixed hearing loss in the left ear ( Fig. 1). Acoustic immitancemetry indicated type A tympanograms bilaterally (Fig. 2). Acoustic reflexes were present only in the left ear contralaterally at the maximum intensity levels at 500, 1000 and 2000 Hz.
Fig. 1: Audiogram in the first audiological evaluation
Fig. 2: Tympanogram in the first audiological evaluation
Three years later, her hearing in the left ear progressed to severe then to profound, and the hearing thresholds in the right ear improved (Fig.
3). A new hearing aid appropriate to her hearing loss was recommended and scheduled for frequent follow-ups. Two years later, although her hearing
thresholds did not change, significantly, her speech discrimination score in the left ear deteriorated to 12% from 68%. Fluctuations in hearing were determined in both ears in the following assessments.
Fig. 4, shows the final audiogram before the implantation. The patient was evaluated for the cochlear implantation at the age of 15 and found to be a good candidate.
Fig. 3: Second audiogram obtained three years after the first audiological assessment
The otorhinological and neurological evaluations were normal. Routine blood chemistries, urinanalysis and complete metabolic work up were also normal.
A temporal bone high resolution computed tomography (HRCT) scanning demonstrated bilateral LVA. Her sister was assessed with HRCT, because of the LVA diagnosis. She was also diagnosed as LVA.
Cochlear implantation to the right ear was performed without any complication. Full
insertion of Nucleus 24M electrode array was achieved. Electrically evoked stapedius reflexes were recorded and electrically evoked compound action potentials were reliably measured using Neural Response Telemetry (NRT) software intraoparatively.
The postoperative performance is encouraging. Her free field hearing thresholds with the cochlear implant were found to be 35 to 45 dB HL from 250 to 8000 Hz ( Fig. 5)
Fig. 5: Free field audiogram with cochlear implant.
Her speech performance after cochlear implantation was evaluated with closed set three syllable words and monosyllabic words and open set three syllable words, monosyllabic words and open set sentences. Table I illustrates the speech perception test results of the patient with cochlear
implant. The improvement in speech discrimination was significant. She continues to use her hearing aid on the opposite ear because of better sound lateralization.
Table I: Speech perception test results after implantation.
Speech test 6 months 1 year 2 years
Closed set 3 syllable words test 100% 100% 100% Closed set monosyllablic words test 82% 98% 98% Open set 3 syllabic words 60% 86% 88% Open set monosyllabic words 56% 60% 76% Open set sentences 72% 76% 80%
DISCUSSION
In LVAS, a conductive component has occasionally been reported although hearing loss is predominantly sensorineural 8,11,12. In our case, although the patient has normal (type A) tympanograms on both ears there was an unexplained conductive component in the left ear. According to Valvassori, the conductive component is probably caused by a decreased mobility of the stapes due to increased perilymphatic or endolymphatic pressure 11. The conductive component had disappeared in subsequent audiograms.
The hearing loss usually begins in early childhood, often with an acute onset and fluctuating or progressive in course in relation to head trauma 8,5,10. In our case, the beginning age of hearing loss is similar to most of the LVAS cases in literature; there were fluctuations in the hearing of both ears; but there was no significant head trauma.
Cochlear implantation in patients with LVAS have been reported since 1995 4,13,14. The audiometric improvement is a common feature in all of them. In this case, sound field warble tone thresholds with the implant were within nearly normal limits and the patient also displayed valuable improvement in speech discrimination. Patients with LVAS usually have an aquired hearing loss, so they may be accepted as good cochlear implant candidates when they can no longer benefit from hearing aids.
REFERENCES
1. Schuknecht HF. Mondini dysplasia: clinical and pathological study. Ann Otol Rhinol Laryngol Suppl., 1980; 89 (suppl 65):1-23.
2. Paparella MM. Mondini’s deafness: a review of histopathology. Ann Otol Rhinol Laryngol Suppl 1980; 89 (suppl 67):1-10.
3. Valvassori GE, Clemis JD. The large vestibular aqueduct syndrome. Laryngoscope 1978; 88:723-728.
4. Harker LA, Vanderheiden S, Veazey D, et al. Multichannel cochlear implantation in children with large vestibular aqueduct syndrome. Ann Otol Rhinol Laryngol 1999; 108:39-43.
5. Okumura T, Takahashi H, Honjo I, et al. Sensorineural hearing loss in patients with large vestibular aqueduct. Laryngoscope 1995; 105:289-294.
6. Griffith AJ, Arts AH, Downs C, et al. Familial large vestibular aqueduct syndrome. Laryngoscope 1996; 106:960-965.
7. Tong KA, Harnsberger HR, Dahlen RT, et al. AJR 1997; 168:1097-1101.
8. Jackler RK, De La Cruz A. The large vestibular aqueduct syndrome. Laryngoscope 1989; 99:1238-1243.
9. Emmett JR. The large vestibular aqueduct syndrome. Am J Otol 1995;387-415.
10. Nowak KC, Mesner AH. Isolated large vestibular aqueduct syndrome in a family. Ann Otol Rhinol Laryngol 2000; 109:40-44.
11. Abe S, Usami S, Shinkawa H. Three familial cases of hearing loss associated with enlargement of the vestibular aqueduct. Ann Otol Rhinol Laryngol 1997; 106:1063-1069.
12. Govaerts PJ, Casselman J, Daener K, et al. Audiologic findings in large vestibular aqueduct syndrome. Int J Pediatr Otorhinolaryngol 1999; 157-164.
13. Bent JP, Chute P, Parisier SC. Cochlear implantation in children with enlarged vestibular aqueducts. Laryngoscope 1999; 109:1019-102. 14. Bichey BG, Hoversland JM, Wyenne MK,
Miyamoto RT. Changes in quality of life and the cost-utility associated with cochlear implantation in patients with large vestibular aqueduct syndrome. Otology&Neurotology 2002; 23:323-327.
